四大机器人的代码

upring

Googlebot/2.1+(+http://www.google.com/bot.html)
1 s2 }$ t% z4 m. LMediapartners-Google/2.1
) F" T3 L, s6 b% d/ l. i
google

6 n% k. f% }# }3 n) ABaiduspider+(+http://www.baidu.com/search/spider.htm)

2 e% A# c/ V+ b" Xbaidu

4 P+ k- O6 o% E+Yahoo!+Slurp;+http://help.yahoo.com/help/us/ysearch/slurp
$ N! I6 q4 H% C* }0 _yahoo
: J1 f1 ^7 |5 H2 Z