全文获取类型
收费全文 | 482052篇 |
免费 | 6047篇 |
国内免费 | 1175篇 |
专业分类
电工技术 | 8520篇 |
综合类 | 415篇 |
化学工业 | 76640篇 |
金属工艺 | 19317篇 |
机械仪表 | 14482篇 |
建筑科学 | 11517篇 |
矿业工程 | 2938篇 |
能源动力 | 10985篇 |
轻工业 | 45885篇 |
水利工程 | 5210篇 |
石油天然气 | 10759篇 |
武器工业 | 44篇 |
无线电 | 51282篇 |
一般工业技术 | 92672篇 |
冶金工业 | 89476篇 |
原子能技术 | 11821篇 |
自动化技术 | 37311篇 |
出版年
2021年 | 3821篇 |
2019年 | 3590篇 |
2018年 | 6433篇 |
2017年 | 6335篇 |
2016年 | 6784篇 |
2015年 | 4307篇 |
2014年 | 7365篇 |
2013年 | 20527篇 |
2012年 | 11778篇 |
2011年 | 16006篇 |
2010年 | 12873篇 |
2009年 | 14544篇 |
2008年 | 15118篇 |
2007年 | 15070篇 |
2006年 | 13352篇 |
2005年 | 12160篇 |
2004年 | 11450篇 |
2003年 | 11040篇 |
2002年 | 11170篇 |
2001年 | 10900篇 |
2000年 | 10541篇 |
1999年 | 10505篇 |
1998年 | 25110篇 |
1997年 | 18340篇 |
1996年 | 14245篇 |
1995年 | 10858篇 |
1994年 | 9846篇 |
1993年 | 9583篇 |
1992年 | 7479篇 |
1991年 | 7162篇 |
1990年 | 7186篇 |
1989年 | 7103篇 |
1988年 | 6923篇 |
1987年 | 5943篇 |
1986年 | 5998篇 |
1985年 | 6922篇 |
1984年 | 6606篇 |
1983年 | 6011篇 |
1982年 | 5636篇 |
1981年 | 5836篇 |
1980年 | 5644篇 |
1979年 | 5483篇 |
1978年 | 5554篇 |
1977年 | 6308篇 |
1976年 | 8125篇 |
1975年 | 5022篇 |
1974年 | 4778篇 |
1973年 | 4912篇 |
1972年 | 4191篇 |
1971年 | 3875篇 |
排序方式: 共有10000条查询结果,搜索用时 828 毫秒
191.
Federico Cernuschi Paolo Bison Daniel E. Mack Marco Merlini Stefano Boldrini Stefano Marchionna Stefano Capelli Stefano Concari Alessia Famengo Alessandro Moscatelli Werner Stamm 《Journal of the European Ceramic Society》2018,38(11):3945-3961
In the perspective of fuelling the future generations of gas turbines by hydrogen rich syngas, the evaluation of the effect of a higher water vapour content into the flue gases on the TBC used, or potentially usable, is a need. For this purpose YPSZ APS TBC with two different microstructures have been exposed for 500?h at different temperatures in the range 1000?°C–1250?°C either in air and air +20% vol. H2O. The comparison between the different testing conditions has been performed in terms of sintering kinetics and phase stability, as evaluated by thermal diffusivity measurements and Synchrotron X-Rays diffraction, respectively. Furthermore the characterisation of thermal properties of two innovative TBCs (GZO-YPSZ and YAG) potentially able to withstand the CMAS attack and erosive environments, respectively, has been carried out.No clear evidence of a different behaviour of TBC has been observed, at least in the considered aging time and temperature range. 相似文献
192.
193.
194.
Radiochemistry - Reaction of solid-phase catalytic heterogeneous isotope exchange of 2-deoxy-D-glucose and its derivative, O(6)-(4-bromothiophenyl)guanine-C8-β-D-glucose with tritium has been... 相似文献
195.
Shchelkunov E. B. Vinogradov S. V. Shchelkunova M. E. Pronin A. I. Buravitsyn D. A. 《Russian Engineering Research》2020,40(5):367-371
Russian Engineering Research - The theoretically possible reconfigurable parallel mechanisms are classified, in terms of the layout of guides on the base. Formulas are derived for the... 相似文献
196.
Programming and Computer Software - In this paper, we overview the approaches and techniques employed by the Svace static analysis tool for intraprocedural analysis. This analysis implies the... 相似文献
197.
198.
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
199.
Juana Maria de Lourdes Medina-Contreras Patrick Mailloux-Salinas Juventino III Colado-Velazquez Norma Leticia Gomez Viquez Gómez-Viquez Rodrigo Velázquez-Espejel Ana del Carmen Susunaga-Notario David Julian Arias-Chávez Guadalupe Bravo 《Journal of the science of food and agriculture》2020,100(7):3212-3219