全文获取类型
收费全文 | 357篇 |
免费 | 43篇 |
国内免费 | 36篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 11篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 20篇 |
2015年 | 5篇 |
2014年 | 33篇 |
2013年 | 40篇 |
2012年 | 30篇 |
2011年 | 36篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 27篇 |
2007年 | 29篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 17篇 |
2002年 | 6篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1988年 | 2篇 |
排序方式: 共有436条查询结果,搜索用时 15 毫秒
121.
122.
图像中邻域内灰度起伏程度越大 ,各点灰度值占邻域内总灰度值的比率的平方和越大 ,由此提出了一种基于邻域灰度分布的弱小目标检测方法。同时考虑到复杂自然背景 ,特别是背景中含有大量边缘和高频点的情况 ,提出了目标检测的改进方法。最后 ,利用邻域判决法实现运动目标的进一步分离。实验表明该方法能够极大地减少候选目标点数 ,准确有效地检测复杂自然背景中的红外运动弱小目标 ,适合于实时和多目标的检测 相似文献
123.
124.
125.
126.
对敌后侦察反军事诱骗的远程火力打击战法的定量分析是战役研究中尚未解决的关键问题之一,根据信息作战原理,运用仿真和统计学分析的混合方法,建立基于概率的二人非零和(TPNZS)非合作博弈模型,设计基于侦察与诱骗博弈的远程火力打击战法,定量分析我方的敌后侦察和敌方的军事诱骗对远程信息与火力联合打击能力的影响,并对一个典型实例的初步试验及分析结果表明:与敌后侦察和军事诱骗有关的正确识别目标和错误识别目标的概率以及远程火力命中目标的概率是评估远程信息与火力联合打击能力的关键,而对评估结果进行博弈分析则是远程火力打击战法设计的关键,用识别正确目标和错误目标能力以及远程火力命中目标能力描述的基于敌后侦察与诱骗博弈的远程火力最优打击战法为Δ*=(0,Δ2*,1-Δ2*)=(0.0000,0.7727,0.2273),被打击方对远程火力打击的最优战法为π*=(π1*,0,1-π1*)=(0.8511,0.0000,0.1489)。 相似文献
127.
128.
Michael Raber 《Arms and Armour》2017,14(1):70-98
The U.S. Armory in Springfield, Massachusetts, rarely appears in Civil War histories except perhaps as an unexplained statistical wonder. By late 1863, the Armory was the largest single supplier of rifles to Union forces. Springfield Armory workers out-produced over thirty American contractors, making more Army rifles at less cost while providing contractors with gauges, inspectors, and models, even though there were significant wartime private-sector mechanical innovations. This article identifies and explains the factors in the Armory’s success, provides context on contemporary American arms production and rifle models, and argues that the Armory’s methods and performance were among the first if not the first example of mass production in American small arms manufacture. The relative brevity of the Civil War episode, and the fact that it was not repeated in any comparable way at the Armory until World War II, has obscured its significance in American manufacturing history. 相似文献
129.
130.
In the literature two common macroscopic evacuation planning approaches exist: The dynamic network flow approach and the Cell–Transmission–Based approach. Both approaches have advantages and disadvantages. Many efficient solution approaches for the dynamic network flow approach exist so that realistic problem instances can be considered. However, the consideration of (more) realistic aspects (eg, density dependent travel times) results in non‐linear model formulations. The Cell‐Transmission‐Based approach on the other hand considers realistic traffic phenomena like shock waves and traffic congestion, but this approach leads to long computational times for realistic problem instances. In this article, we combine the advantages of both approaches: We consider a Cell‐Transmission‐Based Evacuation Planning Model (CTEPM) and present a network flow formulation that is equivalent to the cell‐based model. Thus, the computational costs of the CTEPM are enormously reduced due to the reformulation and the detailed representation of the traffic flow dynamics is maintained. We investigate the impacts of various evacuation scenario parameters on the evacuation performance and on the computational times in a computational study including 90 realistic instances. 相似文献