全文获取类型
收费全文 | 1765篇 |
免费 | 280篇 |
国内免费 | 138篇 |
专业分类
2183篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 19篇 |
2021年 | 38篇 |
2020年 | 49篇 |
2019年 | 29篇 |
2018年 | 51篇 |
2017年 | 87篇 |
2016年 | 72篇 |
2015年 | 54篇 |
2014年 | 155篇 |
2013年 | 174篇 |
2012年 | 126篇 |
2011年 | 170篇 |
2010年 | 119篇 |
2009年 | 156篇 |
2008年 | 113篇 |
2007年 | 111篇 |
2006年 | 108篇 |
2005年 | 102篇 |
2004年 | 96篇 |
2003年 | 68篇 |
2002年 | 58篇 |
2001年 | 50篇 |
2000年 | 27篇 |
1999年 | 22篇 |
1998年 | 27篇 |
1997年 | 9篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 15篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有2183条查询结果,搜索用时 0 毫秒
961.
962.
963.
964.
965.
In this article, we seek to understand how a capacity‐constrained seller optimally prices and schedules product shipping to customers who are heterogeneous on willingness to pay (WTP) and willingness to wait (WTW). The capacity‐constrained seller does not observe each customer's WTP and WTW and knows only the aggregate distributions of WTP and WTW. The seller's problem is modeled as an M/M/Ns queueing model with multiclass customers and multidimensional information screening. We contribute to the literature by providing an optimal and efficient algorithm. Furthermore, we numerically find that customers with a larger waiting cost enjoys a higher scheduling priority, but customers with higher valuation do not necessarily get a higher scheduling priority. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 215–227, 2015 相似文献
966.
针对反舰导弹跃升机动过程的跟踪中,过载系数未知导致跟踪模型与导弹实际运动的不匹配问题,对状态变量进行扩展,应用扩展卡尔曼滤波对过载系数实时估计,实现对跃升俯冲机动过程的跟踪。仿真结果表明,该算法可准确估计出过载系数,显著提高跟踪性能。 相似文献
967.
Anna Antczak-Barzan 《Defense & Security Analysis》2015,31(3):228-245
This article examines Poland's national potential and its international position within the European Union (EU) with respect to security issues. It presents research results based on a comparison of Poland's national potential as it relates to other EU countries, which is useful when evaluating Poland's power within the EU. The article also evaluates Poland's crisis potential, i.e. it identifies those factors that may potentially be treated as threats to national and regional security. Finally, it enables the identification of challenges to Poland's security in the second decade of the twenty-first century. The research is conducted according to a multidimensional comparative analysis, which is perceived by the author as the best available to measure a country's power despite its weaknesses. 相似文献
968.
Garrett Grochowski 《Defense & Security Analysis》2015,31(2):152-158
The USA is currently facing an increasingly diverse range of threats, including non-state actors, particularly violent extremist organizations attempting to do harm. The national leadership has made it clear that for the near future it will employ Special Operations Forces (SOF) as the tool of choice in short-duration, high-intensity operations that have more in common with the battle of Takur Ghar, than those with a larger footprint. It is critical then that the lessons of the past are learnt now and are applied before employing SOF in the future. This becomes especially important given the short lead-time in concert with the short-duration/high-intensity tempo of their operations. In the Battle of Takur Ghar, during Operation Anaconda, rigid adherence to the joint functions, especially clearer and more robust Command and Control (C2) and Intelligence, Surveillance, and Reconnaissance (ISR) in the planning and execution of Operation Anaconda would have yielded a better operational outcome and saved lives. With the benefit of hindsight, many things could have been done differently, but several key issues stand out. The C2 structure must include all components from the outset to synchronize effects and rapidly re-task ISR. There must be multiple communications redundancies and adequate bandwidth. Finally, all SOF, conventional and interagency capabilities must be synchronized under one task force commander with a sufficiently robust C2 infrastructure to direct the entire effort. As our nation calls on SOF at an ever-increasing rate, we must take those lessons learned and apply them to future operations. 相似文献
969.
采用先进测试系统,对氮化铅、硝化棉、梯恩梯和黑索金火炸药静电感度分别进行了定性测量和定量测量,得出了相对静电感度值和实际静电感度值,并对其进行了对比分析。 相似文献
970.
Dr. Ir. F.J. Sluiman 《海军后勤学研究》2017,64(3):225-248
A transit vessel traffic scheduling algorithm has been developed to limit the negative effects on cargo volume throughput in two‐way waterways where separation distances between transiting vessels must be maintained and passage restrictions may hold. It runs in time that is polynomial in the number of ships involved in the computation and finds schedules which increase the utilization of waterways. Three examples illustrate its use. The first example is situated in the Sunda Strait where the algorithm is used to enhance the safety of merchant shipping against a terrorist threat. It illustrates important features of the algorithm and demonstrates how it can be used with cross traffic. The second example is situated in the Strait of Istanbul and offers a comparison between the developed algorithm and the transit vessel scheduling algorithm of Ulusçu et al., J Navig 62 (2009), 59–77. This was done using a plausible model of the Strait of Istanbul. The third and last example shows how the algorithm can be used to schedule transit vessel traffic in two‐way waterways with junctions. This feature is especially useful in congested waters with a high risk of collisions like the Inland Sea of Japan. An extreme test case proves that the developed algorithm is a practical algorithm ready for such use. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 225–248, 2017 相似文献