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   1499262篇
  免费   30882篇
  国内免费   8729篇
电工技术   36669篇
技术理论   5篇
综合类   9246篇
化学工业   274928篇
金属工艺   66366篇
机械仪表   43703篇
建筑科学   48597篇
矿业工程   13025篇
能源动力   51608篇
轻工业   109159篇
水利工程   15302篇
石油天然气   40792篇
武器工业   521篇
无线电   199367篇
一般工业技术   279826篇
冶金工业   143061篇
原子能技术   34458篇
自动化技术   172240篇
  2021年   17521篇
  2020年   13262篇
  2019年   15781篇
  2018年   15995篇
  2017年   15396篇
  2016年   22046篇
  2015年   19092篇
  2014年   30999篇
  2013年   90307篇
  2012年   36945篇
  2011年   48661篇
  2010年   44136篇
  2009年   52585篇
  2008年   45265篇
  2007年   42143篇
  2006年   46056篇
  2005年   40162篇
  2004年   41663篇
  2003年   41439篇
  2002年   40664篇
  2001年   36872篇
  2000年   35802篇
  1999年   34671篇
  1998年   38606篇
  1997年   35659篇
  1996年   33377篇
  1995年   29826篇
  1994年   28052篇
  1993年   27717篇
  1992年   25978篇
  1991年   22952篇
  1990年   23308篇
  1989年   22333篇
  1988年   20791篇
  1987年   19123篇
  1986年   18370篇
  1985年   21709篇
  1984年   22087篇
  1983年   20043篇
  1982年   19091篇
  1981年   19200篇
  1980年   17793篇
  1979年   18367篇
  1978年   17613篇
  1977年   17104篇
  1976年   17519篇
  1975年   15904篇
  1974年   15426篇
  1973年   15517篇
  1972年   12995篇
排序方式: 共有10000条查询结果,搜索用时 687 毫秒
21.
Theoretical Foundations of Chemical Engineering - On the basis of the classic concepts of the theory of solid-phase combustion, for the first time, a model with a detailed scheme of chemical...  相似文献   
22.
23.
Multimedia Tools and Applications - Recently, many concepts in technology has been changed. According to the digital transformation trends, Internet of Things (IoT) represents an interested...  相似文献   
24.
In this study, dilute chemical bath deposition technique has been used to deposit CdZnS thin films on soda-lime glass substrates. The structural, morphological, optoelectronic properties of as-grown films have been investigated as a function of different Zn2+ precursor concentrations. The X-ray diffractogram of CdS thin-film reveals a peak corresponding to (002) plane with wurtzite structure, and the peak shift has been observed with the increase of the Zn2+ concentration upon formation of CdZnS thin film. From morphological studies, it has been revealed that the diluted chemical bath deposition technique provides homogeneous distribution of film on the substrate even at a lower concentration of Zn2+. Optical characterization has shown that the transparency of the film is influenced by Zn2+ concentration and when the Zn2+ concentration is varied from 0 M to 0.0256 M, bandgap values of resulting films range from 2.42 eV to 3.90 eV while. Furthermore, electrical properties have shown that with increasing zinc concentration the resistivity of the film increases. Finally, numerical simulation validates and suggests that CdZnS buffer layer with composition of 0.0032 M Zn2+ concentration would be a promising candidate in CIGS solar cell.  相似文献   
25.
Zhao  Ziyu  Lin  Haitao  Ma  Pibo 《Applied Composite Materials》2022,29(4):1675-1694
Applied Composite Materials - In this paper, the low-velocity impact deformation behavior of biaxial warp-knitted flexible composite was investigated. A simplified finite element model (FEM) of the...  相似文献   
26.
The effects of high-pressure-modified soy 11S globulin (0.1, 200, and 400 MPa) on the gel properties, water-holding capacity, and water mobility of pork batter were investigated. The high-pressure-modified soy 11S globulin significantly increased (P < 0.05) the emulsion stability, cooking yield, hardness, springiness, chewiness, resilience, cohesiveness, the a* and b* values, and the G′ and G′′ values of pork batter at 80 °C, compared with those of 0.1 MPa-modified globulin. In contrast, the centrifugal loss and initial relaxation time of T2b, T21, and T22 significantly decreased (P < 0.05). Meanwhile, the microstructure was denser, and the voids were smaller and more uniform compared with those of 0.1 MPa-modified globulin. In addition, the sample with 11S globulin modified at 400 MPa had the best water-holding capacity, gel structure, and gel properties among the samples. Overall, the use of high-pressure-modified soy 11S globulin improved the gel properties and water-holding capacity of pork batter, especially under 400 MPa.  相似文献   
27.
Combustion, Explosion, and Shock Waves - Results of a numerical study of mixing, ignition, and combustion of a cold hydrogen jet propagating along the lower wall of a channel parallel to a...  相似文献   
28.
Multimedia Tools and Applications - In this work, a new fuzzy logic-based algorithm is proposed for the enhancement of low light color images. A generalization of a fuzzy set known as an...  相似文献   
29.
Multimedia Tools and Applications - The three-dimensional models of brain tumors serve as diagnostic assistance for physicians, surgeons, and radiologists. The proposed system establishes an...  相似文献   
30.

We discuss the temperature dependence of a common low temperature local thermometer, a tunnel junction between a superconductor and a normal metal (NIS junction). Towards the lowest temperatures its characteristics tend to saturate, which is usually attributed to selfheating effects. In this technical note, we reanalyze this saturation and show that the temperature independent subgap current of the junction alone explains in some cases the low temperature behavior quantitatively.

  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