全文获取类型
收费全文 | 485385篇 |
免费 | 5080篇 |
国内免费 | 1581篇 |
专业分类
化学 | 232028篇 |
晶体学 | 6427篇 |
力学 | 24754篇 |
综合类 | 7篇 |
数学 | 88310篇 |
物理学 | 140520篇 |
出版年
2020年 | 2196篇 |
2019年 | 2210篇 |
2018年 | 18980篇 |
2017年 | 19566篇 |
2016年 | 12806篇 |
2015年 | 5117篇 |
2014年 | 5175篇 |
2013年 | 15358篇 |
2012年 | 18384篇 |
2011年 | 33841篇 |
2010年 | 20018篇 |
2009年 | 20268篇 |
2008年 | 28124篇 |
2007年 | 33127篇 |
2006年 | 13459篇 |
2005年 | 20010篇 |
2004年 | 15464篇 |
2003年 | 14303篇 |
2002年 | 11420篇 |
2001年 | 10694篇 |
2000年 | 8401篇 |
1999年 | 6468篇 |
1998年 | 5290篇 |
1997年 | 5094篇 |
1996年 | 5307篇 |
1995年 | 4728篇 |
1994年 | 4472篇 |
1993年 | 4289篇 |
1992年 | 4728篇 |
1991年 | 4585篇 |
1990年 | 4263篇 |
1989年 | 4118篇 |
1988年 | 4440篇 |
1987年 | 4065篇 |
1986年 | 3928篇 |
1985年 | 5655篇 |
1984年 | 5778篇 |
1983年 | 4643篇 |
1982年 | 5130篇 |
1981年 | 5168篇 |
1980年 | 4911篇 |
1979年 | 5036篇 |
1978年 | 5047篇 |
1977年 | 4914篇 |
1976年 | 4886篇 |
1975年 | 4771篇 |
1974年 | 4611篇 |
1973年 | 4818篇 |
1972年 | 2709篇 |
1971年 | 1973篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
I. F. Golovnev E. I. Golovneva L. A. Merzhievsky V. M. Fomin V. E. Panin 《Physical Mesomechanics》2015,18(3):179-186
Molecular dynamics simulation was performed to study the formation of cluster structure, interfaces, and surfaces with different curvature radii in a perfect nanocrystal passed through by a nonlinear wave. It is shown that this process is a type of nanostructure self-organization in response to an external energy flux with subsequent development of a strong rotational field. 相似文献
82.
83.
Hui Li Jian Liu Juan Zhao Huiting He Dr. Dabo Jiang Prof. Steven Robert Kirk Prof. Qiong Xu Dr. Xianxiang Liu Prof. Dulin Yin 《ChemistryOpen》2021,10(4):477-485
A series of tetraimidazolium salts with different anions was prepared and applied in the isomerization of β-pinene oxide. After examining the activity of different catalysts, a remarkable enhancement of the selectivity of perillyl alcohol (47 %) was obtained over [PEimi][HNO3]4 under mild reaction conditions and using DMSO as the solvent. Furthermore, noncovalent interactions between solvent molecules and the catalyst were found by FT-IR spectroscopy and confirmed by computational chemistry. The homogeneous catalyst showed excellent stability and was reused up to six times without significant loss. 相似文献
84.
Ben Jadi S. El Guerraf A. Bazzaoui E.A. Wang R. Martins J.I. Bazzaoui M. 《Journal of Solid State Electrochemistry》2019,23(8):2423-2433
Journal of Solid State Electrochemistry - Due to their distinctive chemical, electronic, and environmental properties, polypyrrole is used as a blocking barrier for methanol leakage in direct... 相似文献
85.
Kounta Moussa Dawson Nathan J. 《Methodology and Computing in Applied Probability》2021,23(3):1155-1172
Methodology and Computing in Applied Probability - The problem of optimally controlling one-dimensional diffusion processes until they enter a given stopping set is extended to include Markov... 相似文献
86.
87.
Ding Q. Yao M. Wu Sh. Zeng M. Xue N. Wu D. Xu J. 《Journal of Applied Spectroscopy》2022,89(4):712-718
Journal of Applied Spectroscopy - Based on partial least squares (PLS) analysis, the effects of different smoothing points and different preprocessing methods on the accuracy and precision of the... 相似文献
88.
Transport in Porous Media - The theme of coupling problems for adsorption, absorption and thermochemical transport in porous media is very important for engineering applications. Based on the... 相似文献
89.
90.
E. V. Shadrina O. N. Malinkina T. G. Khonina A. B. Shipovskaya V. I. Fomina E. Yu. Larchenko N. A. Popova I. G. Zyryanova L. P. Larionov 《Russian Chemical Bulletin》2015,64(7):1633-1639
The biomimetic sol—gel synthesis of silicon—chitosan-containing glycerohydrogels was carried out using silicon tetraglycerolate as a precursor. It was found that chitosan accelerates gel formation in weakly acidic media. In more acidic media, the kinetics of the process changes according to the curve with a maximum, which can be attributed to different mechanisms of silanol condensation before and after the isoelectric point. The investigated silicon—chitosan-containing glycerohydrogels exhibit antibacterial, anti-inflammatory, and wound healing activity. The synthesized hybrid glycerohydrogels are promising materials for biomedical applications. 相似文献