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   2572篇
  免费   358篇
  国内免费   199篇
  2024年   9篇
  2023年   10篇
  2022年   14篇
  2021年   23篇
  2020年   20篇
  2019年   27篇
  2018年   24篇
  2017年   75篇
  2016年   98篇
  2015年   60篇
  2014年   212篇
  2013年   130篇
  2012年   156篇
  2011年   261篇
  2010年   201篇
  2009年   251篇
  2008年   213篇
  2007年   206篇
  2006年   136篇
  2005年   144篇
  2004年   154篇
  2003年   119篇
  2002年   86篇
  2001年   82篇
  2000年   67篇
  1999年   49篇
  1998年   42篇
  1997年   42篇
  1996年   38篇
  1995年   31篇
  1994年   36篇
  1993年   33篇
  1992年   27篇
  1991年   31篇
  1990年   9篇
  1989年   7篇
  1988年   4篇
  1987年   2篇
排序方式: 共有3129条查询结果,搜索用时 15 毫秒
911.
通信电磁环境模拟器是保障完成通信对抗装备检测与训练的重要设备。提出了一种基于任意波形发生器和嵌入式GPRS/GPS模块的远程模拟器设计方案。同时,讨论了一种模拟器的组网拓扑设计,实现了复杂信号环境生成。解决了远程通信电磁环境生成问题,具有很高的工程应用价值。  相似文献   
912.
任务分配是多UCAV协同控制的核心和有效保证,是一类复杂的多目标优化问题。针对一种扩展的混合整数线性规划(MILP)任务分配模型,通过对模型特点的分析,提出一种基于相似度的遗传退火算法解决该问题并进行仿真实验,仿真结果表明该算法具有较强的收敛性和较好的多样性,验证了改进算法解决该问题模型的有效性。  相似文献   
913.
脉冲力的瞬间作用会引起攻角和侧滑角的急剧变化,对末修弹飞行稳定性产生较大的影响.以线性化运动微分方程组为数学解析手段,对末修弹脉冲作用稳定性进行深入分析研究.数值仿真表明,采用小扰动法分析弹丸脉冲控制弹丸飞行稳定性是可行的.  相似文献   
914.
This article puts forth collection action as a unifying theme for the conference essays on arms trade, control, and production. For each of these topics, collective action failures are related to group size and group composition considerations. Other issues are also examined including the manner in which individual contributions determine the overall level of the associated collective good ‐ the so‐called aggregation technology of public supply. Based on alternative aggregation technologies, the game‐theoretic underpinnings of these arms issues are explored.  相似文献   
915.
This study models the structural sources of variation in the use of selective (discriminate) repression within 89 civil wars fought between 1981 and 2005. The severity of repressive violence is modeled as a function of the amount of territory being contested by the insurgents. This idea is operationalized using measures of the location, size, and density of insurgency violence. The analysis finds evidence that the repressive behavior of both governments and rebel groups is linked to conflict geography. Governments violate physical integrity rights more frequently and kill more civilians the greater the overall amount of territory under contestation. Rebels kill more civilians in highly dispersed insurgencies that lack a clear epicenter.  相似文献   
916.
South Asian Security and International Nuclear Order: Creating a Robust Indo-Pakistani Nuclear Arms Control Regime, by Mario Esteban Carranza. Ashgate, 2009. 208 pages, $99.95.  相似文献   
917.
For many years, non-nuclear weapons states have sought binding commitments from nuclear armed states that they would not be the victim of either the threat or use of nuclear weapons—so-called negative security assurances (NSAs). The nuclear weapon states have traditionally resisted granting such unconditional NSAs. Recent U.S. efforts to use nuclear deterrence against the acquisition and use by other states of chemical, biological and radiological weapons, however, have further exacerbated this divide. This article analyzes the historical development of NSAs and contrasts U.S. commitments not to use nuclear weapons with the empirical realities of current U.S. nuclear weapons employment doctrines. The authors conclude that NSAs are most likely to be issued as unilateral declarations and that such pledges are the worst possible manner in which to handle the issue of security assurance.  相似文献   
918.
ABSTRACT

Relations between the United States and Russia are in a prolonged downward spiral. Under these circumstances, cooperation on nuclear issues—once a reliable area of engagement even in difficult political environments—has all but completely halted. There are urgent reasons to find a way out of this situation, particularly the expiration of the New Strategic Arms Reduction Treaty in 2021. However, seemingly intractable disagreements about noncompliance with the Intermediate-range Nuclear Forces Treaty and US ballistic-missile defense, compounded by the Ukraine crisis, the conflict in Syria, and the accusations of Russian interference in the US election of 2016, threaten the future of arms control. Against this backdrop, policy makers and practitioners should identify ways to re-engage on nuclear issues now so they can be ready to implement them as soon as feasible. This article considers how the Comprehensive Nuclear-Test-Ban Treaty (CTBT) could serve as a platform for US–Russia cooperation on nuclear issues when circumstances permit. Taking into account the challenges posed by ongoing US non-ratification, it identifies a menu of CTBT-related activities short of ratification that the two countries could undertake together. It explores how joint work on this issue would advance shared US and Russian interests while helping to create the circumstances necessary for further arms-control work.  相似文献   
919.
ABSTRACT

Whereas much of the debate about the demise of the 1987 Intermediate-range Nuclear Forces (INF) Treaty has focused on the European context and Russia’s alleged treaty violations, Asia looms large in the minds of proponents of the United States’s immediate withdrawal from the treaty. For many proponents, the fast-changing military balance in Asia and China's conventionally armed missiles constitute a sufficient cause for withdrawal. What does the end of the INF Treaty bode for the US-China military balance? This article argues that, although there are some near-term benefits for the US position in the conventional military balance with China, the advantages offered by prohibited missiles are minor and can be readily substituted by extant capabilities that are compliant with the treaty. Given the negative implications of the end of the INF Treaty for the future of arms control, the costs and benefits of withdrawing from the treaty require further examination; the military balance in Asia is an unpersuasive rationale for withdrawing from an important part of the arms-control architecture.  相似文献   
920.
As the United States and Russia contemplate the next stage of nuclear arms reductions beyond the 2010 New Strategic Arms Reduction Treaty, another issue enters the agenda—that of the impact of possible deep reductions on the shape of the global nuclear balance. As the gap between the US/Russian arsenals and the arsenals of “second-tier” nuclear weapon states narrows, the familiar shape of the global balance, which remains, to a large extent, bipolar, is likely to change. The article explores the Russian approach to the relationship between further US-Russian reductions and the prospect of “nuclear multipolarity,” and assesses the relative weight of this issue in Russian arms control policy as well as the views on the two specific regional balances—the one in Europe (including UK and French nuclear weapons) and in Asia (the possible dynamic of the Russian-Chinese nuclear balance).  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