女,57岁,胸闷,呼吸不畅1月。MRI检查见中后纵隔团块状等T1稍高T2信号,上腔静

题型:单项选择题

问题:

女,57岁,胸闷,呼吸不畅1月。MRI检查见中后纵隔团块状等T1稍高T2信号,上腔静脉受压,左右支气管包绕。最可能的诊断为()

 

A.纵隔淋巴瘤

B.结节病

C.转移性淋巴结

D.肺癌

E.胸腺瘤

考点:放射医学(医学高级)MRIMRI题库
题型:单项选择题

关于蒸发和沸腾,下列说法正确的是(  )

A.80℃的水可能正在沸腾

B.蒸发在任何温度下都能发生,但蒸发快慢与温度有关

C.蒸发和沸腾都要吸收热量且温度都保持不变

D.水的沸点为100℃,故水温达到100℃就一定会沸腾

题型:单项选择题

正常状态下的热氮比为()。

A.100kcal:1g以下

B.120kcal:1g

C.125~150kcal:1g

D.250kcal:1g

E.250kcal:1g以上

题型:单项选择题

Pocket的主要功能就是将你要阅读或者一时没有读完的网页标记下来,接着同步到服务器端,然后你就可以在不同的设备上阅读。

题型:单项选择题

随机试验的样本空间为无限个元素。

题型:单项选择题

It is hard to predict how science is going to turn out, and if it is really good science it is impossible to predict. If the things to be found are actually new, they are by definition unknown in advance. You cannot make choices in this matter. (46)You either have science or you don’t, and if you have it you are obliged to accept the surprising and disturbing pieces of information, along with the neat and promptly useful bits.

The only solid piece of scientific troth about which I feel totally confident is that we are profoundly ignorant about nature. Indeed, I regard this as the major discovery of the past hundred years of biology. It is, in its way, an illuminating piece of news. (47)It would have amazed the brightest minds of the 18th century Enlightenment to be told by any of us how little we know and how bewildering the way ahead seems. (48)It is this sudden confrontation with the depth and scope of ignorance that represents the most significant contribution of the 20th century science to the human intellect. In earlier times, we either pretended to understand how things worked or ignored the problem, or simply made up stories to fill the gaps. Now that we have begun exploring in earnest, we are getting glimpses of how huge the questions are, and how far from being answered. Because of this, we are depressed. (49)It is not so bad being ignorant if you are totally ignorant; the hard thing is knowing in some detail the reality of ignorance, the worst spots and here and there the not-so-bad sports, but not true light at the end of the tunnel nor even any tunnels that can yet be trusted.

But we are making a beginning and there ought to be some satisfaction. There are probably no questions we can think up that can’t be answered, sooner or later, including even the matter of consciousness. (50)To be sure, there may well be questions we can’t think up, ever, and therefore limits to the reach of human intellect, but that is another matter. Within our limits, we should be able to work our way through to all our answers if we keep at it long enough, and pay attention.

(50)To be sure, there may well be questions we can’t think up, ever, and therefore limits to the reach of human intellect, but that is another matter.

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