如图所示,两根相距为l的平行直导轨ab、cd、b、d间连有一固定电阻R,导轨电阻

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问题:

如图所示,两根相距为l的平行直导轨ab、cd、b、d间连有一固定电阻R,导轨电阻可忽略不计;MN为放在ab和cd上的一导体杆,与ab垂直,其电阻也为R;整个装置处于匀强磁场中,磁感应强度的大小为B,磁场方向垂直于导轨所在平面(指向图中纸面内);现对MN施力使它沿导轨方向以速度v(如图)做匀速运动;令U表示MN两端电压的大小,则(  )

A.U=vBl,流过固定电阻R的感应电流由b到d

B.U=vBl,流过固定电阻R的感应电流由d到b

C.U=vBl,流过固定电阻R的感应电流由b到d

D.U=vBl,流过固定电阻R的感应电流由d到b

考点:右手定则导体切割磁感线时的感应电动势
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患者男,48岁。突发左侧视野内闪光,约10min后左手麻木,并逐渐扩散至左臂及面部;随后症状逐渐消失,约40min后完全缓解。诊断为()

A.无头痛发作的偏头痛先兆症状

B.癫痫部分性发作

C.短暂性脑缺血发作(TIA.

D.脑卒中

E.神经症

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器官保存应遵循下述原则是低温、预防细胞肿胀和()。

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阅读理解。

      Your body, which has close relations with the food you eat, is the most important thing you own, so

it needs proper treatment and proper nourishment (食物). The old saying "an apple a day keeps the

doctor away." is not as silly as some people think. The body needs fruit and vegetables because they

contain vitamins. Many people take extra vitamins in pill form (丸剂), believing that these will make them

healthy. But a good diet is made up of nutritive food and this gives all the vitamins you need. The body

doesn't need or use extra vitamins, so why they waste money on them?

     In the modern Western world, many people are too busy to bother about eating properly. They throw

anyt hing into their stomachs, eating hurriedly and carelessly. The list of illnesses caused or made worse

by bad eating habits is frightening.

1. The old saying referred to in the passage tells us that        .

A. eating apples regularly does lots of good to our health.  

B. the apple is the best among all kinds of fruits  

C. apples can take the place of doctors

D. an apple is a sure cure for illness

2. In the second paragraph, the writer tries to let us know        .

A. our bodies need food, or we can't live  

B. often eating apples is a good habit  

C. taking extra vitamin pills is completely useless  

D. a good diet is of great importance for our health  

3. In the modern western countries        .

A. people won't want to pay more attention to their eating  

B. people throw everything into their stomachs without chewing.

C. list of people's illness are caused or made worse by bad eating habits

D. people are only too busy to cook meals for themselves  

4. From the passage we can draw a conclusion that if we want to keep healthy, we should        .

A. only eat an apple a day  

B. take as many vitamin pills as possible

C. eat properly    

D. throw something into our stomachs slowly and carefully.

题型:选择题

男,28岁,突起寒颤,高热,恶心,呕吐、腰痛已5天。体检:重病容,眼睑浮肿,球结膜及胸部皮肤充血,腋下见少许点状出血点,血压70/50mmHg,怀疑流行性出血热。本例必须首先考虑的治疗措施是()。

A.丸用升压药

B.补充血容量

C.纠正酸中毒

D.小剂量肝素抗DIC

E.选用抗病毒治疗

题型:选择题

患儿,女性,3岁,低热2天后,一侧腮部肿痛,继而另一侧亦肿痛,边缘不清,触之疼感,咀嚼不便,咽痛,舌红,苔微黄,脉浮散,治疗首选方应是()

A.五味消毒饮

B.普济消毒饮

C.银翘散

D.清瘟败毒饮

E.柴胡葛根汤

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