全文获取类型
收费全文 | 401篇 |
免费 | 133篇 |
国内免费 | 25篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 18篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 18篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 27篇 |
2013年 | 26篇 |
2012年 | 32篇 |
2011年 | 30篇 |
2010年 | 28篇 |
2009年 | 29篇 |
2008年 | 30篇 |
2007年 | 20篇 |
2006年 | 32篇 |
2005年 | 25篇 |
2004年 | 27篇 |
2003年 | 19篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 17篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 15篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 1篇 |
排序方式: 共有559条查询结果,搜索用时 843 毫秒
481.
Jon Strandquist 《Small Wars & Insurgencies》2017,28(2):337-360
Foreign policy program transfer, the shifting of implementation responsibility for a foreign policy program from one organization to another, is a ubiquitous, yet under-studied, counterinsurgency phenomenon. This article conceptually develops program transfer as an important object of study; analyzes, using archival sources, an empirical case of program transfer, Operation Switchback, drawn from US counterinsurgency practice in South Vietnam; and formulates two preliminary theoretical claims related to program transfer: (1) transferred programs will tend to be altered in accordance with the characteristics of the gaining organization, and (2) program transfer may act as a signal or early-warning indicator of foreign policy change. 相似文献
482.
将声子晶体能带理论应用于装备外壳结构设计,把装备外壳圆柱壳段设计成周期结构。基于多子结构的双协调自由界面模态综合法,计算并对比了周期圆柱壳与非周期圆柱壳对弯曲振动的衰减特性。结果表明,周期圆柱壳中有弯曲振动强衰减带隙存在,而非周期结构中则没有带隙存在。进一步研究了轴向周期复合夹层材料圆柱壳的弯曲振动特性。同样,该周期复合夹层结构中依然有弯曲振动带隙存在,且在带隙频率范围内弯曲振动传播将受到明显的抑制。最后,考虑实际装备外壳形状,研究了含周期结构圆柱段的复杂装备外壳振动特性。研究表明,经过局部周期设计的复杂装备外壳保持了带隙特性,这说明了将能带理论应用于工程实际装备外壳的振动控制具有可行性。 相似文献
483.
484.
When the US Air Force set out to acquire a new aerial tanker (the KC-X), two highly suitable alternatives were offered. What could have been a short and simple source selection turned into a prolonged embarrassment. The original selection of 100 leased KC-767s was made in May 2003. But the KC-46 is expected to be operational in 2017 – more than a decade later. Our primary purpose here is to narrate and explain key events in the KC-X program. We search for useful paradigms, based in part on the US Government being better viewed as a quarrelsome committee than a monopsonist. In addition, we consider what this case might tell us about the US defense acquisition system. 相似文献
485.
SBM是支持操作级并行的一种有效的同步机制。文中基于SBM对结点调度和barrier插入算法进行了深入的研究,提出了一套有效的开发操作级并行的方案。用一有向图G(N,A)表示指令之间的相关关系,并以结点的临界路径为关键字将结点从小到大进行排序。按照排序后的结点顺序,描述了一种分配算法,将结点分配给各处理机。同时,描述了相关结点之间的barrier插入算法。 相似文献
486.
通过对皮卡汀尼导轨和燕尾式导轨连接结构的分析,提出瞄准镜与枪械连接结构应具有的特点,即结合瞄具方便快捷、瞄具位置可调、具有自动补偿磨损机制和良好的抗冲击性能,并据此提出新的枪-瞄连接结构设计方案.同时,应用瞄准原理分析枪械上瞄准镜座的高低、方向及前后位置对射击精度和瞄准镜分划刻制的影响. 相似文献
487.
488.
于冬梅 《中国人民武装警察部队学院学报》2013,(11):77-79
通过探讨一例多元案例教学法的教学理念、设计策略、实施方法和过程,解决程序设计课程教学不能点、线、面融合,缺少培养学员设计综合应用程序能力的方法和手段,学员学习目标不明确、缺乏学习兴趣等问题,以有效提高教学效果和质量. 相似文献
489.
The electronics industry provides components and capabilities that are critical to modern defence requirements. It is anticipated that the effectiveness of both weapons systems and the command and control network that supports military operations will become increasingly dependent upon the electronics sub‐systems they employ in the future. With the ascendancy of ‘network centric warfare’, it seems certain that defence electronics will continue to grow in importance in the future, enabling far‐reaching advances in military capability and efficiency. Yet little is known about the structure, conduct, performance and competitiveness of the UK defence electronics sector as it prepares to meet the challenges ahead. This paper reports the findings of a study commissioned in 2002 by Intellect, the UK defence electronics trade association, and supported by the Department of Trade and Industry. The UK defence electronics industry is found to be a high technology, R&D‐intensive and decreasing cost industry, which is competitive in world defence markets. The UK industry faces major competitive threats in the future from established US and European firms and from potential new entrants from China, India, Israel, Singapore, South Korea and Turkey. The future competitiveness of the UK defence electronics industry will depend on maintaining both technical advantage and open access to the large US market. 相似文献
490.
Leo J. Blanken 《Defence and Peace Economics》2013,24(3):317-334
We develop a model of military technology competition among states. States can choose to introduce new military technology, mimic rivals’ level of technology, or withdraw from the contest. States can choose to implement any level of technology within their current feasible technologies. We find that states with significant technological leads should sometimes withhold new technologies, only strategically releasing them to trump rivals’ efforts. We develop the model by refining Admiral Jackie Fisher’s roughly articulated concept of ‘plunging’. We then use this refined argument to reanalyze the case of naval rivalries among European powers between the Crimean War and the First World War. Finally, we conclude by discussing the model’s implications for current US military force structure planning. 相似文献