string(267) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%BE%8E%E5%85%83%E5%9B%BD%E5%80%BA%E4%B8%AD%E5%9B%BD%E6%8C%81%E6%9C%89%E5%A4%9A%E5%B0%91%E9%92%B1 => Failed to connect to 101.89.117.144 port 38076: Connection refused"
美元国债中国持有多少钱
