全文获取类型
收费全文 | 768篇 |
免费 | 15篇 |
出版年
2019年 | 15篇 |
2017年 | 21篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 159篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 13篇 |
2003年 | 8篇 |
2002年 | 12篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 18篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 17篇 |
1988年 | 20篇 |
1987年 | 20篇 |
1986年 | 21篇 |
1985年 | 17篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 15篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 11篇 |
1978年 | 13篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 12篇 |
1973年 | 12篇 |
1972年 | 13篇 |
1971年 | 10篇 |
1970年 | 12篇 |
1969年 | 10篇 |
1968年 | 9篇 |
1967年 | 8篇 |
排序方式: 共有783条查询结果,搜索用时 31 毫秒
91.
A complete analysis and explicit solution is presented for the problem of linear fractional programming with interval programming constraints whose matrix is of full row rank. The analysis proceeds by simple transformation to canonical form, exploitation of the Farkas-Minkowki lemma and the duality relationships which emerge from the Charnes-Cooper linear programming equivalent for general linear fractional programming. The formulations as well as the proofs and the transformations provided by our general linear fractional programming theory are here employed to provide a substantial simplification for this class of cases. The augmentation developing the explicit solution is presented, for clarity, in an algorithmic format. 相似文献
92.
93.
94.
Using a system-point (SP) method of level crossings, we derive the stationary distribution of the inventory level (stock on hand) in a continuous-review inventory system with compound Poisson demand, Erlang as well as hyperexponentially distributed lead times, and lost sales. This distribution is then used to formulate long-run average cost functions with/without a service level constraint. Some numerical results are also presented, and compared with the Hadley and Whitin heuristic. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 259–278, 1998 相似文献
95.
Estimating the performance of an automatic target recognition (ATR) system in terms of its probability of successfully identifying a target involves extensive image collection and processing, which can be very time‐consuming and expensive. Therefore, we investigate the Wald sequential test for the difference in two proportions as a sample size‐reducing alternative to ranking and selection procedures and confidence intervals. An analysis of the test parameters leads to a practical methodology for implementing the Wald test for fairly comparing two systems, based on specific experimental goals. The test is also extended with the modified, sequentially rejective Bonferroni procedure for the multiple pairwise comparison of more than two systems. Two sampling schemes for different experimental goals are also discussed. The test methodology is applied to actual data to compare different configurations of a specific ATR system, with the results demonstrating that the modified Wald sequential procedure is a useful alternative to comparing proportions with confidence intervals, particularly when data are expensive. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 357–371, 1999 相似文献
96.
97.
H. W. Kuhn 《海军后勤学研究》2005,52(1):7-21
This paper has been presented with the Best Paper Award. It will appear in print in Volume 52, No. 1, February 2005. 相似文献
98.
99.
This work presents a numerical simulation of ballistic penetration and high velocity impact behavior of plain and reinforced concrete panels. This paper is divided into two parts. The first part consists of numerical modeling of reinforced concrete panel penetrated with a spherical projectile using concrete damage plasticity (CDP) model, while the second part focuses on the comparison of CDP model and Johnson-Holmquist-2 (JH-2) damage model and their ability to describe the behavior of concrete panel under impact loads. The first and second concrete panels have dimensions of 1500 mm × 1500 mm × 150 mm and 675 mm × 675 mm × 200 mm, respectively, and are meshed using 8-node hexahedron solid elements. The impact object used in the first part is a spherical projectile of 150 mm diameter, while in the second part steel projectile of a length of 152 mm is modeled as rigid element. Failure and scabbing characteristics are studied in the first part. In the second part, the com-parison results are presented as damage contours, kinetic energy of projectile and internal energy of the concrete. The results revealed a severe fracture of the panel and high kinetic energy of the projectile using CDP model comparing to the JH-2 model. In addition, the internal energy of concrete using CDP model was found to be less comparing to the JH-2 model. 相似文献
100.
Person-borne improvised explosive devices (PBIEDs) are often used in terrorist attacks in Western countries. This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people exposed to this hazard. An explosive field test with a typical PBIED composed of a plastic explosive charge and steel nut enhancements was performed to record initial fragment behaviour, including positions, velocity, and trajectory angles. These data were used to predict the full trajectory of PBIED fragments using a probabilistic analysis. In the probabilistic analyses a probability of fatality or serious injury was computed. Based on the results presented, many practical conclusions can be drawn, for instance, regarding safe evacuation distances if a person were exposed to a suspected PBIED. 相似文献