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   658篇
  免费   150篇
  国内免费   20篇
  2024年   1篇
  2023年   4篇
  2022年   6篇
  2021年   11篇
  2020年   14篇
  2019年   32篇
  2018年   17篇
  2017年   53篇
  2016年   50篇
  2015年   38篇
  2014年   44篇
  2013年   107篇
  2012年   37篇
  2011年   43篇
  2010年   40篇
  2009年   41篇
  2008年   33篇
  2007年   48篇
  2006年   34篇
  2005年   29篇
  2004年   33篇
  2003年   19篇
  2002年   22篇
  2001年   20篇
  2000年   21篇
  1999年   7篇
  1998年   5篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1990年   2篇
  1988年   1篇
排序方式: 共有828条查询结果,搜索用时 234 毫秒
751.
The US Navy's audacious Maritime Strategy of the 1980s is often credited with acting as a key catalyst to the demise of the USSR. In assessing the role of strategic missile submarine “bastions” in the country's overall military strategy, the authors are skeptical of the above thesis, explaining that Moscow actually viewed deployments of Tomahawk land-attack cruise missiles on to US submarines (versus direct threats against the Soviet Navy itself) as the most alarming threat. The authors concede that the arms race played a role in the collapse of the USSR, but deny a direct connection with Soviet naval development citing the relatively minor naval proportion of overall defense spending. For the difficulties facing the fleet at the end of the Cold War, they instead blame deep systemic problems internal to the Soviet Navy.  相似文献   
752.
The idea of ‘clean’ bombs, nuclear weapons with a reduced amount of radioactive fallout resulting from their fission part, has met much ridicule since its public inauguration in 1956. Many scholars have regarded the bombs as a propaganda tool, stopping short of analyzing their role in the transformative phase of US nuclear strategy in the 1950s. This paper reexamines the clean bomb episode through 1958, shedding light upon the dynamic relationship between the development of nuclear weapons technology and the evolution of nuclear strategy from massive retaliation to flexible response. It also discusses the mechanism and momentum of nuclear weapons technology innovation until the US suspended nuclear testing in late 1958.  相似文献   
753.
We introduce a generalized orienteering problem (OP) where, as usual, a vehicle is routed from a prescribed start node, through a directed network, to a prescribed destination node, collecting rewards at each node visited, to maximize the total reward along the path. In our generalization, transit on arcs in the network and reward collection at nodes both consume a variable amount of the same limited resource. We exploit this resource trade‐off through a specialized branch‐and‐bound algorithm that relies on partial path relaxation problems that often yield tight bounds and lead to substantial pruning in the enumeration tree. We present the smuggler search problem (SSP) as an important real‐world application of our generalized OP. Numerical results show that our algorithm applied to the SSP outperforms standard mixed‐integer nonlinear programming solvers for moderate to large problem instances. We demonstrate model enhancements that allow practitioners to represent realistic search planning scenarios by accounting for multiple heterogeneous searchers and complex smuggler motion. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
754.
Accelerated life testing (ALT) is commonly used to obtain reliability information about a product in a timely manner. Several stress loading designs have been proposed and recent research interests have emerged concerning the development of equivalent ALT plans. Step‐stress ALT (SSALT) is one of the most commonly used stress loadings because it usually shortens the test duration and reduces the number of required test units. This article considers two fundamental questions when designing a SSALT and provides formal proofs in answer to each. Namely: (1) can a simple SSALT be designed so that it is equivalent to other stress loading designs? (2) when optimizing a multilevel SSALT, does it degenerate to a simple SSALT plan? The answers to both queries, under certain reasonable model assumptions, are shown to be a qualified YES. In addition, we provide an argument to support the rationale of a common practice in designing a SSALT, that is, setting the higher stress level as high as possible in a SSALT plan. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
755.
In this article, we study deterministic dynamic lot‐sizing problems with a service‐level constraint on the total number of periods in which backlogs can occur over a finite planning horizon. We give a natural mixed integer programming formulation for the single item problem (LS‐SL‐I) and study the structure of its solution. We show that an optimal solution to this problem can be found in \begin{align*}\mathcal O(n^2\kappa)\end{align*} time, where n is the planning horizon and \begin{align*}\kappa=\mathcal O(n)\end{align*} is the maximum number of periods in which demand can be backlogged. Using the proposed shortest path algorithms, we develop alternative tight extended formulations for LS‐SL‐I and one of its relaxations, which we refer to as uncapacitated lot sizing with setups for stocks and backlogs. {We show that this relaxation also appears as a substructure in a lot‐sizing problem which limits the total amount of a period's demand met from a later period, across all periods.} We report computational results that compare the natural and extended formulations on multi‐item service‐level constrained instances. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
756.
We introduce an optimal stopping problem for selling an asset when the fixed but unknown distribution of successive offers is from one of n possible distributions. The initial probabilities as to which is the true distribution are given and updated in a Bayesian manner as the successive offers are observed. After receiving an offer, the seller has to decide whether to accept the offer or continue to observe the next offer. Each time an offer is observed a fixed cost is incurred. We consider both the cases where recalling a past offer is allowed and where it is not allowed. For each case, a dynamic programming model and some heuristic policies are presented. Using simulation, the performances of the heuristic methods are evaluated and upper bounds on the optimal expected return are obtained. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
757.
The purpose of this paper is to provide a better conceptualization of insurgent strategies. Specifically, I shall examine Che Guevara's ‘Foco’ theory of insurgency, as it is one of the most theoretically popular and most pervasive strategies of insurgency currently practiced throughout the world. After briefly examining the origins, objectives, and theoretical strengths of the Foco theory (also known as the Vanguard Theory), I will argue that Guevara's theory suffers from an internal tension that I term the ‘Vanguard's Dilemma’. The significance of this dilemma creates a tension within the Vanguard Theory that can be fatal for insurgents if properly exploited by counterinsurgent operations. This paper will examine in detail this dilemma and show how it can be exploited. Given that several insurgent groups within Iraq and Afghanistan currently adhere to the Vanguard Theory of insurgency, a proper understanding of this insurgent strategy is an essential first step in the long road towards confronting and winning asymmetrical conflicts.  相似文献   
758.
This is a biographical analysis of Stepan Stebelski (‘Khrin’) and his time in the Ukrainian Insurgent Army. His military command is an example of classic insurgency tactics and strategies. He was trained in underground tactics before the Second World War, used his image very effectively during his time in the UPA, and used his knowledge of the terrain to become an exceptional enemy against Soviet and Polish authorities.  相似文献   
759.
In 1955, the New Zealand government authorised the creation of a Special Forces unit to operate with British forces in Malaya to counter a communist-inspired guerrilla insurgency. Drawing upon the operational experiences of the New Zealand SAS largely taken from the Cold War period, and underpinned by Colin Gray's Special Forces essentials of ‘economy of force’ and ‘expansion of choice’, this article will show how New Zealand's SAS is now accepted not only as a respected and relevant part of the nation's military capability, but also empowers its political decision-makers with the confidence to take on significant, and at times difficult, strategic foreign-policy choices.  相似文献   
760.
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