首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   216篇
  免费   68篇
  国内免费   20篇
  2024年   1篇
  2023年   2篇
  2022年   1篇
  2020年   8篇
  2019年   9篇
  2018年   7篇
  2017年   15篇
  2016年   7篇
  2015年   5篇
  2014年   15篇
  2013年   27篇
  2012年   12篇
  2011年   15篇
  2010年   12篇
  2009年   18篇
  2008年   10篇
  2007年   11篇
  2006年   14篇
  2005年   11篇
  2004年   8篇
  2003年   12篇
  2002年   8篇
  2001年   14篇
  2000年   4篇
  1999年   11篇
  1998年   6篇
  1997年   4篇
  1996年   2篇
  1995年   4篇
  1994年   6篇
  1993年   3篇
  1992年   4篇
  1991年   5篇
  1990年   6篇
  1989年   6篇
  1988年   1篇
排序方式: 共有304条查询结果,搜索用时 15 毫秒
261.
主要阐述了对构件测试的一种观点 ,并通过对系统测试及集成测试的裁剪 ,给出了对构件的一种测试方法  相似文献   
262.
潜艇感应磁场的三维积分方程法数值计算研究   总被引:2,自引:1,他引:1  
论述了应用积分方程法计算潜艇感应磁场的数值方法 ,采用底面为部分圆环的柱体剖分单元 ,推导了耦合系数的计算公式 .编制了数值计算程序 ,对潜艇船模进行了计算 ,取得了较好的计算结果 .  相似文献   
263.
AD2SOBD是AD公司生产的一种单片集成电路旋转变压器到数字转换器芯片.本文详细介绍了其功能特点、外部引脚、内部结构、工作特性等.最后给出了以AD2S80BD为核心的一种特殊的双速自整角机(或旋转变压器)到数字的转换器.  相似文献   
264.
ABSTRACT

This article examines decision-making mistakes made by U.S. President Nixon and national security advisor Kissinger during the 1971 India-Pakistan crisis and war. It shows that Nixon and Kissinger routinely demonstrated psychological biases that led them to overestimate the likelihood of West Pakistani victory against Bengali rebels as well as the importance of the crisis to broader U.S. policy. The evidence fails to support Nixon and Kissinger’s own framing of the 1971 crisis as a contest between cool-headed realpolitik and idealistic humanitarianism, and instead shows that Kissinger and Nixon’s policy decisions harmed their stated goals because of repeated decision-making errors.  相似文献   
265.
为检验雷达回波传输质量,完成基于莱斯因子K的混响室电磁环境分级,提出混响室条件下雷达回波传输环境模拟评价参数信杂比S,对比分析莱斯因子K和信杂比S的测量原理.实验结果表明:混响室可用于雷达回波传输环境模拟.  相似文献   
266.
碳纤维混凝土受压应力-应变全曲线研究是对其基本力学性能进行全面认识的基础,也是表现碳纤维混凝土基本受压特性的综合宏观反映。对9组(碳纤维体积分数分别为0,0.2%,0.4%,0.6%,0.8%,1.0%,1.2%,1.4%,1.6%)碳纤维混凝土试件进行了立方体和棱柱体抗压强度试验,结果表明碳纤维混凝土立方体和棱柱体抗压强度随碳纤维体积分数的增加呈下降趋势,峰值应变随碳纤维体积分数的增加呈增大趋势。基于各体积分数碳纤维混凝土的棱柱体抗压强度和峰值应变的试验数据,拟合得到了棱柱体抗压强度和峰值应变与体积分数之间的函数表达式。利用微机控制电液伺服压力试验机测定了9组碳纤维混凝土应力-应变全曲线,参照非线弹性理论的混凝土单轴受压应力-应变本构模型,根据测得的全曲线应力-应变数据,拟合得到了应力-应变全曲线上升段表达式参数和下降段表达式参数,最后给出了基于碳纤维体积分数变化的碳纤维混凝土单轴受压应力-应变本构方程。  相似文献   
267.
《Arms and Armour》2013,10(2):163-171
Attention is drawn to the existence of a harpoon-gun putatively from H. M. S. Challenger, a ship whose three-and-a-half-year circumnavigation of the globe (1872–1876), marked the beginning of the science of oceanography. The harpoon gun in question was made by Dundee shipsmith and harpoon-gun maker, David Neave. Only a few other examples of his work are known to exist and this example with a Remington rolling-block action is unusual for a British harpoon gun. It is proposed that it came to Millport's Marine Station via links Sir John Murray (1841–1914) had with the Marine Biological Association of the West of Scotland.  相似文献   
268.
When rational choice theory is applied to the study of terrorism, it is important that attention be given to the derived principles of constrained utility maximization. Particularly useful is the Slutsky equation, which rigorously analyzes the quantity response in one activity to a price change in another. By directing attention to assumptions and/or information about compensated cross price elasticities, expenditure shares, and income elasticities, the Slutsky equation can provide critical guidance in both theoretical and empirical analysis.  相似文献   
269.
Defense budgets in Japan have been complicated compromises from numerous inputs ‐ including threat perceptions, domestic industrial/technological base development, support for the bilateral security treaty with the United States and internal bureaucratic politics ‐ but with the fall of the former Soviet Union, the clearest justification for higher spending disappeared. Double‐digit defense spending increases that were common in the 1980s have been replaced by annual increases lower than present inflation rates, resulting in negative real growth in the country's defense budget. Domestic economic problems and consistent government pressures for smaller budgets have further slowed annual growth in total spending and have contributed to lower procurement budgets. As a result, the domestic Japanese defense industry is facing far more constrained conditions from the growth years of a decade before.

Government policymakers are examining Japan's regional security environment as well as its alliance with the United States to determine the appropriate course for the country to take in the coming years. The formal security treaty with the United States is likely to remain a major element of government positions, but other aspects of the country's overall security posture are open to debate. Perceptions of a reduced threat environment are fueling additional pressures for defense budget cuts.

The domestic defense industry seeks means to assure its survival in domestic defense markets in this constrained environment. Expansion into overseas markets to offset declining domestic markets is an option that currently is constrained by policy restrictions on arms exports. Industry is advocating re‐examination of those policies and unlike earlier years, government appears willing to respond positively but cautiously to this lobbying.  相似文献   
270.
After World War II, the US Navy confronted the challenge of adapting to dramatically altered geopolitical circumstances. Moscow did not have an ocean-going fleet, and early Cold War strategy was dominated by the salient position of nuclear strategic bombing – a mission thought to be outside the purview of the navy. Traditional roles, such as protecting sea lines of communication and supporting ground forces ashore, quickly proved indispensable. However, the navy eventually also succeeded in fielding dramatic technological and institutional innovations, for example, the strategic missile submarine, which enabled the US to successfully leverage maritime power against the continental power of the USSR.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号