string(240) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%85%B3%E4%BA%8E%E9%9B%AA%E7%9A%84%E7%89%A9%E7%90%86%E5%AE%9E%E9%AA%8C => Failed to connect to 101.89.117.144 port 38076: Connection refused"
关于雪的物理实验
