string(231) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%AF%BC%E6%95%B0%E6%9C%89%E5%93%AA%E4%BA%9B%E4%BD%9C%E7%94%A8 => Failed to connect to 101.89.117.144 port 38005: Connection refused"
导数有哪些作用
