全文获取类型
收费全文 | 309622篇 |
免费 | 3218篇 |
国内免费 | 633篇 |
专业分类
电工技术 | 4564篇 |
综合类 | 2491篇 |
化学工业 | 45681篇 |
金属工艺 | 18927篇 |
机械仪表 | 12986篇 |
建筑科学 | 6559篇 |
矿业工程 | 3015篇 |
能源动力 | 4746篇 |
轻工业 | 13718篇 |
水利工程 | 4629篇 |
石油天然气 | 9979篇 |
武器工业 | 12篇 |
无线电 | 28481篇 |
一般工业技术 | 69085篇 |
冶金工业 | 36828篇 |
原子能技术 | 8024篇 |
自动化技术 | 43748篇 |
出版年
2021年 | 2106篇 |
2019年 | 1954篇 |
2018年 | 21997篇 |
2017年 | 21540篇 |
2016年 | 15875篇 |
2015年 | 3057篇 |
2014年 | 3804篇 |
2013年 | 7600篇 |
2012年 | 9691篇 |
2011年 | 20538篇 |
2010年 | 18132篇 |
2009年 | 15447篇 |
2008年 | 16348篇 |
2007年 | 18582篇 |
2006年 | 4872篇 |
2005年 | 8010篇 |
2004年 | 6479篇 |
2003年 | 6224篇 |
2002年 | 4777篇 |
2001年 | 3816篇 |
2000年 | 3818篇 |
1999年 | 3497篇 |
1998年 | 7375篇 |
1997年 | 5411篇 |
1996年 | 4097篇 |
1995年 | 3151篇 |
1994年 | 2811篇 |
1993年 | 2933篇 |
1992年 | 2404篇 |
1991年 | 2427篇 |
1990年 | 2538篇 |
1989年 | 2446篇 |
1988年 | 2416篇 |
1987年 | 2300篇 |
1986年 | 2356篇 |
1985年 | 2405篇 |
1984年 | 2299篇 |
1983年 | 2228篇 |
1982年 | 2075篇 |
1981年 | 2291篇 |
1980年 | 2129篇 |
1979年 | 2350篇 |
1978年 | 2493篇 |
1977年 | 2513篇 |
1976年 | 3200篇 |
1975年 | 2292篇 |
1974年 | 2350篇 |
1973年 | 2383篇 |
1972年 | 2189篇 |
1971年 | 1929篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
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
3.
Zienko S. I. Zhbanova V. L. 《Journal of Communications Technology and Electronics》2022,67(4):395-402
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
4.
Kuznetsov Yu. A. Markov M. A. Kravchenko I. N. Krasikov A. V. Bykova A. D. 《Refractories and Industrial Ceramics》2021,62(4):421-425
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
5.
Engineering new glass compositions have experienced a sturdy tendency to move forward from (educated) trial-and-error to data- and simulation-driven strategies. In this work, we developed a computer program that combines data-driven predictive models (in this case, neural networks) with a genetic algorithm to design glass compositions with desired combinations of properties. First, we induced predictive models for the glass transition temperature (Tg) using a dataset of 45,302 compositions with 39 different chemical elements, and for the refractive index (nd) using a dataset of 41,225 compositions with 38 different chemical elements. Then, we searched for relevant glass compositions using a genetic algorithm informed by a design trend of glasses having high nd (1.7 or more) and low Tg (500 °C or less). Two candidate compositions suggested by the combined algorithms were selected and produced in the laboratory. These compositions are significantly different from those in the datasets used to induce the predictive models, showing that the used method is indeed capable of exploration. Both glasses met the constraints of the work, which supports the proposed framework. Therefore, this new tool can be immediately used for accelerating the design of new glasses. These results are a stepping stone in the pathway of machine learning-guided design of novel glasses. 相似文献
6.
7.
Seredin P. V. Radam Ali Obaid Goloshchapov D. L. Len’shin A. S. Buylov N. S. Barkov K. A. Nesterov D. N. Mizerov A. M. Timoshnev S. N. Nikitina E. V. Arsentyev I. N. Sharafidinov Sh. Kukushkin S. A. Kasatkin I. A. 《Semiconductors》2022,56(4):253-258
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
8.
Boltar K. O. Burlakov I. D. Iakovleva N. I. Vlasov P. V. Lazarev P. S. 《Journal of Communications Technology and Electronics》2022,67(9):1175-1184
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
9.
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
10.
Elli Ntakou Ralph Masiello Farnaz Farzan Shay Bahramirad Aleksi Paaso M.A. Nayeem Maigha Maigha Daniel Kushner 《The Electricity Journal》2019,32(4):45-49
This paper presents part of the work ComEd and Quanta Technology have performed to quantify the locational and temporal value of DER to avoid distribution grid upgrade investments. It focuses on the formulation of a robust and efficient algorithm for DER optimal dispatch on a distribution feeder to mitigate the violation of current and voltage limits using the allocated cost of capacity and locational marginal value of real and reactive DER injection/withdrawal. 相似文献