string(238) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%B8%80%E5%BB%BA%E6%B0%91%E8%88%AA%E6%95%99%E6%9D%90%E5%8F%98%E5%8A%A8 => Failed to connect to 14.18.117.71 port 38133: Connection refused"
一建民航教材变动
