全文获取类型
收费全文 | 524937篇 |
免费 | 7699篇 |
国内免费 | 1466篇 |
专业分类
电工技术 | 9561篇 |
综合类 | 527篇 |
化学工业 | 78693篇 |
金属工艺 | 19962篇 |
机械仪表 | 15198篇 |
建筑科学 | 12704篇 |
矿业工程 | 2269篇 |
能源动力 | 14517篇 |
轻工业 | 47064篇 |
水利工程 | 5219篇 |
石油天然气 | 9335篇 |
武器工业 | 37篇 |
无线电 | 59928篇 |
一般工业技术 | 101792篇 |
冶金工业 | 103555篇 |
原子能技术 | 10560篇 |
自动化技术 | 43181篇 |
出版年
2022年 | 3166篇 |
2021年 | 4900篇 |
2020年 | 3479篇 |
2019年 | 4558篇 |
2018年 | 7810篇 |
2017年 | 7608篇 |
2016年 | 7936篇 |
2015年 | 5564篇 |
2014年 | 9242篇 |
2013年 | 24072篇 |
2012年 | 14629篇 |
2011年 | 20152篇 |
2010年 | 15802篇 |
2009年 | 17702篇 |
2008年 | 18097篇 |
2007年 | 17777篇 |
2006年 | 15508篇 |
2005年 | 14210篇 |
2004年 | 13607篇 |
2003年 | 13400篇 |
2002年 | 12637篇 |
2001年 | 12832篇 |
2000年 | 11871篇 |
1999年 | 12598篇 |
1998年 | 32831篇 |
1997年 | 22908篇 |
1996年 | 17452篇 |
1995年 | 13036篇 |
1994年 | 11285篇 |
1993年 | 10978篇 |
1992年 | 7913篇 |
1991年 | 7419篇 |
1990年 | 7268篇 |
1989年 | 7014篇 |
1988年 | 6472篇 |
1987年 | 5768篇 |
1986年 | 5662篇 |
1985年 | 6268篇 |
1984年 | 5904篇 |
1983年 | 5171篇 |
1982年 | 4901篇 |
1981年 | 4966篇 |
1980年 | 4709篇 |
1979年 | 4613篇 |
1978年 | 4411篇 |
1977年 | 5338篇 |
1976年 | 6978篇 |
1975年 | 3799篇 |
1974年 | 3553篇 |
1973年 | 3666篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
El-Denglawey A. Issa Shams A. M. Saddeek Yasser B. Tekin H. O. Zakaly Hesham M. H. 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(10):3934-3942
Journal of Inorganic and Organometallic Polymers and Materials - This work aimed to investigate the impact of Lead-fluoride based glasses via theoretical and simulation techniques on mechanical and... 相似文献
132.
133.
Lingfeng Zhou Zhipeng Zeng Michael P. Brady Donovan N. Leonard Harry M. Meyer Yukinori Yamamoto Wenyuan Li Greg Collins Xingbo Liu 《International Journal of Hydrogen Energy》2021,46(41):21619-21633
The chromium (Cr) evaporation behavior of several different types of iron (Fe)-based AFA alloys and benchmark Cr2O3-forming Fe-based 310 and Ni-based 625 alloys was investigated for 500 h exposures at 800 °C to 900 °C in air with 10% H2O. The Cr evaporation rates from alumina-forming austenitic (AFA) alloys were ~5 to 35 times lower than that of the Cr2O3-forming alloys depending on alloy and temperature. The Cr evaporation behavior was correlated with extensive characterization of the chemistry and microstructure of the oxide scales, which also revealed a degree of quartz tube Si contamination during the test. Long-term oxidation kinetics were also assessed at 800 to 1000 °C for up to 10,000 h in air with 10% H2O to provide further guidance for SOFC BOP component alloy selection. 相似文献
134.
Simutin A. N. Deineko A. V. Zertsalov M. G. 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2021,55(4):482-486
Power Technology and Engineering - The monitoring of hydraulic structures as high-risk facilities is discussed. Monitoring should ensure the reliability and functioning of a hydraulic structure... 相似文献
135.
Mining high utility itemsets (HUIs) from transaction databases considers such factors as the unit profit and quantity of purchased items. Two-phase tree-based algorithms transform a database into compressed tree structures and generate candidate patterns through a recursive pattern-growth procedure. This procedure requires a lot of memory and time to construct conditional pattern trees. To address this issue, this study employs two compressed tree structures, namely, Utility Count Tree and String Utility Tree, to enumerate valid patterns and thus promote fast utility computation. Furthermore, the study presents an algorithm called single-phase utility computation (SPUC) that leverages these two tree structures to mine HUIs in a single phase by incorporating novel pruning strategies. Experiments conducted on both real and synthetic datasets demonstrate the superior performance of SPUC compared with IHUP, UP-Growth, and UP-Growth+ algorithms. 相似文献
136.
Chertkov Yu. B. Anikin M. N. Lebedev I. I. Naimushin A. G. Smol’nikov N. V. 《Atomic Energy》2021,131(1):42-45
Atomic Energy - The results of calculations and experimental determination of the neutronics characteristics of the IRT-T research reactor are presented. The IRT-T reactor is a pool reactor with... 相似文献
137.
Spiridonova E. A. Rotko V. O. Samonin V. V. Podvyaznikov M. L. 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(1):45-51
Protection of Metals and Physical Chemistry of Surfaces - In this work, a universal sorbent has been obtained that works according to the mechanisms of chemisorption and adsorption by impregnating... 相似文献
138.
Dr. Alejandra A. Carriles Alberto Mills Dr. María-José Muñoz-Alonso Dr. Dolores Gutiérrez Dr. Juan M. Domínguez Prof. Dr. Juan A. Hermoso Prof. Dr. Federico Gago 《Chembiochem : a European journal of chemical biology》2021,22(2):374-391
Spontaneous mutations in the EEF1A2 gene cause epilepsy and severe neurological disabilities in children. The crystal structure of eEF1A2 protein purified from rabbit skeletal muscle reveals a post-translationally modified dimer that provides information about the sites of interaction with numerous binding partners, including itself, and maps these mutations onto the dimer and tetramer interfaces. The spatial locations of the side chain carboxylates of Glu301 and Glu374, to which phosphatidylethanolamine is uniquely attached via an amide bond, define the anchoring points of eEF1A2 to cellular membranes and interorganellar membrane contact sites. Additional bioinformatic and molecular modeling results provide novel structural insight into the demonstrated binding of eEF1A2 to SH3 domains, the common MAPK docking groove, filamentous actin, and phosphatidylinositol-4 kinase IIIβ. In this new light, the role of eEF1A2 as an ancient, multifaceted, and articulated G protein at the crossroads of autophagy, oncogenesis and viral replication appears very distant from the “canonical” one of delivering aminoacyl-tRNAs to the ribosome that has dominated the scene and much of the thinking for many decades. 相似文献
139.
Byakova O. V. Stepanov G. V. Vlasov A. O. Danylyuk V. E. Semenov N. V. Berezovs’kyi O. M. Gnyloskurenko S. V. 《Strength of Materials》2019,51(5):726-734
Strength of Materials - The paper addresses the investigation of high-strain rate compressive behavior of Al foams subjected to impact at the intermediate striking velocity ranged from 40 to... 相似文献
140.
Tribology Letters - The tribological behavior of a nickel-based single crystal superalloy treated by shot-peening has been investigated. Friction tests under three normal loads and three... 相似文献