全文获取类型
收费全文 | 481篇 |
免费 | 46篇 |
国内免费 | 64篇 |
出版年
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 18篇 |
2018年 | 22篇 |
2017年 | 34篇 |
2016年 | 33篇 |
2015年 | 24篇 |
2014年 | 39篇 |
2013年 | 90篇 |
2012年 | 37篇 |
2011年 | 36篇 |
2010年 | 15篇 |
2009年 | 27篇 |
2008年 | 17篇 |
2007年 | 32篇 |
2006年 | 46篇 |
2005年 | 30篇 |
2004年 | 19篇 |
2003年 | 13篇 |
2002年 | 8篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
排序方式: 共有591条查询结果,搜索用时 15 毫秒
241.
结合防化科研工作实际,从四个方面谈了如何在防化科研中贯彻落实科学发展观、提高自主创新能力,推动防化科研又好又快发展的初步想法。 相似文献
242.
243.
赵国烨 《中国人民武装警察部队学院学报》2007,23(3):35-37
以专业视野总结了以色列警卫工作的特点,从以色列警卫力量的职责地位、警卫措施、情报信息、选拔训练、后勤保障等方面进行了多角度的剖析,为进一步研究我国警卫理论提供借鉴。 相似文献
244.
E‐commerce platforms afford retailers unprecedented visibility into customer purchase behavior and provide an environment in which prices can be updated quickly and cheaply in response to changing market conditions. This study investigates dynamic pricing strategies for maximizing revenue in an Internet retail channel by actively learning customers' demand response to price. A general methodology is proposed for dynamically pricing information goods, as well as other nonperishable products for which inventory levels are not an essential consideration in pricing. A Bayesian model of demand uncertainty involving the Dirichlet distribution or a mixture of such distributions as a prior captures a wide range of beliefs about customer demand. We provide both analytic formulas and efficient approximation methods for updating these prior distributions after sales data have been observed. We then investigate several strategies for sequential pricing based on index functions that consider both the potential revenue and the information value of selecting prices. These strategies require a manageable amount of computation, are robust to many types of prior misspecification, and yield high revenues compared to static pricing and passive learning approaches. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
245.
The existing product line design literature devotes little attention to the effect of demand uncertainty. Due to demand uncertainty, the supply‐demand mismatch is inevitable which leads to different degrees of lost sales depending on the configuration of product lines. In this article, we adopt a stylized two‐segment setup with uncertain market sizes and illustrate the interplay between two effects: risk pooling that mitigates the impact of demand uncertainty and market segmentation that facilitates consumer differentiation. Compared to downward substitution, inducing bidirectional substitution through product line decisions including quality levels and prices can yield greater risk pooling effects. However, we show that the additional benefit from the risk pooling effect cannot compensate for the reduced market segmentation effect. We demonstrate that the presence of demand uncertainty can reduce the benefit of market segmentation and therefore the length of product lines in terms of the difference between products. We also propose three heuristics that separate product line and production decisions; each of these heuristics corresponds to one particular form of demand substitution. Our numerical studies indicate that the best of the three heuristics yields performance that is close to optimality. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 143–157, 2015 相似文献
246.
介绍了国外导弹防御系统研制和部署过程中所考虑的进攻方可能采取的几种典型对抗措施,研究分析了对抗导弹防御系统的基本方法、技术和策略。通过使用大量诱饵或假目标、减弱弹头的雷达信号特征或红外特征、隐藏弹头的真实位置,以及进行弹头机动等一种或多种组合的对抗措施,可以有效对付那些使用外大气层碰撞杀伤拦截器的导弹防御系统。 相似文献
247.
运用雷达图分析法,建立防空武器系统的作战能力评估模型,实现战斗力评估可视化。阐述了雷达图法的基本原理,建立了地面防空武器系统战斗力评估指标体系,选取了8个基本指标以实例分析的形式建立3类防空武器系统的雷达图模型,并进行定性定量分析。相对于其他综合评估方法,雷达图法既能直观地反映评估对象在各指标上的相对优劣程度,又便于对评估对象作出全局性、整体性评价,简洁、直观、精确且可操作性强。 相似文献
248.
249.
末端防御武器平台炮控系统性能的好坏直接影响首发命中率和射击反应时间等重要战技指标,在设计试验阶段,对其炮控性能进行检测是必不可少的环节。采用基于三棱锥模型的炮控性能检测方法,建立了三棱锥计算模型并进行Matlab仿真分析以及检测精度分析,从而验证了其工作原理及可行性,满足武器平台炮控性能检测的要求。 相似文献
250.
Raul Gouvea 《Defense & Security Analysis》2015,31(2):137-151
In 2015, Brazil has taken steps toward re-consolidating its domestic defense industry. In the 1980s, Brazil built a dynamic and diversified defense industry. The state-driven effort resulted in a tripod strategy, where the state, state-run companies, and their private sector became the pillars of Brazil's defense industry. Brazil developed an export-driven defense industry; where close to 80–90% of its output was exported to Latin American, African, Arab, and Asian nations. In the 1980s, Brazil became the world's fifth largest exporter of defense products and services, exporting to over 40 countries. In the 1990s and 2000s, Brazil's defense industry suffered a dramatic reduction in size, diversification, and momentum. Successions of domestic political and economic policies have relegated Brazil's once emerging defense industry to a marginal position in the global defense industry. This article analyzes future prospects, challenges, and growth strategies for Brazil's defense industry. 相似文献