string(231) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%AE%97%E5%88%A9%E6%B6%A6%E7%8E%87%E7%9A%84%E5%85%AC%E5%BC%8F => Failed to connect to 101.89.117.144 port 38056: Connection refused"
算利润率的公式
