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   1946篇
  免费   295篇
  国内免费   150篇
  2024年   1篇
  2023年   9篇
  2022年   18篇
  2021年   37篇
  2020年   45篇
  2019年   29篇
  2018年   59篇
  2017年   98篇
  2016年   77篇
  2015年   58篇
  2014年   170篇
  2013年   175篇
  2012年   132篇
  2011年   198篇
  2010年   141篇
  2009年   164篇
  2008年   131篇
  2007年   123篇
  2006年   122篇
  2005年   118篇
  2004年   107篇
  2003年   74篇
  2002年   64篇
  2001年   61篇
  2000年   29篇
  1999年   24篇
  1998年   29篇
  1997年   10篇
  1996年   18篇
  1995年   17篇
  1994年   15篇
  1993年   4篇
  1992年   10篇
  1991年   8篇
  1990年   6篇
  1989年   6篇
  1988年   2篇
  1987年   1篇
  1975年   1篇
排序方式: 共有2391条查询结果,搜索用时 15 毫秒
991.
US military operations are increasingly conducted within urban environments and with these operations come the risk of increasing the number of civilian casualties and infrastructure damage. The use of non-lethal weaponry, such as directed-energy weapons, is one method for minimizing collateral damage. This method enables US military forces to effectively fight within urban environments through force escalation capabilities. Using a series of historical examples and future scenarios for urban warfare, this article highlights deficiencies affecting military capabilities in military urban operations, addresses the consequences of collateral damage, assesses the effectiveness of directed-energy weapons in military urban operations and encourages further funding, research and integration of non-lethal weaponry, such as directed-energy weapons, within the US military.  相似文献   
992.
Efforts at winning hearts and minds (WHAM) impact on and are affected by perceptions of legitimacy. In the Namibian war for independence (1966–1989) efforts of the South African counterinsurgent forces at winning hearts and minds focused mainly on persuading the population to cooperate in exchange for material benefits and services. The article demonstrates that this successfully contributed to a dimension of legitimacy that is conceptualized as pragmatic legitimacy. However, other dimensions of legitimacy are identified in which the South Africans were lacking, that is in moral, legal, and identity-based legitimacy. Furthermore, in areas where control was contested and where the population could not be shielded from insurgent intimidation, it is argued that the effects of coercion outweighed legitimacy altogether.  相似文献   
993.
From the late 1970s and until the end of the Cold War, the ‘High North’ constituted a central theatre for military forces. Extensive NATO preparations were made, a solid infrastructure developed in northern Norway, and frequent and large-scale exercises were carried out. These developments, from the late 1970s, were much discussed by scholars and strategists. However, the change of perception, laying the foundation for the military build-up, had actually occurred a decade earlier, in the late 1960s. This change has not yet been given its rightful attention, partly because the relevant documents have only recently become available. This essay takes the chronology of events back into the 1960s and to NATO's secret discussions between the national Ministers of Defence and Chiefs of Staff. The most significant turning-points were the Flexible Response strategy of 1967; SACLANT's concern over increased Soviet naval activity and his ‘Maritime Strategy’ studies of 1965 and 1967; NATO's awakening to the Soviet SSBN threat in 1967; and the concept of ‘External Reinforcement of the Flanks’ of 1968 – finally followed by the ‘Brosio Study’ (named after the then NATO Secretary-General) of 1969. As a consequence of these developments NATO's ‘tactical northern flank’ was set to become an independent strategic theatre.  相似文献   
994.
本文针对星载多通道高分辨宽测绘带合成孔径雷达系统,提出了一种地面运动目标检测和参数估计方法,该方法首先利用空时自适应处理进行杂波抑制,然后采用传统SAR成像处理得到模糊的运动目标图像,接着利用恒虚警检测技术检测出所有运动目标,包括真实目标和由于多普勒模糊引起的虚假目标,再根据模糊图像的空间位置关系从所有成像目标中检测出运动目标的真实成像位置,最后根据运动目标的斜距历程得到因运动目标速度引起的图像位置偏移,由此估计得到运动目标速度。该方法具有运算量小、检测精度高等优点,星载仿真数据验证了本文方法有效性。  相似文献   
995.
This study revisits the causal relationship between military spending and economic growth in 10 Middle East countries via a panel causality analysis that accounts for cross-sectional dependence and heterogeneity across countries. Our results indicate unidirectional causality from military spending to growth for Turkey; one-way causality from economic growth to military spending for Egypt, Kuwait, Lebanon, and Syria; bidirectional causality for Israel; and no causality in either direction for Jordan, Oman, and Saudi Arabia. The empirical evidence does not provide consistent results regarding the causal relationship between defense expenditure and economic growth in these countries.  相似文献   
996.
ABSTRACT

This article uses the case of illegal street vending in Harare to explore the interface between urban governance and politics. Drawing on the ideas of urban governance and informal governance, it illustrates how polarisation between the opposition political party Movement for Democratic Change-dominated municipal council and the Zimbabwe African National Union Patriotic Front-led government is affecting governance in general and in particular Harare municipality’s ability to handle the illegal street vending problem. While the paper essentially identifies political expediency as the major reason why a lasting solution is elusive in handling the illegal street vending problem, it acknowledges that there are broad reasons for its persistence. Consequently, the article demonstrates some of the reasons why illegal street vending is difficult to end using the conventional methods and provides some alternatives.  相似文献   
997.
In June 2000, the Conference of Heads of State and Government of the Economic Community of Central African States (ECCAS) adopted the Protocol on the establishment of the Peace and Security Council for Central Africa (COPAX), with its two technical structures, namely the Central African Multinational Force (FOMAC) and the Central African Early Warning Mechanism (MARAC). MARAC is tasked with collecting and analysing data for the early detection and prevention of conflicts and crises. It currently consists of the Central Structure located at the ECCAS Executive Secretariat in Libreville (Gabon) and 31 Decentralised Correspondents spread throughout the ten member states of ECCAS. This article assesses the performance of MARAC in the light of its assigned objectives. Bearing in mind the peace and security challenges facing the central African sub-region, the central argument of this article is that while the establishment of MARAC is commendable, it flowed more from the logic and context of the establishment of similar mechanisms on the African continent during the same period than from any displayed capacity and/or readiness on the part of ECCAS to implement the recommendations due to emanate from such a structure.  相似文献   
998.
ABSTRACT

International Organisations (IOs) are crucial actors in spearheading the global adoption of anti-money-laundering (AML) legislation. However, the extent to which AML legislation has been implemented in Zimbabwe under the aegis of the Financial Action Task Force (FATF) and East Africa and Southern Africa Money Laundering Group (ESSAMALG) may put the efficacy of legislation passed at the behest of IOs into question. This article suggests that glocalisation may enhance the international fight against money-laundering. That is to say, international standards should be applied domestically with due regard for local legislative environment.  相似文献   
999.
地下工程防水防潮一直是工程界的难题,传统技术存在难根治、易反复的缺点。选择某一洞库进行电渗透技术工程试点研究:先详细介绍电渗透技术和施工工艺情况;再采用在工程内布置电极并施加脉冲电压的方法,利用电场力迫使水分向工程外岩体移动,达到降低工程内部湿度、防水防潮的目的。工程应用表明,电渗透防水防潮技术拥有效果明显、运行费用低等突出优点,具有推广前景。  相似文献   
1000.
构建高效的防空反导系统是防空反导作战的基础。运用复杂网络理论,建立基于无标度网络防空反导系统模型,并将其统计特征同基于WS小世界网络的模型进行了比较,得出基于无标度网络的防空反导系统有更好鲁棒性和抗毁性,对网络化防空反导系统的构建有一定参考价值。  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