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   178627篇
  免费   1986篇
  国内免费   448篇
电工技术   2856篇
综合类   517篇
化学工业   28337篇
金属工艺   9861篇
机械仪表   6114篇
建筑科学   3562篇
矿业工程   2048篇
能源动力   2979篇
轻工业   9898篇
水利工程   2838篇
石油天然气   8999篇
武器工业   90篇
无线电   15472篇
一般工业技术   39694篇
冶金工业   29455篇
原子能技术   6996篇
自动化技术   11345篇
  2021年   1851篇
  2019年   1747篇
  2018年   3287篇
  2017年   3401篇
  2016年   3659篇
  2015年   1972篇
  2014年   3359篇
  2013年   6951篇
  2012年   4904篇
  2011年   6088篇
  2010年   4972篇
  2009年   5369篇
  2008年   5489篇
  2007年   5368篇
  2006年   4592篇
  2005年   4181篇
  2004年   3937篇
  2003年   3818篇
  2002年   3738篇
  2001年   3708篇
  2000年   3584篇
  1999年   3446篇
  1998年   7601篇
  1997年   5503篇
  1996年   4086篇
  1995年   3071篇
  1994年   2741篇
  1993年   2843篇
  1992年   2307篇
  1991年   2359篇
  1990年   2446篇
  1989年   2359篇
  1988年   2363篇
  1987年   2219篇
  1986年   2267篇
  1985年   2323篇
  1984年   2226篇
  1983年   2158篇
  1982年   2009篇
  1981年   2229篇
  1980年   2074篇
  1979年   2286篇
  1978年   2450篇
  1977年   2472篇
  1976年   3140篇
  1975年   2257篇
  1974年   2311篇
  1973年   2353篇
  1972年   2166篇
  1971年   1916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.
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   
7.
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   
8.
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   
9.
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   
10.
Fullerenes are candidates for theranostic applications because of their high photodynamic activity and intrinsic multimodal imaging contrast. However, fullerenes suffer from low solubility in aqueous media, poor biocompatibility, cell toxicity, and a tendency to aggregate. C70@lysozyme is introduced herein as a novel bioconjugate that is harmless to a cellular environment, yet is also photoactive and has excellent optical and optoacoustic contrast for tracking cellular uptake and intracellular localization. The formation, water-solubility, photoactivity, and unperturbed structure of C70@lysozyme are confirmed using UV-visible and 2D 1H, 15N NMR spectroscopy. The excellent imaging contrast of C70@lysozyme in optoacoustic and third harmonic generation microscopy is exploited to monitor its uptake in HeLa cells and lysosomal trafficking. Last, the photoactivity of C70@lysozyme and its ability to initiate cell death by means of singlet oxygen (1O2) production upon exposure to low levels of white light irradiation is demonstrated. This study introduces C70@lysozyme and other fullerene-protein conjugates as potential candidates for theranostic applications.  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