全文获取类型
| 收费全文 | 1003篇 |
| 免费 | 0篇 |
专业分类
| 1003篇 |
出版年
| 2021年 | 16篇 |
| 2019年 | 31篇 |
| 2018年 | 14篇 |
| 2017年 | 26篇 |
| 2016年 | 21篇 |
| 2015年 | 24篇 |
| 2014年 | 23篇 |
| 2013年 | 197篇 |
| 2011年 | 8篇 |
| 2010年 | 9篇 |
| 2009年 | 14篇 |
| 2007年 | 11篇 |
| 2006年 | 11篇 |
| 2005年 | 16篇 |
| 2004年 | 18篇 |
| 2003年 | 10篇 |
| 2002年 | 14篇 |
| 2000年 | 12篇 |
| 1999年 | 10篇 |
| 1998年 | 18篇 |
| 1997年 | 20篇 |
| 1996年 | 15篇 |
| 1994年 | 23篇 |
| 1993年 | 15篇 |
| 1992年 | 12篇 |
| 1991年 | 23篇 |
| 1990年 | 11篇 |
| 1989年 | 19篇 |
| 1988年 | 20篇 |
| 1987年 | 24篇 |
| 1986年 | 23篇 |
| 1985年 | 17篇 |
| 1984年 | 13篇 |
| 1983年 | 14篇 |
| 1982年 | 13篇 |
| 1981年 | 12篇 |
| 1980年 | 11篇 |
| 1979年 | 17篇 |
| 1978年 | 17篇 |
| 1977年 | 10篇 |
| 1976年 | 14篇 |
| 1975年 | 12篇 |
| 1974年 | 14篇 |
| 1973年 | 17篇 |
| 1972年 | 13篇 |
| 1971年 | 9篇 |
| 1970年 | 15篇 |
| 1969年 | 12篇 |
| 1968年 | 9篇 |
| 1967年 | 11篇 |
排序方式： 共有1003条查询结果，搜索用时 0 毫秒
731.
732.
Brandon M. Boylan 《Civil Wars》2019,21(1):104-127
Why does terrorist violence escalate from some ethnic groups but not others? According to theoretical insights, many groups endure conditions that should spur on terrorist campaigns, but in reality only some carry them out. In contrast to studies emphasising motivations, this article constructs a framework centred on opportunity structures that contributes to our understanding of the rise of terrorism waged along ethnic lines. It argues that beyond grievances or other motivations, terrorist campaigns develop from communities when moderate political leaders depart from their positions in nationalist movements, causing terrorists to fill the subsequent power vacuum, while little terrorism occurs when leaders do not relinquish the nationalist agenda. This argument is evaluated with evidence from the Tamil and Muslim cases in the context of the Sri Lankan Civil War. Tamil United Liberation Front leaders left the Tamil nationalist movement in the early 1980s, enabling the Liberation Tigers of Tamil Eelam’s rise to dominate the nationalist agenda for three decades, while the Sri Lanka Muslim Congress did not relinquish the Muslim cause, which in part precluded the normalisation of violence in the community. 相似文献
733.
Blažo M. Radović 《Defense & Security Analysis》2018,34(3):211-231
ABSTRACTThe uncritical layering of western liberal defence governance norms and concepts on top of existing legacy concepts has impeded achieving coherent military capabilities and capacities when Serbia’s political and military leadership tried to reform the defence system using Western benchmarking principles and Western countries’ best practices. The process of this change has been more valuable than its actual output, as defined by increased capabilities. Such outcomes should be reflective of policy guidance, and can be thought of as closing the trinity loop of a defence planning system: plans, money and execution. This article addresses two key functional areas of the Serbian defence institution. First, it assesses the current state of defence planning to discern its strengths and weaknesses to ascertain if plans are tied to financial decision-making. Second, a full examination of current Serbian defence management is conducted to discern whether weaknesses exist that distract from producing operational capabilities. Both areas are analyzed thoroughly and some solutions for change are proposed. Also, the article analyzes the appearance of two negative phenomena in the planning process – economization and managerialism. 相似文献
734.
Determination of the gunfire probability of kill against a target requires two parameters to be taken into consideration: the likelihood of hitting the target (susceptibility) and the conditional probability of kill given a hit (vulnerability). Two commonly used methods for calculating the latter probability are (1) treating each hit upon the target independently, and (2) setting an exact number of hits to obtain a target kill. Each of these methods contains an implicit assumption about the probability distribution of the number of hits‐to‐kill. Method (1) assumes that the most likely kill scenario occurs with exactly one hit, whereas (2) implies that achieving a precise number of hits always results in a kill. These methods can produce significant differences in the predicted gun effectiveness, even if the mean number of hits‐to‐kill for each distribution is the same. We therefore introduce a new modeling approach with a more general distribution for the number of hits‐to‐kill. The approach is configurable to various classes of damage mechanism and is able to match both methods (1) and (2) with a suitable choice of parameter. We use this new approach to explore the influence of various damage accumulation models on the predicted effectiveness of weapon‐target engagements. 相似文献
735.
Claire M. Metelits 《Small Wars & Insurgencies》2018,29(4):680-708
The conflict between the rebel group, the Polisario Front, and the Kingdom of Morocco is nearing its 43rd year. Though under-reported, the conflict itself garners attention for the resilience – some would say tenacity – of the ethnically Sahrawi Polisario Front. Despite shifting regional and international politics and the nearly 150,000 Sahrawi refugees waiting in nearby Algerian camps, the rebel group has survived. What explains its resilience? This article uses Bourdieu’s ‘forms of capital’ to understand the Polisario Front’s persistence. Based on field research in Algeria, Western Sahara, and the United States, it finds that social, cultural, symbolic, and economic capital may provide an explanation. 相似文献
736.
David R. Morrison Jason J. Sauppe Wenda Zhang Sheldon H. Jacobson Edward C. Sewell 《海军后勤学研究》2017,64(1):64-82
The cyclic best‐first search (CBFS) strategy is a recent search strategy that has been successfully applied to branch‐and‐bound algorithms in a number of different settings. CBFS is a modification of best‐first search (BFS) that places search tree subproblems into contours which are collections of subproblems grouped in some way, and repeatedly cycles through all non‐empty contours, selecting one subproblem to explore from each. In this article, the theoretical properties of CBFS are analyzed for the first time. CBFS is proved to be a generalization of all other search strategies by using a contour definition that explores the same sequence of subproblems as any other search strategy. Further, a bound is proved between the number of subproblems explored by BFS and the number of children generated by CBFS, given a fixed branching strategy and set of pruning rules. Finally, a discussion of heuristic contour‐labeling functions is provided, and proof‐of‐concept computational results for mixed‐integer programming problems from the MIPLIB 2010 database are shown. © 2017 Wiley Periodicals, Inc. Naval Research Logistics, 64: 64–82, 2017 相似文献
737.
We study a multi‐stage dynamic assignment interdiction (DAI) game in which two agents, a user and an attacker, compete in the underlying bipartite assignment graph. The user wishes to assign a set of tasks at the minimum cost, and the attacker seeks to interdict a subset of arcs to maximize the user's objective. The user assigns exactly one task per stage, and the assignment costs and interdiction impacts vary across stages. Before any stage commences in the game, the attacker can interdict arcs subject to a cardinality constraint. An interdicted arc can still be used by the user, but at an increased assignment cost. The goal is to find an optimal sequence of assignments, coupled with the attacker's optimal interdiction strategy. We prove that this problem is strongly NP‐hard, even when the attacker can interdict only one arc. We propose an exact exponential‐state dynamic‐programming algorithm for this problem as well as lower and upper bounds on the optimal objective function value. Our bounds are based on classical interdiction and robust optimization models, and on variations of the DAI game. We examine the efficiency of our algorithms and the quality of our bounds on a set of randomly generated instances. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 373–387, 2017 相似文献
738.
Andrew J. Gawthorpe 《Small Wars & Insurgencies》2017,28(4-5):839-852
AbstractAlthough the concept of legitimacy is central to Western counterinsurgency theory, most discourse in this area black-boxes the concept. It hence remains under-specified in many discussions of counterinsurgency. Fortunately, recent research on rebel governance and legitimacy contributes to our understanding of the problems faced by counterinsurgents who want to boost state legitimacy while undermining that of the rebels. Taken together, this research illustrates that a rational choice approach to legitimacy is simplistic; that micro-level factors ultimately drive legitimacy dynamics; and that both cooption of existing legitimate local elites and their replacement from the top–down is unlikely to succeed. Western counterinsurgency doctrine has failed to grasp the difficulties this poses for it. 相似文献
739.
Daniel J. Milton 《Contemporary Security Policy》2017,38(3):345-370
The goal of diplomats is to represent their countries’ interests through diplomacy, not arms. Because they are not military personnel, they may be perceived as at lower risk of being the target of terrorists. However, recent events have called this perception into question. Despite this danger, there has been little research on terrorist attacks against diplomats. Drawing on the terrorism studies literature, this article argues that diplomats are targeted more than non-diplomatic targets in countries where certain U.S. foreign policies are implemented. An empirical analysis of 471 attacks against U.S. diplomats from 1970 to 2011 reveals that while U.S. alliances and foreign aid increase the likelihood of attacks against diplomats, U.S. military intervention and civil war, on the other hand, increase the risk of terrorism against non-diplomatic targets. This finding is relevant because it shows terrorist attacks against diplomats result from certain types of foreign policy. 相似文献
740.
NATO burden sharing has become an especially timely issue in the past several years as a result of a number of factors, including Russian annexation of Crimea and destabilization of eastern Ukraine in 2014. This article argues that alliance unity among the great democracies of Europe and North America is indispensable to peace and stability on the Eurasian continent. A fractured NATO, and especially, a large divide in purposes or commitments as between the United States and its European security partners, invites aggression and the possibility of inadvertent escalation. Past successes and failures in US-involved multinational peace and stability operations, within and outside of Europe, show that mission accomplishment requires give and take, including the occasional acceptance of unequal costs and benefits among the members, in order to achieve peace and security objectives. 相似文献