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   331篇
  免费   126篇
  国内免费   24篇
  2024年   1篇
  2022年   3篇
  2021年   14篇
  2020年   7篇
  2019年   6篇
  2018年   4篇
  2017年   17篇
  2016年   25篇
  2015年   13篇
  2014年   24篇
  2013年   34篇
  2012年   22篇
  2011年   24篇
  2010年   18篇
  2009年   28篇
  2008年   32篇
  2007年   27篇
  2006年   20篇
  2005年   27篇
  2004年   15篇
  2003年   17篇
  2002年   15篇
  2001年   13篇
  2000年   5篇
  1999年   10篇
  1998年   12篇
  1997年   6篇
  1996年   4篇
  1995年   2篇
  1994年   5篇
  1993年   5篇
  1992年   2篇
  1991年   4篇
  1990年   18篇
  1989年   2篇
排序方式: 共有481条查询结果,搜索用时 78 毫秒
401.
依据中远程空空导弹武器平台系统的战术指标,建立了中远程空空导弹武器平台系统的效能评价体系.对ADC扩展模型中的人为因素K进行了修正,在能力矩阵C中增加对载机生存能力和信息支持能力的体现.在此基础上给出了修正扩展模型下的系统效能,计算了在原始ADC模型下的系统效能,并对两种模型下的效能差异进行了比较.  相似文献   
402.
军用飞机的效能与费用是两个相互制约的因素,对两者进行科学合理的综合评估,对于军用飞机的发展和使用有着很重要的意义。在分析综合效能/费用的基本评估指标基础上,提出了在军用飞机全寿命周期综合效能/费用评估指标,重点对作战使用阶段的最佳效能/费用进行评估分析,最后给出结论。  相似文献   
403.
This article uses captured Iraqi state records to examine Saddam Hussein's reaction to US arms to sales to Iran during the Iran–Iraq War (the Iran/Contra scandal). These records show that ‘Irangate’ marked a decisive departure in Saddam's relations with the United States. Irangate reinforced Saddam's preexisting suspicions of US policy, convincing him that Washington was a strategic enemy that could not be trusted. Saddam concealed his anger to preserve a working relationship with the Reagan administration, but this episode nevertheless cemented his negative views of the United States and forged a legacy of hostility and mistrust that would inform his strategic calculus for years to come.  相似文献   
404.
This article is devoted to the study of an M/G/1 queue with a particular vacation discipline. The server is due to take a vacation as soon as it has served exactly N customers since the end of the previous vacation. N may be either a constant or a random variable. If the system becomes empty before the server has served N customers, then it stays idle until the next customer arrival. Such a vacation discipline arises, for example, in production systems and in order picking in warehouses. We determine the joint transform of the length of a visit period and the number of customers in the system at the end of that period. We also derive the generating function of the number of customers at a random instant, and the Laplace–Stieltjes transform of the delay of a customer. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 646–658, 2015  相似文献   
405.
根据海战仿真对潜艇作战仿真的多分辨率需求,采用聚合与解聚的方法对潜艇智能兵力作战行为模型进行层次划分和结构化设计,利用J2EE/EJB组件建模技术构建了潜艇智能兵力作战行为仿真组件模型,通过行为决策模型构建和多分辨率接口设计,对兵力作战任务进行解聚和聚合,仿真不同分辨率下的作战任务行为和作战指标,并通过任务行为决策控制参数调整实现兵力作战行为重构,满足了系统对智能兵力作战行为多分辨率建模和战法战术验证的功能需求,并有效提高了模型利用效率和可重用性。  相似文献   
406.
针对某半自动输弹机系统实际的输弹过程,提出了模糊控制系统的控制方案,根据本输弹机系统的模型设计了模糊控制参数。运用Matlab/Simulink仿真软件分别对采用模糊控制的系统和采用普通PID控制算法的系统进行仿真,得到各系统的单位阶跃响应曲线图和抗干扰信号图。对输弹机进行上炮试验,对比采用模糊控制的系统和采用普通PID控制算法的系统的实验结果,得到采用模糊算法的输弹机系统的卡膛一致性能很好的满足要求,具有一定的实践意义。  相似文献   
407.
Defense budgets in Japan have been complicated compromises from numerous inputs ‐ including threat perceptions, domestic industrial/technological base development, support for the bilateral security treaty with the United States and internal bureaucratic politics ‐ but with the fall of the former Soviet Union, the clearest justification for higher spending disappeared. Double‐digit defense spending increases that were common in the 1980s have been replaced by annual increases lower than present inflation rates, resulting in negative real growth in the country's defense budget. Domestic economic problems and consistent government pressures for smaller budgets have further slowed annual growth in total spending and have contributed to lower procurement budgets. As a result, the domestic Japanese defense industry is facing far more constrained conditions from the growth years of a decade before.

Government policymakers are examining Japan's regional security environment as well as its alliance with the United States to determine the appropriate course for the country to take in the coming years. The formal security treaty with the United States is likely to remain a major element of government positions, but other aspects of the country's overall security posture are open to debate. Perceptions of a reduced threat environment are fueling additional pressures for defense budget cuts.

The domestic defense industry seeks means to assure its survival in domestic defense markets in this constrained environment. Expansion into overseas markets to offset declining domestic markets is an option that currently is constrained by policy restrictions on arms exports. Industry is advocating re‐examination of those policies and unlike earlier years, government appears willing to respond positively but cautiously to this lobbying.  相似文献   
408.
This paper examines the short-run behaviour of migrant remittances in the face of terrorism. Using monthly data for post 9/11 terrorist attacks in Pakistan, the study finds evidence of increase in the volume of remittances sent from abroad. This increase is evident in the aggregate, as well as for the three main source regions of North America, the Persian Gulf and Europe. The positive association holds for all the top five migrant-hosting countries of Pakistan. The findings point in favour of an altruistic behaviour of migrant remittances at the macroeconomic level.  相似文献   
409.
In recent international armed conflicts private security contractors (PSCs) have played an ever increasing role and military advisors and tribunals are facing the dilemma of assessing the primary and secondary status of PSCs under international humanitarian law. In this article the misconception that PSCs are necessarily mercenaries will be dispelled. The possibility that PSCs might be categorised as combatants or civilians will then be explored. The conclusion is that where they are incorporated into the armed forces of a state, PSCs might attain combatant status. However, given that states are reluctant to formally incorporate PSCs into their armed forces, they will most likely remain essentially civilian. Their degree of participation in hostilities will determine whether they retain their immunity under international humanitarian law from attack and prosecution (as civilians) or whether they are rendered unlawful belligerents.  相似文献   
410.
为研究掺砂率对高庙子膨润土一砂混合型缓冲/回填材料液塑限的影响,利用液塑限联合测定仪进行了试验研究,并运用最小二乘法对混合物液塑限试验数据进行了分析。试验结果表明膨润土一砂混合物的可塑性、液塑限值和塑性指数均随掺砂率的增大而降低。对试验结果进行分析,得到了考虑掺砂率影响的混合物液塑限经验公式。混合物的液塑限并不是随掺砂率增大成比例降低,而是液限的实测值小于理论值,塑限的实测值大于理论值。得到的不同掺砂率的膨润土一砂混合型缓冲/回填材料液塑限试验数据可为高放废物深地质处置库建设提供科学依据。  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