全文获取类型
收费全文 | 1364篇 |
免费 | 352篇 |
国内免费 | 66篇 |
专业分类
1782篇 |
出版年
2024年 | 5篇 |
2023年 | 12篇 |
2022年 | 13篇 |
2021年 | 16篇 |
2020年 | 18篇 |
2019年 | 22篇 |
2018年 | 27篇 |
2017年 | 75篇 |
2016年 | 84篇 |
2015年 | 49篇 |
2014年 | 92篇 |
2013年 | 150篇 |
2012年 | 118篇 |
2011年 | 131篇 |
2010年 | 90篇 |
2009年 | 109篇 |
2008年 | 87篇 |
2007年 | 94篇 |
2006年 | 82篇 |
2005年 | 82篇 |
2004年 | 70篇 |
2003年 | 64篇 |
2002年 | 48篇 |
2001年 | 53篇 |
2000年 | 39篇 |
1999年 | 32篇 |
1998年 | 23篇 |
1997年 | 16篇 |
1996年 | 12篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 4篇 |
排序方式: 共有1782条查询结果,搜索用时 15 毫秒
161.
162.
163.
针对复杂信号环境下雷达对抗情报侦察面临的信号分选问题,提出一种基于双站协同侦察的雷达信号分选新方法。根据不同位置雷达的脉冲信号到达两个侦察接收站的时间差不同进行信号分选。在满足误差的要求下,求解该方法的分选模糊区域,分析分选性能。调整布站,优化分选性能,提高分选准确性。理论分析和计算机仿真表明,该方法可以较好地解决制约雷达对抗情报获取中的信号分选瓶颈难题。 相似文献
164.
随着火炮武器系统的发展,火炮所配属的弹药类型越来越多,针对不同目标选择合适的弹药以达到最佳作战效能具有重要意义。首先,按照"最大化对敌火力效果、最小化附带损伤,最小化费用"的原则,分析了随伴支援炮兵弹药选择模型要考虑的决策指标,包括毁伤比、压制比、非敌伤亡率、安全距离、费用。建立了决策指标的效用函数,在此基础上建立了整体的决策指标,对决策指标的权重系数进行了分析探讨。最后用实例证明该方法是一种有效综合各类因素的弹药选择方法,能够很好地解决弹药选择问题。 相似文献
165.
166.
167.
针对网络攻防环境中防御方以提高系统生存能力为目的所进行的最优生存防御策略的选取问题,提出了一种基于完全信息动态博弈理论的生存防御策略优化配置算法。将恶意攻击方、故障意外事件及防御方作为博弈的参与人,提出了一种混合战略模式下的三方动态博弈模型,对博弈的主要信息要素进行了说明,以混合战略纳什均衡理论为基础,将原纳什均衡条件式的表达式转化为可计算数值结果的表达式,并据此增加了近似的概念,最后,将提出的模型和近似纳什均衡求解算法应用到一个网络实例中,结果证明了模型和算法的可行性和有效性。 相似文献
168.
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
169.
A. Garnaev 《海军后勤学研究》2007,54(1):109-114
This paper deals with a two searchers game and it investigates the problem of how the possibility of finding a hidden object simultaneously by players influences their behavior. Namely, we consider the following two‐sided allocation non‐zero‐sum game on an integer interval [1,n]. Two teams (Player 1 and 2) want to find an immobile object (say, a treasure) hidden at one of n points. Each point i ∈ [1,n] is characterized by a detection parameter λi (μi) for Player 1 (Player 2) such that pi(1 ? exp(?λixi)) (pi(1 ? exp(?μiyi))) is the probability that Player 1 (Player 2) discovers the hidden object with amount of search effort xi (yi) applied at point i where pi ∈ (0,1) is the probability that the object is hidden at point i. Player 1 (Player 2) undertakes the search by allocating the total amount of effort X(Y). The payoff for Player 1 (Player 2) is 1 if he detects the object but his opponent does not. If both players detect the object they can share it proportionally and even can pay some share to an umpire who takes care that the players do not cheat each other, namely Player 1 gets q1 and Player 2 gets q2 where q1 + q2 ≤ 1. The Nash equilibrium of this game is found and numerical examples are given. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
170.
In this article, we discuss the optimal allocation problem in a multiple stress levels life‐testing experiment when an extreme value regression model is used for statistical analysis. We derive the maximum likelihood estimators, the Fisher information, and the asymptotic variance–covariance matrix of the maximum likelihood estimators. Three optimality criteria are defined and the optimal allocation of units for two‐ and k‐stress level situations are determined. We demonstrate the efficiency of the optimal allocation of units in a multiple stress levels life‐testing experiment by using real experimental situations discussed earlier by McCool and Nelson and Meeker. Monte Carlo simulations are used to show that the optimality results hold for small sample sizes as well. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献