string(265) "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%E6%91%98%E8%A6%81%E5%86%85%E5%AE%B9%E8%A6%81%E9%A1%B6%E6%A0%BC%E5%86%99%E5%90%97 => Failed to connect to 14.18.117.71 port 38220: Connection refused"
论文摘要内容要顶格写吗
