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   132篇
  免费   21篇
  国内免费   1篇
  2022年   2篇
  2021年   3篇
  2020年   5篇
  2019年   8篇
  2018年   8篇
  2017年   7篇
  2016年   1篇
  2015年   6篇
  2014年   7篇
  2013年   39篇
  2012年   4篇
  2011年   10篇
  2010年   8篇
  2009年   7篇
  2008年   5篇
  2007年   6篇
  2006年   3篇
  2005年   2篇
  2004年   3篇
  2003年   3篇
  2002年   1篇
  2001年   3篇
  2000年   3篇
  1999年   4篇
  1998年   2篇
  1996年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
排序方式: 共有154条查询结果,搜索用时 31 毫秒
51.
In fiscal year 1999, the US Air Force introduced a bonus program designed to encourage longer enlistment terms. This regime shift provides a unique opportunity to estimate the elasticity of labor supply at a new margin: the length of the employment contract. A $5000 bonus differential is estimated to increase the probability that a recruit will choose a 6‐year enlistment over a 4‐year enlistment by 30 percentage points. The program is found to be cost‐effective relative to other policies to increase man‐years.  相似文献   
52.
According to the International Committee of the Red Cross (ICRC) publication Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law, all civilians (including child soldiers) lose their immunity from direct targeting ‘for so long as’ their actions amount to direct participation in hostilities. All civilians can, however, access the revolving door of protection and return to their civilian activities – complete with full immunity from direct targeting – provided the nature of their direct participation was spontaneous and disorganised. Once it can be ascertained that their participation in hostilities amounts to continuous combative functions, they relinquish their access to the revolving door of protection, and can be targeted at all times until they abandon their formal or functional membership of the belligerent group. This piece analyses how the revolving door phenomenon and the notion of continuous combative functions apply in instances where civilian child soldiers are directly participating in hostilities.  相似文献   
53.
This article explores the challenges that Australia faces in reconciling its commitments to nonproliferation and uranium exports during a time when the international nuclear nonproliferation regime is under major stress and the world uranium market is bullish. The “grand bargain” that has framed Australian participation in the nonproliferation regime and the nuclear fuel market since the 1970s was only tenable in an era of stagnant uranium demand and a stable nuclear balance. However, contemporary nuclear proliferation dynamics and the revival of interest in nuclear energy have accentuated the incompatibility between Australia's commitment to nonproliferation and the desire to profit from uranium exports. The contemporary international strategic environment, international nonproliferation regime, and nuclear energy market are characterized by developments that not only undermine the basis of Australia's grand bargain, but also present challenges and opportunities for the refashioning of Australian policy.  相似文献   
54.
This article examines the ways in which the two normative concerns of casualty-aversion and civilian protection influenced US military strategy in the particular context of the asymmetric conflict in Somalia in the early 1990s. The article critically evaluates US military operations through the prism of international humanitarian law and examines whether American forces started prioritizing casualty-aversion over the safeguarding of Somali civilians. Finally, by drawing on emerging moral guidelines (such as Michael Walzer's idea of ‘due care’), the article examines whether lower numbers of Somali civilian deaths could have been achieved if marginal increases to the risks faced by US soldiers had been accepted.  相似文献   
55.
This article distills insights for the scholarship of deterrence by examining the 1983 nuclear crisis – the moment of maximum danger of the late Cold War. Important contributions notwithstanding, our understanding of this episode still has caveats, and a significant pool of theoretical lessons for strategic studies remain to be learned. Utilizing newly available sources, this article suggests an alternative interpretation of Soviet and US conduct. It argues that the then US deterrence strategy almost produced Soviet nuclear overreaction by nearly turning a NATO exercise into a prelude to a preventive Soviet attack. Building on historical findings, this article offers insights about a mechanism for deterrence effectiveness evaluation, recommends establishing a structure responsible for this endeavor, and introduces a new theoretical term to the strategic studies lexicon – a ‘culminating point of deterrence’.  相似文献   
56.
Observers of United States (US) interventions have almost universally characterized the 1994 Haiti intervention as multilateral, a model for how international cooperation can achieve common security goals. A closer analysis of the intervention reveals that the planning and execution of the intervention were almost entirely unilateral and therefore cost the US few if any of the theoretical costs of coalition warfare, including interoperability and policy compromise. Mapped onto the unilateral strategy and operation of the intervention, however, was a multilateral diplomatic effort that secured United Nations Security Council authorization and provided a cover for an intervention that the US had already planned and intended to execute with or without that authorization. That the US sought a multilateral cover for an intervention that it could easily accomplish unilaterally shows the importance of two factors: A domestic audience that opposed unilateral peacekeeping but would accept using US resources as part of a broader multilateral operation, and a local population that would be more responsive to a multilateral coalition than a use of force that was perceived to be unilateral. The Haiti intervention shows that the determinants of success in operations other than war are as much political as military. When the US already has overwhelming military superiority vis-à-vis its adversary, building military coalitions becomes as much about enlisting political support as aggregating material capability.  相似文献   
57.
在发动机台架上,通过控制发动机冷却水温度、油门开度、负荷、运转时间等模拟车辆起动、怠速、预热、起步、工作水温等5种工况,对节油驾驶操作进行研究.结果表明:车辆怠速超过1 min时,应熄火;车辆预热可采用中低转速,但严禁乱轰油门;车辆起动后,经短时间预热即可起步,低速低负荷运行至冷却水温度达到发动机正常工作温度;正常行驶...  相似文献   
58.
由于无灰型柴油添加剂不存在二次污染问题,将是节能降污柴油添加剂发展的趋势,但是无灰型添加剂的加入可能会改变燃油多项理化指标和发动机台架评定结果,采用灰模式关联决策在众多添加剂中确定最优无灰型添加剂是一种较为科学的方法.通过对含有无灰型柴油添加剂油样的各项理化指标测试、模拟评价测试和发动机台架试验结果进行灰模式关联决策,...  相似文献   
59.
为促使北斗系统特别是北斗三号系统尽早加入国际原子时计算,利用中国科学院国家授时中心以及捷克无线电工程和电子学院两个守时实验室接收机产生的北斗三号新信号体制观测数据,开展基于北斗三号新信号体制共视时间比对试验。结果表明,北斗三号信号的多路径噪声影响小于北斗二号信号,且信噪比优于北斗二号信号。对比已有的研究,北斗三号新信号体制(B1C和B2a)共视时间比对的噪声相对于北斗三号卫星播发的北斗二号兼容信号体制(B1I和B3I)有较大的改善,其结果与GPS、Galileo共视比对结果相当,且在零基线共钟比对中,基于北斗三号新信号体制比对钟差的标准偏差相对于北斗二号信号提高了40%以上;利用北斗三号新信号体制共视得到的亚欧两地钟差噪声小于北斗二号信号,且比对钟差的稳定度相对于北斗二号提高了10%以上。该试验也可为北斗三号时间比对纳入国际原子时计算提供相关的研究基础。  相似文献   
60.
冰点是表征航空燃料低温使用性能的重要指标。常规冰点测定方法操作步骤复杂,测定时间长,影响航空燃料质量检测效率。基于光散射原理,将温度传感和光电检测技术应用于航空燃料冰点测定,利用燃料结晶对光散射和透射的影响,实现航空燃料冰点快速测定。该方法操作简单快速,检测1个油样用时少于15 min,大幅提高了冰点检测效率;试样体积仅需2 mL,有利于试验环境保护;测定结果重复性好,与标准方法 GB/T2430—2008具有良好的相关性。  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