全文获取类型
收费全文 | 251704篇 |
免费 | 4102篇 |
国内免费 | 1044篇 |
专业分类
电工技术 | 4327篇 |
综合类 | 201篇 |
化学工业 | 37110篇 |
金属工艺 | 8217篇 |
机械仪表 | 7263篇 |
建筑科学 | 6785篇 |
矿业工程 | 541篇 |
能源动力 | 7236篇 |
轻工业 | 28638篇 |
水利工程 | 2120篇 |
石油天然气 | 1852篇 |
武器工业 | 5篇 |
无线电 | 33393篇 |
一般工业技术 | 46175篇 |
冶金工业 | 46452篇 |
原子能技术 | 3366篇 |
自动化技术 | 23169篇 |
出版年
2021年 | 1798篇 |
2020年 | 1346篇 |
2019年 | 1667篇 |
2018年 | 2571篇 |
2017年 | 2593篇 |
2016年 | 2875篇 |
2015年 | 2163篇 |
2014年 | 3655篇 |
2013年 | 11954篇 |
2012年 | 6754篇 |
2011年 | 9664篇 |
2010年 | 7444篇 |
2009年 | 8394篇 |
2008年 | 8916篇 |
2007年 | 8932篇 |
2006年 | 8278篇 |
2005年 | 7485篇 |
2004年 | 7208篇 |
2003年 | 7094篇 |
2002年 | 6591篇 |
2001年 | 7020篇 |
2000年 | 6324篇 |
1999年 | 6822篇 |
1998年 | 16376篇 |
1997年 | 11367篇 |
1996年 | 8581篇 |
1995年 | 6543篇 |
1994年 | 5707篇 |
1993年 | 5566篇 |
1992年 | 3996篇 |
1991年 | 3774篇 |
1990年 | 3548篇 |
1989年 | 3369篇 |
1988年 | 3276篇 |
1987年 | 2589篇 |
1986年 | 2487篇 |
1985年 | 3156篇 |
1984年 | 2797篇 |
1983年 | 2559篇 |
1982年 | 2344篇 |
1981年 | 2390篇 |
1980年 | 2201篇 |
1979年 | 2048篇 |
1978年 | 1879篇 |
1977年 | 2176篇 |
1976年 | 2724篇 |
1975年 | 1584篇 |
1974年 | 1489篇 |
1973年 | 1558篇 |
1972年 | 1144篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
John D. Rodney S. Deepapriya M. Cyril Robinson C. Justin Raj Suresh Perumal Byung Chul Kim S. Krishnan S. Jerome Das 《International Journal of Hydrogen Energy》2021,46(54):27585-27596
The production of hydrogen, a favourable alternative to an unsustainable fossil fuel remains as a significant hurdle with the pertaining challenge in the design of proficient, highly productive and sustainable electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, the dysprosium (Dy) doped copper oxide (Cu1-xDyxO) nanoparticles were synthesized via solution combustion technique and utilized as a non-noble metal based bi-functional electrocatalyst for overall water splitting. Due to the improved surface to volume ratio and conductivity, the optimized Cu1-xDyxO (x = 0.01, 0.02) electrocatalysts exhibited impressive HER and OER performance respectively in 1 M KOH delivering a current density of 10 mAcm?2 at a potential of ?0.18 V vs RHE for HER and 1.53 V vs RHE for OER. Moreover, the Dy doped CuO electrocatalyst used as a bi-functional catalyst for overall water splitting achieved a potential of 1.56 V at a current density 10 mAcm?2 and relatively high current density of 66 mAcm?2 at a peak potential of 2 V. A long term stability of 24 h was achieved for a cell voltage of 2.2 V at a constant current density of 30 mAcm?2 with only 10% of the initial current loss. This showcases the accumulative opportunity of dysprosium as a dopant in CuO nanoparticles for fabricating a highly effective and low-cost bi-functional electrocatalyst for overall water splitting. 相似文献
2.
Mobile Networks and Applications - Blockchain applications have continuously improved ever since its first debut on cryptocurrency. From then on, its uses have branched out from the financial... 相似文献
3.
Norfariza Jamaluddin David C. Stuckey Arbakariya B. Ariff 《Critical reviews in food science and nutrition》2018,58(14):2453-2465
ABSTRACTBacteriocin is a proteinaceous biomolecule produced by bacteria (both Gram-positive and Gram-negative) that exhibits antimicrobial activity against closely related species, and food-borne pathogens. It has recently gained importance and attracted the attention of several researchers looking to produce it from various substrates and bacterial strains. This ushers in a new era of food preservation where the use of bacteriocin in food products will be an alternative to chemical preservatives, and heat treatment which are understood to cause unwanted side effects, and reduce sensory and nutritional quality. However, this new market depends on the success of novel downstream separation schemes from various types of crude feedstocks which are both effective and economic. This review focuses on the downstream separation of bacteriocin from various sources using both conventional and novel techniques. Finally, recommendations for future interesting areas of research that need to be pursued are highlighted. 相似文献
4.
Gomes A. C. S. A. Costa L. C. Brito D. C. Frana R. J. Marques Mnica R. C. 《Polymer Bulletin》2020,77(4):1969-1981
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with... 相似文献
5.
Photonic Network Communications - Optical packet switching is a prominent technology proposing not only a reduction in the energy consumption by the elimination of numerous... 相似文献
6.
7.
8.
9.
10.
The Journal of Supercomputing - Infrastructure-as-a-service container-based virtualization is gaining interest as a platform for running distributed applications. With increasing scale of cloud... 相似文献