string(267) "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%A6%82%E4%BD%95%E6%A0%87%E5%BC%95%E7%94%A8%E6%96%87%E7%8C%AE%E9%A1%B5%E7%A0%81 => Failed to connect to 101.89.159.206 port 38100: Connection refused"
论文如何标引用文献页码
