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   122篇
  免费   21篇
  国内免费   10篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   3篇
  2019年   6篇
  2018年   4篇
  2017年   10篇
  2016年   7篇
  2015年   6篇
  2014年   16篇
  2013年   36篇
  2012年   12篇
  2011年   4篇
  2010年   3篇
  2009年   4篇
  2008年   6篇
  2007年   3篇
  2006年   4篇
  2005年   4篇
  2004年   5篇
  2003年   2篇
  2002年   2篇
  2001年   2篇
  2000年   1篇
  1999年   3篇
  1997年   1篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
排序方式: 共有153条查询结果,搜索用时 15 毫秒
81.
在推力器机动技术与零燃料机动(Zero Propellant Maneuver,ZPM)技术的基础上,提出了一种新的空间站大角度姿态机动技术概念——控制力矩陀螺辅助机动(Control Momentum Gyroscopes Assisting Maneuver,CMGs AM)技术。文章给出了CMGs AM燃料最优控制问题模型,在对燃料最优解控制结构分析的基础上,采用基于改进的伪谱结点法的求解策略,求解了CMGs AM燃料最优机动问题,与仅基于推力器机动的燃料最优解和空间站上的绕特征轴的常速率机动进行了比较,结果表明相对于推力器机动,CMGs AM技术更加节省燃料,并同时实现了机动始末动量管理模式的光滑连接;相对于ZPM机动,其机动时间大大缩短,同时具有更强的抵御干扰的能力。CMGs AM技术实现了对推力器技术与零燃料机动技术的高效综合,进一步丰富了空间站大角度机动技术。  相似文献   
82.
A nation's structure and culture of civil-military relations are important and largely overlooked factors in explaining the performance of armed forces involved in complex expeditionary operations. The US model of ‘Huntingtonian’, divided civil-military structures and poor interagency cooperation, makes the US military less suited for complex expeditionary operations. British civil-military relations involve a Defence Ministry that conscientiously integrates military and civilian personnel, as well as extensive interagency cooperation and coordination. This ‘Janowitzean’, integrated form of civil-military relations makes the British military more likely to provide for the planning and implementation of comprehensive campaigns that employ and coordinate all instruments of power available to the state, as well as troops in the field displaying the flexibility and cultural and political understanding that are necessary in complex expeditionary operations.  相似文献   
83.
In this article, we consider a problem in which two suppliers can sell their respective products both individually and together as a bundle, and study the impact of bundle pricing. Four pricing models (centralized, decentralized, coop–comp, and comp–coop) are analyzed with regard to the competition formats and sequences. As one would expect, the firms are always better off when pricing decisions are centralized. However, rather surprisingly, we find that firms may be worse off if the bundle prices are set in a cooperative way; we provide analytical characterization of those instances. Numerical studies show that these insights also hold for some nonlinear demand. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
84.
In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.  相似文献   
85.
针对基于信息系统的装甲兵体系作战中的协同问题,在综合分析装甲机械化部队体系作战协同过程及信息流程的基础上,构建了基于精确性、有序性、灵活性、时效性等原则的协同效果评估指标体系,采用基于人工神经网络的多指标综合评价方法,建立基于BP神经网络的综合评价模型,并结合实证分析,利用MATLAB软件进行仿真计算,为装甲兵体系作战协同效果评估提供了较好的途径,为装甲兵指挥员更加合理地组织信息化条件下体系作战协同提供决策依据.  相似文献   
86.
ABSTRACT

While nuclear suppliers compete in markets, they simultaneously partner in other fields. This produces a delicate relationship between civilian nuclear programs and nuclear weapon proliferation. This study explores how export competition affects suppliers’ conditions of supply related to nuclear nonproliferation. We investigated three export cases (India, North Korea, and South Korea) and identified four effects that competition has on the conditions of supply related to nonproliferation. First, under highly competitive conditions, suppliers might hesitate to enforce the conditions of supply to avoid negotiation conflicts with recipients. Second, suppliers focus on politically and economically attractive recipients while mostly ignoring unattractive ones, perhaps allowing proliferation problems to fester out of view in marginal states. Third, suppliers can build consensus on the conditions of supply to avoid being the only party experiencing negotiation conflicts. Fourth, suppliers can constrain others from relaxing the conditions of supply to maintain economic benefits and nonproliferation norms. The first two effects accelerate proliferation while the last two promote nonproliferation. Although the extent of these effects can vary with changes in nonproliferation norms, they can contribute to our understanding of the relationship between nonproliferation and civilian nuclear programs.  相似文献   
87.
This article analyzes the public side of the NH90 network consisting of four participating countries (Germany, France, Italy, and the Netherlands) and their industrial partners. Comparable to observations in earlier international projects in the defense sector, the development and production of the NH90 defense helicopter did not match original plans and costs estimates. On the basis of four mechanisms that were intended to facilitate the cooperation between the partnering countries (the General Memorandum of Understanding; coalition formation; the role of the central agency; and the process of vertical escalation) the question is posed whether or not there was a true alignment of national interests and “logics.” The lack of standardization, as well as program delays and issues concerning the division of the work-share, lead to the emerging alignment being characterized as “quasi-alignment” at best.  相似文献   
88.
本文旨在为舰艇编队实现多平台协同防空反导提供一种系统逻辑结构设计思路,通过提出具有三层逻辑网络的舰艇编队多平台协同防空作战系统逻辑结构,并分析三层逻辑网络的结构和功能,以及阐明三层逻辑网络间的信息传递逻辑关系,从而使编队内各舰艇作战系统网络化连接,实现了编队协同防空反导,最大限度地发挥了编队兵力兵器的整体防空作战能力。  相似文献   
89.
针对自由漂浮空间机器人在关节故障情况下关节锁定位置的辨识问题,根据其线动量守恒和角动量守恒特性,建立了关节故障锁定位置辨识的误差模型,提出了利用混沌粒子群优化(CPSO)搜索关节故障位置的辨识算法。最后采用虚拟样机技术,建立了空间机器人系统的虚拟样机,对空间机器人系统进行动力学仿真,获取了运动数据,采用此数据对提出的关节故障位置辨识算法进行了有效性验证。  相似文献   
90.
在全球毒品问题继续蔓延的趋势下,海峡两岸跨境毒品犯罪愈演愈烈。要有效遏制毒品犯罪给海峡两岸社会治安带来的危害,海峡两岸的警察机关应不断完善跨境追逃合作机制、犯罪资产追缴协助机制、调查取证协助机制,健全毒品犯罪情报交流机制,构建区际“控制下交付”合作机制,逐步拓宽打击跨境毒品犯罪警务合作渠道,以有效遏制海峡两岸毒品犯罪的发展蔓延。  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