string(265) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BA%8C%E7%BA%A7%E5%BB%BA%E9%80%A0%E5%B8%88%E6%95%99%E6%9D%90%E5%8F%98%E5%8A%A8%E6%83%85%E5%86%B5 => Failed to connect to 14.116.215.7 port 38225: Connection refused"
二级建造师教材变动情况
