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【单选题】
下列试验不属于流行病学实验研究的是A.
观察性研究
B.
社区试验
C.
现场试验
D.
临床试验
E.
类试验
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举一反三
【简答题】Write the Chinese meaning of "reaction" in general English.
【单选题】Do you find getting up in the morning so difficult that it 's painful? This might be called laziness, but Dr. Kleitman has a new explanation. He has proved that everyone has a daily energy cycle. Duri...
A.
he is a lazy person
B.
he refuses to follow his own energy cycle
C.
he is not sure when his energy is low
D.
he is at his peak in the afternoon or evening
【简答题】Do you ever find yourself getting really unhappy for almost no reason? Or suddenly feeling down without knowing why? Going from sadness to anger to joy in a matter of minutes can make many s feel ...
【单选题】Do you find getting up in the morning so difficult that it's painful? This might be called laziness, but Dr. Kleitman has a new explanation. He has proved that everyone has a daily energy cycle. Durin...
A.
he is a lazy person
B.
he refuses to follow his own energy cycle
C.
he is not sure when his energy is low
D.
he is at his peak in the afternoon or evening
【单选题】设计键连接的几项主要内容是：a.按轮毂长度选择键的长度 b.按使用要求选择键的适当类型c.按轴的直径选择键的剖面尺寸 d.对键进行必要的强度校核在具体设计时一般顺序为_________。
A.
b →a→c→d
B.
b→c→a→d
C.
a→c→b→d
D.
c→d→b→a
【简答题】字符串"sgabacbadfgbacst" 中存在( )个与字符串"ba"相同的子串。
【单选题】设计键连接的几项主要内容是:a)按轮毂长度选择键的长度;b)按使用要求选择键的类型;c)按轴的直径选择键的剖面尺寸;d)对连接进行必要的强度校核。正确顺序应是 ( ) 。
A.
b-c-a-d
B.
b-a-c-d
C.
a-c-b-d
D.
c-d-b-a
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