string(257) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%B1%82%E5%87%80%E5%88%A9%E6%B6%A6%E7%9A%84%E8%AE%A1%E7%AE%97%E5%85%AC%E5%BC%8F%E6%98%AF%E4%BB%80%E4%B9%88 => Received HTTP code 403 from proxy after CONNECT"
求净利润的计算公式是什么
