问题 单项选择题

设有对照组但未用随机方法分组的研究属于

A.一级证据
B.二级证据
C.三级证据
D.四级证据
E.五级证据

答案

参考答案:C

解析: 本组题考查循证医学证据分类。
五个证据分类:循证医学中的证据:主要指临床人体研究的证据,包括病因、诊断、预防、治疗、康复和预后等方面的研究。治疗依据按质量和可靠程度大体可分为为五级。
(1)一级:按照特定病种的特定疗法收集所有质量可靠的随机对照试验(randomized controlled trail,RCT)后所作的系统评述(systematic review,SR)。SR包括Meta分析(汇总分析、荟萃分析)。这是国际公认的为某种疾病的防治提供的最有效、最安全、最可靠的依据。
(2)二级:单个的样本量足够的随机对照试验结果。
(3)三级:设有对照组但未用随机方法分组的研究。
(4)四级:无对照的系列病例观察,其可靠性较上述二、三级为低。
(5)五级:根据专家个人多年的临床经验提出的诊治方案。

阅读理解

阅读理解。

     It was a village in India. The people were poor. However, they were not unhappy. After all, their forefathers

had lived in the same way for centuries.

     Then one day. Some visitors from the city arrived. They told the villagers there were some people elsewhere

who liked to eat frog's legs. However, they did not have enough frogs of their own, and so they wanted to buy

frogs from other place.

     This seemed like money for nothing. There were millions of frogs in the fields around, and they were no use

to the villagers. All they had to do was catch them. Agreement was reached, and the children were sent into the

fields to catch frogs. Every week a truck arrived to collect the catch and hand over the money. For the first

time, the people were able to dream of a batter future, But the dream didn't last long.

     The change was hardly noticed at first, but it seemed as if the crops were not doing so well. More worrying

was that the children fell ill more often, and, there seemed to be more insects around lately.

     The villagers decided that they couldn't just wait to see the crops failing and the children getting weak. They

would have to use the money earned to buy pesticides (杀虫剂) and medicines. Soon there was no money left.

     Then the people realized what was happening. It was the frog. They hadn't been useless. They had been

doing an important job-eating insects. Now with so many frogs killed, the insects were increasing more

rapidly. They were damaging the crops and spreading diseases.

     Now, the people are still poor. But in the evenings they sit in the village square and listen to sounds of

insects and frogs. These sounds of the night now have a much deeper meaning.

1. From paragraph I we learn that the villagers _____. [ ]

A. worked very hard for centuries

B. dreamed of having a better life

C. were poor but somewhat content

D. lived a different life from their forefathers

2. Why did the villagers agree to sell frogs? [ ]

A. the frogs were easy money

B. They needs money to buy medicine

C. they wanted to please the visitors

D. the frogs made too much noise

3. What might be the cause if the children's sickness? [ ]

A. the crops didn't do well

B. there were too many insects

C. the visits brought in diseases

D. the pesticides were overused

4. What can we inform from the last sentence of the text? [ ]

A. Happiness comes from peaceful life in the country

B. Health is more important than money

C. The harmony between man and nature is important

D. good old day will never be forgotten

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