全文获取类型
收费全文 | 227811篇 |
免费 | 4645篇 |
国内免费 | 2331篇 |
专业分类
化学 | 120175篇 |
晶体学 | 3554篇 |
力学 | 9093篇 |
综合类 | 72篇 |
数学 | 20911篇 |
物理学 | 66932篇 |
综合类 | 14050篇 |
出版年
2020年 | 1863篇 |
2018年 | 1925篇 |
2016年 | 3135篇 |
2015年 | 2603篇 |
2014年 | 3515篇 |
2013年 | 9366篇 |
2012年 | 7133篇 |
2011年 | 8597篇 |
2010年 | 5787篇 |
2009年 | 5719篇 |
2008年 | 7642篇 |
2007年 | 7704篇 |
2006年 | 7315篇 |
2005年 | 6721篇 |
2004年 | 6036篇 |
2003年 | 5375篇 |
2002年 | 5252篇 |
2001年 | 6911篇 |
2000年 | 5410篇 |
1999年 | 4416篇 |
1998年 | 3256篇 |
1997年 | 3233篇 |
1996年 | 3186篇 |
1995年 | 2947篇 |
1994年 | 3016篇 |
1993年 | 2609篇 |
1992年 | 3210篇 |
1991年 | 3051篇 |
1990年 | 3045篇 |
1989年 | 2976篇 |
1988年 | 2897篇 |
1987年 | 2876篇 |
1986年 | 2647篇 |
1985年 | 3487篇 |
1984年 | 3451篇 |
1983年 | 2865篇 |
1982年 | 3011篇 |
1981年 | 2947篇 |
1980年 | 2852篇 |
1979年 | 3095篇 |
1978年 | 3311篇 |
1977年 | 3117篇 |
1976年 | 3022篇 |
1975年 | 2907篇 |
1974年 | 2945篇 |
1973年 | 2820篇 |
1972年 | 1852篇 |
1968年 | 2162篇 |
1967年 | 2385篇 |
1966年 | 2174篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Saleh Z. M. Nasser H. Özkol E. Günöven M. Abak K. Canli S. Bek A. Turan R. 《Journal of nanoparticle research》2015,17(10):1-12
Journal of Nanoparticle Research - Plasmonic interfaces consisting of silver nanoparticles of different sizes (50–100&;nbsp;nm) have been processed by the self-assembled dewetting... 相似文献
62.
63.
João Marcos G. Barbosa Milenna K. Fernandes Rodrigues Lurian C. David Taynara C. e Silva Danielly A. Fortuna Lima Naiara Z. Pereira Emmanuel B. D'Alessandro Anselmo E. de Oliveira Paulo H. Jorge da Cunha Maria Clorinda S. Fioravanti Nelson R. Antoniosi Filho 《Biomedical chromatography : BMC》2020,34(11):e4935
An innovative volatolomic approach employs the detection of biomarkers present in cerumen (earwax) to identify cattle intoxication by Stryphnodendron rotundifolium Mart., Fabaceae (popularly known as barbatimão). S. rotundifolium is a poisonous plant with the toxic compound undefined and widely distributed throughout the Brazilian territory. Cerumen samples from cattle of two local Brazilian breeds (‘Curraleiro Pé-Duro’ and ‘Pantaneiro’) were collected during an experimental intoxication protocol and analyzed using headspace (HS)/GC–MS followed by multivariate analysis (genetic algorithm for a partial least squares, cluster analysis, and classification and regression trees). A total of 106 volatile organic metabolites were identified in the cerumen samples of bovines. The intoxication by S. rotundifolium influenced the cerumen volatolomic profile of the bovines throughout the intoxication protocol. In this way, it was possible to detect biomarkers for cattle intoxication. Among the biomarkers, 2-octyldecanol and 9-tetradecen-1-ol were able to discriminate all samples between intoxicated and nonintoxicated bovines. The cattle intoxication diagnosis by S. rotundifolium was accomplished by applying the cerumen analysis using HS/GC–MS, in an easy, accurate, and noninvasive way. Thus, the proposed bioanalytical chromatography protocol is a useful tool in veterinary applications to determine this kind of intoxication. 相似文献
64.
65.
Sha Xia Dan Wang Nian-Ke Chen Dong Han Xian-Bin Li Hong-Bo Sun 《Annalen der Physik》2020,532(3):1900318
Defects play a central role in controlling the electronic properties of two-dimensional (2D) materials and realizing the industrialization of 2D electronics. However, the evaluation of charged defects in 2D materials within first-principles calculation is very challenging and has triggered a recent development of the WLZ (Wang, Li, Zhang) extrapolation method. This method lays the foundation of the theoretical evaluation of energies of charged defects in 2D materials within the first-principles framework. Herein, the vital role of defects for advancing 2D electronics is discussed, followed by an introduction of the fundamentals of the WLZ extrapolation method. The ionization energies (IEs) obtained by this method for defects in various 2D semiconductors are then reviewed and summarized. Finally, the unique defect physics in 2D dimensions including the dielectric environment effects, defect ionization process, and carrier transport mechanism captured with the WLZ extrapolation method are presented. As an efficient and reasonable evaluation of charged defects in 2D materials for nanoelectronics and other emerging applications, this work can be of benefit to the community. 相似文献
66.
67.
Aequationes mathematicae - We discuss equivalence conditions for the non-existence of non-trivial meromorphic solutions to the Fermat Diophantine equation $$f^m(z)+g^n(z)=1$$ with integers $$m,n\ge... 相似文献
68.
69.
70.