全文获取类型
收费全文 | 2359篇 |
免费 | 70篇 |
国内免费 | 28篇 |
专业分类
化学 | 1539篇 |
晶体学 | 27篇 |
力学 | 57篇 |
数学 | 448篇 |
物理学 | 386篇 |
出版年
2023年 | 20篇 |
2022年 | 71篇 |
2021年 | 83篇 |
2020年 | 50篇 |
2019年 | 53篇 |
2018年 | 45篇 |
2017年 | 43篇 |
2016年 | 91篇 |
2015年 | 75篇 |
2014年 | 99篇 |
2013年 | 145篇 |
2012年 | 137篇 |
2011年 | 145篇 |
2010年 | 99篇 |
2009年 | 102篇 |
2008年 | 136篇 |
2007年 | 139篇 |
2006年 | 117篇 |
2005年 | 106篇 |
2004年 | 97篇 |
2003年 | 79篇 |
2002年 | 55篇 |
2001年 | 37篇 |
2000年 | 38篇 |
1999年 | 32篇 |
1998年 | 37篇 |
1997年 | 24篇 |
1996年 | 28篇 |
1995年 | 29篇 |
1994年 | 25篇 |
1993年 | 19篇 |
1992年 | 25篇 |
1991年 | 20篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 20篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 8篇 |
1976年 | 3篇 |
1974年 | 4篇 |
1966年 | 1篇 |
排序方式: 共有2457条查询结果,搜索用时 0 毫秒
11.
We study a boundary version of the gauged WZW model with a Poisson–Lie group G as the target. The Poisson–Lie structure of G is used to define the Wess–Zumino term of the action on surfaces with boundary. We clarify the relation of the model to the topological Poisson sigma model with the dual Poisson–Lie group G
* as the target and show that the phase space of the theory on a strip is essentially the Heisenberg double of G introduced by Semenov–Tian–Shansky. 相似文献
12.
We present a detailed study of the Schrödinger picture space of states in theSU(2) Chern-Simons topological gauge theory in the simplest geometry. The space coincides with that of the solutions of the chiral Ward identities for the WZW model. We prove that its dimension is given by E. Verlinde's formulae. 相似文献
13.
This paper proposes a method for solving optimisation problems involving piecewise quadratic functions. The method provides a solution in a finite number of iterations, and the computational complexity of the proposed method is locally polynomial of the problem dimension, i.e., if the initial point belongs to the sufficiently small neighbourhood of the solution set. Proposed method could be applied for solving large systems of linear inequalities. 相似文献
14.
The aim of this study is to investigate market depth as a stock market liquidity dimension. A new methodology for market depth measurement exactly based on Shannon information entropy for high-frequency data is introduced and utilized. The proposed entropy-based market depth indicator is supported by an algorithm inferring the initiator of a trade. This new indicator seems to be a promising liquidity measure. Both market entropy and market liquidity can be directly measured by the new indicator. The findings of empirical experiments for real-data with a time stamp rounded to the nearest second from the Warsaw Stock Exchange (WSE) confirm that the new proxy enables us to effectively compare market depth and liquidity for different equities. Robustness tests and statistical analyses are conducted. Furthermore, an intra-day seasonality assessment is provided. Results indicate that the entropy-based approach can be considered as an auspicious market depth and liquidity proxy with an intuitive base for both theoretical and empirical analyses in financial markets. 相似文献
15.
Krzysztof Pomorski José M. Blanco Pavel V. Kostryukov Artur Dobrowolski Bo?ena Nerlo-Pomorska Micha? Warda Zhi-Gang Xiao Yong-Jing Chen Li-Le Liu Jun-Long Tian Xin-Yue Diao Qiang-Hua Wu 《中国物理C(英文版)》2021,45(5):054109-054109-11
Fission properties of the actinide nuclei are deduced from theoretical analysis. We investigate potential energy surfaces and fission barriers and predict the fission fragment mass yields of actinide isotopes. The results are compared with experimental data where available. The calculations were performed in the macroscopic-microscopic approximation with the Lublin-Strasbourg Drop (LSD) for the macroscopic part, and the microscopic energy corrections were evaluated in the Yukawa-folded potential. The Fourier nuclear shape parametrization is used to describe the nuclear shape, including the non-axial degree of freedom. The fission fragment mass yields of the nuclei considered are evaluated within a 3D collective model using the Born-Oppenheimer approximation. 相似文献
16.
Krzysztof Kempa 《固体物理学:研究快报》2013,7(12):1112-1112
In the Letter by K. Kempa, the definitions of two auxiliary constants in Eqs. (10) and (11) were incorrectly given by the author. He now wishes to correct these equations. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
17.
Anna Chachaj-Brekiesz Krzysztof Zborowski Joanna Zemła Katarzyna Makyła-Juzak 《Molecular physics》2013,111(24):3567-3577
Symmetrical triblock semifluorinated n-alkane, di(perfluorohexyl)hexane of the formula F(CF2)6(CH2)6(CF2)6F (abbreviated F6H6F6), has been synthesised and investigated at the air/water interface. Our results show for the first time that this unusual film-forming material, completely hydrophobic in nature and possessing no polar group, is capable of stable film formation at the free water surface. The surface pressure–area isotherm of the studied compound exhibited two regions: corresponding to monotonous pressure rise, followed by a pseudo-plateau region. Visualisation of film structure with Brewster angle microscope (BAM) proved the formation of domains within the pseudo-plateau region. A closer insight into the structure of these domains with atomic force microscope (AFM) proved their ordered, circular shape. The average area of F6H6F6 domain was found to depend on surface pressure value, as it is 4.98 ± 1.75 μm2 at π = 1.2 mN/m to 16.54 ± 0.31 μm2 at π = 1.7 mN/m. Following performed quantum-chemical calculations, it can be concluded that the observed surface aggregates from F6H6F6 are formed by linear conformers with shifted CF and CH parts. The calculated domain thickness is between 20 and 21 Å, which perfectly agrees with the experimental value estimated from AFM measurements (20.3 ± 1.4 Å). 相似文献
18.
19.
20.
X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) have been used to investigate the effect of reactive ion etching (RIE) on poly(methylhydrogensiloxane-co-dimethylsiloxane) surface in fluorine-based plasmas. Polysiloxane layers supported on the standard silicon wafers were etched using SF6 + O2 or CF4 + O2 plasmas. SEM studies show that the polysiloxane morphology depends on plasma chemical composition strongly. Presence of a columnar layer likely covered with a fluorine rich compound was found on the elastomer surface after the CF4 + O2 plasma exposure. After the SF6 + O2 or CF4 + O2 plasma treatment the polysiloxane surface enriches with fluorine or with fluorine and aluminum, respectively. Different morphologies and surface chemical compositions of the silicone elastomer etched in both plasmas indicate different etching mechanisms. 相似文献