string(249) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BF%A1%E5%8F%B7%E5%B8%A6%E5%AE%BD%E7%9A%84%E8%AE%A1%E7%AE%97%E5%85%AC%E5%BC%8F => Failed to connect to 101.89.117.144 port 38076: Connection refused"
信号带宽的计算公式
