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   1435篇
  免费   144篇
  国内免费   118篇
电工技术   33篇
综合类   134篇
化学工业   25篇
金属工艺   22篇
机械仪表   76篇
建筑科学   75篇
矿业工程   15篇
能源动力   14篇
轻工业   1篇
水利工程   14篇
石油天然气   4篇
武器工业   12篇
无线电   198篇
一般工业技术   93篇
冶金工业   75篇
原子能技术   9篇
自动化技术   897篇
  2024年   2篇
  2023年   18篇
  2022年   16篇
  2021年   14篇
  2020年   32篇
  2019年   19篇
  2018年   22篇
  2017年   31篇
  2016年   42篇
  2015年   48篇
  2014年   87篇
  2013年   78篇
  2012年   78篇
  2011年   107篇
  2010年   98篇
  2009年   95篇
  2008年   108篇
  2007年   111篇
  2006年   81篇
  2005年   84篇
  2004年   76篇
  2003年   73篇
  2002年   66篇
  2001年   53篇
  2000年   48篇
  1999年   21篇
  1998年   31篇
  1997年   22篇
  1996年   24篇
  1995年   26篇
  1994年   22篇
  1993年   17篇
  1992年   6篇
  1991年   9篇
  1990年   6篇
  1989年   6篇
  1988年   4篇
  1987年   1篇
  1986年   3篇
  1985年   2篇
  1984年   1篇
  1983年   3篇
  1981年   2篇
  1977年   1篇
  1962年   1篇
  1961年   1篇
  1957年   1篇
排序方式: 共有1697条查询结果,搜索用时 15 毫秒
11.
There is no good method to measure the shape and the strain distributions of a structure changing with time. We have previously proposed the Fourier transform grid method (FTGM) to measure the three-dimensional shape and surface strain distributions of stationary objects by analysing the two-dimensional grating images recorded with two cameras. In the stereoscopic method, it is very important to determine the accurate geometric parameters of the camera system. In this paper, the positions and the directions of cameras are accurately determined using the FTGM applied to images of a reference object on which a two-dimensional grating is drawn. Applications for analysing shape and strain distributions of vibrating rubber plates and a moving human skin are shown.  相似文献   
12.
13.
对象管理     
本文论述了面向对象数据库系统WHYMX的对象管理机制,重点讨论了复杂对象的对象操作。  相似文献   
14.
15.
Maximizing the satisfaction of a value in an engineering design is usually limited by tradeoffs in which other values become unacceptably sacrificed. In a few cases, however, the maximization is limited by a boundary between what is mathematically possible and what is not. Round wheels, vertical pillars, and binary memory elements are examples of optimum engineering structures which result from such mathematical limits. It is proposed that optimum characteristics of a language data model result similarly by minimizing the variety of primitive data objects, the complexity of those objects, and the number of objects needed to represent data states. Reducing these measures is needed to combine both rich data structure and powerful operations in one language. The minimizations lead to a narrow range of designs for language semantics in which the potential advantages of specialization is small compared with the advantages of commonality. Universal language for support of technical literacy appears to be an appropriate scope of generality in language design.  相似文献   
16.
基于C8051F040的CAN总线通讯系统设计   总被引:7,自引:0,他引:7  
田奕  刘秀红 《现代电子技术》2006,29(15):29-30,33
作为一种很有前途的现场总线,CAN总线通信相对于一般的串行通信总线,他的实时性、可靠性和灵活性的特点更加突出。介绍了C8051F040内部集成的CAN控制器的使用方法,给出了以此芯片为核心的CAN总线智能节点通讯接口的硬件和软件设计,实际的运行验证了设计的正确性。其设计通用性好、可靠性高、性价比高,具有广泛的应用前景。  相似文献   
17.
Educational research over the past three years has intensified such that the context of learning resources needs to be properly modeled. Many researchers have described and even mandated the use of ontologies in the research being conducted, yet the process of actually connecting one or more ontologies to a learning object has not been extensively discussed. This paper describes a practical model for associating multiple ontologies with learning objects while making full use of the IEEE LOM specification. The model categorizes these ontologies according to five major categories of context based on the most popular fields of study actively being pursued by the educational research community: Thematic context, Pedagogical context, Learner context, Organizational context, and Historical/Statistical context.  相似文献   
18.
In Part 1 of this two-part series, we introduced Katamic memory—a neural network architecture capable of robust sequence learning and recognition. In Part 2, we introduce the Blobs World taskjdomain for language learning and describe the DETE language learning system, which is composed of over 50 Katamic memory modules. DETE currently learns small subsets of English and Spanish via association with perceptual! motor inputs. In addition to Kaiamic memory, DETE employs several other novel features: (1) use of feature planes, to encode visual shapes, spatial relationships and the motions of objects, (2) phase-locking of neural firing, in order to represent focus of atention and to bind objects across multiple feature planes, and (3) a method for encoding temporal relationships, so that DETE can learn utterances involving the immediate past and future. We compare DETE to related models and discuss the implications of this approach for language-learning research.  相似文献   
19.
This paper presents a robust rule-based approach for the splitting of binary clumps that are formed by objects of diverse shapes and sizes. First, the deepest boundary pixels, i.e., the concavity pixels in a clump, are detected using a fast and accurate scheme. Next, concavity-based rules are applied to generate the candidate split lines that join pairs of concavity pixels. A figure of merit is used to determine the best split line from the set of candidate lines. Experimental results show that the proposed approach is robust and accurate.  相似文献   
20.
复杂形体目标激光散射特征测量系统的研制   总被引:1,自引:0,他引:1  
复杂形体目标激光散射特征的测量系统中,利用反射式离轴光路满足了可见到远红外波段的测量需要,通过大孔径(250mm)物方远心接收光路实现了对实际远场的模拟测量,以光滑镀金球体作为标准器,可直接获得任意目标散射截面的绝对值。在0.6328、1.06和10.6μm三个波段针对标准器的实测结果表明,平均误差小于4.95%。  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