string(250) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BB%80%E4%B9%88%E5%8F%AB%E5%81%9Ab2b%E9%94%80%E5%94%AE%E6%B8%A0%E9%81%93%E5%91%A2 => Failed to connect to 14.18.117.71 port 38164: Connection refused"
什么叫做b2b销售渠道呢
