string(285) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%8A%97%E5%8E%8B%E5%BC%BA%E5%BA%A6%E6%8D%A2%E7%AE%97%E5%80%BC%E4%BF%9D%E7%95%99%E5%87%A0%E4%BD%8D%E5%B0%8F%E6%95%B0 => Failed to connect to 101.89.117.144 port 38208: Connection refused"
抗压强度换算值保留几位小数
