string(258) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%99%AA%E9%9F%B3%E6%B1%A1%E6%9F%93%E6%98%AF%E6%8C%87%E5%A4%9A%E5%B0%91db%E4%BB%A5%E4%B8%8A => Failed to connect to 14.18.117.71 port 38133: Connection refused"
噪音污染是指多少db以上
