首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   602篇
  免费   24篇
  2021年   8篇
  2019年   12篇
  2018年   8篇
  2017年   15篇
  2016年   12篇
  2015年   10篇
  2014年   13篇
  2013年   95篇
  2011年   8篇
  2010年   7篇
  2009年   8篇
  2007年   7篇
  2006年   7篇
  2005年   7篇
  2004年   10篇
  2002年   11篇
  2001年   10篇
  2000年   7篇
  1999年   9篇
  1998年   10篇
  1997年   15篇
  1996年   8篇
  1995年   14篇
  1994年   15篇
  1993年   19篇
  1992年   11篇
  1991年   14篇
  1990年   7篇
  1989年   8篇
  1988年   17篇
  1987年   9篇
  1986年   8篇
  1985年   16篇
  1984年   16篇
  1983年   8篇
  1981年   10篇
  1980年   11篇
  1979年   14篇
  1978年   10篇
  1977年   10篇
  1976年   8篇
  1975年   8篇
  1974年   13篇
  1973年   7篇
  1972年   10篇
  1971年   12篇
  1970年   6篇
  1969年   7篇
  1968年   6篇
  1967年   6篇
排序方式: 共有626条查询结果,搜索用时 15 毫秒
601.
602.
In this article, we study generalizations of some of the inventory models with nonlinear costs considered by Rosling in (Oper. Res. 50 (2002) 797–809). In particular, we extend the study of both the periodic review and the compound renewal demand processes from a constant lead time to a random lead time. We find that the quasiconvexity properties of the cost function (and therefore the existence of optimal (s, S) policies), holds true when the lead time has suitable log‐concavity properties. The results are derived by structural properties of renewal delayed processes stopped at an independent random time and by the study of log‐concavity properties of compound distributions. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 345–356, 2015  相似文献   
603.
This article generalizes the dynamic and stochastic knapsack problem by allowing the decision‐maker to postpone the accept/reject decision for an item and maintain a queue of waiting items to be considered later. Postponed decisions are penalized with delay costs, while idle capacity incurs a holding cost. This generalization addresses applications where requests of scarce resources can be delayed, for example, dispatching in logistics and allocation of funding to investments. We model the problem as a Markov decision process and analyze it through dynamic programming. We show that the optimal policy with homogeneous‐sized items possesses a bithreshold structure, despite the high dimensionality of the decision space. Finally, the value (or price) of postponement is illustrated through numerical examples. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 267–292, 2015  相似文献   
604.
Isabelle Côté 《Civil Wars》2015,17(3):357-378
Why are large population movements conflict-prone in some regions while they remain peacefully integrated elsewhere? I argue that clashes between ethnically distinct indigenous populations and migrants – i.e. ‘Sons of the Soil (SoS) conflict’ – erupt when there are large socio-economic and political horizontal inequalities between ‘dominant migrants’ and locals. A comparative case study of two Chinese minority regions based on ethnographic fieldwork and population data provides a vivid illustration of the mechanisms linking migration to SoS conflict. With fewer HIs between migrants and locals, Inner Mongolia avoided many of the violent clashes that were commonplace in Qinghai, a province fraught with disparities.  相似文献   
605.
This paper reviews some of the theoretical and econometric issues involved in estimating growth models that include military spending. While the mainstream growth literature has not found military expenditure to be a significant determinant of growth, much of the defence economics literature has found significant effects. The paper argues that this is largely the product of the particular specification, the Feder–Ram model, that has been used in the defence economics literature but not in the mainstream literature. The paper critically evaluates this model, detailing its problems and limitations and suggests that it should be avoided. It also critically evaluates two alternative theoretical approaches, the Augmented Solow and the Barro models, suggesting that they provide a more promising avenue for future research. It concludes with some general comments about modelling the links between military expenditure and growth.  相似文献   
606.
For a three‐sector Feder‐Ram framework, we present time‐series, cross‐sectional estimates for two cohorts, consisting of Asian and Latin American countries. The estimates indicate that private investment, and defense and non‐defense public spending are growth promoting for alternative error components representations. For the best error components representation, greater growth enhancement is associated with the two forms of public spending in Asia than in Latin America, while the opposite comparison characterizes private investment. Although defense is growth promoting, an opportunity cost exists insofar as non‐defense spending, financed by defense spending, appears to give a small net boost to growth in Latin America.  相似文献   
607.
608.
This article assesses South Africa's 20 years of democracy, which has frequently been bedevilled by local protests. This article is particularly interested in those unrest incidents that have been distinct for one reason or another. In South Africa, the surge in local unrest incidents is often linked to police behaviour, which has become increasingly militant and brutal when quelling protests. While the right to protest is constitutional, the damage caused during protest action can be immense owing to acts of violence. Protestors' resorting to violent protest action is often linked to increased frustrations as a result of the government's inability to live up to the expectations of marginalised and poor communities. While this article draws primarily on existing scholarly debates focusing on social protests, the primary objective is to examine the impact of unrest incidents on local protests in post-apartheid South Africa. The article further argues that ‘spaces’ for participation in local governance should be created so that citizens can become architects of development and their own future.  相似文献   
609.
610.
SHADOW WARS     
The Secret War with Iran: The 30-Year Clandestine Struggle Against the World's Most Dangerous Terrorist Power, by Ronen Bergman. Free Press, 2008. 432 pages, $28

Fallout: The True Story of the CIA's Secret War on Nuclear Trafficking, by Catherine Collins and Douglas Frantz. Free Press, 2011. 304 pages, $26.

The Twilight War: The Secret History of America's Thirty-Year War with Iran, by David Crist. Penguin Press, 2012. 638 pages, $36.

Israel vs. Iran: The Shadow War, by Yaakov Katz and Yoaz Hendel. Potomac Books Inc., 2012. 254 pages, $30.

Spies Against Armageddon: Inside Israel's Secret Wars, by Dan Raviv. Levant, 2012. 356 pages, $17.

Confront and Conceal: Obama's Secret Wars and Surprising Use of American Power, by David E. Sanger. Crown Publishers, 2012. 476 pages, $28.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号