全文获取类型
收费全文 | 459篇 |
免费 | 136篇 |
国内免费 | 27篇 |
出版年
2024年 | 6篇 |
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 15篇 |
2019年 | 22篇 |
2018年 | 16篇 |
2017年 | 38篇 |
2016年 | 38篇 |
2015年 | 20篇 |
2014年 | 36篇 |
2013年 | 53篇 |
2012年 | 38篇 |
2011年 | 34篇 |
2010年 | 28篇 |
2009年 | 26篇 |
2008年 | 28篇 |
2007年 | 17篇 |
2006年 | 31篇 |
2005年 | 29篇 |
2004年 | 35篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 20篇 |
1999年 | 4篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
排序方式: 共有622条查询结果,搜索用时 15 毫秒
611.
612.
613.
基于常用的多带滤波器组的紧支撑性及FIFO(First-in First-out)缓存技术提出了一种具有低内存需求的通用树状多带滤波器组(Tree-structured Filter Bank,TSrS)的实现方法SBFB.该方法具有两大特点:(1)生成与全局变换法相同的子带系数,但是内存需求大大减小且仅与图像宽度及采用的TSFB相关;(2)在FIFO缓存中直接生成父子树(Parent-children Tree,PCT).基于PCT的编码器可直接对位于缓存中的PCT进行编码,而无须在SBFB与编码器之间引入中间缓存.通过分析TSFB的各分解层中的数据流,给出了样本点与子带系数之间的时序关系,并且使用该关系从数学上严格证明了SBFB的正确性. 相似文献
614.
针对高轨高价值目标护卫问题,提出了一种基于可达域覆盖的多航天器协同护卫策略。从相对运动视角对协同护卫任务进行了描述,并将威胁源多脉冲机动可达域问题建模为凸优化问题求解。在滚动优化框架下,根据动态更新的威胁源终端可达域,设计协同护卫平面及护卫点,以此为终端位置约束构建多航天器协同轨迹规划模型,生成相应护卫轨迹。仿真结果表明,所提出的可达域分析方法能够快速计算威胁源终端可达域,协同护卫策略在多个场景下均能有效阻止威胁源,且护卫成功率随护卫航天器机动能力增强而增大。 相似文献
615.
Lukas Milevski 《Defense & Security Analysis》2020,36(3):300-313
ABSTRACT The post-Cold War period nearly up to the present has been characterised as the age of liberal wars, yet key facets of the liberal guidance of war remain under appreciated. This article seeks to address this wider gap with regard to the particular concern of war termination and the fulfilment or failure of policy. First, it develops characterisations of liberal wars based on the existing literature, identifying three broad types through consideration of context—defensive versus offensive—and of political and strategic agency, particularly regarding the motives for and intents of action. Three types of liberal wars result: defensive liberal wars, offensive liberal wars with humanitarian motive and geopolitical intent, and offensive liberal wars with geopolitical motive and humanitarian intent. The article then presents one exemplary case for each liberal war with an emphasis on how liberal strategy required an illiberal ally and that ally's effect on the subsequent peace. 相似文献
616.
Richard Reid 《Small Wars & Insurgencies》2019,30(4-5):1040-1069
ABSTRACT While the study of organised violence is considered essential to understanding the history of the West, and accordingly imbued with various layers of meaning and remembrance, war is widely regarded as inimical to the modern nation in Africa and stable development more broadly. Using examples drawn from primarily from East Africa, this paper considers the ways in which warfare in the deeper (‘precolonial’) past has been framed and envisioned in recent decades, in particular by governments whose own roots lie in revolutionary armed struggle and who began life as guerrilla movements. While in some cases particular elements of the deeper past were indeed mobilised in pursuit of contemporary political goals, in many other scenarios histories of precolonial violence were beheld as problematic and unworthy of remembrance. This paper highlights the paradox and ambiguity which has attended the memory of key aspects of Africa’s deeper past. 相似文献
617.
James J. Wirtz 《Defense & Security Analysis》2020,36(1):88-100
ABSTRACTA call for innovation as a means to outpace the acceleration of technological change and to bolster capabilities quickly is a central theme of contemporary U.S. Naval Strategy. The need for innovation is accepted, but the integration of readily available technologies into the Fleet is slow. Innovation unfolds according to “Navy-Time,” a cycle lasting between a long-decade and thirty-years. To accelerate the innovation process in the U.S. Navy, the article offers a Concept of Operations for Innovation that outlines how a deliberate process of analysis, weaponisation and integration can move new ideas and weapons into the Fleet in a strategically relevant time-frame. 相似文献
618.
Peter Haynes 《Defense & Security Analysis》2020,36(1):101-108
ABSTRACTFor the first time in a generation, the US Navy finds itself in an era of great power competition. As US naval strategists and defense planners begin to organise materially and conceptually to confront the strategic and operational-level challenges posed by China and Russia, what should they keep in mind? What should frame their thinking? Absorbed with the day-to-day tasks associated with managing how the fleet is being built, operated, and rationalised, these busy officers and civilians seldom can step back and gain some perspective on fundamental aspects of the security environment and relate those to naval purpose. To that end, this article provides a primer on what to keep in mind and how to think in an era of maritime great power competition. 相似文献
619.
LTC Joseph Guido 《Small Wars & Insurgencies》2019,30(1):176-199
ABSTRACTIncreasing attention paid to US casualties in far-flung places such as Tongo Tongo, Niger, and headlines claiming ‘secret wars’ have fueled discussion about American military’s involvement in Africa. Though the continent has been a part of the American way of war since the beginnings of the US – consider the early combat actions of US Marines in Tripoli –, current African conflicts are challenging our understanding of war and approaches to winning it. This article examines the ways America seeks to achieve its ends in Africa with a particular focus upon the last 10 years of US counter-terrorism and stability operations in Niger and the Sahel Region. The author proposes unifying American, Allied, and partner efforts through a strategy of Active Containment. 相似文献
620.
Jon Rahbek-Clemmensen 《Defense & Security Analysis》2019,35(4):343-361
ABSTRACTThis article examines the strategic purpose of Individual Augmentee Officers (IAOs) for junior partners in multinational military operations through an exploratory case study of Danish IAOs in Iraq and South Sudan between 2014 and 2017. IAOs are individual officers who are moved from their normal functions to be seconded to other units of the armed forces of their own or another country or an international institution. The study concludes that IAOs function as strategically important, yet not necessarily indispensable, supplements to military contingents in several ways: making tangible contributions to the overall mission (contributing), gaining access to information, knowledge, and experience (learning), and lobbying decision-making processes within mission headquarters (lobbying). The usefulness of IAOs depends on whether the junior partner has specific interests and a significant presence in the theatre and whether the mission is conducted as a UN mission, a NATO mission, or an ad hoc coalition. 相似文献