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   5917篇
  免费   104篇
  国内免费   63篇
  6084篇
  2025年   16篇
  2024年   22篇
  2023年   52篇
  2022年   42篇
  2021年   71篇
  2020年   58篇
  2019年   98篇
  2018年   82篇
  2017年   181篇
  2016年   225篇
  2015年   134篇
  2014年   345篇
  2013年   349篇
  2012年   318篇
  2011年   370篇
  2010年   276篇
  2009年   371篇
  2008年   308篇
  2007年   326篇
  2006年   354篇
  2005年   333篇
  2004年   290篇
  2003年   219篇
  2002年   168篇
  2001年   168篇
  2000年   113篇
  1999年   122篇
  1998年   102篇
  1997年   90篇
  1996年   85篇
  1995年   68篇
  1994年   74篇
  1993年   54篇
  1992年   60篇
  1991年   52篇
  1990年   49篇
  1989年   23篇
  1988年   12篇
  1987年   3篇
  1975年   1篇
排序方式: 共有6084条查询结果,搜索用时 0 毫秒
991.
    
Africa and for that matter the Gulf of Guinea cannot be indifferent to the global energy politics of the 21st century. The increasing importance of the region has attracted major actors in the energy sector. The competing interests of these actors are played out in various forms. This heightened interest in the region, especially with the discovery of oil in huge commercial quantities, has brought the importance of the area into focus in global oil politics. This paper looks at the importance of the region in light of the huge energy potentials of the Gulf of Guinea and how the institution of proper governance systems could serve as an important factor in ensuring the proper management of the resource.  相似文献   
992.
The Sri Lankan Civil War (1983–2009) is regarded as a violent reflection of deepening divides along political and ethnic lines. During this civil war the Sri Lankan Government and its security forces have been implicated in unlawful killings carried out in a pervasive manner against civilians, whilst at the same time specifically targeting ethnic Tamils, humanitarian workers and journalists. The human rights of all citizens suffered as a result and ultimately led to the weakening of the rule of law. With the end of the civil war, the Sri Lankan Government has made little progress in providing accountability for wartime abuses. Its absence of and reluctance to ensure justice is seen as a logical culmination of decades of impunity. The importance of acknowledging historical behaviour and taking accountability for past violations will be discussed. In an analysis for paving the way to a new democracy in Sri Lanka, the main outcomes of this article are calls for accountability arising out of the government’s actions during the war; an investigation into the present state of human rights, the rule of law and finally; an examination into the political solution going forward to ensure a process of reconciliation and peaceful co-existence.  相似文献   
993.
为探索信息化作战中指挥控制关键因素,提出改进作战指挥体制的对策措施,采用系统动力学理论,对协同决策的结构、参与者和信息反馈关系等关键因素进行了分析,在此基础上构建了基于系统动力学的协同决策模型并进行了模拟仿真。结果表明,增加指挥控制机构之间的信息共享可以有效提升协同决策的效率,为建立协同决策指挥控制体制提供了借鉴意义。  相似文献   
994.
针对器材保障现状,运用数据挖掘技术,探索器材保障决策支持问题.设计了器材保障决策支持系统中数据挖掘应用的解决方案,该方案包括了项目规划和应用设计,并以器材平时消耗预测为例,运用多元回归模型算,法进行了挖掘实现.数据挖掘为保障决策提供了更加丰富和科学的信息,可以较好地满足器材保障决策支持的需要.  相似文献   
995.
为对遮弹层防护性能进行综合评价,建立了遮弹层防护性能评价指标体系,采用多对象模糊综合评价和加权多层次灰色关联评价相结合的方法.得到了遮弹层防护性能的二级模糊灰色关联评价模型,并对五种遮弹层的防护性能进行了评估.结果表明,综合考虑直接成本、施工条件、伪装性能等因素,刚玉块石混凝土遮弹层防护性能最佳.该模型为遮弹层防护能力综合评估提供了理论依据.  相似文献   
996.
    
An area defense consists of several groups that act independently, i.e., do not communicate with each other. Each group has a fixed number of defenders and a controller that allocates these defenders optimally against the individual attackers comprising an attack. We analyze the effectiveness of this partially coordinated defense against a simultaneous attack of known size in which all attackers are considered to be equally lethal. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2005.  相似文献   
997.
    
We consider a make‐to‐order production–distribution system with one supplier and one or more customers. A set of orders with due dates needs to be processed by the supplier and delivered to the customers upon completion. The supplier can process one order at a time without preemption. Each customer is at a distinct location and only orders from the same customer can be batched together for delivery. Each delivery shipment has a capacity limit and incurs a distribution cost. The problem is to find a joint schedule of order processing at the supplier and order delivery from the supplier to the customers that optimizes an objective function involving the maximum delivery tardiness and the total distribution cost. We first study the solvability of various cases of the problem by either providing an efficient algorithm or proving the intractability of the problem. We then develop a fast heuristic for the general problem. We show that the heuristic is asymptotically optimal as the number of orders goes to infinity. We also evaluate the performance of the heuristic computationally by using lower bounds obtained by a column generation approach. Our results indicate that the heuristic is capable of generating near optimal solutions quickly. Finally, we study the value of production–distribution integration by comparing our integrated approach with two sequential approaches where scheduling decisions for order processing are made first, followed by order delivery decisions, with no or only partial integration of the two decisions. We show that in many cases, the integrated approach performs significantly better than the sequential approaches. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005  相似文献   
998.
武器系统采购费与维修费权衡的依据分析   总被引:4,自引:2,他引:2  
根据武器系统寿命周期费用的理论和方法,建立了系统的费用模型,依据数学分析和优化理论,在已知可用武器系统目标数的前提下,建立了费用优化条件,确定了采购费与维修费的比例限值,用以确定武器系统采购费和维修费的最优比例,从而对系统方案确定的权衡分析提供量化依据.  相似文献   
999.
对信息优势进行了简要说明,通过分析信息优势下潜艇鱼雷武器系统的系统组成及其作战过程,得出信息优势影响系统作战效能的主要因素.采用WSEIAC效能评估模型对系统作战效能进行评估,并用影响度的方法分析了信息优势的影响,最后,通过一个算例给出了评估结果和影响度分析结果,即在具备信息优势的情形下,潜艇鱼雷武器系统的作战效能得到大大提高.  相似文献   
1000.
弹炮结合防空武器系统机动生存能力模型研究   总被引:1,自引:0,他引:1  
从弹炮结合防空武器系统通过机动作战提高生存能力的角度出发,结合防空武器系统机动作战过程中的战术背景,提取了该过程中决定防空武器系统生存能力的决定性要素,然后分析了该过程中影响防空武器系统生存能力的总机动时间、被发现概率、抗击成功率、被毁伤概率等各项指标的特点,在此基础上建立了用于研究该过程的数学模型,最后给出实例进行了仿真计算,通过对计算结果的分析,证明了该模型的有效性,从而为防空兵机动作战模拟提供了一定的参考.  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