string(231) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%87%80%E5%88%A9%E6%B6%A6%E5%85%AC%E5%BC%8F%E6%98%AF%E5%95%A5 => Failed to connect to 101.89.117.144 port 38208: Connection refused"
净利润公式是啥
