string(285) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E8%AE%BA%E6%96%87%E5%BC%95%E7%94%A8%E5%A6%82%E4%BD%95%E6%A0%87%E6%B3%A8%E4%B8%8D%E4%BC%9A%E8%A2%AB%E9%87%8D%E5%A4%8D => Failed to connect to 125.88.227.171 port 38062: Connection refused"
论文引用如何标注不会被重复
