string(292) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%8D%A2%E7%AE%97%E6%88%90%E6%A0%87%E5%87%86%E5%B0%BA%E5%AF%B8%E7%9A%84%E6%8A%97%E5%8E%8B%E5%BC%BA%E5%BA%A6%E5%85%AC%E5%BC%8F => Failed to connect to 61.171.74.35 port 38027: Connection refused"
换算成标准尺寸的抗压强度公式
