string(305) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%88%91%E4%BB%AC%E5%B8%B8%E8%AF%B4%E7%9A%84%E5%99%AA%E5%A3%B0%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 101.89.117.144 port 38022: Connection refused"
我们常说的噪声污染是指多少db以上
