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   13660篇
  免费   1256篇
  国内免费   16篇
电工技术   134篇
综合类   8篇
化学工业   3458篇
金属工艺   185篇
机械仪表   418篇
建筑科学   591篇
矿业工程   30篇
能源动力   337篇
轻工业   2629篇
水利工程   115篇
石油天然气   39篇
无线电   1039篇
一般工业技术   2643篇
冶金工业   952篇
原子能技术   41篇
自动化技术   2313篇
  2024年   46篇
  2023年   194篇
  2022年   233篇
  2021年   531篇
  2020年   408篇
  2019年   409篇
  2018年   543篇
  2017年   546篇
  2016年   654篇
  2015年   542篇
  2014年   751篇
  2013年   1317篇
  2012年   1144篇
  2011年   979篇
  2010年   732篇
  2009年   685篇
  2008年   691篇
  2007年   621篇
  2006年   568篇
  2005年   388篇
  2004年   335篇
  2003年   317篇
  2002年   293篇
  2001年   196篇
  2000年   157篇
  1999年   142篇
  1998年   226篇
  1997年   189篇
  1996年   139篇
  1995年   129篇
  1994年   96篇
  1993年   99篇
  1992年   56篇
  1991年   44篇
  1990年   38篇
  1989年   41篇
  1988年   41篇
  1987年   20篇
  1986年   32篇
  1985年   39篇
  1984年   29篇
  1983年   27篇
  1982年   26篇
  1981年   22篇
  1980年   24篇
  1979年   25篇
  1978年   14篇
  1977年   14篇
  1976年   21篇
  1973年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Hyperbaric storage (HS) was evaluated as a new food preservation methodology at room temperature (RT) for beef and pork meat, both minced and in pieces, and compared to refrigeration (RF) storage. The meat samples were stored at 50, 75 and 100 MPa and variable RT up to 60 days. HS at 75 and 100 MPa could not only inhibit microbial growth but also inactivate microorganisms. Regarding physicochemical analyses, an overall equal to better pH maintenance in HS samples was achieved, and similar colour differences between HS and RF were observed. Generally, similarities in moisture content and drip loss between HS (mostly 75 and 100 MPa) and RF were detected (tendency for lower values in the former and higher values in the latter for the higher pressure level). Protein solubility revealed a decrease of sarcoplasmic protein values during storage with a pressure level dependency in some samples.  相似文献   
23.
Chiral molecules, especially enantiomers and diastereomers of purity > 99 %, present a significant market share within the chemical, pharmaceutical, and flavor industries. Antisolvent precipitations, both batch and semicontinuous operations to serve the current trends in flow chemistry were demonstrated to be environmentally benign and efficient tools in achieving high optical purities. Although salts are known to be insoluble in supercritical CO2, instabilities of the nascent salts were detected and applied for increasing efficiency. Diastereomeric excess values of the crystalline products exceeded 99 % in maximum of three consecutive steps both by repeated resolution with half molar equivalent of the amine to the acid and by direct recrystallization of the salts.  相似文献   
24.
25.
26.
The Journal of Supercomputing - Deadlock-free dynamic network reconfiguration process is usually studied from the routing algorithm restrictions and resource reservation perspective. The dynamic...  相似文献   
27.
Neural Computing and Applications - The goal of this paper is to introduce a novel hybrid model called multi-fuzzy N-soft set, and to design an adjustable decision-making methodology for solving...  相似文献   
28.
Supercritical fluid dyeing is a promising technology that was first proposed in the 1980s to overcome the high energy demand and water consumption of conventional textile coloration. This review covers its advances from 2014 to the present, from the successful industrial implementation of supercritical fluid dyeing of polyethylene terephthalate to the most recent results obtained for the dyeing of other synthetic and natural textiles. Specific attention is also dedicated to the most innovative applications of supercritical fluid dyeing such as the functionalisation of textile and non‐textile substrates, which may give rise to the development of other sustainable processes or novel advanced materials in the near future.  相似文献   
29.
Abstract

In this work, a new g-C3N4-based Z-scheme with γ-Fe2O3 and β-Ag2Se both n-type semiconductors, and graphite to favor electron exchange is presented. The composite material was studied by XRD, FTIR, UV-Vis, TEM, XPS, TGA, DSC and TOF-SIMS, and the ability of this photocatalytic system to act as a photo-reductant was assessed using crystal violet (CV+) dye. Solar light driven photo-reduction of CV+ in the presence of tri-sodium citrate evidenced a synergistic enhancement of the activity of the composite toward reduction, with ~20 times higher conversion rates per unit of surface area than those of g-C3N4. Photo-oxidation experiments under Xe lamp irradiation in the presence of H2O2 also showed that the AgFeCN composite featured a higher activity (~8×) than g-C3N4. This Z-scheme may deserve further study as a photo-reductant to obtain hydrogen or hydrogenated compounds. Moreover, the use of CV+ may represent a facile procedure that can aid in the selection of new photocatalysts to be used in hydrogen production.  相似文献   
30.
Personal and Ubiquitous Computing - This article presents a study concerning the evaluation of a smart home control system for elderly people with a sample of 10 users in a city in the interior of...  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