string(236) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%B8%A6%E5%AE%BD%E5%8D%95%E4%BD%8D%E6%98%AFhz%E8%BF%98%E6%98%AFb%2Fs => Failed to connect to 14.18.117.71 port 38220: Connection refused"
带宽单位是hz还是b/s
