MR成像过程中,金属产生伪影是因为() A.干扰主磁场的均匀性 B.部分体积效应 C

题型:单项选择题

问题:

MR成像过程中,金属产生伪影是因为()

A.干扰主磁场的均匀性

B.部分体积效应

C.产生热量

D.电阻大

E.密度大

考点:广西住院医师基础知识基础知识题库
题型:单项选择题

(8分)如图甲所示,长木板a放在光滑的水平面上,质量为1kg的小滑块b以水平初速度v0=6m/s从a的左端冲上长木板,运动过程中a、b的v-t图线如图乙所示。试求:从t=0时开始到t=3s的过程中,

(1)小滑块b克服摩擦力做的功是多少?

(2)a、b组成的系统产生的内能是多少?

题型:单项选择题

Have you ever thought of taking a train and having an adventure(奇遇)?Riding the train can be a real adventure. That is how I feel every time I take Amtrak. I often take a four-hour trip to visit my children. Every time I take this trip I never know what will happen.

Last week when I was on the train and over an hour into the train ride,there was a man sitting by himself in the back of the train carrying on a mobile phone conversation-in another language. It was loud and disturbed most of the people on the train. I think it was annoying.

Fortunately I sat next to a wonderful old lady who was taking a two-day trip by train. She said her two daughters were distraught at the thought of her driving for three days to reach her home,although she had no trouble driving. The train ride was the only choice for her. She loved to look out of the window and watch the world go by on the train.

She was fun to talk to and asked me when my children started being parents. That is a very good question. Both of us are old and have children. She asked that same question from time to time.

There are always many people on the train from all walks of life,different countries,and many  languages. Riding the train is a great way to increase your knowledge and take in all kinds of cultures. If you get hungry,you can buy food in the food car at any time. If you need to use the restroom there is always one available.

It sure beats driving the car,which has to stop for food and restrooms. And it is better than taking the bus.

小题1:According to the passage,the purpose of the author’s train ride was    .

A.to do business

B.to see her children

C.to visit places of interest

D.to see her old friends小题2:Which of the following is the closest in meaning to the underlined word “distraught” in Paragraph 3?

A.Disappointed.

B.Satisfied.

C.Worried.

D.Pleased.小题3:Which of the following is TRUE about the old lady sitting next to the author?

A.She is too old to drive now.

B.She does not like to take trains.

C.Although she is old,she has a good memory.

D.Her daughters live far away from her home.小题4:What is the best title for this passage?

A.Train ride-a cultural experience

B.A painful experience on the train

C.The history of Amtrak

D.A wonderful lady

题型:单项选择题

预防风心病加重的根本措施是()

A.积极治疗心力衰竭

B.积极锻炼身体

C.饮食清淡,避免妊娠

D.预防和治疗感染

E.卧床休息

题型:单项选择题

枕前位分娩机制正确的是:

A.胎头进入骨盆入口时呈俯屈状态
B.下降贯穿于分娩全过程
C.下降动作呈持续性
D.俯屈动作完成后,胎头以枕额径通过产道
E.胎头颅骨最低点达骨盆最大平面时出现内旋转

题型:单项选择题

生产性企业向境外投资的外购的二手设备应退税额按( )计算。

A.核定金额
B.市场上相关产品的价格
C.公允价值
D.发票上注明的金额

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