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   278015篇
  免费   4839篇
  国内免费   831篇
电工技术   5458篇
综合类   387篇
化学工业   41757篇
金属工艺   10773篇
机械仪表   8923篇
建筑科学   7091篇
矿业工程   1197篇
能源动力   6724篇
轻工业   25400篇
水利工程   2681篇
石油天然气   3934篇
武器工业   72篇
无线电   35832篇
一般工业技术   54791篇
冶金工业   47055篇
原子能技术   5577篇
自动化技术   26033篇
  2021年   2450篇
  2020年   1878篇
  2019年   2352篇
  2018年   4092篇
  2017年   4175篇
  2016年   4448篇
  2015年   2929篇
  2014年   4802篇
  2013年   12765篇
  2012年   7443篇
  2011年   9965篇
  2010年   7908篇
  2009年   8696篇
  2008年   9613篇
  2007年   9515篇
  2006年   8475篇
  2005年   7685篇
  2004年   7328篇
  2003年   7164篇
  2002年   6826篇
  2001年   6820篇
  2000年   6492篇
  1999年   6519篇
  1998年   14460篇
  1997年   10497篇
  1996年   8301篇
  1995年   6615篇
  1994年   5874篇
  1993年   5720篇
  1992年   4693篇
  1991年   4334篇
  1990年   4155篇
  1989年   3885篇
  1988年   3715篇
  1987年   3268篇
  1986年   3145篇
  1985年   3765篇
  1984年   3560篇
  1983年   3152篇
  1982年   2964篇
  1981年   3094篇
  1980年   2872篇
  1979年   2738篇
  1978年   2593篇
  1977年   3029篇
  1976年   3632篇
  1975年   2401篇
  1974年   2389篇
  1973年   2392篇
  1972年   1886篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
To overcome the drawbacks of solid microporous materials for CO2 capture, this proof‐of‐concept study demonstrates a low‐cost and rapid method for producing composites consisting of hypercrosslinked polymers (HCP) with a polyethyleneimine (PEI) binder. The resulting materials capture CO2 through physical and chemical absorption simultaneously. Compared with HCP, the composites exhibit higher CO2 uptake, higher volumetric density, and improved tolerance to water which is attributed to the PEI binder.  相似文献   
42.
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   
43.
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   
44.
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   
45.
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   
46.
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   
47.
Neural Computing and Applications - This study presents the design of a tenth-order multiple feedback Chebyshev low-pass filter (MF-C-LPF). Component selection and gain calculation of filters are...  相似文献   
48.
49.
Metallurgical and Materials Transactions B - The quality requirements of aluminum products are steadily increasing, and the presence of non-metallic inclusions have a large impact on the quality of...  相似文献   
50.
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