string(276) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%B8%89%E7%A7%8D%E6%8E%A8%E5%B9%BF%E6%96%B9%E5%BC%8F%E7%9A%84%E5%8C%BA%E5%88%AB%E4%B8%8E%E8%81%94%E7%B3%BB => Failed to connect to 101.89.159.206 port 38100: Connection refused"
三种推广方式的区别与联系
