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   209660篇
  免费   16329篇
  国内免费   479篇
电工技术   3598篇
综合类   504篇
化学工业   43955篇
金属工艺   10096篇
机械仪表   6761篇
建筑科学   5103篇
矿业工程   2043篇
能源动力   3673篇
轻工业   15936篇
水利工程   3109篇
石油天然气   8969篇
武器工业   87篇
无线电   21861篇
一般工业技术   49917篇
冶金工业   28741篇
原子能技术   7017篇
自动化技术   15098篇
  2021年   2109篇
  2020年   2843篇
  2019年   4836篇
  2018年   6211篇
  2017年   6627篇
  2016年   7330篇
  2015年   5773篇
  2014年   7055篇
  2013年   11483篇
  2012年   7338篇
  2011年   8067篇
  2010年   7327篇
  2009年   7640篇
  2008年   7161篇
  2007年   6910篇
  2006年   5958篇
  2005年   5318篇
  2004年   5091篇
  2003年   4904篇
  2002年   4767篇
  2001年   4629篇
  2000年   4494篇
  1999年   3765篇
  1998年   7159篇
  1997年   5278篇
  1996年   3904篇
  1995年   2989篇
  1994年   2677篇
  1993年   2771篇
  1992年   2301篇
  1991年   2348篇
  1990年   2453篇
  1989年   2341篇
  1988年   2330篇
  1987年   2205篇
  1986年   2265篇
  1985年   2302篇
  1984年   2212篇
  1983年   2139篇
  1982年   1988篇
  1981年   2201篇
  1980年   2062篇
  1979年   2274篇
  1978年   2436篇
  1977年   2435篇
  1976年   3103篇
  1975年   2247篇
  1974年   2312篇
  1973年   2348篇
  1972年   2155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.
直通链路技术己广泛应用于车联网场景。对于直通链路技术的潜在技术方向给出可行的建议,包括传统直通链路技术的增强方向,如载波聚合、使用非授权频谱等;侧行链路对于中继场景的应用扩展,包括终端到终端之间的中继,以及中继的多链接场景;在高精度定位场景使用直通链路技术。并且,给出直通链路技术与各种新技术的融合应用,如智能反射面与区块链技术,从而解决直通链路技术自身的缺陷。  相似文献   
5.
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   
6.
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   
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.
Recent advances in three‐dimensional (3D) printing have enabled the fabrication of interesting structures which are not achievable using traditional fabrication approaches. The 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks, which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through a facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions with a chitosan polymer matrix are achieved. Consequently, the mechanical properties of the 3D printed composites improve when nanogrooved carbon microtubes are used, compared to untreated microtubes. We show that by carefully controlling the coagulation bath, extrusion pressure, printing distance and printed line distance, we can 3D print composite lattices which are composed of well‐defined and separated printed lines. The conductive composite 3D structures with highly customised design presented in this work provide a suitable platform for applications ranging from soft robotics to smart tissue engineering scaffolds. © 2019 Society of Chemical Industry  相似文献   
9.
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   
10.
Ultrawide band gap semiconductor materials have attracted considerable attention in recent years owing to their great potential in the photocatalytic field. In this study, Zn-doped Ga2O3 nanofibers with various concentrations were synthesized via electrospinning; they exhibited a superior photocatalytic degradation performance of rhodamine B dye compared to that of undoped Ga2O3 nanofibers. The Zn dopant replaced Ga sites via replacement doping, which could increase the concentration of oxygen vacancies and lead to enhanced photocatalytic properties. When the Zn concentration increased, a Ga2O3/ZnGa2O4 hybrid structure formed, which could further enhance the photocatalytic performance. The separation of photogenerated carriers due to Zn doping and heterojunctions were the primary causes of the enhanced photocatalytic performance. This study provides experimental data for the fabrication of high-performance photocatalysts based on Ga2O3 nanomaterials.  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