全文获取类型
收费全文 | 769篇 |
免费 | 130篇 |
国内免费 | 159篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 17篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 9篇 |
2017年 | 55篇 |
2016年 | 79篇 |
2015年 | 35篇 |
2014年 | 65篇 |
2013年 | 41篇 |
2012年 | 77篇 |
2011年 | 76篇 |
2010年 | 37篇 |
2009年 | 85篇 |
2008年 | 75篇 |
2007年 | 59篇 |
2006年 | 85篇 |
2005年 | 62篇 |
2004年 | 35篇 |
2003年 | 31篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 3篇 |
排序方式: 共有1058条查询结果,搜索用时 15 毫秒
881.
882.
基于贴近度的机械设备技术状态综合评估方法 总被引:7,自引:0,他引:7
讨论了模糊逻辑方法应用于技术状态综合评估的问题,提出了基于贴近度概念的技术状态综合评估方法;介绍了专家系统开发时,基准状态集的建立、基准状态中特征参数的选择、特征参数归一化处理模型等关键技术;讨论了专家系统的运行方式和知识库扩充的基本步骤. 相似文献
883.
多种武器攻击下舰船电力系统生命力的模糊综合评判 总被引:2,自引:1,他引:1
应用模糊数学理论对舰船电力系统生命力进行了模糊综合评判,讨论了舰船电力系统在多种武器攻击下的模糊评估模型,并以某型舰艇的电力系统为例,通过对其子系统的模糊评估分析,得出整个电力系统的生命力指标.评估的结果说明了根据加权模糊综合评判模型,可以把模糊性很强的舰船生命力指标定量化,为电力系统设计方案选优提供依据. 相似文献
884.
通过研究“4+1”人才培养模式下学员军事基础素质培养过程,改革军事基础课程教学体系和学员队管理模式,实现军事基础教学与学员队管理的有机衔接,强化学员旅的教学管理职能,形成“三位一体”的学员军事基础素质培养模式,建立学员军事基础素质评价的指标体系。 相似文献
885.
886.
本文提出了一种基于熵值的装备维修性综合评价模型,该模型包括评价指标的熵值度量模型、装备维修信息结构图和行为控制图以及基于熵值的评价指标聚合模型等3个方面.本研究首先在分析装备维修一般过程和维修性评价内容的基础上,构建了定性指标和定量指标相结合的装备维修性评价指标体系,分析了维修任务复杂度、维修保障复杂度和基于熵值的维修... 相似文献
887.
Stephan De Spiegeleire Karlijn Jans Mischa Sibbel Khrystyna Holynska Deborah Lassche 《Defense & Security Analysis》2019,35(1):59-81
Most countries put significant amounts of time and effort in writing and issuing high-level policy documents. These are supposed to guide subsequent national defence efforts. But do they? And how do countries even try to ensure that they do? This paper reports on a benchmarking effort of how a few “best of breed” small- to medium-sized defence organisations (Australia, Canada, and New Zealand) deal with these issues. We find that most countries fail to link goals to resources and pay limited attention to specific and rigorous ex-ante or post-hoc evaluation, even when compared to their own national government-wide provisions. We do, however, observe a (modest) trend towards putting more specific goals and metrics in these documents that can be – and in a few rare cases were – tracked. The paper identifies 42 concrete policy “nuggets” – both “do’s and don’ts” – that should be of interest to most defence policy planning/analysis communities. It ends with two recommendations that are in line with recent broader (non-defence) scholarship on the policy formulation-policy implementation gap: to put more rigorous emphasis on implementation (especially on achieving desired policy effects), but to do so increasingly in more experiential (“design”) ways, rather than in industrial-age bureaucratic ones (“PPBS”-systems). 相似文献
888.
889.
890.
We introduce and study a generalization of the classic sequential testing problem, asking to identify the correct state of a given series system that consists of independent stochastic components. In this setting, costly tests are required to examine the state of individual components, which are sequentially tested until the correct system state can be uniquely identified. The goal is to propose a policy that minimizes the expected testing cost, given a‐priori probabilistic information on the stochastic nature of each individual component. Unlike the classic setting, where variables are tested one after the other, we allow multiple tests to be conducted simultaneously, at the expense of incurring an additional set‐up cost. The main contribution of this article consists in showing that the batch testing problem can be approximated in polynomial time within factor , for any fixed . In addition, we explain how, in spite of its highly nonlinear objective function, the batch testing problem can be formulated as an approximate integer program of polynomial size, while blowing up its expected cost by a factor of at most . Finally, we conduct extensive computational experiments, to demonstrate the practical effectiveness of these algorithms as well as to evaluate their limitations. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 275–286, 2016 相似文献