问题
单项选择题
下列研究设计中，因果论证强度最弱的是（）
A.随机对照试验
B.前瞻性队列研究
C.回顾性队列研究
D.病例对照研究
E.生态学研究
答案
参考答案：E
解析：一般而言在因果论证强度上，实验性研究大于观察性研究，有对照的研究大于无对照的研究，以个体为分析单位的研究大于以群组为分析单位的研究。
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下列研究设计中，因果论证强度最弱的是（）
A.随机对照试验
B.前瞻性队列研究
C.回顾性队列研究
D.病例对照研究
E.生态学研究
参考答案：E
解析：一般而言在因果论证强度上，实验性研究大于观察性研究，有对照的研究大于无对照的研究，以个体为分析单位的研究大于以群组为分析单位的研究。
| 阅读理解。 | |
| Blood Donation (献血) A grown-up person has ten or eleven pints (品脱) of blood inside his or her body. We can lose a pint of blood without feeling, but if we lose too much blood, we feel weak and cold. Our faces become pale. We may die. This is what often happen when somebody is hurt in an accident, or a soldier is hurt in a war. 1______ But today they can be taken to hospital and given more blood. Almost at once they feel better. their faces are no longer pale. They do not die. 2______ People may donate blood to a blood bank so that it can be used to save people's lives. When they go to donate blood, a special kind of needle(针) is put into the arm. It does not hurt. The blood runs through the needle and through a rubber tube (橡胶管) into a bottle or a bag. A pint of blood is taken in this way. The person who has given blood drinks a cup of tea of coffee and rests for a few minutes, then he feels well. 3______ A person who gives blood feels happy, because he knows that his blood will be used to someone's life. 4______ When you are older, you may give blood, too. But you can't do this until you are eighteen. | |
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| 5. A person who gives blood feels happy, because ______. | |
| A. he knows his blood maybe save someone's life. B. he gets a lot of money. C. He knows that his blood is very good. D. He can drink a cup of tea or coffee and rests. |