用以治疗肺痈,肠痈的药物是()
Rubidium, potassium and carbon are
three common elements used to date the history of Earth. The rates of
radioactive decay of these elements are absolutely regular when averaged out
over a period of time; nothing is known to change them. To be useful as clocks,
the elements have to be fairly common in natural minerals, unstable but decay
slowly over millions of years to form recognizable "daughter" products which are
preserved minerals. For example, an atom of radioactive rubidium decays to form an atom of strontium (another element) by converting a neutron in its nucleus to a proton and releasing an electron, generating energy in the process. The radiogenic daughter products of the decay-in this case strontium atoms--diffuse away and are lost above a certain very high temperature. So by measuring the exact proportions of rubidium and strontium atoms t A. Rubidium is everywhere in the rock. B. Strontium atoms are hard to detect at the normal temperature. C. It cannot date sediments. D. It is time-consuming. [多选题] 1号线闸机采用独立于主控单元运行的通行逻辑控制板(GCU),主要负责( )等功能,这样可以大大减轻主控单元的负担,提高乘客通行效率。
A.通行逻辑的判断 B. 控制扇门动作指令 C. 控制蜂鸣器报警 D. 控制警示灯及通行指示器显示 [判断题]电子调速器具有很高的响应速度与调节精度,也易于准确地实现恒速调速,能够满足柴油发电机组的无差并联运行的要求。( )
A.正确 B.错误 [单项选择]根据我国《合同法》,债务人将标的物提存,债权人领取提存物的权利,自提存之日起几年内消灭()
A. 1年 B. 2年 C. 3年 D. 5年 [单项选择]旅客列车、挂有超限货物车辆的列车,应接入()。
A. 任意线路 B. 规定线路 C. 临时线路 [判断题]使用Agile Controller单点登录,用户注销后,防火墙上的在线用户需等待超时时间后才能下线。
A.正确 B.错误 [判断题]根据作业的风险程度,抽加盲板作业分三级管理
A.正确 B.错误 [单选题]在 MySQL 中,左外连接的结果集包括()。
A.左表的所有记录和右表中满足连接条件的记录的简单叠加。 B.左表的所有记录和右表中满足连接条件的记录的笛卡尔积。 C.左表的所有记录和笛卡尔积中满足连接条件的记录。 D.左表的所有记录和右表中 null 值的笛卡尔积。 我来回答: 提交
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