全文获取类型
收费全文 | 488篇 |
免费 | 12篇 |
专业分类
500篇 |
出版年
2021年 | 11篇 |
2019年 | 20篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 95篇 |
2011年 | 5篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 6篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 15篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1992年 | 4篇 |
1991年 | 14篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1973年 | 12篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有500条查询结果,搜索用时 6 毫秒
181.
We consider parallel‐machine scheduling with a common server and job preemption to minimize the makespan. While the non‐preemptive version of the problem is strongly NP‐hard, the complexity status of the preemptive version has remained open. We show that the preemptive version is NP‐hard even if there is a fixed number of machines. We give a pseudo‐polynomial time algorithm to solve the case with two machines. We show that the case with an arbitrary number of machines is unary NP‐hard, analyze the performance ratios of some natural heuristic algorithms, and present several solvable special cases. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 388–398, 2017 相似文献
182.
183.
Målfrid Braut-Hegghammer 《The Nonproliferation Review》2013,20(1):17-34
Decisionmaking processes leading to the acquisition of nuclear weapons by democratic states have served as the basis for theories about nuclear proliferation. In contrast, less is known about how a totalitarian regime responds to immense external pressure to abolish unconventional weapons it considers crucial for its security and survival. This article will analyze how we can explain Iraq's behavior after the passing of Resolution 1441 and during the United Nations inspections in 2002–2003. 相似文献
184.
185.
186.
In this article, a distribution system is studied where the sum of transportation and inventory costs is to be minimized. The inventory holding cost is assumed to be the same for all retailers. A fixed partition (FP) periodic policy is proposed with tight asymptotic worst‐case performance of 3/2 with respect to the best possible policy. This bound cannot be improved in the class of FP periodic policies. In partition‐based PB policies, the retailers are first partitioned into sets and then the sets are grouped in such a way that sets of retailers within a group are served together at selected times. A PB periodic, policy is presented with tight worst‐case asymptotic performance of with respect to the best possible policy. This latter performance improves the worst‐case asymptotic performance of of the previously best known policy for this problem. We also show that the proposed PB periodic policy has the best worst‐case asymptotic performance within the class of PB policies. Finally, practical heuristics inspired by the analyzed policies are designed and tested. The asymptotic worst–case performances of the heuristics are shown to be the same of those of the analyzed policies. Computational results show that the heuristics suggested are less than 6.4% on average from a lower bound on the optimal cost when 50 or more retailers are involved. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 00: 000–000, 2013 相似文献
187.
Colin M. Fleming 《战略研究杂志》2013,36(2):213-241
Over the last 18 years or so, much of the debate about modern warfare has been about whether it should be described as ‘old’ or ‘new’. However, there has not been a definitive answer as to which best reflects war in the modern world. Increasingly, the alternative arguments are polarised into opposing camps. Indeed, it would be fair to say that there is little in the way of debate at all. By revaluating the strengths and weaknesses of each argument, this paper aims to reinvigorate that discussion by examining whether changes in the way we understand war are really required. Finding that the ideas are not in fact mutually exclusive, it suggests that future research could benefit from a combined approach. 相似文献
188.
NJUNGA M MULIKITA 《African Security Review》2013,22(4):105-115
This article argues that whereas the waves of democratization which enveloped the continent in the early 1990s following the collapse of Eastern European one-party socialism genera ted expectations of a ‘new dawn’ for ‘good governance’ and sustainable human development on the continent, one wave after another appears to have suffered serious setbacks. Indeed, a decade later, some of the most articulate pro-democracy leaders, who came into office on the crest of the democratic waves of the 1990s have sought to manipulate their countries' constitutions in order to perpetuate their presidential tenure. Such undemocratic behaviour will only fuel speculation in the industrialized world that the New Partnership for Africa's Development is just another decorative blue-print drawn up by beleaguered African despots in order to obtain new resource inflows at a time the international community under the hegemonic leadership of the Uni ted States will be wholly preoccupied with rebuilding post-Saddam Iraq and the Israeli-Palestinian roadmap. 相似文献
189.
This paper examines whether non-lethal weapons (NLWs) enhance the capability of the US armed forces to conduct irregular warfare (IW) operations. With expectations that the operational environment will only continue to become more complex in the future, NLWs may reduce the level of violence received, as well as dispensed, by US forces while performing tasks in the IW spectrum. We argue that NLWs increase the ability of US forces to address the long tail of warfare and their deployment should be increased in the near term. 相似文献
190.
Andrew M. Francis 《Defence and Peace Economics》2013,24(5):395-411
This paper explores the relationship between human capital and international conflict. In theory, human capital may increase the opportunity cost of military service and the economic cost of injury and loss of life in combat; it may decrease the benefits of conflict as human capital cannot be easily appropriated or transferred; it may affect societal norms toward peace and war; and it may alter military productivity through new technology and complementarities between military technology and personnel. Using a panel of politically relevant dyads, I find robust empirical evidence that human capital may significantly decrease the likelihood of militarized conflict between nations. In short, the findings suggest that promoting human capital‐oriented development may help to increase peace in the world. 相似文献