全文获取类型
收费全文 | 1261篇 |
免费 | 543篇 |
国内免费 | 127篇 |
出版年
2024年 | 1篇 |
2023年 | 21篇 |
2022年 | 16篇 |
2021年 | 29篇 |
2020年 | 39篇 |
2019年 | 28篇 |
2018年 | 21篇 |
2017年 | 97篇 |
2016年 | 103篇 |
2015年 | 84篇 |
2014年 | 108篇 |
2013年 | 110篇 |
2012年 | 111篇 |
2011年 | 84篇 |
2010年 | 69篇 |
2009年 | 128篇 |
2008年 | 91篇 |
2007年 | 101篇 |
2006年 | 106篇 |
2005年 | 88篇 |
2004年 | 83篇 |
2003年 | 55篇 |
2002年 | 50篇 |
2001年 | 51篇 |
2000年 | 41篇 |
1999年 | 31篇 |
1998年 | 26篇 |
1997年 | 27篇 |
1996年 | 20篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 20篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 20篇 |
1989年 | 11篇 |
1988年 | 1篇 |
排序方式: 共有1931条查询结果,搜索用时 3 毫秒
51.
52.
In many practical multiserver queueing systems, servers not only serve randomly arriving customers but also work on the secondary jobs with infinite backlog during their idle time. In this paper, we propose a c‐server model with a two‐threshold policy, denoted by (e d), to evaluate the performance of this class of systems. With such a policy, when the number of idle servers has reached d (<c), then e (<d) idle agents will process secondary jobs. These e servers keep working on the secondary jobs until they find waiting customers exist in the system at a secondary job completion instant. Using the matrix analytic method, we obtain the stationary performance measures for evaluating different (e, d) policies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007. 相似文献
53.
In this paper we consider the capacitated multi‐facility Weber problem with the Euclidean, squared Euclidean, and ?p‐distances. This problem is concerned with locating m capacitated facilities in the Euclidean plane to satisfy the demand of n customers with the minimum total transportation cost. The demand and location of each customer are known a priori and the transportation cost between customers and facilities is proportional to the distance between them. We first present a mixed integer linear programming approximation of the problem. We then propose new heuristic solution methods based on this approximation. Computational results on benchmark instances indicate that the new methods are both accurate and efficient. © 2006 Wiley Periodicals, Inc. Naval Research Logistics 2006 相似文献
54.
We consider the infinite horizon serial inventory system with both average cost and discounted cost criteria. The optimal echelon base‐stock levels are obtained in terms of only probability distributions of leadtime demands. This analysis yields a novel approach for developing bounds and heuristics for optimal inventory control polices. In addition to deriving the known bounds in literature, we develop several new upper bounds for both average cost and discounted cost models. Numerical studies show that the bounds and heuristic are very close to optimal.© 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
55.
MUSIC方法是空间谱估计中经典的子空间方法。提出了一种构造参考信号的预处理模型,提出了一种适合于MUSIC方法的多级维纳滤波结构。新方法避免了采样数据二阶统计的特征值分解,降低了运算量。仿真结果证明了方法的有效性。 相似文献
56.
57.
58.
59.
60.
In this paper we present a new combinatorial problem, called minmax multidimensional knapsack problem (MKP), motivated by a military logistics problem. The logistics problem is a two‐period, two‐level, chance‐constrained problem with recourse. We show that the MKP is NP‐hard and develop a practically efficient combinatorial algorithm for solving it. We also show that under some reasonable assumptions regarding the operational setting of the logistics problem, the chance‐constrained optimization problem is decomposable into a series of MKPs that are solved separately. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献