全文获取类型
收费全文 | 5218篇 |
免费 | 734篇 |
国内免费 | 658篇 |
专业分类
化学 | 386篇 |
晶体学 | 34篇 |
力学 | 392篇 |
综合类 | 140篇 |
数学 | 3811篇 |
物理学 | 1847篇 |
出版年
2024年 | 13篇 |
2023年 | 86篇 |
2022年 | 104篇 |
2021年 | 100篇 |
2020年 | 169篇 |
2019年 | 131篇 |
2018年 | 170篇 |
2017年 | 173篇 |
2016年 | 196篇 |
2015年 | 117篇 |
2014年 | 249篇 |
2013年 | 417篇 |
2012年 | 227篇 |
2011年 | 297篇 |
2010年 | 254篇 |
2009年 | 310篇 |
2008年 | 347篇 |
2007年 | 343篇 |
2006年 | 324篇 |
2005年 | 317篇 |
2004年 | 271篇 |
2003年 | 285篇 |
2002年 | 258篇 |
2001年 | 202篇 |
2000年 | 214篇 |
1999年 | 183篇 |
1998年 | 162篇 |
1997年 | 136篇 |
1996年 | 105篇 |
1995年 | 89篇 |
1994年 | 66篇 |
1993年 | 49篇 |
1992年 | 36篇 |
1991年 | 24篇 |
1990年 | 23篇 |
1989年 | 16篇 |
1988年 | 17篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 23篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1957年 | 3篇 |
排序方式: 共有6610条查询结果,搜索用时 15 毫秒
991.
992.
Orientation Angle of Molecules at Hexadecane-Water Interface Studied with Total Internal Reflection Second Harmonic Generation
下载免费PDF全文
![点击此处可从《化学物理学报(中文版)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The orientation angle is an important parameter that reflects the structure of molecules at interfaces. In order to obtain this parameter, second order nonlinear spectroscopic techniques including second harmonic generation (SHG) and sum frequency generation-vibrational spectroscopy (SFG-VS) have been successfully applied through analysis of the nonlinear signal from various polarizations. In some SHG and SFG-VS experiments, total internal reflection (TIR) configuration has been adopted to get enhanced signals. However, the reports on the detailed procedure of the polarization analysis and the calculation of the orientation angle of interfacial molecules under TIR configuration are still very few. In this paper, we measured the orientation angles of two molecules at the hexadecane-water interface under TIR and Non-TIR experimental configurations. The results measured from polarization analysis in TIR configuration consist with those obtained from Non-TIR configuration. This work demonstrates the feasibility and accuracy of polarization analysis in the determination of the orientation angle of molecules at the interfaces under TIR-SHG configuration. 相似文献
993.
994.
995.
This paper is a continuation of our recent work on the localization of the eigenvalues of matrices. We give new bounds for the real and imaginary parts of the eigenvalues of matrices. Applications to the localization of the zeros of polynomials are also given. 相似文献
996.
Zhixiong TAO 《数学年刊B辑(英文版)》2016,37(5):767-776
The author discusses 2-adjacency of two-component links and study
the relations between the signs of the crossings to realize
2-adjacency and the coefficients of the Conway polynomial of two
related links. By discussing the coefficient of the lowest $m$ power
in the Homfly polynomial, the author obtains some results and
conditions on whether the trivial link is 2-adjacent to a nontrivial
link, whether there are two links 2-adjacent to each other, etc.
Finally, this paper shows that the Whitehead link is not 2-adjacent
to the trivial link, and gives some examples to explain that for any
given two-component link, there are infinitely many links 2-adjacent
to it. In particular, there are infinitely many links 2-adjacent to
it with the same Conway polynomial. 相似文献
997.
998.
Tijani A. Apalara Salim A. Messaoudi Ahmed A. Keddi 《Mathematical Methods in the Applied Sciences》2016,39(10):2671-2684
In this work, we study the well‐posedness and the asymptotic stability of a one‐dimensional linear thermoelastic Timoshenko system, where the heat conduction is given by Cattaneo's law and the coupling is via the displacement equation. We prove that the system is exponentially stable provided that the stability number χτ=0. Otherwise, we show that the system lacks exponential stability. Furthermore, in the latter case, we show that the solution decays polynomially. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
Iiris Attorps Kjell Björk Mirko Radic 《International Journal of Mathematical Education in Science & Technology》2016,47(1):45-57
In this paper, we report a teaching experiment regarding the theory of polynomial approximations at the university mathematics teaching in Sweden. The experiment was designed by applying Variation theory and by using the free dynamic mathematics software GeoGebra. The aim of this study was to investigate if the technology-assisted teaching of Taylor polynomials compared with traditional way of work at the university level can support the teaching and learning of mathematical concepts and ideas. An engineering student group (n = 19) was taught Taylor polynomials with the assistance of GeoGebra while a control group (n = 18) was taught in a traditional way. The data were gathered by video recording of the lectures, by doing a post-test concerning Taylor polynomials in both groups and by giving one question regarding Taylor polynomials at the final exam for the course in Real Analysis in one variable. In the analysis of the lectures, we found Variation theory combined with GeoGebra to be a potentially powerful tool for revealing some critical aspects of Taylor Polynomials. Furthermore, the research results indicated that applying Variation theory, when planning the technology-assisted teaching, supported and enriched students’ learning opportunities in the study group compared with the control group. 相似文献
1000.