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1.
We consider the salvo policy problem, in which there are k moments, called salvos, at which we can fire multiple missiles simultaneously at an incoming object. Each salvo is characterized by a probability pi: the hit probability of a single missile. After each salvo, we can assess whether the incoming object is still active. If it is, we fire the missiles assigned to the next salvo. In the salvo policy problem, the goal is to assign at most n missiles to salvos in order to minimize the expected number of missiles used. We consider three problem versions. In Gould's version, we have to assign all n missiles to salvos. In the Big Bomb version, a cost of B is incurred when all salvo's are unsuccessful. Finally, we consider the Quota version in which the kill probability should exceed some quota Q. We discuss the computational complexity and the approximability of these problem versions. In particular, we show that Gould's version and the Big Bomb version admit pseudopolynomial time exact algorithms and fully polynomial time approximation schemes. We also present an iterative approximation algorithm for the Quota version, and show that a related problem is NP-complete.  相似文献   
2.
We consider the problem of nonparametric multi-product dynamic pricing with unknown demand and show that the problem may be formulated as an online model-free stochastic program, which can be solved by the classical Kiefer-Wolfowitz stochastic approximation (KWSA) algorithm. We prove that the expected cumulative regret of the KWSA algorithm is bounded above by where κ1, κ2 are positive constants and T is the number of periods for any T = 1, 2, … . Therefore, the regret of the KWSA algorithm grows in the order of , which achieves the lower bounds known for parametric dynamic pricing problems and shows that the nonparametric problems are not necessarily more difficult to solve than the parametric ones. Numerical experiments further demonstrate the effectiveness and efficiency of our proposed KW pricing policy by comparing with some pricing policies in the literature.  相似文献   
3.
烟幕干扰技术综述   总被引:4,自引:0,他引:4  
现代战争中,面对我国重要经济目标数量多、防护力量和资源有限的现状,选择各种高效费比的防护措施才能适应我国国情。烟幕正是一种成本低、效果明显、操作简单的干扰手段。阐述了烟幕的产生、干扰原理,重点介绍了各波段的烟幕干扰材料、常用的烟幕器材及烟幕的具体应用,对重要经济目标防护工作的实际操作具有一定借鉴意义。  相似文献   
4.
Radioactive sealed sources have a long history and a much wider worldwide distribution than do weapons-usable fissile materials. This article compares the mechanisms for controlling radioactive sources with those of weapons-usable materials and makes the case for improved policy making on the safe and secure management of radioactive sources (often referred to simply as “sources”). Such sources have been widely distributed with commercial and government support to nearly every country, yet there are no legally binding, international agreements or regulations to control any aspect of their life cycle. This is problematic because some sources that are disused, abandoned, or otherwise fall out of regulatory control could be used in the form of a radiological dispersal device (RDD, or dirty bomb). An RDD could pose significant economic and psychological impacts with the potential for detrimental effects on public health. The lack of international measures to control sources is troubling for several reasons: creating an RDD is much easier than fashioning a nuclear weapon from scratch or from stolen fissile materials; given the many incidents involving diversion from regulatory control and the misuse of sources, an RDD attack would be one of the more likely scenarios; materials security for sources is generally weak and inconsistent; it is nearly impossible to determine the total amount of sources manufactured and distributed; used sources are frequently found uncontrolled and transiting borders, and penalties are light at best; the market-based supply and demand of sources facilitates their rapid and loosely regulated distribution; and the “peaceful uses” aspect of the Treaty on the Non-Proliferation of Nuclear Weapons along with norms that began developing around the time of Atoms for Peace have promoted the nearly unchecked global distribution of sources. Several immediate and long-term actions are suggested to reduce the threat posed by radiological sources.  相似文献   
5.
ABSTRACT

Nuclear disarmament is often seen as eventually requiring access to nuclear warheads or to the warhead-dismantlement process to verify that a state has not hidden weapons or weapon-materials despite promising to disarm. This article suggests this view is misplaced, and that what is needed is a verification mechanism able to provide reliable assurances of the absence of fissile materials available for use in weapons after a state has disarmed. Such a mechanism will need an initial declaration of the amount of fissile materials held by a state for all purposes, military and civilian. In a state with a nuclear arsenal awaiting elimination, this declaration would have to include materials that may not be available for verification because they are in nuclear weapons or are in other classified or proliferation-sensitive forms. This article describes a verification arrangement that does not require access to materials in weapons and in sensitive forms while still allowing checks on the overall accuracy of the declaration. Verification of the completeness and correctness of the declaration is deferred to the time when the weapons-relevant material enters the disposition process, at which point it no longer has any sensitive attributes. By removing the focus on monitoring warheads and dismantlement, this new approach could provide a more manageable path to nuclear disarmament.  相似文献   
6.
针对目前海战场信息系统的不足,引入时空数据技术对战场数据建模,并支持设计了海战场时空数据库原型系统.对系统要求的时空查询问题进行归纳,结合海战场数据特性加以分析,为后续的索引建立提供了依据.3D R-tree相较现有的其他时空索引更适用于海战场的环境,并通过扩充部分的弥补了其检索效率的不足.  相似文献   
7.
提高“两课”教学的生动性,就要在备课和讲课时,注重追求思想上的深刻、资料上的精彩和语言上的震撼与精美。力求思想深刻,内容精彩,语言精美。  相似文献   
8.
分析了航空核辐射侦察信息的时序关系,结合相关测量设备的发展现状,认为更新率应以水平定位信息为准。分析了侦察过程中定位设备的各种工作状态,指出了其最优工作状态。最后在此工作状态下依据现实可用的定位设备给出了信息更新率。  相似文献   
9.
三方物流联盟已成为现代物流发展的必由之路,通过研究重庆邮政和重庆港务集团所建立的三方物流联盟的运行和管理模式,提出了三方物流联盟的流程重组、信息衔接和组织管理模式等,研究了利用信息化集成手段对物流资源进行重组、形成具有多个核心竞争能力和更广泛用户的三方物流联盟方法.对于构筑和优化三方物流联盟、促进现代物流业深入发展具有一定借鉴作用.  相似文献   
10.
针对武器装备定型试验时如何把验前积累大量的先验信息科学合理利用,根据武器装备不同种类的验前信息,确定其分布类型并采用参数和非参数检验方法进行相容性检验,使经过预处理的验前信息能够为试验所用,并通过实例验证了该方法的科学可行性。该方法对验前信息在武器装备试验及结果评定中的应用具有一定意义。  相似文献   
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