string(251) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BA%8C%E5%BB%BA%E6%9C%BA%E7%94%B5%E6%95%99%E6%9D%90%E7%94%B5%E5%AD%90%E7%89%882022 => Failed to connect to 14.18.117.71 port 38041: Connection refused"
二建机电教材电子版2022
