全文获取类型
收费全文 | 86252篇 |
免费 | 622篇 |
国内免费 | 409篇 |
专业分类
化学 | 29725篇 |
晶体学 | 845篇 |
力学 | 6964篇 |
综合类 | 5篇 |
数学 | 32970篇 |
物理学 | 16774篇 |
出版年
2023年 | 76篇 |
2022年 | 262篇 |
2021年 | 261篇 |
2020年 | 225篇 |
2019年 | 246篇 |
2018年 | 10583篇 |
2017年 | 10354篇 |
2016年 | 6357篇 |
2015年 | 1112篇 |
2014年 | 642篇 |
2013年 | 860篇 |
2012年 | 4360篇 |
2011年 | 11134篇 |
2010年 | 6026篇 |
2009年 | 6448篇 |
2008年 | 7123篇 |
2007年 | 9180篇 |
2006年 | 656篇 |
2005年 | 1655篇 |
2004年 | 1840篇 |
2003年 | 2218篇 |
2002年 | 1214篇 |
2001年 | 393篇 |
2000年 | 417篇 |
1999年 | 229篇 |
1998年 | 266篇 |
1997年 | 217篇 |
1996年 | 260篇 |
1995年 | 165篇 |
1994年 | 144篇 |
1993年 | 161篇 |
1992年 | 121篇 |
1991年 | 100篇 |
1990年 | 82篇 |
1989年 | 83篇 |
1988年 | 86篇 |
1987年 | 78篇 |
1986年 | 80篇 |
1985年 | 76篇 |
1984年 | 68篇 |
1983年 | 67篇 |
1982年 | 59篇 |
1981年 | 68篇 |
1980年 | 65篇 |
1979年 | 69篇 |
1978年 | 63篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
The influence of different referencing methods on the accuracy of δ13C value measurement of ethanol fuel by gas chromatography/combustion/isotope ratio mass spectrometry 下载免费PDF全文
3.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
4.
5.
6.
7.
8.
9.
Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye
Santos José Eudes L. de Moura Dayanne Chianca da Silva Djalma Ribeiro Panizza Marco Martínez-Huitle Carlos A. 《Journal of Solid State Electrochemistry》2019,23(2):351-360
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an... 相似文献
10.
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