string(258) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%AE%80%E8%BF%B0%E4%BA%92%E8%81%94%E7%BD%91%E7%9A%84%E5%8F%91%E5%B1%95%E9%98%B6%E6%AE%B5 => Failed to connect to 101.89.117.144 port 38056: Connection refused"
简述互联网的发展阶段
