现代信息检索
http://wenku.baidu.com/view/d2f4f78d6529647d26285203.html?from=search
http://wenku.baidu.com/view/ddb634eb4afe04a1b171de07.html?re=view
http://wenku.baidu.com/link?url=tZpVk-YaWNkQeSLJI7OqVlrFeLMSMIypcukZWuvTgFwf8xkDMOpRcRNBnLe3b3gao_pa1a-LOO-Hkwp0dqoZbEkxXKQcTmrrwUQa8kPudau
http://wenku.baidu.com/view/d2f4f78d6529647d26285203.html?from=search
http://wenku.baidu.com/view/ddb634eb4afe04a1b171de07.html?re=view
http://wenku.baidu.com/link?url=tZpVk-YaWNkQeSLJI7OqVlrFeLMSMIypcukZWuvTgFwf8xkDMOpRcRNBnLe3b3gao_pa1a-LOO-Hkwp0dqoZbEkxXKQcTmrrwUQa8kPudau