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   566篇
  免费   57篇
  国内免费   20篇
  2023年   1篇
  2022年   3篇
  2021年   7篇
  2020年   9篇
  2019年   10篇
  2018年   8篇
  2017年   16篇
  2016年   8篇
  2015年   6篇
  2014年   61篇
  2013年   67篇
  2012年   44篇
  2011年   45篇
  2010年   57篇
  2009年   40篇
  2008年   37篇
  2007年   45篇
  2006年   29篇
  2005年   29篇
  2004年   25篇
  2003年   29篇
  2002年   13篇
  2001年   19篇
  2000年   7篇
  1999年   5篇
  1998年   7篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1989年   4篇
排序方式: 共有643条查询结果,搜索用时 31 毫秒
181.
党的十八大和十八届三中全会提出"健全鼓励高校毕业生到基层工作的服务保障机制"的工作任务,基层就业成为大学生就业的重要渠道之一。为深入了解兵团高校大学生赴到兵团基层单位就业的状况,以石河子大学为个案,通过分析和梳理石河子大学毕业生到兵团基层就业情况及存在问题,尝试构建高校毕业生到兵团基层单位就业新机制,以期更好的为兵团基层发展提供智力支持和人才保障。  相似文献   
182.
研究主题是指某一研究领域内的主要研究内容,反映了该领域的科研工作者和管理者的研究热点和工作重点。研究采用计量分析法对1994-2013年刊载在《学前教育研究》中与幼儿园"游戏"研究主题密切相关的165篇文献进行分析,建构了"游戏"研究主题的分析框架。回顾20年来幼儿园"游戏"研究,学术界对幼儿园游戏的关注度不够,游戏理论研究与实践研究的深度和广度均不足,理论研究与实践研究"脱离"现象明显。研究认为在以后的研究中,应树立"大课程"观的游戏理念;深化理论研究,建构本土化游戏理论;加强实践研究,探索游戏活动促进游戏者发展的路径;注重"关系"研究和"机制"研究,为理论研究和实践研究关联搭建桥梁。  相似文献   
183.
The authors propose five principles for addressing the major deficiencies of the current treaty-based approach to nonproliferation. These involve: effectively closing the door to withdrawals from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT); defining which nuclear technologies fall within the NPT's “inalienable right” provision, so as to maintain a reasonable safety margin against possible military application; expansion of International Atomic Energy Agency inspections to include greater readiness to use its “special” inspection authority; creation of an NPT enforcement regime, to include a secretariat; and universalizing the NPT so as to apply to all states, while creating a path for current non-parties to come into compliance. There is no illusion here about the prospects for the adoption of this approach. At a minimum, the world needs to be frank about the gap between nuclear programs and current nonproliferation protection. Encouragement of greater use of nuclear power should be predicated on closing that gap.  相似文献   
184.
This paper investigates the potential for modeling and simulation to contribute to new defense system development, by increasing the productivity of traditional R&D in developing system‐specific technology. Building on a previous optimal control model of defense system R&D, it shows that (1) the optimal use of modeling is related in a natural way to that of traditional R&D, and (2) both have similar optimal profiles over time. Simulated results based on limited historical data suggest that optimal use of modeling could increase the rate of growth in system‐specific technology significantly.  相似文献   
185.
How do we assess the health of international regimes? Many analysts have insisted recently that the nuclear nonproliferation regime is in urgent need of repair or that it should even be discarded because of its supposed ineffectiveness. However, it is essential that statements about the regime being in crisis be scrutinized for veracity and utility. While the spread of nuclear weapons poses an undeniable and serious threat to international security, a mistaken crisis mentality with respect to the regime could lead to rash attempts to alter it in unnecessary or ineffective ways or, at worst, to discard it completely. This paper returns to a theoretical framework that differentiates regimes, across both issue areas and time, to provide a more specified evaluation of regime health. By disaggregating the nuclear nonproliferation regime and assessing the individual and interactive health of multiple dimensions, a number of dimension-specific, regime-strengthening policy recommendations emerge.  相似文献   
186.
ABSTRACT

Since the 1950s, the United States has engaged in nuclear sharing with its NATO allies. Today, 150-200 tactical nuclear weapons remain on European soil. However, the Treaty on the Non-proliferation of Nuclear Weapons (NPT) prohibits the transfer of nuclear weapons to non-nuclear weapon states. The potential discrepancy between text and practice raises the question of how the NPT's negotiators dealt with NATO's nuclear-sharing arrangements while drafting the treaty that would eventually become the bedrock of the international nonproliferation regime. Using a multitiered analysis of secret negotiations within the White House National Security Council, NATO, and US-Soviet bilateral meetings, this article finds that NATO's nuclear-sharing arrangements strengthened the NPT in the short term by lowering West German incentives to build the bomb. However, this article also finds that decision makers and negotiators in the Lyndon B. Johnson administration had a coordinated strategy of deliberately inserting ambiguous language into drafts of Articles I and II of the Treaty to protect and preserve NATO's pre-existing nuclear-sharing arrangements in Europe. This diplomatic approach by the Johnson administration offers lessons for challenges concerning NATO and relations with Russia today.  相似文献   
187.
ABSTRACT

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) allows states to exempt nuclear material from international safeguards for use in nuclear submarine programs. This material, however, could be diverted for nuclear weapons purposes without the knowledge of inspectors, creating a potentially dangerous loophole in the treaty. This article argues that exercising that loophole today would amount to admitting a nuclear weapon program, making it a particularly poor pathway to a weapon for a potential proliferant. Still, if states like Brazil ultimately exempt nuclear material from safeguards for a nuclear submarine effort, they could set a dangerous precedent that makes it easier for others to use the loophole as a route to a nuclear weapon capability. There are several policy options available to mitigate the damage of such a precedent; most promising is the prospect of a voluntary safeguards arrangement that would allow international inspectors to keep an eye on nuclear material even after it has been dedicated to a naval nuclear propulsion program.  相似文献   
188.
The 2010 Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) produced a Final Document calling for an extension of the principles of the nonproliferation norm as well as steps toward complete disarmament. This article looks beyond the rhetoric, however, to examine recent decisions by great powers to expand nuclear trade with non-NPT countries and the implications of these decisions on the traditional nonproliferation norm of restraint. This article seeks to contribute to constructivist theory by supplementing existing accounts of norm creation and establishment with a new model of norm change. The article develops a case study of the 2008 US-India nuclear deal to highlight the role of elite agency in key stages of norm change, including redefinition and constructive substitution through contestation. It concludes that the traditional nonproliferation norm may be evolving in new directions that are not well captured by existing theoretical frames.  相似文献   
189.
ABSTRACT

South Africa's nuclear disarmament is a unique historical case, notable in part for the dramatic shift from deception to cooperation. The unprecedented transparency it demonstrated in order to convince the international community of the veracity of their disarmament is heralded as an exemplar for verifiable denuclearization. Less known is how this case affords insights into how a nuclear weapon program can be clandestinely hidden by the ambiguity provided by an otherwise completely legitimate, peaceful, nuclear energy program. Using a variety of open sources, including newly declassified internal South African and US government reports, it can be shown that South Africa employed a variety of deceptive tactics before it disarmed, and even for nearly two years after becoming a signatory to the Treaty on the Non-Proliferation of Nuclear Weapons. This article reviews that information to derive instructive lessons on the lengths that a nuclear proliferant state might go to conceal its true capabilities and intentions, and to thwart international discovery of the existence and full extent of an existing—or, in this case, a former—nuclear weapon program.  相似文献   
190.
In this article, a distribution system is studied where the sum of transportation and inventory costs is to be minimized. The inventory holding cost is assumed to be the same for all retailers. A fixed partition (FP) periodic policy is proposed with tight asymptotic worst‐case performance of 3/2 with respect to the best possible policy. This bound cannot be improved in the class of FP periodic policies. In partition‐based PB policies, the retailers are first partitioned into sets and then the sets are grouped in such a way that sets of retailers within a group are served together at selected times. A PB periodic, policy is presented with tight worst‐case asymptotic performance of with respect to the best possible policy. This latter performance improves the worst‐case asymptotic performance of of the previously best known policy for this problem. We also show that the proposed PB periodic policy has the best worst‐case asymptotic performance within the class of PB policies. Finally, practical heuristics inspired by the analyzed policies are designed and tested. The asymptotic worst–case performances of the heuristics are shown to be the same of those of the analyzed policies. Computational results show that the heuristics suggested are less than 6.4% on average from a lower bound on the optimal cost when 50 or more retailers are involved. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 00: 000–000, 2013  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