string(259) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BA%8C%E5%BB%BA%E6%95%99%E6%9D%90pdf%E5%85%8D%E8%B4%B9%E4%B8%8B%E8%BD%BD%E7%BD%91%E7%AB%99 => Failed to connect to 14.18.117.71 port 38164: Connection refused"
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