string(274) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%A4%AE%E8%A1%8C%E7%A5%A8%E6%8D%AE%E7%9A%84%E4%B8%BB%E8%A6%81%E5%8A%9F%E8%83%BD%E6%98%AF%E4%BB%80%E4%B9%88 => Failed to connect to 14.116.215.7 port 38230: Connection refused"
央行票据的主要功能是什么
