string(249) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%A0%87%E5%87%86%E5%B7%AE%E5%92%8C%E6%96%B9%E5%B7%AE%E4%B8%80%E6%A0%B7%E5%90%97 => Failed to connect to 101.89.117.144 port 38076: Connection refused"
标准差和方差一样吗
