全文获取类型
收费全文 | 29104篇 |
免费 | 818篇 |
国内免费 | 232篇 |
专业分类
化学 | 19769篇 |
晶体学 | 136篇 |
力学 | 673篇 |
综合类 | 1篇 |
数学 | 5515篇 |
物理学 | 4060篇 |
出版年
2022年 | 160篇 |
2021年 | 286篇 |
2020年 | 361篇 |
2019年 | 323篇 |
2018年 | 287篇 |
2017年 | 298篇 |
2016年 | 609篇 |
2015年 | 630篇 |
2014年 | 678篇 |
2013年 | 1429篇 |
2012年 | 1438篇 |
2011年 | 1740篇 |
2010年 | 976篇 |
2009年 | 837篇 |
2008年 | 1513篇 |
2007年 | 1497篇 |
2006年 | 1592篇 |
2005年 | 1431篇 |
2004年 | 1357篇 |
2003年 | 1121篇 |
2002年 | 1070篇 |
2001年 | 468篇 |
2000年 | 416篇 |
1999年 | 403篇 |
1998年 | 388篇 |
1997年 | 441篇 |
1996年 | 408篇 |
1995年 | 363篇 |
1994年 | 400篇 |
1993年 | 362篇 |
1992年 | 342篇 |
1991年 | 326篇 |
1990年 | 289篇 |
1989年 | 290篇 |
1988年 | 272篇 |
1987年 | 228篇 |
1986年 | 255篇 |
1985年 | 375篇 |
1984年 | 381篇 |
1983年 | 326篇 |
1982年 | 360篇 |
1981年 | 328篇 |
1980年 | 352篇 |
1979年 | 283篇 |
1978年 | 314篇 |
1977年 | 296篇 |
1976年 | 229篇 |
1975年 | 196篇 |
1974年 | 210篇 |
1973年 | 183篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
81.
82.
83.
Peter Šimon 《Journal of Thermal Analysis and Calorimetry》2006,83(3):521-522
This
issue of Journal of Thermal Analysis and Calorimetry contains selected papers
based on presentations in the field of thermal characteristics of advanced
polymer systems presented at the 8th International
Symposium on Polymers for Advanced Technologies (PAT 2005) held in Budapest,
September 2005.
Guest Editors 相似文献
84.
In this paper, the possibility of using the gradients of the temperature and of the internal parameters as additional state variables in Continuum Thermodynamics is considered. The expressions of the two principles are discussed and Clausius–Duhem inequality is derived under an appropriate statement of the internal entropy production. Several formulations are proposed and compared to existing results in the literature. To cite this article: P. Ireman, Q.S. Nguyen, C. R. Mecanique 332 (2004). 相似文献
85.
86.
A new parallel storm surge model, the Parallel Environmental Model (PEM), is developed and tested by comparisons with analytic solutions. The PEM is a 2‐D vertically averaged, wetting and drying numerical model and can be operated in explicit, semi‐implicit and fully implicit modes. In the implicit mode, the propagation, Coriolis and bottom friction terms can all be treated implicitly. The advection and diffusion terms are solved with a parallel Eulerian–Lagrangian scheme developed for this study. The model is developed specifically for use on parallel computer systems and will function accordingly in either explicit of implicit modes. Storm boundary conditions are based on a simple exponential decay of pressure from the centre of a storm. The simulated flooding caused by a major Category 5 hurricane making landfall in the Indian River Lagoon, Florida is then presented as an example application of the PEM. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
87.
A cube factorization of the complete graph on n vertices, Kn, is a 3‐factorization of Kn in which the components of each factor are cubes. We show that there exists a cube factorization of Kn if and only if n ≡ 16 (mod 24), thus providing a new family of uniform 3‐factorizations as well as a partial solution to an open problem posed by Kotzig in 1979. © 2004 Wiley Periodicals, Inc. 相似文献
88.
Peter G. Casazza Gitta Kutyniok Mark C. Lammers 《Journal of Fourier Analysis and Applications》2004,10(4):383-408
Duality principles in Gabor theory such as the Ron–Shen duality principle and the
Wexler–Raz biorthogonality relations play a fundamental role for analyzing Gabor systems. In this
article we present a general approach to derive duality principles in abstract frame theory. For
each sequence in a separable Hilbert space we define a corresponding sequence dependent only
on two orthonormal bases. Then we characterize exactly properties of the first sequence in terms
of the associated one, which yields duality relations for the abstract frame setting. In the last part
we apply our results to Gabor systems. 相似文献
89.
Willi Jager Peter Lax Cathleen Synge Morawetz 《Journal of Mathematical Sciences》2004,120(3):1242-1246
90.
Deformation quantization is a powerful tool for quantizing theories with bosonic and fermionic degrees of freedom. The star products involved generate the mathematical structures which have recently been used in attempts to analyze the algebraic properties of quantum field theory. In the context of quantum mechanics they provide a quantization procedure for systems with either bosonic or fermionic degrees of freedom. We illustrate this procedure for a number of physical examples, including bosonic, fermionic, and supersymmetric oscillators. We show how non-relativistic and relativistic particles with spin can be naturally described in this framework. 相似文献