全文获取类型
收费全文 | 185938篇 |
免费 | 2099篇 |
国内免费 | 214篇 |
专业分类
电工技术 | 2755篇 |
综合类 | 137篇 |
化学工业 | 30289篇 |
金属工艺 | 9785篇 |
机械仪表 | 6104篇 |
建筑科学 | 3993篇 |
矿业工程 | 1936篇 |
能源动力 | 3194篇 |
轻工业 | 10439篇 |
水利工程 | 2849篇 |
石油天然气 | 8747篇 |
武器工业 | 13篇 |
无线电 | 16030篇 |
一般工业技术 | 41215篇 |
冶金工业 | 30750篇 |
原子能技术 | 7118篇 |
自动化技术 | 12897篇 |
出版年
2021年 | 1989篇 |
2019年 | 1933篇 |
2018年 | 3390篇 |
2017年 | 3471篇 |
2016年 | 3828篇 |
2015年 | 2088篇 |
2014年 | 3465篇 |
2013年 | 7396篇 |
2012年 | 5146篇 |
2011年 | 6486篇 |
2010年 | 5176篇 |
2009年 | 5701篇 |
2008年 | 5779篇 |
2007年 | 5608篇 |
2006年 | 4824篇 |
2005年 | 4392篇 |
2004年 | 4101篇 |
2003年 | 3949篇 |
2002年 | 3862篇 |
2001年 | 3743篇 |
2000年 | 3670篇 |
1999年 | 3545篇 |
1998年 | 7729篇 |
1997年 | 5609篇 |
1996年 | 4196篇 |
1995年 | 3194篇 |
1994年 | 2856篇 |
1993年 | 2979篇 |
1992年 | 2429篇 |
1991年 | 2452篇 |
1990年 | 2540篇 |
1989年 | 2445篇 |
1988年 | 2436篇 |
1987年 | 2302篇 |
1986年 | 2355篇 |
1985年 | 2429篇 |
1984年 | 2336篇 |
1983年 | 2246篇 |
1982年 | 2064篇 |
1981年 | 2291篇 |
1980年 | 2133篇 |
1979年 | 2365篇 |
1978年 | 2517篇 |
1977年 | 2544篇 |
1976年 | 3232篇 |
1975年 | 2322篇 |
1974年 | 2378篇 |
1973年 | 2404篇 |
1972年 | 2206篇 |
1971年 | 1960篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
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.
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
3.
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
4.
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
5.
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
6.
Golam Haider Krishna Sampathkumar Tim Verhagen Lukáš Nádvorník Farjana J. Sonia Václav Valeš Jan Sýkora Peter Kapusta Petr Němec Martin Hof Otakar Frank Yang-Fang Chen Jana Vejpravová Martin Kalbáč 《Advanced functional materials》2021,31(29):2102196
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.
Blagoveshchenskii D. I. Kozlovskii V. N. Vasin S. A. 《Russian Engineering Research》2021,41(12):1255-1259
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.
William M. Pitts Martin Werrel Marco Fernandez Mary A. Long Evan A. Eisenberg James Filliben Cory D. Runyon 《火与材料》2021,45(1):127-154
Fire spread and growth on real‐scale four cushion mock‐ups of residential upholstered furniture (RUF) were investigated with the goal of identifying whether changes in five classes of materials (barrier, flexible polyurethane foam, polyester fiber wrap, upholstery fabric, and sewing thread), referred to as factors, resulted in statistically significant changes in burning behavior. A fractional factorial experimental design plus practical considerations yielded a test matrix with 20 material combinations. Experiments were repeated a minimum of two times. Measurements included fire spread rates derived from video recordings and heat release rates (HRRs). A total of 13 experimental parameters (3 based on the videos and 10 on the HRR results), referred to as responses, characterized the measurements. Statistical analyses based on Main Effects Plots (main effects) and Block Plots (main effects and factor interactions) were used. The results showed that three of the factors resulted in statistically significant effects on varying numbers of the 13 responses. The Barrier and Fabric factors had the strongest main effects with roughly comparable magnitudes. Foam was statistically significant for fewer of the responses and its overall strength was weaker than for Barrier and Fabric. No statistically significant main effects were identified for Wrap or Thread. Multiple two‐term interactions between factors were identified as being statistically significant. The Barrier*Fabric interaction resulted in the highest number of and strongest statistically significant effects. The existence of two‐term interactions means that it will be necessary to consider their effects in approaches designed to predict the burning behavior of RUF. 相似文献
10.
Zhuchkov V. I. Nazansky S. L. Frolkova A. K. Ganina K. D. 《Theoretical Foundations of Chemical Engineering》2021,55(4):786-791
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