最近网站的收录突然从3万多，一下降到只有2千，我就分析了一下日志，发现每天几乎同一时间都有一次以下的访问，IP是220.181.51.77，网上查了应该是百度的，这是在干嘛呢？

2014-12-11 01:37
'reffer'=> http://www.baidu.com/s?wd=www.我的域名.com&rsv_bp=0&rsv_spt=3&rsv_n=2&inputT=28032
'user-agent'=>Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2

2014-12-10 12:54
'reffer'=> http://www.baidu.com/s?wd=www.我的域名.com&rsv_bp=0&rsv_spt=3&rsv_n=2&inputT=48411
'user-agent'=>Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2

2014-12-09 12:54
'reffer'=> http://www.baidu.com/s?wd=www.我的域名.com&rsv_bp=0&rsv_spt=3&rsv_n=2&inputT=24048
'user-agent'=>Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2

2014-12-08 01:00
'reffer'=> http://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_spt=3&wd=www.我的域名.com&inputT=16722
'user-agent'=>Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2

2014-12-07 01:06
'reffer'=> http://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_spt=3&wd=www.我的域名.com&inputT=26562
'user-agent'=>Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2

2014-12-06 01:02
'reffer'=> http://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_spt=3&wd=www.我的域名.com&inputT=2339
'user-agent'=>Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2

看不懂。