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   1055篇
  免费   50篇
  国内免费   6篇
电工技术   12篇
综合类   2篇
化学工业   237篇
金属工艺   36篇
机械仪表   46篇
建筑科学   22篇
矿业工程   2篇
能源动力   93篇
轻工业   86篇
水利工程   6篇
石油天然气   13篇
无线电   140篇
一般工业技术   262篇
冶金工业   50篇
原子能技术   10篇
自动化技术   94篇
  2024年   3篇
  2023年   24篇
  2022年   42篇
  2021年   48篇
  2020年   46篇
  2019年   36篇
  2018年   56篇
  2017年   52篇
  2016年   54篇
  2015年   26篇
  2014年   54篇
  2013年   74篇
  2012年   60篇
  2011年   75篇
  2010年   42篇
  2009年   42篇
  2008年   62篇
  2007年   41篇
  2006年   30篇
  2005年   26篇
  2004年   14篇
  2003年   15篇
  2002年   26篇
  2001年   9篇
  2000年   11篇
  1999年   11篇
  1998年   14篇
  1997年   9篇
  1996年   7篇
  1995年   5篇
  1994年   8篇
  1993年   6篇
  1992年   8篇
  1991年   9篇
  1990年   10篇
  1989年   3篇
  1988年   7篇
  1987年   3篇
  1986年   5篇
  1985年   6篇
  1984年   7篇
  1982年   4篇
  1981年   4篇
  1980年   4篇
  1979年   3篇
  1977年   3篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
  1968年   1篇
排序方式: 共有1111条查询结果,搜索用时 15 毫秒
1.
Wireless Personal Communications - A dual purpose system is presented in this paper which serves not only as a door closer, but is equally effective for surveillance purposes. The currently...  相似文献   
2.
3.
4.
The Journal of Supercomputing - In the last decade, cloud computing has brought enormous changes to people’s lives. Cloud computing gives a client-driven computational model. In this case,...  相似文献   
5.
A theoretical analysis of the springback of narrow rectangular strips of non-linear work-hardening material under torsional loading has been carried out. This theoretical analysis is supported by experimental results for rectangular mild steel strips of different thicknesses and lengths. Finally an analytical generalized expression relating angle of twist to twisting moment and residual angle of twist per unit length for rectangular strips under plastic torsion is obtained in non-dimensionalized form. A comparison between the results obtained for bars of non- linear and linear work-hardening materials loaded under torsion is also made.  相似文献   
6.
Some substituted coumarins have been synthesized by von-Pechmann condensation using SnCl2 · 2H2O (10 mol %) as catalyst in ethanolic medium. The reactions are simple, easy in handling and environmentally benign.  相似文献   
7.
Buffalo milk Cheddar cheese samples of different ages were analysed for compositional attributes (CA), ripening indices (RI) and Instron Textural Profile (ITP). All samples were compositionally alike, except for pH and salt-in-moisture (SM) contents. RI showed significant variations. CA and RI showed highly significant correlations within themselves and with each other, except for moisture with pH, SM with moisture, MNFS, Fat and FDM and Fat with MNFS. The ITPs of cheeses showed significant variations and had highly significant intercorrelations indicating their interdependence. CA (except moisture and MNFS) and RI showed a highly significant correlationship with ITPs. Moisture content showed a highly significant correlationship with all ITPs, except cohesiveness and springiness, where it was significant. MNFS content showed significant correlations only with hardness and brittleness. Stepwise regression analysis revealed that MI was the most predominant factor influencing cheese texture, followed by pH, SM, FDM and TVFA. Knowing Ca and RI, the textural properties of cheeses can be forecast through mathematical equations. Similarly the age of cheese can also be predicted if RI and/or textural properties are known.  相似文献   
8.
9.
At high temperatures in clean oxidizing environments, SiC forms a very protective SiO2 film, but, in environments containing low levels of gaseous alkali salt contaminants or where condensed salts may deposit on the surface, the resistance of the film is significantly reduced. Oxidation kinetics of SiC were measured by continuous thermogravimetric analysis in a controlled environment containing CO2, H2O, and O2 plus low levels of potassium-containing salts. Potassium was found to be incorporated into the SiO2 scale and to significantly change its transport properties and its morphology. The rate of scale formation was found to increase directly in proportion to K in the scale. A change in mechanism was observed when water vapor was added to the reacting gas stream.  相似文献   
10.
Low-power and high-speed discrete cosine transform (DCT) implementation of the images captured by the satellites presents a hardware design problem. The cost of the DCT implementation is dominated by the complexity of the multiplication of input data (image) with the DCT matrix. The techniques for minimising the complexity of multiplication by employing a differential pixel method are presented. In the proposed method 8times8 blocks of input image matrix are considered, the difference between the adjacent pixels is calculated and those differential pixels are used in DCT transformation. Synthesis results on 0.18 mum CMOS technology show that the proposed method gives an average of 13.2% reduction in power consumption and 10.9% improvement in speed over the conventional method. The proposed method can also be combined with the common subexpression elimination method for further reduction.  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