string(230) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%8A%95%E5%85%A5%E4%BA%A7%E5%87%BA%E7%8E%87%E8%AE%A1%E7%AE%97 => Failed to connect to 101.91.112.32 port 38221: Connection refused"
投入产出率计算
