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   2851篇
  免费   554篇
  国内免费   368篇
  2024年   5篇
  2023年   6篇
  2022年   18篇
  2021年   38篇
  2020年   37篇
  2019年   33篇
  2018年   37篇
  2017年   121篇
  2016年   149篇
  2015年   80篇
  2014年   187篇
  2013年   149篇
  2012年   201篇
  2011年   207篇
  2010年   128篇
  2009年   225篇
  2008年   191篇
  2007年   190篇
  2006年   242篇
  2005年   216篇
  2004年   193篇
  2003年   137篇
  2002年   118篇
  2001年   129篇
  2000年   87篇
  1999年   101篇
  1998年   88篇
  1997年   72篇
  1996年   68篇
  1995年   58篇
  1994年   80篇
  1993年   50篇
  1992年   43篇
  1991年   40篇
  1990年   25篇
  1989年   15篇
  1988年   6篇
  1987年   3篇
排序方式: 共有3773条查询结果,搜索用时 31 毫秒
971.
介绍了数据仓库和数据挖掘的概念、数据挖掘的过程和方法,简单分析了现代战争中信息处理的特点和需求,阐述了数据挖掘在军事指挥控制系统中的应用必要性,提出了军事应用中数据挖掘系统的层次体系结构,并针对该层次体系结构进一步提出了指挥控制系统中数据挖掘技术的应用模型.  相似文献   
972.
针对协同性联合作战向一体化联合作战转变对作战指挥产生的影响,在正确定位指挥信息流通体系的基础上,从一体化联合作战的本质特征及对指挥信息流通体系的影响出发,设计了基本作战单元指挥信息输入、输出模型,并通过将作战体系区分为四类模块,得出了指挥信息流通体系的逻辑结构.  相似文献   
973.
Burn-in is the preconditioning of assemblies and the accelerated power-on tests performed on equipment subject to temperature, vibration, voltage, radiation, load, corrosion, and humidity. Burn-in techniques are widely applied to integrated circuits (IC) to enhance the component and system reliability. However, reliability prediction by burn-in at the component level, such as the one using the military (e.g., MIL-STD-280A, 756B, 217E [23–25]) and the industrial standards (e.g., the JEDEC standards), is usually not consistent with the field observations. Here, we propose system burn-in, which can remove many of the residual defects left from component and subsystem burn-in (Chien and Kuo [6]). A nonparametric model is considered because 1) the system configuration is usually very complicated, 2) the components in the system have different failure mechanisms, and 3) there is no good model for modeling incompatibility among components and subsystems (Chien and Kuo [5]; Kuo [16]). Since the cost of testing a system is high and, thus, only small samples are available, a Bayesian nonparametric approach is proposed to determine the system burn-in time. A case study using the proposed approach on MCM ASIC's shows that our model can be applied in the cases where 1) the tests and the samples are expensive, and 2) the records of previous generation of the products can provide information on the failure rate of the system under investigation. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 655–671, 1997  相似文献   
974.
本文讨论了一种小型的高压毫微秒脉冲装置。该装置可以产生幅值120kV,上升前沿陡度大于5kV/ns、脉宽100ns 的高压脉冲,并已被用作REB 加速器的触发源、高压EMP 模拟器的脉冲源和研究介质击穿特性的能源。  相似文献   
975.
Why did the United States fail to stop Israeli acquisition of nuclear weapons? Existing research argues that patrons such as the U.S. should have an easy time halting proliferation by militarily and economically vulnerable clients. Nevertheless, Israel acquired nuclear weapons with relatively little American opposition. Utilizing extensive primary source research, we argue that problematic intelligence-policy relations hindered U.S. efforts to arrest Israeli proliferation as (1) policymakers often gave mixed guidance to the intelligence community, resulting in (2) limited information on Israeli efforts that reinforced policy ambiguity. The results carry implications for understanding the dynamics of nuclear proliferation and intelligence-policy relations.  相似文献   
976.
We consider the classical problem of whether certain classes of lifetime distributions are preserved under the formation of coherent systems. Under the assumption of independent and identically distributed (i.i.d.) component lifetimes, we consider the NBUE (new better than used in expectation) and NWUE (new worse than used in expectation) classes. First, a necessary condition for a coherent system to preserve the NBUE class is given. Sufficient conditions are then obtained for systems satisfying this necessary condition. The sufficient conditions are satisfied for a collection of systems which includes all parallel systems, but the collection is shown to be strictly larger. We also prove that no coherent system preserves the NWUE class. As byproducts of our study, we obtain the following results for the case of i.i.d. component lifetimes: (a) the DFR (decreasing failure rate) class is preserved by no coherent systems other than series systems, and (b) the IMRL (increasing mean residual life) class is not preserved by any coherent systems. Generalizations to the case of dependent component lifetimes are briefly discussed.  相似文献   
977.
This article examines contemporary modes of American warfare. It posits the concept of “vicarious warfare” as a means of capturing prominent patterns in warfighting approaches. Although rooted in long-standing traditions of military practice, vicarious warfare is sufficiently novel as to be identifiable as a distinct phenomenon. The precise manifestation or combination of vicarious methods vary according to the specific circumstances and political contexts prevailing in different theaters. However, America’s general preference is to fight its wars by delegating tasks to proxies and limiting exposure of its own military to danger. Where U.S. forces are employed directly, this takes place largely in the shadows. Such approaches have clear attractions, offer undoubted tactical advantages, and permit successive administrations to maintain a persistent tempo of operations that evades rigorous democratic scrutiny. Yet, prominent cases and numerous studies suggest that vicarious warfare has a high potential to generate counterproductive effects and significant strategic harm.  相似文献   
978.
This article focuses on the systemic failures of the Nigerian police force to unravel the mysteries surrounding homicides in the country, along with the security, social and political implications of the ongoing trend. The article draws on documented pieces of evidence of high-profile murders, along with the causes of the upsurge in murder incidences and the inhibitive factors relating to the investigative procedures of the police. The suitability of the theory of subaltern realism and the concept of third-world security predicaments in explaining the peculiarities of Nigeria’s internal security challenges is examined, along with the problems of the legitimacy of political regimes and weak borders. There is a need for the National Assembly of Nigeria to exercise its constituted powers in reawakening and supervising investigations into dormant cases of murder through its committees on police affairs, public safety and national security. The police should check its organisational failures, which may be related to using the wrong investigative approaches, low levels of information, limited resources, corrupt practices, and pressure to obtain quick results.  相似文献   
979.
武器装备维修是武器装备维修保障的重要内容,加强装备维修绩效评价,建立科学规范的绩效评价指标体系,对深入推进装备维修工作健康发展将发挥积极作用。以平衡计分卡为研究手段,运用"5M1E"分析法,从一个内核和四个维度出发,分析武器装备维修绩效评价的影响因素,据此建立评价指标体系,并应用于装备维修管理实践,为有效提高装备维修保障效益提供有益借鉴。  相似文献   
980.
ZHANG Xiao 《国防科技》2018,39(1):005-008
党的十九大报告把军民融合发展战略作为七大国家战略之一,明确提出要"更加注重军民融合"。必须将交通领域军民融合视作整个军民融合深度发展的重要突破口,建设军民融合大交通体系。提出以新形势下军事战略方针为统揽,以军民深度融合为途径,聚焦保障军队打赢,大力推进民用交通设施工具贯彻要求;依托国家路网基础,大力推进军地交通运输网络统筹纳入;强化应战应急一体,大力推进各种交通力量建设互补衔接;着眼战略投送能力,大力推进军民交通物流体系有机结合。  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