string(249) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%BE%8E%E5%9B%BD%E5%9B%BD%E5%80%BA%E6%8C%81%E6%9C%89%E7%8E%87%E6%83%85%E5%86%B5 => Failed to connect to 101.89.117.144 port 38017: Connection refused"
美国国债持有率情况
