IP地址 | 服务器名称 | 所属国家 |
---|---|---|
66.102.6.166 | google-proxy-66-102-6-166.google.com | US |
64.233.172.199 | google-proxy-64-233-172-199.google.com | US |
66.102.6.164 | google-proxy-66-102-6-164.google.com | US |
64.233.172.201 | google-proxy-64-233-172-201.google.com | US |
66.102.6.168 | google-proxy-66-102-6-168.google.com | US |
64.233.172.197 | google-proxy-64-233-172-197.google.com | US |
66.249.83.52 | google-proxy-66-249-83-52.google.com | US |
66.249.83.54 | google-proxy-66-249-83-54.google.com | US |
66.249.83.100 | google-proxy-66-249-83-100.google.com | US |
66.249.83.9 | google-proxy-66-249-83-9.google.com | US |
74.125.212.134 | google-proxy-74-125-212-134.google.com | US |
74.125.212.132 | google-proxy-74-125-212-132.google.com | US |
74.125.212.136 | google-proxy-74-125-212-136.google.com | US |
64.233.172.160 | google-proxy-64-233-172-160.google.com | US |
64.233.172.191 | google-proxy-64-233-172-191.google.com | US |
64.233.172.189 | google-proxy-64-233-172-189.google.com | US |
66.249.83.56 | google-proxy-66-249-83-56.google.com | US |
66.249.83.92 | google-proxy-66-249-83-92.google.com | US |
66.249.92.59 | rate-limited-proxy-66-249-92-59.google.com | US |
66.249.92.213 | rate-limited-proxy-66-249-92-213.google.com | US |
66.249.92.144 | rate-limited-proxy-66-249-92-144.google.com | US |
64.233.172.187 | google-proxy-64-233-172-187.google.com | US |
66.249.92.94 | rate-limited-proxy-66-249-92-94.google.com | US |
66.249.92.56 | rate-limited-proxy-66-249-92-56.google.com | US |
66.249.92.131 | rate-limited-proxy-66-249-92-131.google.com | US |
66.102.6.250 | google-proxy-66-102-6-250.google.com | US |
66.249.83.123 | google-proxy-66-249-83-123.google.com | US |
66.249.92.34 | rate-limited-proxy-66-249-92-34.google.com | US |
66.249.93.28 | google-proxy-66-249-93-28.google.com | US |
74.125.216.249 | rate-limited-proxy-74-125-216-249.google.com | US |
74.125.214.102 | google-proxy-74-125-214-102.google.com | US |
74.125.214.100 | google-proxy-74-125-214-100.google.com | US |
66.102.7.185 | google-proxy-66-102-7-185.google.com | US |
66.102.7.188 | google-proxy-66-102-7-188.google.com | US |
66.102.7.182 | google-proxy-66-102-7-182.google.com | US |
66.249.83.102 | google-proxy-66-249-83-102.google.com | US |
66.249.83.222 | google-proxy-66-249-83-222.google.com | US |
66.249.93.24 | google-proxy-66-249-93-24.google.com | US |
66.249.93.20 | google-proxy-66-249-93-20.google.com | US |
66.249.93.22 | google-proxy-66-249-93-22.google.com | US |
66.249.93.103 | google-proxy-66-249-93-103.google.com | US |
66.249.93.99 | google-proxy-66-249-93-99.google.com | US |
66.102.7.40 | google-proxy-66-102-7-40.google.com | US |
66.102.6.6 | google-proxy-66-102-6-6.google.com | US |
66.102.6.8 | google-proxy-66-102-6-8.google.com | US |
66.102.7.36 | google-proxy-66-102-7-36.google.com | US |
66.102.7.38 | google-proxy-66-102-7-38.google.com | US |
66.102.6.4 | google-proxy-66-102-6-4.google.com | US |
66.249.83.85 | google-proxy-66-249-83-85.google.com | ? |
66.249.93.251 | google-proxy-66-249-93-251.google.com | US |
66.249.93.112 | google-proxy-66-249-93-112.google.com | |
66.249.83.223 | google-proxy-66-249-83-223.google.com | US |
66.249.83.40 | google-proxy-66-249-83-40.google.com | US |
66.249.83.42 | google-proxy-66-249-83-42.google.com | US |
66.249.83.41 | google-proxy-66-249-83-41.google.com | US |
66.249.93.130 | google-proxy-66-249-93-130.google.com | US |
66.102.7.240 | google-proxy-66-102-7-240.google.com | US |
66.102.7.237 | google-proxy-66-102-7-237.google.com | US |
66.102.7.243 | google-proxy-66-102-7-243.google.com | US |
66.102.7.56 | google-proxy-66-102-7-56.google.com | US |
66.102.7.54 | google-proxy-66-102-7-54.google.com | US |
66.102.6.20 | google-proxy-66-102-6-20.google.com | US |
66.102.6.22 | google-proxy-66-102-6-22.google.com | US |
66.102.6.24 | google-proxy-66-102-6-24.google.com | US |
66.102.7.52 | google-proxy-66-102-7-52.google.com | US |
74.125.212.148 | google-proxy-74-125-212-148.google.com | US |
74.125.212.152 | google-proxy-74-125-212-152.google.com | US |
74.125.212.150 | google-proxy-74-125-212-150.google.com | US |
74.125.212.146 | google-proxy-74-125-212-146.google.com | US |
66.249.93.166 | google-proxy-66-249-93-166.google.com | |
66.249.93.72 | google-proxy-66-249-93-72.google.com | US |
66.249.83.4 | google-proxy-66-249-83-4.google.com | US |
66.249.83.97 | google-proxy-66-249-83-97.google.com | US |
66.249.83.99 | google-proxy-66-249-83-99.google.com | US |
66.249.83.192 | google-proxy-66-249-83-192.google.com | US |
66.102.6.184 | google-proxy-66-102-6-184.google.com | US |
74.125.212.17 | google-proxy-74-125-212-17.google.com | US |
74.125.212.21 | google-proxy-74-125-212-21.google.com | US |
74.125.212.25 | google-proxy-74-125-212-25.google.com | US |
64.233.172.100 | google-proxy-64-233-172-100.google.com | US |
64.233.172.102 | google-proxy-64-233-172-102.google.com | US |
209.85.238.133 | rate-limited-proxy-209-85-238-133.google.com | US |
66.249.92.42 | rate-limited-proxy-66-249-92-42.google.com | US |
66.249.92.15 | rate-limited-proxy-66-249-92-15.google.com | US |
66.249.92.13 | rate-limited-proxy-66-249-92-13.google.com | US |
66.249.83.3 | google-proxy-66-249-83-3.google.com | US |
66.249.83.208 | google-proxy-66-249-83-208.google.com | US |
66.249.92.43 | rate-limited-proxy-66-249-92-43.google.com | US |
66.249.92.32 | rate-limited-proxy-66-249-92-32.google.com | US |
66.102.6.182 | google-proxy-66-102-6-182.google.com | US |
72.14.199.253 | rate-limited-proxy-72-14-199-253.google.com | US |
72.14.199.130 | rate-limited-proxy-72-14-199-130.google.com | US |
66.102.6.180 | google-proxy-66-102-6-180.google.com | US |
74.125.214.40 | google-proxy-74-125-214-40.google.com | US |
74.125.214.36 | google-proxy-74-125-214-36.google.com | ? |
74.125.214.38 | google-proxy-74-125-214-38.google.com | US |
66.249.92.130 | rate-limited-proxy-66-249-92-130.google.com | US |
66.249.92.44 | rate-limited-proxy-66-249-92-44.google.com | US |
66.249.93.68 | google-proxy-66-249-93-68.google.com | US |
66.249.92.134 | rate-limited-proxy-66-249-92-134.google.com | US |
66.249.93.129 | google-proxy-66-249-93-129.google.com | |
66.102.6.178 | google-proxy-66-102-6-178.google.com | US |
66.102.6.186 | google-proxy-66-102-6-186.google.com | US |
66.102.6.188 | google-proxy-66-102-6-188.google.com | US |
74.125.212.13 | google-proxy-74-125-212-13.google.com | US |
74.125.212.9 | google-proxy-74-125-212-9.google.com | US |
66.102.6.190 | google-proxy-66-102-6-190.google.com | ? |
66.102.7.161 | google-proxy-66-102-7-161.google.com | US |
66.249.93.5 | google-proxy-66-249-93-5.google.com | US |
74.125.212.5 | google-proxy-74-125-212-5.google.com | US |
66.102.7.164 | google-proxy-66-102-7-164.google.com | US |
66.102.7.190 | google-proxy-66-102-7-190.google.com | US |
74.125.215.156 | google-proxy-74-125-215-156.google.com | ? |
74.125.215.158 | google-proxy-74-125-215-158.google.com | US |
74.125.212.158 | google-proxy-74-125-212-158.google.com | US |
74.125.212.154 | google-proxy-74-125-212-154.google.com | US |
74.125.212.156 | google-proxy-74-125-212-156.google.com | ? |
74.125.214.62 | google-proxy-74-125-214-62.google.com | US |
74.125.214.58 | google-proxy-74-125-214-58.google.com | US |
74.125.214.60 | google-proxy-74-125-214-60.google.com | ? |
66.102.6.62 | google-proxy-66-102-6-62.google.com | US |
66.102.6.61 | google-proxy-66-102-6-61.google.com | US |
66.102.6.63 | google-proxy-66-102-6-63.google.com | US |
66.102.6.124 | google-proxy-66-102-6-124.google.com | US |
66.102.6.122 | google-proxy-66-102-6-122.google.com | US |
66.102.6.126 | google-proxy-66-102-6-126.google.com | US |
66.102.6.100 | google-proxy-66-102-6-100.google.com | US |
66.102.6.102 | google-proxy-66-102-6-102.google.com | US |
66.102.6.104 | google-proxy-66-102-6-104.google.com | US |
74.125.212.249 | google-proxy-74-125-212-249.google.com | US |
66.249.83.35 | google-proxy-66-249-83-35.google.com | US |
66.249.83.67 | google-proxy-66-249-83-67.google.com | US |
66.249.83.196 | google-proxy-66-249-83-196.google.com | US |
64.233.172.58 | google-proxy-64-233-172-58.google.com | US |
64.233.172.158 | google-proxy-64-233-172-158.google.com | US |
64.233.172.156 | google-proxy-64-233-172-156.google.com | US |
74.125.212.253 | google-proxy-74-125-212-253.google.com | US |
64.233.172.154 | google-proxy-64-233-172-154.google.com | US |
64.233.172.132 | google-proxy-64-233-172-132.google.com | US |
64.233.172.134 | google-proxy-64-233-172-134.google.com | US |
64.233.172.60 | google-proxy-64-233-172-60.google.com | US |
64.233.172.62 | google-proxy-64-233-172-62.google.com | US |
66.102.6.251 | google-proxy-66-102-6-251.google.com | US |
66.102.6.253 | google-proxy-66-102-6-253.google.com | US |
66.249.93.8 | google-proxy-66-249-93-8.google.com | |
66.249.83.197 | google-proxy-66-249-83-197.google.com | US |
66.249.83.7 | google-proxy-66-249-83-7.google.com | US |
66.249.83.195 | google-proxy-66-249-83-195.google.com | US |
64.233.172.45 | google-proxy-64-233-172-45.google.com | US |
66.102.6.249 | google-proxy-66-102-6-249.google.com | US |
64.233.172.44 | google-proxy-64-233-172-44.google.com | US |
64.233.172.46 | google-proxy-64-233-172-46.google.com | US |
66.102.7.160 | google-proxy-66-102-7-160.google.com | US |
64.233.172.140 | google-proxy-64-233-172-140.google.com | US |
64.233.172.141 | google-proxy-64-233-172-141.google.com | US |
66.102.7.170 | google-proxy-66-102-7-170.google.com | US |
64.233.172.142 | google-proxy-64-233-172-142.google.com | US |
66.102.7.173 | google-proxy-66-102-7-173.google.com | US |
66.102.7.169 | google-proxy-66-102-7-169.google.com | ? |
66.102.7.168 | google-proxy-66-102-7-168.google.com | US |
66.249.93.4 | google-proxy-66-249-93-4.google.com | US |
66.249.93.3 | google-proxy-66-249-93-3.google.com | ? |
66.102.9.225 | google-proxy-66-102-9-225.google.com | US |
66.102.9.226 | google-proxy-66-102-9-226.google.com | US |
74.125.214.97 | google-proxy-74-125-214-97.google.com | US |
74.125.214.98 | google-proxy-74-125-214-98.google.com | US |
74.125.214.99 | google-proxy-74-125-214-99.google.com | US |
74.125.214.108 | google-proxy-74-125-214-108.google.com | US |
74.125.214.110 | google-proxy-74-125-214-110.google.com | US |
74.125.214.109 | google-proxy-74-125-214-109.google.com | US |
74.125.214.45 | google-proxy-74-125-214-45.google.com | US |
74.125.214.46 | google-proxy-74-125-214-46.google.com | US |
74.125.214.44 | google-proxy-74-125-214-44.google.com | US |
66.102.6.233 | google-proxy-66-102-6-233.google.com | US |
66.102.6.234 | google-proxy-66-102-6-234.google.com | US |
66.102.6.50 | google-proxy-66-102-6-50.google.com | US |
66.102.6.49 | google-proxy-66-102-6-49.google.com | US |
66.102.6.51 | google-proxy-66-102-6-51.google.com | US |
66.249.93.2 | google-proxy-66-249-93-2.google.com | US |
66.102.6.172 | google-proxy-66-102-6-172.google.com | US |
66.102.6.174 | google-proxy-66-102-6-174.google.com | US |
74.125.212.236 | google-proxy-74-125-212-236.google.com | US |
74.125.212.238 | google-proxy-74-125-212-238.google.com | US |
74.125.212.237 | google-proxy-74-125-212-237.google.com | ? |
66.102.7.165 | google-proxy-66-102-7-165.google.com | US |
74.125.214.47 | google-proxy-74-125-214-47.google.com | US |
66.102.6.44 | google-proxy-66-102-6-44.google.com | US |
74.125.214.34 | google-proxy-74-125-214-34.google.com | US |
74.125.214.35 | google-proxy-74-125-214-35.google.com | US |
74.125.214.33 | google-proxy-74-125-214-33.google.com | US |
74.125.212.226 | google-proxy-74-125-212-226.google.com | US |
74.125.212.227 | google-proxy-74-125-212-227.google.com | US |
64.233.172.37 | google-proxy-64-233-172-37.google.com | US |
74.125.212.141 | google-proxy-74-125-212-141.google.com | US |
74.125.215.99 | google-proxy-74-125-215-99.google.com | US |
74.125.215.97 | google-proxy-74-125-215-97.google.com | US |
66.102.9.237 | google-proxy-66-102-9-237.google.com | US |
142.250.32.10 | google-proxy-142-250-32-10.google.com | US |
142.250.32.9 | google-proxy-142-250-32-9.google.com | US |
66.102.6.46 | google-proxy-66-102-6-46.google.com | US |
66.102.6.138 | google-proxy-66-102-6-138.google.com | US |
66.102.6.139 | google-proxy-66-102-6-139.google.com | US |
66.102.6.137 | google-proxy-66-102-6-137.google.com | US |
66.102.7.233 | google-proxy-66-102-7-233.google.com | US |
66.102.7.234 | google-proxy-66-102-7-234.google.com | US |
66.102.7.235 | google-proxy-66-102-7-235.google.com | US |
66.102.7.225 | google-proxy-66-102-7-225.google.com | US |
66.102.7.224 | google-proxy-66-102-7-224.google.com | US |
66.102.6.43 | google-proxy-66-102-6-43.google.com | US |
66.102.6.45 | google-proxy-66-102-6-45.google.com | US |
142.250.32.8 | google-proxy-142-250-32-8.google.com | US |
66.102.7.67 | google-proxy-66-102-7-67.google.com | US |
66.102.7.66 | google-proxy-66-102-7-66.google.com | US |
66.102.7.65 | google-proxy-66-102-7-65.google.com | US |
66.102.6.235 | google-proxy-66-102-6-235.google.com | US |
74.125.212.4 | google-proxy-74-125-212-4.google.com | US |
64.233.172.171 | google-proxy-64-233-172-171.google.com | US |
64.233.172.169 | google-proxy-64-233-172-169.google.com | US |
66.102.6.33 | google-proxy-66-102-6-33.google.com | US |
66.102.6.35 | google-proxy-66-102-6-35.google.com | US |
66.102.6.34 | google-proxy-66-102-6-34.google.com | US |
66.102.9.3 | google-proxy-66-102-9-3.google.com | US |
66.102.9.2 | google-proxy-66-102-9-2.google.com | US |
64.233.172.170 | google-proxy-64-233-172-170.google.com | US |
66.249.93.97 | google-proxy-66-249-93-97.google.com | US |
66.249.93.98 | google-proxy-66-249-93-98.google.com | US |
66.249.93.100 | google-proxy-66-249-93-100.google.com | US |
66.102.9.4 | google-proxy-66-102-9-4.google.com | US |
64.233.172.161 | google-proxy-64-233-172-161.google.com | US |
142.250.32.40 | google-proxy-142-250-32-40.google.com | US |
142.250.32.41 | google-proxy-142-250-32-41.google.com | US |
66.102.6.5 | google-proxy-66-102-6-5.google.com | US |
66.102.9.6 | google-proxy-66-102-9-6.google.com | US |
66.102.9.5 | google-proxy-66-102-9-5.google.com | US |
66.102.9.7 | google-proxy-66-102-9-7.google.com | US |
142.250.32.39 | google-proxy-142-250-32-39.google.com | US |
142.250.32.37 | google-proxy-142-250-32-37.google.com | US |
142.250.32.38 | google-proxy-142-250-32-38.google.com | US |
142.250.32.36 | google-proxy-142-250-32-36.google.com | US |
142.250.32.35 | google-proxy-142-250-32-35.google.com | US |
66.249.93.101 | google-proxy-66-249-93-101.google.com | ? |
142.250.32.32 | google-proxy-142-250-32-32.google.com | US |
66.102.9.227 | google-proxy-66-102-9-227.google.com | US |
66.102.9.236 | google-proxy-66-102-9-236.google.com | US |
66.102.9.238 | google-proxy-66-102-9-238.google.com | US |
66.102.6.98 | google-proxy-66-102-6-98.google.com | US |
66.249.93.96 | google-proxy-66-249-93-96.google.com | US |
74.125.212.110 | google-proxy-74-125-212-110.google.com | US |
66.102.7.167 | google-proxy-66-102-7-167.google.com | US |
74.125.212.108 | google-proxy-74-125-212-108.google.com | US |
74.125.212.109 | google-proxy-74-125-212-109.google.com | US |
66.102.8.236 | google-proxy-66-102-8-236.google.com | US |
66.102.8.237 | google-proxy-66-102-8-237.google.com | US |
66.102.6.99 | google-proxy-66-102-6-99.google.com | US |
142.250.32.5 | google-proxy-142-250-32-5.google.com | US |
142.250.32.6 | google-proxy-142-250-32-6.google.com | US |
142.250.32.7 | google-proxy-142-250-32-7.google.com | US |
142.250.32.4 | google-proxy-142-250-32-4.google.com | US |
192.178.9.13 | google-proxy-192-178-9-13.google.com | US |
74.125.214.42 | google-proxy-74-125-214-42.google.com | US |
74.125.214.41 | google-proxy-74-125-214-41.google.com | US |
66.102.6.97 | google-proxy-66-102-6-97.google.com | US |
74.125.210.140 | google-proxy-74-125-210-140.google.com | US |
74.125.210.142 | google-proxy-74-125-210-142.google.com | US |
66.102.9.130 | google-proxy-66-102-9-130.google.com | US |
66.102.8.238 | google-proxy-66-102-8-238.google.com | US |
66.102.9.129 | google-proxy-66-102-9-129.google.com | US |
66.102.9.131 | google-proxy-66-102-9-131.google.com | US |
66.102.8.108 | google-proxy-66-102-8-108.google.com | US |
66.102.8.109 | google-proxy-66-102-8-109.google.com | US |
66.102.8.110 | google-proxy-66-102-8-110.google.com | ? |
IP地址 | 服务器名称 | 所属国家 |
---|---|---|
66.249.92.59 | rate-limited-proxy-66-249-92-59.google.com | US |
66.249.92.213 | rate-limited-proxy-66-249-92-213.google.com | US |
66.249.92.144 | rate-limited-proxy-66-249-92-144.google.com | US |
64.233.172.187 | google-proxy-64-233-172-187.google.com | US |
66.249.92.94 | rate-limited-proxy-66-249-92-94.google.com | US |
66.249.92.56 | rate-limited-proxy-66-249-92-56.google.com | ? |
66.249.92.131 | rate-limited-proxy-66-249-92-131.google.com | ? |
66.102.6.250 | google-proxy-66-102-6-250.google.com | US |
66.249.83.123 | google-proxy-66-249-83-123.google.com | US |
66.249.92.34 | rate-limited-proxy-66-249-92-34.google.com | US |
FeedBurner是一个于2004年在美国芝加哥市成立的网站馈送管理供应商。FeedBurner为博客作者、Podcast与其他基于网络的内容发布者提供订制的RSS馈送与管理工具,提供予发布者的服务包括流量分析以及一个可供选择的广告系统。
基本上可以使用Feedburner作为 “代理”。
据我所知,它的主要用途是。创建一个带有大量URLs的feed(针对一个目标网站)并提交给Google Feedburner。然后Feedburner会尝试访问feed中的所有页面。Feedburner 是一个分布式的服务,所以可以建立很多连接。
一般来说,只是通过用户代理来阻止。如果不使用 Feedburner,应该不会有合法的 UA 流量。
此外,封锁IP也没有什么坏处(只要对特定的IP进行封锁)–因为Googlebot(通常是Google唯一 “关心 “的流量)不会来自这些IP。
(它在一定程度上是作为DDOS的放大作用,但它也可以被用于爬虫。由于feedburner做的是抓取,通常提供一个 “简明 “的页面摘要。但最终的Feed将包含所获取页面的内容)。
搜索引擎蜘蛛对移动设备和桌面设备的处理可以有一些不同之处。以下是一些常见的区别:
尽管搜索引擎蜘蛛对移动设备和桌面设备的处理可能略有不同,但总体目标是提供最佳的用户体验和相关的搜索结果。因此,为了获得良好的搜索可见性,建议采取以下措施:采用响应式网站设计、优化移动页面和内容、确保快速加载速度,并提供高质量和有价值的用户体验。
可以通过以下几种方式来识别和避免被搜索引擎蜘蛛认为是“过度优化”:
搜索引擎蜘蛛在处理重复内容时,会采用一些策略来判断哪些内容是重要的,哪些是不重要的。例如,如果两个网页的内容完全相同,那么搜索引擎可能会选择只保留其中一个网页的版本,或者根据链接的质量来确定哪个版本更重要。此外,有些搜索引擎还会使用相似性算法来检测内容之间的相似性,并将相似的内容进行分组,以便用户在搜索时能够更快速地找到所需的信息。
搜索引擎蜘蛛在处理重复内容时会采取一些处理策略,以确保搜索结果的质量和多样性。以下是搜索引擎蜘蛛处理重复内容的常见方法:
需要注意的是,尽管搜索引擎蜘蛛会处理重复内容,但重复内容本身可能对搜索引擎优化(SEO)产生负面影响。重复内容可能导致搜索引擎索引中的页面混淆和竞争,从而降低特定页面的排名和可见性。因此,在设计和维护网站时,应避免出现重复内容,保持页面的独特性和价值。
sitemap(网站地图)是一种XML文件,它包含了网站中所有网页的URL地址和这些页面的更新频率、更改频率等元数据。网站地图可以帮助搜索引擎蜘蛛更好地了解网站的架构和内容,从而更好地爬取网站中的网页。
搜索引擎蜘蛛是搜索引擎的自动程序,负责浏览互联网并收集网页内容,用于搜索引擎的索引和排名。当搜索引擎蜘蛛访问一个网站时,它通常会首先查找网站的sitemap。通过查看sitemap,蜘蛛可以了解网站的整体结构和可抓取的页面。这样,搜索引擎蜘蛛可以更加全面地抓取网站的内容,并将其添加到搜索引擎的索引中。
通过提供一个完整且准确的sitemap,网站所有可访问的页面都可以被搜索引擎蜘蛛发现和索引。这有助于确保网站的所有重要页面都被搜索引擎收录,从而提高页面在搜索引擎结果中的可见性和排名机会。
总结而言,sitemap是一个包含网站页面信息的XML文件,它将网站结构呈现给搜索引擎蜘蛛,以帮助其更好地抓取和索引网站内容。
可以通过以下几种方式来优化网站的加载速度以改善搜索引擎排名:
总的来说,加载速度是影响搜索引擎排名的重要因素之一。通过以上方法优化网站的加载速度可以提高搜索引擎排名,从而获得更好的流量和转化率。
可以通过以下几种方式来提高网站被搜索引擎蜘蛛抓取的频率: