string(274) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%BD%91%E7%BB%9C%E8%90%A5%E9%94%80%E4%B8%BB%E8%A6%81%E6%9C%89%E5%93%AA%E4%BA%9B%E7%89%B9%E7%82%B9%E5%91%A2 => Failed to connect to 14.18.117.71 port 38164: Connection refused"
网络营销主要有哪些特点呢
