string(277) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%94%A8rank%E5%87%BD%E6%95%B0%E8%AE%A1%E7%AE%97%E6%8E%92%E5%90%8D%E5%85%AC%E5%BC%8F%E6%98%AF%E4%BB%80%E4%B9%88 => Failed to connect to 14.18.46.51 port 38206: Connection refused"
用rank函数计算排名公式是什么
