全文获取类型
收费全文 | 886篇 |
免费 | 47篇 |
国内免费 | 13篇 |
专业分类
化学 | 418篇 |
晶体学 | 10篇 |
力学 | 30篇 |
数学 | 322篇 |
物理学 | 166篇 |
出版年
2023年 | 6篇 |
2022年 | 24篇 |
2021年 | 29篇 |
2020年 | 48篇 |
2019年 | 33篇 |
2018年 | 56篇 |
2017年 | 31篇 |
2016年 | 47篇 |
2015年 | 39篇 |
2014年 | 36篇 |
2013年 | 67篇 |
2012年 | 76篇 |
2011年 | 51篇 |
2010年 | 35篇 |
2009年 | 29篇 |
2008年 | 36篇 |
2007年 | 24篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 20篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1972年 | 3篇 |
1971年 | 4篇 |
排序方式: 共有946条查询结果,搜索用时 500 毫秒
101.
We have studied systematically room-temperature photoluminescence (PL) properties of many nanostructured ZnO samples grown by chemical vapour deposition (CVD). Their PL spectra consist of two emissions peaked in the ultraviolet (UV) and green regions. The relative intensity of these emissions depends on the excitation energy density, size and morphology of ZnO nanostructures. Based on the excitation-density dependence of the integrated intensity ratio of UV-to-green emission, we could classify PL spectra of ZnO nanostructures into three groups characteristic of size and morphology. Our study also reveals that with increasing excitation density, the UV-peak position shifts slightly towards longer wavelengths while the green emission around 514-520 nm is almost unchanged. This green-luminescence emission is dominant when the nanostructure sizes range from 20 to 200 nm, which is related to a large surface-to-volume ratio. 相似文献
102.
B.Z. Jiang T.L. Phan D.S. Yang K.W. Lee S.C. Yu 《Solid State Communications》2010,150(39-40):1932-1935
103.
The subgradient extragradient method can be considered as an improvement of the extragradient method for variational inequality problems for the class of monotone and Lipschitz continuous mappings. In this paper, we propose two new algorithms as combination between the subgradient extragradient method and Mann-like method for finding a common element of the solution set of a variational inequality and the fixed point set of a demicontractive mapping. 相似文献
104.
105.
Weighted Calderón-Zygmund Estimates for Weak Solutions of Quasi-Linear Degenerate Elliptic Equations
Potential Analysis - This paper studies regularity estimates in Sobolev spaces for weak solutions of a class of degenerate and singular quasi-linear elliptic problems of the form... 相似文献
106.
Tuoc Phan & Yannick Sire 《分析论及其应用》2020,36(2):111-127
We establish local and global well-posedness of the 2D dissipative quasi-geostrophic equation in critical mixed norm Lebesgue spaces. The result demonstrates
the persistence of the anisotropic behavior of the initial data under the evolution of
the 2D dissipative quasi-geostrophic equation. The phenomenon is a priori nontrivial
due to the nonlocal structure of the equation. Our approach is based on Kato's method
using Picard's iteration, which can be adapted to the multi-dimensional case and
other nonlinear non-local equations. We develop time decay estimates for solutions of
fractional heat equation in mixed norm Lebesgue spaces that could be useful for other
problems. 相似文献
107.
The existence of exponential attractor for the diffusive Hindmarsh-Rose equations on a three-dimensional bounded domain in the study of neurodynamics is proved through uniform estimates and a new theorem on the squeezing property of the abstract reaction-diffusion equation established in this paper. This result on the exponential attractor infers that the global attractor whose existence has been proved in [22] for the diffusive Hindmarsh-Rose semiflow has a finite fractal dimension. 相似文献
108.
Global dynamics for a new mathematical model in neurodynamics of the diffusive Hindmarsh-Rose equations on a bounded domain is investigated in this paper. The existence of a global attractor and its regularity are proved through uniform estimates showing the dissipative properties and the asymptotically compact and smoothing characteristics. 相似文献
109.
We investigate the global exponential stability of equilibrium solutions of a projected dynamical system for variational inequalities. Under strong pseudomonotonicity and Lipschitz continuity assumptions, we prove that the dynamical system has a unique equilibrium solution. Moreover, this solution is globally exponentially stable. Some examples are given to analyze the effectiveness of the theoretical results. The numerical results confirm that the trajectory of the dynamical system globally exponentially converges to the unique solution of the considered variational inequality. The results established in this paper improve and extend some recent works. 相似文献