string(292) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8B%E6%80%8E%E4%B9%88%E8%A7%A3%E5%85%AC%E5%BC%8F%E6%9C%80%E7%AE%80%E5%8D%95 => Failed to connect to 14.18.117.71 port 38093: Connection refused"
一元二次方程怎么解公式最简单
