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   515927篇
  免费   7094篇
  国内免费   1407篇
电工技术   10116篇
综合类   869篇
化学工业   76375篇
金属工艺   18650篇
机械仪表   15533篇
建筑科学   12875篇
矿业工程   1842篇
能源动力   13701篇
轻工业   47337篇
水利工程   4690篇
石油天然气   7034篇
武器工业   75篇
无线电   66086篇
一般工业技术   97866篇
冶金工业   95772篇
原子能技术   9639篇
自动化技术   45968篇
  2021年   3947篇
  2019年   3802篇
  2018年   6429篇
  2017年   6351篇
  2016年   6681篇
  2015年   4488篇
  2014年   7708篇
  2013年   23419篇
  2012年   12580篇
  2011年   17331篇
  2010年   13568篇
  2009年   15537篇
  2008年   16552篇
  2007年   16346篇
  2006年   14767篇
  2005年   13500篇
  2004年   13121篇
  2003年   12836篇
  2002年   12368篇
  2001年   12469篇
  2000年   11964篇
  1999年   12433篇
  1998年   29069篇
  1997年   21042篇
  1996年   16627篇
  1995年   12958篇
  1994年   11627篇
  1993年   11285篇
  1992年   8739篇
  1991年   8277篇
  1990年   8082篇
  1989年   7649篇
  1988年   7434篇
  1987年   6373篇
  1986年   6364篇
  1985年   7532篇
  1984年   6914篇
  1983年   6392篇
  1982年   5835篇
  1981年   6097篇
  1980年   5633篇
  1979年   5483篇
  1978年   5212篇
  1977年   6157篇
  1976年   7812篇
  1975年   4666篇
  1974年   4489篇
  1973年   4545篇
  1972年   3685篇
  1971年   3365篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
51.
Topics in Catalysis - In this work, a simple thermal-catalytic system was used to valorize peanut shells (Arachis hypogaea), the residual biomass from the peanut industry. To accomplish this...  相似文献   
52.
Potato processing industry has a high degree of discarding, which currently has low added value being used primarily for animal feed. However, potato wastes offer a broad range of interesting components such as antioxidants, starch, protein or fibre with potential applications in the food and non-food industries. The recovery of these high valuable fractions using efficient multistage and multiproduct processes could be of great interest. This short review provides a general overview on the integral valorisation of potato wastes, offering an updated vision of the main residual parts generated during potato harvesting and processing, the high valuable obtained components focusing on the bioactive ones and the potential of the emerging extraction techniques over conventional ones. In addition, innovative applications are discussed to highlight the scientific and applied interest of these underutilised and undervalued fractions and to emphasise the integral valorisation of raw materials.  相似文献   
53.
Theoretical Foundations of Chemical Engineering - New research results, as well as those published earlier by the authors, on the synthesis of azo compounds based on nitroanilines obtained by the...  相似文献   
54.
A method is proposed to generate categorical colour observer functions (individual colour matching functions) for any field size based on the CIE 2006 system of physiological observer functions. The method combines proposed categorical observer techniques of Sarkar et al with a physiologically-based individual observer model of Asano et al and a clustering technique to produce the optimal set of categorical observers. The number of required categorical observers varies depending on an application with as many as 50 required to predict individual observers' matches when a laser projector is viewed. However, 10 categorical observers are sufficient to represent colour-normal populations for personalized colour imaging. The proposed and recommended categorical observers represent a robust and inclusive technique to examine and quantify observer metamerism in any application of colorimetry.  相似文献   
55.
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with...  相似文献   
56.
57.
58.
59.
Metallurgical and Materials Transactions A - The influence of the chemical composition on the crystallization process, amorphous phase formation, and the anticorrosion properties of Al-Zr-Ni-Fe-Y...  相似文献   
60.
ABSTRACT

This paper deals with asymptotic stabilisation of a class of nonlinear input-delayed systems via dynamic output feedback in the presence of disturbances. The proposed strategy has the structure of an observer-based control law, in which the observer estimates and predicts both the plant state and the external disturbance. A nominal delay value is assumed to be known and stability conditions in terms of linear matrix inequalities are derived for fast-varying delay uncertainties. Asymptotic stability is achieved if the disturbance or the time delay is constant. The controller design problem is also addressed and a numerical example with an unstable system is provided to illustrate the usefulness of the proposed strategy.  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