string(243) "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%E5%B7%A5%E7%A8%8B%E8%AE%B2%E4%B9%89pdf => Failed to connect to 101.89.143.195 port 38175: Connection refused"
二建机电工程讲义pdf
