全文获取类型
收费全文 | 476篇 |
免费 | 11篇 |
出版年
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 16篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 133篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 10篇 |
2006年 | 4篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 6篇 |
1999年 | 8篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 9篇 |
1972年 | 9篇 |
1971年 | 10篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 7篇 |
1967年 | 3篇 |
1966年 | 3篇 |
1948年 | 3篇 |
排序方式: 共有487条查询结果,搜索用时 31 毫秒
301.
302.
W. Robert J. Alexander 《Defence and Peace Economics》2013,24(2):213-221
The issue of guns or butter is one of the most fundamental economic questions, yet there is no consensus on a theoretical framework for examining it. Over the last decade, a version of a simple Keynesian macroeconomic model has been applied a number of times to examining the link between defence spending and economic growth in a range of countries. There are reasons for doubting the soundness of this model as a basis for empirical work. 相似文献
303.
David Zounmenou 《African Security Review》2013,22(3):167-174
Mali has been a battleground for more than a year now. While the armed conflict came in the aftermath of the Libyan crisis that left the regional security environment depleted, it also served as a catalyst for the collapse of state authority in Mali. This created conditions conducive for the proliferation of, and attacks by, radical religious armed groups in the northern regions of the country, including the Tuareg armed movement: the National Movement for the Liberation of Azawad (MNLA). But, far from being a new phenomenon, the Tuareg-led armed insurrection in the northern regions is as old as the post-colonial Malian state, and continues to pose tremendous challenges in West Africa and the Sahel region for both regional and extra-regional actors. The recent crisis in the Sahel region is seen as one of the most serious since the end of the Cold War, with anticipated dire long-term impacts on the security of the region and beyond. While attention is predominantly focused on defeating the jihadist groups that have threatened the survival of the Malian state, one must not lose sight of the fact that the ‘Tuareg Factor’, as represented by the rebellion launched by MNLA, remains critical both in terms of appreciating the deterioration of the situation and attempting to frame long-lasting solutions. The paper argues that the Tuareg's persistent recourse to rebellion against Bamako needs to be understood within a historical trajectory that takes into consideration three key parameters: firstly, the post-colonial state in Mali and its African leadership's relations with the descendants of the Tuareg communities; secondly, the amalgamation created by the so-called war on terror; and, finally, the contradictions of the democratisation process of the 1990s.1 相似文献
304.
David A. Cooper 《The Nonproliferation Review》2013,20(1):145-163
When it was concluded more than a quarter century ago, the Intermediate-Range Nuclear Forces (INF) Treaty between the United States and the Soviet Union was hailed as a disarmament watershed, eliminating entire classes of nuclear missiles from the arsenals of the arms-racing Cold War superpowers. Over the intervening decades, there have been repeated calls to convert this legacy treaty into a new international norm against nuclear and missile proliferation by broadening it into a global prohibition on ground-launched ballistic and cruise missiles with ranges between 500 and 5,500 kilometers. Indeed, variations on this proposal have been knocking around for so long and with so little success that the entire concept has come to be dismissed by many knowledgeable insiders as something of a farce. Looking beyond its inauspicious pedigree, however, this viewpoint suggests that the time is opportune for Washington to give the idea a fresh look. Drawing on a detailed review of the history of “Global INF” and an analysis of the contemporary context, the author recommends that the Obama administration consider a simple declaratory approach that promises modest initial benefits, avoids previous and foreseeable pitfalls, and plausibly lays a solid foundation for achieving significant long-term progress. 相似文献
305.
We study a stochastic interdiction model of Morton et al. IIE Transactions, 39 (2007):3–14 that locates radiation sensors at border crossings to detect and prevent the smuggling of nuclear material. In this model, an interdictor places sensors at customs checkpoints to minimize a potential smuggler's maximum probability of crossing a border undetected. We focus on a model variant in which the interdictor has different, and likely more accurate, perceptions of the system's parameters than the smuggler does. We introduce a model that is tighter and uses fewer constraints than that of Morton et al. We also develop a class of valid inequalities along with a corresponding separation procedure that can be used within a cutting‐plane approach to reduce computational effort. Computational results demonstrate the effectiveness of our approach.Copyright © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 91–100, 2014 相似文献
306.
Moment estimators for the parameters of the Weibull distribution are considered in the context of analysis of field data. The data available are aggregated, with individual failure times not recorded. In this case, the complexity of the likelihood function argues against the use of maximum-likelihood estimation, particularly for relatively large sets of data, and moment estimators are a reasonable alternative. In this article, we derive the asymptotic covariance matrix of the moment estimators, and provide listings for BASIC computer programs which generate tables useful for calculation of the estimates as well as for estimating the asymptotic covariance matrix using aggregated data. 相似文献
307.
308.
309.
We discuss a time dependent optimal ordering policy for a finite horizon inventory system for which the provision of service is essential and thus no stockout is allowed. It is assumed that the system can place an order at any point in time during the horizon when it cannot meet the customer's demand and that lead time is negligible. The demand is considered to be distributed as a compound Poisson process with known parameters and the functional equation approach of dynamic programming is used to formulate the objective function. An algorithm has been developed to obtain the solution for all the cases. In addition, analytical solutions of the basic equation under two limiting conditions are presented. 相似文献
310.
The present analysis deals with very high-dimensional data sets, each one containing close to 900 binary variables. Each data set corresponds to an evaluation of one complex system. These data sets are characterized by large portions of missing data where, moreover, the unobserved variables are not the same in different evaluations. Thus, the problems which confront the statistical analysis are those of multivariate binary data analysis, where the number of variables is much larger than the sample size and in which missing data varies with the sample elements. The variables, however, are hierarchically structured and the problem of clustering variables to groups does not exist in the present study. In order to motivate the statistical problem under consideration, the Marine Corps Combat Readiness Evaluation System (MCCRES) is described for infantry battalions and then used for exposition. The present article provides a statistical model for data from MCCRES and develops estimation and prediction procedures which utilize the dependence structure. The E-M algorithm is applied to obtain maximum-likelihood estimates of the parameters of interest. Numerical examples illustrate the proposed methods. 相似文献