全文获取类型
收费全文 | 109482篇 |
免费 | 8537篇 |
国内免费 | 2997篇 |
专业分类
电工技术 | 4213篇 |
技术理论 | 10篇 |
综合类 | 4538篇 |
化学工业 | 21114篇 |
金属工艺 | 4323篇 |
机械仪表 | 4750篇 |
建筑科学 | 6759篇 |
矿业工程 | 1894篇 |
能源动力 | 3028篇 |
轻工业 | 12749篇 |
水利工程 | 1717篇 |
石油天然气 | 3827篇 |
武器工业 | 527篇 |
无线电 | 10052篇 |
一般工业技术 | 15110篇 |
冶金工业 | 10226篇 |
原子能技术 | 902篇 |
自动化技术 | 15277篇 |
出版年
2024年 | 376篇 |
2023年 | 1542篇 |
2022年 | 2962篇 |
2021年 | 4178篇 |
2020年 | 3219篇 |
2019年 | 2867篇 |
2018年 | 3789篇 |
2017年 | 3787篇 |
2016年 | 3799篇 |
2015年 | 3973篇 |
2014年 | 4995篇 |
2013年 | 7130篇 |
2012年 | 6900篇 |
2011年 | 7381篇 |
2010年 | 5912篇 |
2009年 | 5615篇 |
2008年 | 5538篇 |
2007年 | 5130篇 |
2006年 | 4527篇 |
2005年 | 3888篇 |
2004年 | 3030篇 |
2003年 | 2744篇 |
2002年 | 2488篇 |
2001年 | 2108篇 |
2000年 | 2180篇 |
1999年 | 2506篇 |
1998年 | 4104篇 |
1997年 | 2933篇 |
1996年 | 2375篇 |
1995年 | 1716篇 |
1994年 | 1438篇 |
1993年 | 1142篇 |
1992年 | 690篇 |
1991年 | 540篇 |
1990年 | 456篇 |
1989年 | 423篇 |
1988年 | 348篇 |
1987年 | 265篇 |
1986年 | 215篇 |
1985年 | 200篇 |
1984年 | 157篇 |
1983年 | 117篇 |
1982年 | 137篇 |
1981年 | 141篇 |
1980年 | 135篇 |
1979年 | 67篇 |
1978年 | 75篇 |
1977年 | 154篇 |
1976年 | 281篇 |
1973年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
101.
Hierarchical micro-nanostructured albite-based glass-ceramic for high dielectric strength insulators
V. Fuertes M.J. Cabrera J. Seores D. Muñoz J.F. Fernández E. Enríquez 《Journal of the European Ceramic Society》2018,38(7):2759-2766
A novel glass-ceramic material based on albite type Na-rich feldspar has been synthesized by conventional ceramic process. High crystallinity, >94%?Vol.% is obtained by fast sintering which allows energy saving processing. Albite is the main crystalline phase and tetragonal SiO2 is a secondary phase. Electrical properties were examined by complex impedance, DC measurements, and dielectric breakdown test. Dielectric characterization shows a non-Debye type dielectric behavior with low dielectric constant, 4.6 at 1?MHz, low dielectric losses, (~10?3 at 1?MHz, and a large dielectric strength, ~60?kV/mm), that it is the largest value reported in ceramic insulators. Those dielectric properties are attained by the low glassy phase content in the samples and their unique micro-nanostructure. All these properties make this novel material a very promising candidate in the market of ceramic electrical insulator, highlighting for high-voltage applications. 相似文献
102.
103.
Peng Jiang Jiafeng Lu Kun Li Xiquan Chen Ruiqi Dan 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(5):381-386
AbstractPreparation condition can affect the structure and the properties of nanofiber membrane. In order to explore suitable conditions to prepare the Fe3O4/PVDF nanofiber membrane with good hydrophobicity, the hydrophobicity of Fe3O4/PVDF nanofiber membranes obtained by electrospinning was investigated by changing preparation conditions like weight percentage of Fe3O4 nanoparticles, blending quality concentration of poly (vinylidene fluoride) (PVDF) and Fe3O4 nanoparticles, and positive voltage. And the variations of hydrophobicity of Fe3O4/PVDF nanofiber membranes modified by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane were studied. The results show that the hydrophobicity of Fe3O4/PVDF nanofiber membranes has changed under different preparation conditions. The contact angles of samples increased after a modification by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane, which indicates that the hydrophobicity of Fe3O4/PVDF nanofiber membranes has been enhanced. 相似文献
105.
Application of high‐temperature Fenton oxidation for the treatment of sulfonation plant wastewater
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
106.
Crespo Juan-José Sánchez José L. Alfaro-Cortés Francisco J. Flich José Duato José 《The Journal of supercomputing》2021,77(11):12826-12856
The Journal of Supercomputing - Deadlock-free dynamic network reconfiguration process is usually studied from the routing algorithm restrictions and resource reservation perspective. The dynamic... 相似文献
107.
Neural Computing and Applications - The goal of this paper is to introduce a novel hybrid model called multi-fuzzy N-soft set, and to design an adjustable decision-making methodology for solving... 相似文献
108.
109.
Roberto C. Dante Pablo Martín-Ramos Pedro Chamorro-Posada Dario Rutto José Vázquez-Cabo Denisse G. Dante 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(7):533-540
AbstractIn this work, a new g-C3N4-based Z-scheme with γ-Fe2O3 and β-Ag2Se both n-type semiconductors, and graphite to favor electron exchange is presented. The composite material was studied by XRD, FTIR, UV-Vis, TEM, XPS, TGA, DSC and TOF-SIMS, and the ability of this photocatalytic system to act as a photo-reductant was assessed using crystal violet (CV+) dye. Solar light driven photo-reduction of CV+ in the presence of tri-sodium citrate evidenced a synergistic enhancement of the activity of the composite toward reduction, with ~20 times higher conversion rates per unit of surface area than those of g-C3N4. Photo-oxidation experiments under Xe lamp irradiation in the presence of H2O2 also showed that the AgFeCN composite featured a higher activity (~8×) than g-C3N4. This Z-scheme may deserve further study as a photo-reductant to obtain hydrogen or hydrogenated compounds. Moreover, the use of CV+ may represent a facile procedure that can aid in the selection of new photocatalysts to be used in hydrogen production. 相似文献
110.
Tsuchiya Letícia Diniz Braga Lucas Fiorini de Faria Oliveira Otávio de Bettio Raphael Winckler Greghi Juliana Galvani Freire André Pimenta 《Personal and Ubiquitous Computing》2021,25(2):281-295
Personal and Ubiquitous Computing - This article presents a study concerning the evaluation of a smart home control system for elderly people with a sample of 10 users in a city in the interior of... 相似文献