string(259) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%B3%A2%E7%BA%B9%E7%AE%A1a%E5%9E%8B%E7%AE%A1%E5%92%8Cb%E5%9E%8B%E7%AE%A1%E5%8C%BA%E5%88%AB => Failed to connect to 101.91.112.32 port 38162: Connection refused"
波纹管a型管和b型管区别
