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   388篇
  免费   205篇
  国内免费   26篇
  619篇
  2024年   4篇
  2023年   11篇
  2022年   8篇
  2021年   17篇
  2020年   6篇
  2019年   10篇
  2018年   11篇
  2017年   19篇
  2016年   31篇
  2015年   24篇
  2014年   43篇
  2013年   35篇
  2012年   41篇
  2011年   29篇
  2010年   24篇
  2009年   28篇
  2008年   26篇
  2007年   33篇
  2006年   20篇
  2005年   21篇
  2004年   30篇
  2003年   18篇
  2002年   15篇
  2001年   17篇
  2000年   19篇
  1999年   17篇
  1998年   8篇
  1997年   4篇
  1996年   8篇
  1995年   7篇
  1994年   4篇
  1993年   9篇
  1992年   3篇
  1991年   8篇
  1990年   7篇
  1989年   3篇
  1988年   1篇
排序方式: 共有619条查询结果,搜索用时 0 毫秒
531.
针对舰船特点和任务要求,提出了舰船航渡中的松弛时间问题。在对问题分析的基础上,给出了松弛时间的定义并对其进行了建模,讨论了航渡失败的判断准则,给出了松弛时间的上下限以及航渡中实际的松弛时间的计算方法,并采用仿真的方法进行了典型航渡过程的松弛时间和成功概率的计算。在大量计算的基础上,初步探讨了航渡成功概率与各类航渡参数之间的关系,并对舰船最优航渡策略问题进行了初步分析,最后对于优化目标、计算初值、结果的表达方式等提出了一个可行的解决方案。  相似文献   
532.
战时装备损坏率预计是确定保障力量需求和组织保障活动的前提。在分析装备损坏影响因素的基础上,依据可靠性理论及兰彻斯特方程,提出了一种新的战时装备损坏率预计方法。该方法将经验计算和模拟计算相结合,能够快速、客观地预测装备损坏情况,满足未来作战精确保障的要求。  相似文献   
533.
潜艇自航式诱饵组合使用方法的优劣主要评判依据是使用的方法最终使得潜艇对抗鱼雷成功的概率,对抗时间和诱骗距离是影响对抗成功概率的两个重要因素,它们又主要围绕发射时机、初始航向以及潜艇机动等几个问题展开。该文通过分析各个诱饵的作战使命,在一定态势下,根据诱饵的性能、鱼雷报警距离及舷角等各方面因素,建立大小口径声诱饵协同作战的弹道模型,并由此得到了诱饵发射时机、初始航向等参数。  相似文献   
534.
This article examines the arms control logic that was applied to the only regional arms control talks that have taken place in the Middle East to date: the Arms Control and Regional Security (ACRS) working group that was part of the multilateral track of the Madrid peace process in the early 1990s. It highlights both the successes and major constraints of the ACRS talks in an effort to assess what might be relevant to the weapons of mass destruction-free zone conference proposed for later this year. In addition to the basic arms control dilemmas that will continue to challenge this conference—as they did ACRS—the article suggests that current conditions in the Middle East are even less conducive to regional dialogue than they were in the earlier period, due to the internal upheavals in several key Arab states, and the specific challenge of Iran's move to develop a military nuclear capability.  相似文献   
535.
This article reviews the origins and evolution of the Middle East weapons of mass destruction-free zone (WMDFZ) concept and the proposal for a 2012 conference on the subject, and explores new challenges and opportunities for regional arms control in the current regional environment. It suggests that new models may be necessary to revitalize regional arms control efforts. The establishment of a broad regional security forum could include, but should not be limited to, curtailing weapons of mass destruction through the zone approach. Even if the 2012 conference fails to materialize, or is limited to a one-time event, the proposal for such a conference has provided an important opportunity to rethink future options for a regional arms control and security process.  相似文献   
536.
The Constitutive Act of the African Union (AU) provides for the right of the continental body to intervene in the face of war crimes, genocide and crimes against humanity. According to its formulation, Article 4(h) intervention entails military force, which is triggered when a target state fails to discharge its duty to protect its population from mass atrocities. Although Article 4(h) is an ambitious statutory commitment to intervene in a member state by the AU, the Libyan crisis in 2011 showed the ambivalence of the continental institution to act in a decisive and timely manner. The AU's failure to invoke Article 4(h) exposed the need for building the capacity and political will to intervene and to interpret Article 4(h). Therefore, the primary focus of this article is on how Article 4(h) should be interpreted. Flowing from the Pretoria Principles, which seek to provide clarity on the implementation of the AU's right of intervention, Article 4(h) should be viewed as a duty rather than a right to prevent or stop mass atrocities. The duty dimension of Article 4(h) derives from the international instruments that AU member states have ratified to prevent mass atrocities. Rather than being a paper tiger, Article 4(h) should be used in a proactive and timely manner as a military option available to the AU to persuade member states to prevent or halt atrocities. As a last resort, military force pursuant to Article 4(h) should aim at protecting the population at risk and pursuing the perpetrators in order to avoid contravening Article 2(4) of the Charter of the United Nations (UN). Although military intervention can save lives in the short term, it cannot necessarily address the underlying, structural causes of atrocities, such as ethnic rivalries, economic inequalities and scramble for natural resources, among others. Therefore, the prevention of mass atrocities should not be equated with, or be seen through the prism of, Article 4(h) intervention alone. The focus should instead be on the entire spectrum of preventive strategies at the disposal of the AU in the face of mass atrocities, including the African human rights system and the African Peer Review Mechanism.  相似文献   
537.
一体化联合作战中信息流作用研究   总被引:3,自引:0,他引:3  
以复杂系统理论为基础,从动力学角度出发,阐述了如何以信息流变化为依据、以相空间重构为手段,对作战系统状态转移轨迹进行反演计算,进而预测态势发展趋势的构想。同时针对一体化联合作战的“联合增效”作用,讨论信息流协调作用对一体化联合作战组织结构有序度的影响,建立了基于信息流协调度评价的一体化联合作战要素优化组合模型。  相似文献   
538.
The allocation of redundancies in a system to optimize the reliability of system performance is an interesting problem in reliability engineering and system security. In this article, we focus on the optimal allocation of two exponentially distributed active (standby) redundancies in a two‐component series system using the tool of stochastic ordering. For the case of active redundancy, stochastic comparisons are carried out in terms of the likelihood ratio and reversed hazard rate orders. For the case of standby redundancy, a likelihood ratio ordering result is developed. The results established here generalize and strengthen corresponding results in the recent literature. In addition, several numerical examples are used to explicate the results. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
539.
排空是机动管线的一项经常性作业。在水顶油排空过程中,不可避免地会产生混油,因此混油的切割工艺尤为关键。通过对机动管线水顶油排空作业终端混油切割流程、设备操作的分析,提出了采用1个三通球阀代替2个闸阀的切割流程,自行搭建了实验平台,测量了三通球阀的流动特性,论证了三通球阀作为机动管线混油切割阀的可行性。实验表明,新流程的使用降低了切割操作难度,提高了切割作业的快速性和准确性。  相似文献   
540.
《防务技术》2019,15(3):398-408
The mathematical model used to describe the detonation multi-physics phenomenon is usually given by highly coupled nonlinear partial differential equations. Numerical simulation and the computer aided engineering (CAE) technique has become the third pillar of detonation research, along with theory and experiment, due to the detonation phenomenon is difficult to explain by the theoretical analysis, and the cost required to accredit the reliability of detonation products is very high, even some physical experiments of detonation are impossible. The numerical simulation technique can solve these complex problems in the real situation repeatedly and reduce the design cost and time stunningly. But the reliability of numerical simulation software and the serviceability of the computational result seriously hinders the extension, application and the self-restoration of the simulation software, restricts its independently innovational ability. This article deals with the physical modeling, numerical simulation, and software development of detonation in a unified way. Verification and validation and uncertainty quantification (V&V&UQ) is an important approach in ensuring the credibility of the modeling and simulation of detonation. V&V of detonation is based on our independently developed detonation multi-physics software-LAD2D. We propose the verification method based on mathematical theory and program function as well as availability of its program execution. Validation is executed by comparing with the experiment data. At last, we propose the future prospect of numerical simulation software and the CAE technique, and we also pay attention to the research direction of V&V&UQ.  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