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   118910篇
  免费   9885篇
  国内免费   4990篇
电工技术   7135篇
技术理论   7篇
综合类   7644篇
化学工业   20537篇
金属工艺   6492篇
机械仪表   7355篇
建筑科学   9725篇
矿业工程   3475篇
能源动力   3524篇
轻工业   7750篇
水利工程   2135篇
石油天然气   7334篇
武器工业   879篇
无线电   13442篇
一般工业技术   14347篇
冶金工业   5531篇
原子能技术   1291篇
自动化技术   15182篇
  2024年   558篇
  2023年   2043篇
  2022年   3566篇
  2021年   4912篇
  2020年   3755篇
  2019年   3164篇
  2018年   3402篇
  2017年   3953篇
  2016年   3330篇
  2015年   4717篇
  2014年   5742篇
  2013年   6807篇
  2012年   7469篇
  2011年   8014篇
  2010年   7000篇
  2009年   6686篇
  2008年   6490篇
  2007年   6110篇
  2006年   6379篇
  2005年   5537篇
  2004年   3785篇
  2003年   3296篇
  2002年   3086篇
  2001年   2816篇
  2000年   2961篇
  1999年   3174篇
  1998年   2683篇
  1997年   2286篇
  1996年   2103篇
  1995年   1827篇
  1994年   1475篇
  1993年   1056篇
  1992年   862篇
  1991年   678篇
  1990年   491篇
  1989年   437篇
  1988年   354篇
  1987年   245篇
  1986年   167篇
  1985年   97篇
  1984年   65篇
  1983年   49篇
  1982年   63篇
  1981年   39篇
  1980年   35篇
  1979年   10篇
  1978年   3篇
  1965年   3篇
  1959年   4篇
  1951年   1篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
111.
112.
In this paper, we present a gradient domain image fusion framework based on the Markov Random Field (MRF) fusion model. In this framework, the salient structures of the input images are fused in the gradient domain, then the final fused image is reconstructed by solving a Poisson equation which forces the gradients of the fused image to be close to the fused gradients. To fuse the structures in the gradient domain, an effective MRF-based fusion model is designed based on both the per-pixel fusion rule defined by the local saliency and also the smoothness constraints over the fusion weights, which is optimized by graph cut algorithm. This MRF-based fusion model enables the accurate estimation of region-based fusion weights for the salient objects or structures. We apply this method to the applications of multi-sensor image fusion, including infrared and visible image fusion, multi-focus image fusion and medical image fusion. Extensive experiments and comparisons show that the proposed fusion model is able to better fuse the multi-sensor images and produces high-quality fusion results compared with the other state-of-the-art methods.  相似文献   
113.
Because subjective evaluation is not adequate for assessing work in an automatic system, using an objective image fusion performance metric is a common approach to evaluate the quality of different fusion schemes. In this paper, a multi-resolution image fusion metric using visual information fidelity (VIF) is presented to assess fusion performance objectively. This method has four stages: (1) Source and fused images are filtered and divided into blocks. (2) Visual information is evaluated with and without distortion information in each block. (3) The visual information fidelity for fusion (VIFF) of each sub-band is calculated. (4) The overall quality measure is determined by weighting the VIFF of each sub-band. In our experiment, the proposed fusion assessment method is compared with several existing fusion metrics using the subjective test dataset provided by Petrovic. We found that VIFF performs better in terms of both human perception matching and computational complexity.  相似文献   
114.
With the general theory of standard quantum process tomography, we shall develop a scheme to decide an arbitrary matrix element of χ, which is in the Choi matrix representation, in a scalable way. Our observation is that: To decide the diagonal matrix element, one just needs a single measurement; To decide an arbitrary off-diagonal matrix element, we should carry out sixteen measurements. This result is independent of the actual dimension of the system. Compared with the known methods of partial QPT, our scheme does not require any additional resources. It can be applied for the case where a clean ancilla system is not available.  相似文献   
115.
We investigate the dynamics of quantum correlation between two separated qubits trapped in one-dimensional plasmonic waveguide. It is found that for a class of initial states, the quantum discord shows a sudden change phenomenon during the dynamical evolution. Furthermore, we demonstrate that the quantum discord can be enhanced if a proper product of the plasmon wave number and two qubits distance is chosen. Finally, we find that the non-zero quantum discord between two qubits can be created for the states without initial quantum discord during the time evolution of the system.  相似文献   
116.
本文主要介绍了校园安防的发展趋势。  相似文献   
117.
本文针对当前贫穷地区高职高专计算机网络实验教学的特点,结合学校和本地实际情况,从实验课程教学内容及形式方法等方面探讨了计算机网络实验环境架构的有关问题.对计算机网络实验的环境构架存在的不足,给出了解决方案.  相似文献   
118.
从设计思想、业务流程和系统结构这三个方面阐述了宾馆信息系统的分析和设计流程.  相似文献   
119.
本文针对计算机专业学生学习计算机算法语言存在的问题,引用互动式教学的理论,设计了互动式教学模式,即"建-仿-读-改-写",提出了互动式教学的环境要求,分析了互动式教学的教学效果,基本形成了一套完整的教学方案。对提高计算机专业教学效果具有一定的指导意义。  相似文献   
120.
A new output feedback variable structure control scheme is developed based on a novel passivity idea. This scheme may practically stabilize a class of higher‐relative‐degree uncertain linear systems, and realize output tracking and disturbance attenuation as well. The controller is composed of linear filters and a single relay, without employing real‐time exact differentiators. Under this framework, we also explain how actuator dynamics affect the closed loop behavior. A simulation example shows the simplicity and efficiency of this method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society  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