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   101篇
  免费   27篇
  国内免费   6篇
  134篇
  2024年   1篇
  2023年   3篇
  2022年   6篇
  2021年   2篇
  2020年   3篇
  2019年   1篇
  2018年   3篇
  2017年   7篇
  2016年   5篇
  2015年   6篇
  2014年   12篇
  2013年   13篇
  2012年   6篇
  2011年   8篇
  2010年   5篇
  2009年   7篇
  2008年   2篇
  2007年   8篇
  2006年   8篇
  2005年   6篇
  2004年   3篇
  2003年   4篇
  2002年   5篇
  2001年   3篇
  2000年   2篇
  1998年   2篇
  1996年   2篇
  1989年   1篇
排序方式: 共有134条查询结果,搜索用时 0 毫秒
111.
为评估炸药在封闭容器内爆炸产生的振动效应对周围环境的影响,对封闭式爆炸容器小药量TNT炸药爆炸产生的爆炸振动效应进行了爆源邻近实地监测和测试。结果表明:小药量炸药爆炸引起的爆炸振动效应对距爆源100 m以外的普通砖结构民用住宅产生的速度强度远低于其临界峰值速度,不会对其结构产生明显影响。  相似文献   
112.
小灵巧炸弹是一种采用倾斜转弯(BTT)控制方式的小型面对称电视制导航空弹药,在实际飞行中必须确保其导引头框架角不超出可用范围。针对上述问题,根据时变偏置比例导引的思想,在三维空间中设计视线角速率偏置项,通过姿态角时变修正实现框架角约束,提出了一种带导引头框架角约束的三维纯比例导引律。仿真结果表明该方法在保证小灵巧炸弹战技指标要求的同时有效减少了框架角需求。  相似文献   
113.
故障样本选取是测试性验证中的关键环节,直接影响测试性验证试验的效率和结果的正确性。在板级电路的故障样本选取过程中,运用传染病思想中的元胞自动机模型分析了电路故障的传播行为,提出了一种基于元胞自动机的故障样本选取方法,实现了故障样本的等效选取。以某型装备关键部件为例,建立了故障传播模型,计算并改进了元胞自动机状态计算方法,通过注入易操作的故障样本,简化了故障注入的流程,提高了故障注入效率。  相似文献   
114.
重大疫情具有突发性强、危害性大等特点,一旦发生,极易在防疫准备不充足的小散远部队单位造成爆发。加强基层疫情防控基础建设贵在平时,势在必行。本文首先对重大疫情的特点和小散远部队单位防疫工作面临的现实困难进行了分析,并对开展新时代基层单位疫情防控工作进行了思考,最后提出了应在思想政治教育、军地联动、心理辅导和防疫效果评估等方面予以加强的小散远部队单位疫情防控工作系统框架,以期为提高部队基层防疫效率提供参考。  相似文献   
115.
The purpose of this paper is to investigate the problem of constructing an appointment template for scheduling patients at a specific type of multidisciplinary outpatient clinic called an integrated practice unit (IPU). The focus is on developing and solving a stochastic optimization model for a back pain IPU in the face of random arrivals, an uncertain patient mix, and variable service times. The deterministic version of the problem is modeled as a mixed integer program with the objective of minimizing a weighted combination of clinic closing time (duration) and total patient waiting time (length of stay). A two‐stage stochastic program is then derived to account for the randomness and the sequential nature of the decisions. Although it was not possible to solve the two‐stage problem for even a limited number of scenarios, the wait‐and‐see (WS) problem was sufficiently tractable to provide a lower bound on the stochastic solution. The introduction of valid inequalities, limiting indices, and the use of special ordered sets helped to speed up the computations. A greedy heuristic was also developed to obtain solutions much more quickly. Out of practical considerations, it was necessary to develop appointment templates with time slots at fixed intervals, which are not available from the WS solution. The first to be derived was the expected value (EV) template that is used to find the expected value of the EV solution (EEV). This solution provides an upper bound on the objective function value of the two‐stage stochastic program. The average gap between the EEV and WS solutions was 18%. Results from extensive computational testing are presented for the EV template and for our adaptation of three other templates found in the literature. Depending on the relative importance of the two objective function metrics, the results demonstrate the trade‐off that exists between them. For the templates investigated, the “closing time” ranged from an average of 235 to 275 minutes for a 300‐minute session, while the corresponding “total patient time in clinic” ranged from 80 to 71 minutes.  相似文献   
116.
The period from December 1940 through to the spring of 1941 saw the British Army win a series of rapid and decisive victories over Italian and Vichy French forces in North and East Africa and the Middle East. A key feature of these operations was the extensive British use of fast-moving all-arms mobile formations utilising superior speed and mobility to out-manoeuvre considerably larger Italian formations. A number of reasons have been given for the British Army adopting this mode of warfare, but the paper contends that the best explanation is that they were an organic evolution from methods used by the British Army in ‘small wars’ throughout the early twentieth century, use of mobile ‘frontier columns’ at the operational and tactical level of war being described and recommended by Callwell himself and visible with the Army in practice in operations in India and the Middle East in particular. The inter-war period saw the combination of this model of warfare with post-First World War military technology, notably tanks, close air support and coordination by wireless. Colonial operations in this period also saw some utilisation of what would later be identified as ‘Special Forces’ – also used extensively in the Desert War – the most obvious example being Captain Orde Wingate's Special Night Squads in Palestine in 1938.  相似文献   
117.
Transnational terrorism data are difficult to forecast because they contain an unknown number of structural breaks of unknown functional form. The rise of religious fundamentalism, the demise of the Soviet Union, and the rise of al Qaeda have changed the nature of transnational terrorism. ‘Old School’ forecasting methods simply smooth or difference the data. ‘New School’ methods use estimated break dates to control for regime shifts when forecasting. We compare the various forecasting methods using a Monte Carlo study with data containing different types of breaks. The study's results are used to forecast various types of transnational terrorist incidents.  相似文献   
118.
全面分析了轻武器在未来战争中的地位和作用 ,总结了轻武器现装备的主要特点 ,归纳了近二十年来在轻武器装备领域的主要技术成果 ,提出了轻武器未来发展趋势。  相似文献   
119.
针对装甲装备关键部件维修性验证中出现的小子样问题,提出了基于Bayes理论的小子样维修性验证,重点针对对数正态分布下维修性指标验证的验后似然比验证方法进行了深入研究。通过对装甲装备某关键部件的试验数据的实例分析,验证了该方法在减少样本容量及试验费用方面的有效性和合理性。  相似文献   
120.
针对装备软件成本估算时面临的历史数据少的小样本难题,提出把机器学习理论运用到装备软件成本估算研究领域,构建了基于相关向量机的小样本装备软件成本估算模型,采用COCOMO模型数据库中的数据对所构建模型进行训练和验证。为进一步验证所构建模型的合理性,在机器学习领域分别运用支持向量机模型和神经网络模型对相同数据进行估算,实验结果证明了基于相关向量机估算模型在小样本装备软件成本估算时比其他两种模型更精确。  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