全文获取类型
收费全文 | 283篇 |
免费 | 65篇 |
国内免费 | 11篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 21篇 |
2018年 | 13篇 |
2017年 | 34篇 |
2016年 | 24篇 |
2015年 | 16篇 |
2014年 | 29篇 |
2013年 | 44篇 |
2012年 | 20篇 |
2011年 | 13篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 12篇 |
2004年 | 18篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有359条查询结果,搜索用时 171 毫秒
61.
We consider a firm which faces a Poisson customer demand and uses a base‐stock policy to replenish its inventories from an outside supplier with a fixed lead time. The firm can use a preorder strategy which allows the customers to place their orders before their actual need. The time from a customer's order until the date a product is actually needed is called commitment lead time. The firm pays a commitment cost which is strictly increasing and convex in the length of the commitment lead time. For such a system, we prove the optimality of bang‐bang and all‐or‐nothing policies for the commitment lead time and the base‐stock policy, respectively. We study the case where the commitment cost is linear in the length of the commitment lead time in detail. We show that there exists a unit commitment cost threshold which dictates the optimality of either a buy‐to‐order (BTO) or a buy‐to‐stock strategy. The unit commitment cost threshold is increasing in the unit holding and backordering costs and decreasing in the mean lead time demand. We determine the conditions on the unit commitment cost for profitability of the BTO strategy and study the case with a compound Poisson customer demand. 相似文献
62.
Thomas Waldman 《Defence Studies》2019,19(1):85-105
This paper explores the notion that US efforts to evade the political costs of war paradoxically contribute to the subsequent exacerbation of costs over time. Leaders seek to purchase political capital in the short term by limiting the costs and requirements of military operations, but in doing so cause strategic and political liabilities to mount in the long run. While identification of such behaviour is not new, insufficient attention has been devoted to explaining its causes, dynamics, and manifestations in relation to key decisions on and in war. Evidence derived from studies of recent American discretionary campaigns is analysed to advance an argument with respect to this pattern of self-defeating strategic behaviour. 相似文献
63.
Buying off the shelf procurements (OTS) has become an important part of the national acquisition strategy in several countries, and this paper seeks to bring empirical evidence on OTS as the preferred acquisition strategy by use of data from 2015 to 2022 investment portfolio of the Norwegian Armed Forces. We develop definitions for three categories of procurement – OTS, modified OTS and development projects – as well as a method to classify projects into these categories. Our first finding is that the characteristics of OTS projects correspond to modified OTS and development projects. Our second finding indicates that OTS projects perform better when it comes to the completion of projects according to the initial schedule, compared to development projects. 相似文献
64.
65.
66.
随着美国揭开第三次"抵消战略"重点发展对象的面纱,研发"颠覆性技术"已成为主要军事大国获得技术优势的手段。当前世界新一轮科技革命、产业革命、军事革命交织并行,给颠覆性技术提供了难得的良好机遇。但当我们看见颠覆性技术引领时代新型武器装备潮流发展的同时,也应理性看待其背后潜藏的风险。通过概述总结颠覆性技术研究现状,分析其推动的科技内生性变革,从本质上对其进行理性认知。研究表明,发展颠覆性技术必须积极作为,谨慎对待。 相似文献
67.
本文提出了一个用于消除空间杆梁结构有限元模型中的无刚度“奇点”的元素及相应的刚度矩阵计算公式。在无刚度“奇点”出现处以此元素替代拉压杆元,可使空间杆梁结构模型中的无刚度“奇点”消失,能够在不增加整个计算模型自由度的情况下提高计算结果的精度。在微型计算机上运用全部三维12自由度梁单元计算模型、拉压杆元——加弹性支座计算模型和本文提出的计算模型对某型军舰的桅杆结构进行了实例计算比较。计算结果表明:用本文方法得到的应力值、位移值与全部三维12自由度梁单元模型的计算结果符合良好。 相似文献
68.
69.
本文先用面积法求出线式巡逻潜艇发现目标的概率,然后对潜艇发现目标距离作了分析。在此基础上,建立了潜艇线式巡逻的矩阵对策模型,并用计算机对此模型进行求解,得到了潜艇线式巡逻的最佳对策。最后,对最佳对策作了讨论。本文建立的矩阵对策模型和求得的结果以及求解方法可为组织潜艇进行线式巡逻提供决策的科学依据。 相似文献
70.