string(210) "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%E9%9A%BE%E4%B8%8D%E9%9A%BE => Connection timed out after 30001 milliseconds"
一建民航难不难网!