string(239) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%9B%AE%E6%A0%87%E7%BE%A4%E4%BD%93%E7%9A%84%E5%AE%9A%E4%B9%89%E6%98%AF%E4%BB%80%E4%B9%88 => Received HTTP code 403 from proxy after CONNECT"
目标群体的定义是什么
