string(267) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BB%80%E4%B9%88%E6%98%AF%E5%A4%AE%E8%A1%8C%E5%9B%9E%E8%B4%AD%E5%92%8C%E9%80%86%E5%9B%9E%E8%B4%AD => Failed to connect to 101.89.117.144 port 38005: Connection refused"
什么是央行回购和逆回购
