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   663篇
  免费   91篇
  国内免费   25篇
  2023年   4篇
  2022年   3篇
  2021年   12篇
  2020年   26篇
  2019年   24篇
  2018年   7篇
  2017年   23篇
  2016年   26篇
  2015年   18篇
  2014年   56篇
  2013年   132篇
  2012年   37篇
  2011年   27篇
  2010年   28篇
  2009年   39篇
  2008年   35篇
  2007年   27篇
  2006年   28篇
  2005年   32篇
  2004年   36篇
  2003年   21篇
  2002年   13篇
  2001年   15篇
  2000年   16篇
  1999年   14篇
  1998年   13篇
  1997年   11篇
  1996年   10篇
  1995年   5篇
  1994年   8篇
  1993年   13篇
  1992年   6篇
  1991年   6篇
  1990年   5篇
  1989年   2篇
  1975年   1篇
排序方式: 共有779条查询结果,搜索用时 17 毫秒
101.
A recently published collection of captured Iraqi records offers an opportunity to better understand Saddam Hussein's perception of US and Israeli deterrence signals, affording innovative insights into the reasons behind Iraq's restraint from using weapons of mass destruction against Israeli targets during the 1991 Gulf War. This article tests a wide range of suggested hypotheses, and suggests that US and Israeli deterrence played only a minimal role in dissuading Iraqi use of WMD. The article concludes with some thoughts on the practical implications, particularly on the effectiveness of a “no-first-use” nuclear policy.  相似文献   
102.
Abstract

We use the k-th-order nonparametric causality test at monthly frequency over the period of 1985:1 to 2016:06 to analyze whether geopolitical risks can predict movements in stock returns and volatility of 24 global defense firms. The nonparametric approach controls for the existing misspecification of a linear framework of causality, and hence, the mild evidence of causality obtained under the standard Granger tests cannot be relied upon. When we apply the nonparametric test, we find that there is no evidence of predictability of stock returns of these defense companies emanating from the geopolitical risk measure. However, the geopolitical risk index does predict realized volatility in 50% of the companies. Our results indicate that while global geopolitical events over a period of time is less likely to predict returns, such global risks are more inclined in affecting future risk profile of defense firms.  相似文献   
103.
Since the post-World War II genesis of nuclear deterrence, two presidential initiatives have been presented to deliver humanity from the threat of its failure. The first was the Strategic Defense Initiative (SDI), a constellation of space- and ground-based systems that President Ronald Reagan envisioned would render nuclear weapons “impotent and obsolete.” The second is President Barack Obama's roadmap to “a world without nuclear weapons,” commonly referred to as “Global Zero.” While these proposals appear to have little in common, deeper investigation reveals a number of provocative similarities in motivation and presentation. Moreover, both generated fierce debate, often with ideological overtones, about their strategic desirability and technical feasibility. We use these parallels, as well as prominent dissimilarities, to draw lessons from the SDI experience that can be applied to the debate over Global Zero.  相似文献   
104.
Eating Grass: The Making of the Pakistani Bomb, by Feroz Hassan Khan. Stanford University Press, 2012. 544 pages, $29.95.

Managing India's Nuclear Forces, by Verghese Koithara. Brookings Institution Press, 2012. 304 pages, $59.95.  相似文献   
105.
Nuclear deterrence is sometimes treated as a known quantity—a definite thing that keeps us safe and ensures our security. It has also often been used as a justification for possessing nuclear weapons. Nuclear deterrence, however, is based on an unexamined notion: the belief that the threat to destroy cities provides decisive leverage. An examination of history (including recent reinterpretations of the bombing of Hiroshima) shows that destroying cities rarely affects the outcome of wars. How is it possible that an action that is unlikely to be decisive can make an effective threat? Recent work on terrorism suggests that attacks against civilians are often not only ineffective but also counterproductive. And a review of the practical record of nuclear deterrence shows more obvious failures than obvious successes. Given this, the record of nuclear deterrence is far more problematic than most people assume. If no stronger rationale for keeping these dangerous weapons can be contrived, perhaps they should be banned.  相似文献   
106.
为解决小子样条件下进行产品固有可用度试验验证的问题,基于Bayes理论,提出了一种固有可用度定时截尾试验方案.该试验方案在假设故障间隔时间和修复时间均服从指数分布的前提下,将现场试验分为同时进行的可靠性和维修性定时截尾试验2个部分,要求在利用验前试验信息的基础上,使本次试验获得的验后分布还可以作为下一次现场试验的验前分布,提高了试验数据的利用率,具有较好的经济效益.  相似文献   
107.
xxxx超声速引射器是高空模拟试车台的重要组件,在发动机启动前利用引射器对试验舱预抽真空可避免发动机启动初始时刻燃气漏入试验舱造成燃气在发动机中分离,对获取发动机在高空环境下的完整推力特性具有重要意义。而该工况下超声速引射器的启动过程是引射器工作过程中最为恶劣的工况,设计不合理的引射器会导致启动压力过高甚至不能实现启动。建立了缩比超声速空气引射器试验台对超声速引射器的启动特性进行研究,采用压力测量方法结合纹影技术对超声速引射器处于极限启动压比时的流场进行了描述,研究结果表明混合室收缩比越小,引射器极限启动压比越低。同时给出了定位超声速引射器不启动原因的判据:当引射器不启动是由引射总压不足引起时,盲腔压力在引射总压提高时降低,并在临界启动状态下达到最小值;而由混合室收缩比过小导致的引射器不启动在引射总压提高时盲腔压力单调上升。  相似文献   
108.
从战术导弹靶场试验风险因素存在的主要环节分析入手,建立了风险因素指标体系,结合靶场试验特点阐述了风险辨识、评估、处理的原则和方法,结合某型舰空导弹试验靶标保障的工程问题,对该靶标供靶风险进行了辨识,对风险发生的概率和后果严重性作出了评估,并在此基础上提出了解决问题的基本途径.  相似文献   
109.
The Indian government has not made a public comment about the status of its nuclear weapon program since approving a nuclear doctrine in 2003. However, there is now enough information in the public domain to determine that the command-and-control system for the nuclear program has steadily matured in accordance with the intent of the approved nuclear doctrine. The Indian government has successfully mitigated many of the issues that plague the conventional military. The result is a basic command-and-control system that is focused only on the delivery, if ordered by the prime minister, of nuclear weapons. The system is not as robust as those of the United States and Russia, but is in place and ready as new Indian nuclear weapons enter into operation. The command-and-control system is developing to meet India's needs and political compulsions, but not necessarily as part of a more assertive nuclear policy.  相似文献   
110.
The number of bilateral nuclear cooperation agreements surged during the “nuclear renaissance” of the past decade. This proliferation is only partially explained by the prevailing approaches that focus on strategic imperatives. To supplement these explanations, this study draws on neoliberal models of economic competition to posit that bilateral agreement negotiations also exhibit conditions of “uncoordinated interdependence” and maneuvering to gain market share. Case evidence suggests the contours of supplier state bids for civilian assistance are determined at least as much by considerations about economic competition as they are by positive strategic goals. In addition, this study identifies several cases of cooperation where there appears to be little or no strategic motive for export agreements. The study concludes that patterns of economic competition and the influence of peers in defined competitive spaces alter material payoffs and impact policies. It also identifies a surprising role for principled restraint in dampening strategic and economic competition in some dyads.  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