全文获取类型
收费全文 | 680篇 |
免费 | 221篇 |
国内免费 | 44篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 11篇 |
2018年 | 11篇 |
2017年 | 37篇 |
2016年 | 38篇 |
2015年 | 33篇 |
2014年 | 60篇 |
2013年 | 70篇 |
2012年 | 52篇 |
2011年 | 48篇 |
2010年 | 47篇 |
2009年 | 56篇 |
2008年 | 49篇 |
2007年 | 59篇 |
2006年 | 47篇 |
2005年 | 47篇 |
2004年 | 41篇 |
2003年 | 27篇 |
2002年 | 20篇 |
2001年 | 31篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 13篇 |
1994年 | 14篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 2篇 |
排序方式: 共有945条查询结果,搜索用时 343 毫秒
31.
研究了形如X'(t)∈-Ax(t)+F(t,x(t)),0≤t≤T,X(0)=x0的微分包含解的存在的局部性和整体性的结果,并在某种条件下研究了解的稳定性。 相似文献
32.
应用分离表提出了求解BOOLEAN方程的新方法,该方法的基本思想是在求解BOOLEAN方程的过程中,去掉冗余计算,使得其计算速度大大的提高。同时还研究了该方法在数字电路测试产生中的应用。 相似文献
33.
A genetic algorithm with neighborhood search for the resource‐constrained project scheduling problem
The resource‐constrained project scheduling problem (RCPSP) consists of a set of non‐preemptive activities that follow precedence relationship and consume resources. Under the limited amount of the resources, the objective of RCPSP is to find a schedule of the activities to minimize the project makespan. This article presents a new genetic algorithm (GA) by incorporating a local search strategy in GA operators. The local search strategy improves the efficiency of searching the solution space while keeping the randomness of the GA approach. Extensive numerical experiments show that the proposed GA with neighborhood search works well regarding solution quality and computational time compared with existing algorithms in the RCPSP literature, especially for the instances with a large number of activities. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011 相似文献
34.
We study a stochastic inventory model of a firm that periodically orders a product from a make‐to‐order manufacturer. Orders can be shipped by a combination of two freight modes that differ in lead‐times and costs, although orders are not allowed to cross. Placing an order as well as each use of each freight mode has a fixed and a quantity proportional cost. The decision of how to allocate units between the two freight modes utilizes information about demand during the completion of manufacturing. We derive the optimal freight mode allocation policy, and show that the optimal policy for placing orders is not an (s,S) policy in general. We provide tight bounds for the optimal policy that can be calculated by solving single period problems. Our analysis enables insights into the structure of the optimal policy specifying the conditions under which it simplifies to an (s,S) policy. We characterize the best (s,S) policy for our model, and through extensive numerical investigation show that its performance is comparable with the optimal policy in most cases. Our numerical study also sheds light on the benefits of the dual freight model over the single freight models. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011 相似文献
35.
36.
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
37.
空间环境条件对地面航天器发射和空间航天器系统运行有很大影响。为了减少空间环境对航天器的影响作用,必须重视航天器的空间环境可靠性设计、空间环境试验以及空间环境保障。提出了在航天器设计、飞行试验与运行过程中,必须考虑可能带来影响的空间环境条件因素。 相似文献
38.
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
39.
中国非传统安全面临的挑战及思考 总被引:3,自引:1,他引:2
高太存 《中国人民武装警察部队学院学报》2007,23(1):6-8
在对我国21世纪初期安全环境进行综合分析判断的基础上,重点从金融、环境、信息安全、流行疾病、人口安全等方面对中国非传统安全领域面临的挑战进行了深入的分析,探究了非传统安全因素对国家安全形势的影响,提出了有利于安全环境的几点预防性对策。 相似文献
40.
郭际伟 《中国人民武装警察部队学院学报》2007,23(5):89-91
军人伤亡保险作为军人保险制度的重要组成部分,其经济补偿功能已经被广大官兵逐渐认可。但作为分散军人职业风险的特定机制,其作用并未被充分开发出来,主要表现在较低的补偿水平等方面。因此,应充分借鉴国内外的相关经验,扬长避短,以充分发挥军人伤亡保险的作用。 相似文献