string(247) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%8E%A8%E5%B9%BF%E8%B4%B9%E7%94%A8%E5%85%AC%E5%BC%8F%E6%98%AF%E4%BB%80%E4%B9%88 => Failed to connect to 14.18.117.71 port 38069: Connection refused"
推广费用公式是什么
