string(321) "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%E5%BA%94%E7%94%A8%E6%8A%80%E6%9C%AF%E5%8F%91%E5%B1%95%E7%9A%84%E5%90%AB%E4%B9%89%E5%92%8C%E7%89%B9%E5%BE%81 => Failed to connect to 125.88.227.171 port 38114: Connection refused"
简述互联网应用技术发展的含义和特征
