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   905篇
  免费   35篇
  国内免费   2篇
电工技术   5篇
综合类   2篇
化学工业   248篇
金属工艺   21篇
机械仪表   23篇
建筑科学   20篇
矿业工程   1篇
能源动力   34篇
轻工业   37篇
水利工程   1篇
石油天然气   7篇
无线电   78篇
一般工业技术   259篇
冶金工业   50篇
原子能技术   15篇
自动化技术   141篇
  2024年   4篇
  2023年   6篇
  2022年   24篇
  2021年   32篇
  2020年   29篇
  2019年   30篇
  2018年   36篇
  2017年   37篇
  2016年   35篇
  2015年   16篇
  2014年   26篇
  2013年   70篇
  2012年   35篇
  2011年   60篇
  2010年   40篇
  2009年   28篇
  2008年   34篇
  2007年   23篇
  2006年   20篇
  2005年   15篇
  2004年   14篇
  2003年   19篇
  2002年   7篇
  2001年   9篇
  2000年   11篇
  1999年   14篇
  1998年   14篇
  1997年   19篇
  1996年   15篇
  1995年   14篇
  1994年   17篇
  1993年   19篇
  1992年   23篇
  1991年   13篇
  1990年   5篇
  1989年   11篇
  1988年   8篇
  1987年   9篇
  1985年   13篇
  1984年   13篇
  1983年   6篇
  1982年   5篇
  1981年   5篇
  1980年   8篇
  1979年   12篇
  1978年   6篇
  1975年   3篇
  1974年   5篇
  1973年   5篇
  1971年   3篇
排序方式: 共有942条查询结果,搜索用时 31 毫秒
1.
The present study attempts quantitative determination of changes in the morphological surface features viz. fractal dimension, lower and upper cut off length scale through Power Spectral Density analysis prior to and after irradiation of 100 KeV Ar+ ion beam at incidence angles of 0°, 40° and 60° on ZnO thin films. All the unirradiated and irradiated samples are subjected to photoelectrochemical characterization and a correlation between photoelectrochemical performance and morphological parameters is established. Sample irradiated at 40° angle at the fluence of 5 × 1016 ions/cm2 is found to possess maximum fractal dimension of 2.72, lower and upper cut off length scale of 3.16 nm and 63.00 nm respectively. This sample exhibits maximum photocurrent density of 3.19 mA/cm2 and applied bias photon-to-current efficiency of 1.12% at 1.23 V/RHE. Hydrogen gas collected for duration of 1 h for the same sample was ~4.83 mLcm?2.  相似文献   
2.
Neural Computing and Applications - We propose “Deep Autoencoders for Feature Learning in Recommender Systems,” a novel discriminative model based on the incorporation of features from...  相似文献   
3.
4.
Human faces undergo considerable amounts of varialions with aging. While face recognition systems have been proven to be sensitive to factors such as illumination and pose, their sensitivity to facial aging effects is yet to be studied. How does age progression affect the similarity between a pair of face images of an individual? What is the confidence associated with establishing the identity between a pair of age separated face images? In this paper, we develop a Bayesian age difference classifier that classifies face images of individuals based on age differences and performs face verification across age progression. Further, we study the similarity of faces across age progression. Since age separated face images invariably differ in illumination and pose, we propose preprocessing methods for minimizing such variations. Experimental results using a database comprising of pairs of face images that were retrieved from the passports of 465 individuals are presented. The verification system for faces separated by as many as nine years, attains an equal error rate of 8.5%.  相似文献   
5.
A critical review of the current status of tungsten resources, of state-of-the-art processing technology and of product development in India vis-a-vis the world scenario is presented. An attempt has been made to identify technology gap areas requiring attention.  相似文献   
6.
7.
Al-Li alloys being developed as lighter, substitutes for conventional high strength Al alloys are to be processed by routine methods. During extrusion of a 8090 Al-Li alloy, the extrusion die container failed causing some alarm. This failed die container was analysed to examine if the failure was caused by interaction of Li diffusing out of Al-Li alloy with the carbides of die steel. The evidence, although not conclusive, is sufficient to exercise caution during such processing.  相似文献   
8.
An analysis is presented to investigate the effects of buoyancy and curvature on convection along vertical cylinders and needles placed in a micropolar fluid. The governing equations for momentum, angular momentum and energy are solved numerically by finite difference scheme. The heat transfer results are presented for a range of values of the buoyancy parameters, the curvature parameter and the material parameters of the fluid. The effect of the microrotation boundary conditions on heat transfer is discussed.  相似文献   
9.
In this paper, the problem of simultaneous structure from motion estimation for multiple independently moving objects from a monocular image sequence is addressed. Two Bayesian algorithms are presented for solving this problem using the sequential importance sampling (SIS) technique. The empirical posterior distribution of object motion and feature separation parameters is approximated by weighted samples. The first algorithm addresses the problem when only two moving objects are present. A singular value decomposition (SVD)-based sample clustering algorithm is shown to be capable of separating samples related to different objects. A pair of SIS procedures is used to track the posterior distribution of the motion parameters. In the second algorithm, a balancing step is added into the SIS procedure to preserve samples of low weights so that all objects have enough samples to propagate empirical motion distributions. By using the proposed algorithms, the relative motions of all the moving objects with respect to the camera can be simultaneously estimated. Both algorithms have been tested on synthetic and real-image sequences. Improved results have been achieved.  相似文献   
10.
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