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   177041篇
  免费   1656篇
  国内免费   229篇
电工技术   2671篇
综合类   140篇
化学工业   28516篇
金属工艺   9638篇
机械仪表   5937篇
建筑科学   3574篇
矿业工程   1918篇
能源动力   2873篇
轻工业   9578篇
水利工程   2782篇
石油天然气   8703篇
武器工业   13篇
无线电   15069篇
一般工业技术   39676篇
冶金工业   29283篇
原子能技术   6996篇
自动化技术   11559篇
  2019年   1690篇
  2018年   3144篇
  2017年   3201篇
  2016年   3533篇
  2015年   1861篇
  2014年   3202篇
  2013年   6897篇
  2012年   4704篇
  2011年   5936篇
  2010年   4825篇
  2009年   5281篇
  2008年   5368篇
  2007年   5284篇
  2006年   4501篇
  2005年   4130篇
  2004年   3923篇
  2003年   3737篇
  2002年   3675篇
  2001年   3630篇
  2000年   3518篇
  1999年   3365篇
  1998年   7275篇
  1997年   5340篇
  1996年   3974篇
  1995年   3054篇
  1994年   2715篇
  1993年   2854篇
  1992年   2384篇
  1991年   2377篇
  1990年   2497篇
  1989年   2393篇
  1988年   2405篇
  1987年   2256篇
  1986年   2300篇
  1985年   2371篇
  1984年   2298篇
  1983年   2195篇
  1982年   2045篇
  1981年   2275篇
  1980年   2121篇
  1979年   2352篇
  1978年   2498篇
  1977年   2495篇
  1976年   3150篇
  1975年   2301篇
  1974年   2337篇
  1973年   2388篇
  1972年   2179篇
  1971年   1937篇
  1970年   1724篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Grachev  A. I. 《Semiconductors》2022,56(2):67-70
Semiconductors - In this work, we discuss for the first time the principle of rotation in the constant electric field of a conducting particle with participation of the Lorentz force, which ensures...  相似文献   
2.
Journal of Communications Technology and Electronics - A quantitative comparison of the spectral characteristics of the human visual system and matrix photodetectors is carried out. Criteria for a...  相似文献   
3.
Refractories and Industrial Ceramics - The paper introduces a promising technology for utilizing a traditional scheme for implementing a flow-through micro-arc oxidation method to restore localized...  相似文献   
4.
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid...  相似文献   
5.
Journal of Communications Technology and Electronics - In recent years, there has been a rapid improvement in photonics products due to the use of multilayer heterostructures grown on the basis of...  相似文献   
6.
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability.  相似文献   
7.
Automation and Remote Control - A linear-quadratic positional differential game of three persons is considered. Coefficient criteria are established under which there is no Nash equilibrium...  相似文献   
8.
Russian Engineering Research - Digital tools for managing improvements in automobile production are developed. An operative tool provides warnings regarding the operational quality of the vehicles...  相似文献   
9.
Theoretical Foundations of Chemical Engineering - Using gas–liquid chromatography, the activity coefficients upon the infinite dilution of the components of the reaction mixture for obtaining...  相似文献   
10.
Ceria-based solid solutions are important materials for high- and medium-temperature electrochemical applications. However, the stabilities of both binary and ternary ceria-based solid solutions are insufficient at elevated temperatures, which limits their application as solid electrolytes or SOFC cathodes. Data on the high-temperature stability of ceria-based ceramics are unavailable in the literature. In the present study, we report a thermodynamic stability investigation of Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions. The thermal prehistories of binary and ternary systems were investigated using STA, XRD, and ESCA techniques. The vaporization processes were investigated in the temperature range of 1577–2227°С via the Knudsen effusion mass spectrometry technique. Using data on the component activity in solid-phase thermodynamic properties of Y2O3-CeO2 solid solutions, which is represented as the Gibbs energy, the excess Gibbs energy was calculated as a function of the ceria mol. %. It was shown that the reduction of Ce4+ to Ce3+ in Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions corresponds to less-negative Gibbs energy compared to ZrO2-CeO2 solid solutions.  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