一个输出电压几乎不变的设备有载运行,当负载增大时,是指()A、负载电阻增大 B、负载电

题型:单项选择题

问题:

一个输出电压几乎不变的设备有载运行,当负载增大时,是指()

A、负载电阻增大

B、负载电阻减小

C、电源输出的电流增大

考点:电路分析电路分析题库
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在数据库中用数据模型这个工具来抽象、表示和处理现实世界中的数据和信息。常见的数据模型有3种,它们分别是层次模型、网状模型和______。

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先天性弓形虫病的药物治疗首选()

A.乙胺嘧啶及磺胺嘧啶

B.甲氧苄啶加磺胺甲基异唑

C.红霉素

D.氨苄西林和庆大霉素

E.乙胺嘧啶及磺胺异唑

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阅读下面材料,在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

If you feel stressed by responsibilities at work, you should take a step back and identify (识别) those of   61  (great)and less importance. Then, handle the most important tasks first so you’ll feel a real sense of   62  (achieve). Leaving the less important things until tomorrow   63  (be) often acceptable.

Most of us are more focused   64   our tasks in the morning than we are later in the day. So, get an early start and try to be as productive   65   possible before lunch. This will give you the confidence you need to get you through the afternoon and go home feeling accomplished.

Recent   66  (study) show that we are far more productive at work if we take short breaks   67  (regular). Give your body and brain a rest by stepping outside for   68   while, exercising, or dong something you enjoy.

If you find something you love doing outside of the office, you’ll be less likely   69  (bring) your work home. It could be anything-gardening, cooking, music, sports—but whatever it is,   70  (make) sure it’s a relief from daily stress rather than another thing to worry about.

61()

题型:单项选择题

质量管理的发展包括以下()阶段。

A.质量检验管理阶段

B.统计质量管理阶段

C.全面质量管理阶段

D.标准质量管理阶段

题型:单项选择题

设a0=4,a1=1,an-2=n(n-1)an,n≥2.

求S(x)的极值.

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