string(237) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%BC%BA%E5%8F%A3%E5%88%86%E6%9E%90%E7%9A%84%E5%B1%80%E9%99%90%E6%80%A7 => Failed to connect to 14.18.46.51 port 38206: Connection refused"
缺口分析的局限性
