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   409951篇
  免费   24880篇
  国内免费   12962篇
电工技术   18767篇
技术理论   56篇
综合类   21417篇
化学工业   66989篇
金属工艺   22857篇
机械仪表   23874篇
建筑科学   27762篇
矿业工程   11450篇
能源动力   10798篇
轻工业   21970篇
水利工程   6474篇
石油天然气   23281篇
武器工业   2600篇
无线电   45182篇
一般工业技术   54651篇
冶金工业   20789篇
原子能技术   3466篇
自动化技术   65410篇
  2024年   1296篇
  2023年   5230篇
  2022年   8908篇
  2021年   12579篇
  2020年   9848篇
  2019年   8041篇
  2018年   22068篇
  2017年   22336篇
  2016年   18287篇
  2015年   12801篇
  2014年   16122篇
  2013年   19408篇
  2012年   23112篇
  2011年   31127篇
  2010年   26812篇
  2009年   23400篇
  2008年   24273篇
  2007年   24688篇
  2006年   18412篇
  2005年   17285篇
  2004年   11411篇
  2003年   10260篇
  2002年   8671篇
  2001年   7583篇
  2000年   8191篇
  1999年   9741篇
  1998年   8225篇
  1997年   6804篇
  1996年   6412篇
  1995年   5349篇
  1994年   4397篇
  1993年   3101篇
  1992年   2508篇
  1991年   1985篇
  1990年   1508篇
  1989年   1235篇
  1988年   1028篇
  1987年   682篇
  1986年   535篇
  1985年   342篇
  1984年   243篇
  1983年   204篇
  1982年   196篇
  1981年   130篇
  1980年   130篇
  1979年   67篇
  1976年   55篇
  1965年   49篇
  1955年   63篇
  1954年   68篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
72.
Gesture plays an important role for recognizing lecture activities in video content analysis. In this paper, we propose a real-time gesture detection algorithm by integrating cues from visual, speech and electronic slides. In contrast to the conventional “complete gesture” recognition, we emphasize detection by the prediction from “incomplete gesture”. Specifically, intentional gestures are predicted by the modified hidden Markov model (HMM) which can recognize incomplete gestures before the whole gesture paths are observed. The multimodal correspondence between speech and gesture is exploited to increase the accuracy and responsiveness of gesture detection. In lecture presentation, this algorithm enables the on-the-fly editing of lecture slides by simulating appropriate camera motion to highlight the intention and flow of lecturing. We develop a real-time application, namely simulated smartboard, and demonstrate the feasibility of our prediction algorithm using hand gesture and laser pen with simple setup without involving expensive hardware.   相似文献   
73.
State space explosion is a key problem in the analysis of finite state systems. The sweep-line method is a state exploration method which uses a notion of progress to allow states to be deleted from memory when they are no longer required. This reduces the peak number of states that need to be stored, while still exploring the full state space. The technique shows promise but has never achieved reductions greater than about a factor of 10 in the number of states stored in memory for industrially relevant examples. This paper discusses sweep-line analysis of the connection management procedures of a new Internet standard, the Datagram Congestion Control Protocol (DCCP). As the intuitive approaches to sweep-line analysis are not effective, we introduce new variables to track progress. This creates further state explosion. However, when used with the sweep-line, the peak number of states is reduced by over two orders of magnitude compared with the original. Importantly, this allows DCCP to be analysed for larger parameter values. Somsak Vanit-Anunchai was partially supported by an Australian Research Council Discovery Grant (DP0559927) and Suranaree University of Technology. Guy Edward Gallasch was supported by an Australian Research Council Discovery Grant (DP0559927).  相似文献   
74.
This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time and promising to be merged into other application systems. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008  相似文献   
75.
含V、N无缝钢管表面外折缺陷产生原因的分析   总被引:1,自引:0,他引:1  
通过对鞍钢生产的部分批号V、N微合金强化无缝钢管及生产该钢管的原料连铸坯和连轧管坯的表面缺陷进行研究,分析了含V、N钢管表面外折缺陷的成因,提出了改善钢管表面质量的方法。采用改进后工艺生产的无缝管,其表面外折废品量大幅度降低。  相似文献   
76.
77.
78.
79.
80.
An improved multivariable, probabilistic method for the safety analysis of power grounding systems is presented. The application of this method is demonstrated in four examples. The first three examples illustrate the practical evaluation of one new and two existing substation grounding grids when the substation is connected to an overhead distribution system. The fourth example ascertains the relative impact of a difference between the S curve of IEC Publication 479 and Dalziel's equation for the allowable body current used in ANSI/IEEE Std 80-1986 on the validity of an exposure model based on the requirements of Std 80. In this example, the statistical data on ground faults have been taken from actual system records. Further possible refinements of the exposure model are discussed  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