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   410篇
  免费   8篇
  2021年   3篇
  2019年   8篇
  2018年   9篇
  2017年   7篇
  2016年   5篇
  2015年   8篇
  2014年   7篇
  2013年   94篇
  2011年   4篇
  2010年   3篇
  2009年   5篇
  2008年   3篇
  2007年   3篇
  2005年   6篇
  2004年   4篇
  2003年   8篇
  2002年   4篇
  2001年   3篇
  2000年   6篇
  1999年   4篇
  1997年   3篇
  1996年   5篇
  1995年   7篇
  1994年   7篇
  1993年   7篇
  1992年   5篇
  1991年   7篇
  1990年   6篇
  1989年   9篇
  1988年   13篇
  1987年   9篇
  1986年   12篇
  1985年   7篇
  1984年   3篇
  1983年   5篇
  1982年   8篇
  1980年   7篇
  1979年   6篇
  1978年   4篇
  1977年   5篇
  1976年   5篇
  1975年   7篇
  1974年   11篇
  1973年   8篇
  1972年   9篇
  1971年   10篇
  1970年   6篇
  1969年   9篇
  1968年   8篇
  1948年   4篇
排序方式: 共有418条查询结果,搜索用时 15 毫秒
141.
This paper empirically examines whether the aging of a fleet affects operational availability and operating cost using a unique data-set on the 117 47-foot Motor Lifeboats (MLBs) of the United States Coast Guard (USCG). Procured from 1997 to 2003, the 47-foot MLB is the standard lifeboat of the USCG and all 117 MLBs remain in service. The aging of the MLB fleet has resulted in higher annual operating costs and lower operational availability, although the nature of this relationship remains unclear. Our estimation strategy utilizes an error components estimator to examine these issues. We employ three variants of the dependent variables (i.e. the standard logarithmic transformation as is most commonly seen in the literature, inverse hyperbolic sine [IHS], and level outcomes). The point estimates from the standard logarithmic model finds operational availability for the MLBs decreases at a rate between 0.83 and 1.8% per year and cost increases at a rate between 0.33 and 7.81% per year. Similar effects are shown with the IHS and level outcome specifications. In terms of nonlinearity effects, we find the most pronounced changes in operational availability and cost occur for MLBs aged 15 years or more (in comparison to younger MLBs).  相似文献   
142.
In most western countries, there is a strong incentive for defence department budget-holders to expend all of the funds they are authorized to spend in a fiscal year. In this paper, we question whether this emphasis makes sense. We develop a model of a defence department’s operating expenditure assuming a fixed level of funding for a year and uncertain costs. The results of the model suggest that the incentive for departmental managers to expend all authorized funds is inefficient. We explore the implications of the model for the Department of National Defence (DND) in Canada in light of the recent criticism of DND lapsed funding by the Auditor-General of Canada.  相似文献   
143.
144.
This paper presents a game‐theoretic model of suicide terrorism containing three agents: the terrorist leader; a targeted government; and potential terrorist supporters. Supporters join the terrorist group if they gain more from their participation than from their economic opportunities. Preemptive measures by the government can result in a backlash that encourages recruitment through new grievances. Suicide attacks can also lead to recruitment. Increases in preemption costs and/or economic opportunities can reduce the overall level of terrorism, while increasing the proportion of suicide to normal attacks. An increase in the effect of preemption on recruitment, or the propaganda effect of suicide bombings has the opposite effect of increasing normal and suicide attacks, but decreasing the proportion of suicide to normal attacks in the terrorist organization’s strategy profile.  相似文献   
145.

This paper presents a model for converting legacy defense production facilities into private‐sector economic resources. Specifically, this paper will examine as a case study the first successful conversion of a former U.S. Department of Energy nuclear weapons production installation, including reasons for its success, its costs and benefits, and lessons for public policy. It is envisioned that this model may be useful for mitigating local economic hardship resulting from defense “downsizing” and for privatizing production capacities critical for national defense.  相似文献   
146.
Export controls and international safeguards are central to ensuring international confidence in the peaceful uses of nuclear materials and technologies and to achieving adequate oversight on the transfer and use of nuclear materials, technology, and equipment required for the development of proliferation-sensitive parts of the nuclear fuel cycle. Although the independent strengths of export controls and international safeguards rely largely on universal adherence, there may be opportunities to exploit the shared strengths of these systems. This article provides background information on the separate evolution of export controls and international safeguards, considers how these two elements of the nonproliferation regime interact, and identifies some possible avenues that could, over time, lead to wholly integrated activities.  相似文献   
147.
ABSTRACT

This study seeks to evaluate the threat of malicious chemical use by non-state actors. It finds that non-state actors have primarily turned to ready-to-use crude chemical weapons (CW) instead of traditional CW agents. Interestingly, the worst crude CW attacks have been more destructive than those employing traditional CW. Scenarios for catastrophic consequences exist, but chemical attacks have typically been used to accomplish tactical goals, which leverage psychological and economic impacts. Therefore, successful efforts to counter CW proliferation by non-state actors must be substantially different from those targeting states.  相似文献   
148.
149.
Indonesia, Thailand, and Vietnam recently announced that they are launching nuclear energy programs, and Malaysia and the Philippines soon may follow suit. As a result, by 2020, at least three states in Southeast Asia could possess latent nuclear capabilities—the option to pursue military applications of dual-use nuclear technology. Analysis of the nuclear programs, domestic proliferation pressures, and the external threat environment in Southeast Asia leads the authors to conclude that the nuclear intentions of states in that region are entirely peaceful and the probability of future nuclear breakout there is low. However, this finding does not justify complacency. In the long term, the benign outlook for regional security may change, and in the near term weak regulatory regimes present serious challenges to nuclear safety and create opportunities that non-state actors may exploit. To minimize these risks, the authors recommend creating a “proliferation firewall” around the region, which would combine strong global support for Southeast Asian nuclear energy programs with innovative regional multilateral nuclear arrangements.  相似文献   
150.
Between 1957 and 1959 the West German company Telefunken and the Bonn government became prime targets in the French army's campaign against the Front de Libération Nationale's (FLN) efforts to establish communications networks. To the French military, the prevention of sales of Telefunken equipment to the FLN or its allies constituted a matter of strategic importance. To the Germans, it was an act of economic protectionism that exposed France's continued misgivings of Germany. The problem exerted a considerable strain between Paris and Bonn, and even threatened to harm German-Arab relations. The Telefunken affair thus highlights the Algerian war's international ramifications. It further reveals the responsibility of the French military in the internationalisation of that war.  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