全文获取类型
收费全文 | 3309篇 |
免费 | 82篇 |
国内免费 | 1篇 |
专业分类
3392篇 |
出版年
2021年 | 37篇 |
2019年 | 88篇 |
2018年 | 51篇 |
2017年 | 80篇 |
2016年 | 78篇 |
2015年 | 61篇 |
2014年 | 64篇 |
2013年 | 691篇 |
2010年 | 35篇 |
2009年 | 37篇 |
2008年 | 47篇 |
2007年 | 52篇 |
2006年 | 36篇 |
2005年 | 42篇 |
2004年 | 56篇 |
2003年 | 42篇 |
2002年 | 57篇 |
1999年 | 41篇 |
1998年 | 46篇 |
1997年 | 47篇 |
1996年 | 61篇 |
1995年 | 41篇 |
1994年 | 59篇 |
1993年 | 63篇 |
1992年 | 58篇 |
1991年 | 74篇 |
1990年 | 39篇 |
1989年 | 72篇 |
1988年 | 78篇 |
1987年 | 68篇 |
1986年 | 70篇 |
1985年 | 64篇 |
1984年 | 36篇 |
1983年 | 42篇 |
1982年 | 43篇 |
1981年 | 46篇 |
1980年 | 51篇 |
1979年 | 45篇 |
1978年 | 49篇 |
1977年 | 45篇 |
1976年 | 45篇 |
1975年 | 46篇 |
1974年 | 52篇 |
1973年 | 50篇 |
1972年 | 52篇 |
1971年 | 43篇 |
1970年 | 40篇 |
1969年 | 40篇 |
1968年 | 34篇 |
1967年 | 34篇 |
排序方式: 共有3392条查询结果,搜索用时 15 毫秒
671.
672.
673.
674.
Karen V. Fair 《Small Wars & Insurgencies》2013,24(1):107-126
Scholars disagree on the prevailing focus on insurgent ideology. Some claim that the dominant Marxist ideology of the Cold War era has been supplanted by a new focus on ethnic and national identity. Others claim that many insurgencies were always focused on identity, but the Cold War and superpower antipathies distorted perceptions of insurgencies as politically-economically focused. Yet the heart of the matter is that analysts are not faced with an ‘either/or’ proposition. 相似文献
675.
The reformulation‐linearization technique (RLT) is a methodology for constructing tight linear programming relaxations of mixed discrete problems. A key construct is the multiplication of “product factors” of the discrete variables with problem constraints to form polynomial restrictions, which are subsequently linearized. For special problem forms, the structure of these linearized constraints tends to suggest that certain classes may be more beneficial than others. We examine the usefulness of subsets of constraints for a family of 0–1 quadratic multidimensional knapsack programs and perform extensive computational tests on a classical special case known as the 0–1 quadratic knapsack problem. We consider RLT forms both with and without these inequalities, and their comparisons with linearizations derived from published methods. Interestingly, the computational results depend in part upon the commercial software used. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2010 相似文献
676.
Andrew J. Dowdle 《Small Wars & Insurgencies》2013,24(2):161-174
Previous research on African military spending suggests the existence of civil strife as the best predictor of high levels of military spending. However, little is known about why some African nations maintain strong ‘auxiliary’ or paramilitary organizations while others do not. This study finds that the presence of civil or interstate war does not strengthen reserve or irregular forces. Civilian governments promote strong paramilitary organizations to counter any threat the regular military might pose to regime survivability as a form of clientelist politics. 相似文献
677.
We explore the impact of strategic assessment efforts on military organizations at war. To do so, we construct a model to explore the impact of a principal’s choice among imperfect performance metrics for a military operation. In doing so, the principal must consider both the incentivizing and informational properties of the metric. We show the conditions under which uncertainty regarding the nature of the agent, as well as uncertainty regarding the operational environment, drives a metric choice that induces pathological behavior from the agent. More specifically, a poor metric choice can create an overly optimistic assessment and end up prolonging the conflict. We illustrate the model’s insights in the cases of World War II and the Vietnam War. 相似文献
678.
Alan R. Washburn 《海军后勤学研究》1998,45(3):243-257
The problem of searching for randomly moving targets such as children and submarines is known to be fundamentally difficult, but finding efficient methods for generating optimal or near optimal solutions is nonetheless an important practical problem. This paper investigates the efficiency of Branch and Bound methods, with emphasis on the tradeoff between the accuracy of the bound employed and the time required to compute it. A variety of bounds are investigated, some of which are new. In most cases the best bounds turn out to be imprecise, but very easy to compute. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 243–257, 1998 相似文献
679.
680.
The purpose of this research is to investigate simulation algorithms for nonhomogeneous Poisson processes with proportional intensities. Two algorithmic approaches are studied: inversion and thinning. Motivated by industrial practices, the covariate vector involved in the simulation is permitted to change after every event (or observation). The algorithms are extended to permit the simulation of general nonhomogeneous Poisson processes with possible discontinuities both in baseline intensity and covariate vector. This latter extension can be used to facilitate a wide range of failure situations that can arise with repairable systems. © 1994 John Wiley & Sons, Inc. 相似文献