全文获取类型
收费全文 | 2943篇 |
免费 | 238篇 |
国内免费 | 395篇 |
学科分类
数理化 | 3576篇 |
出版年
2024年 | 8篇 |
2023年 | 24篇 |
2022年 | 58篇 |
2021年 | 56篇 |
2020年 | 66篇 |
2019年 | 72篇 |
2018年 | 68篇 |
2017年 | 66篇 |
2016年 | 61篇 |
2015年 | 62篇 |
2014年 | 111篇 |
2013年 | 326篇 |
2012年 | 108篇 |
2011年 | 154篇 |
2010年 | 143篇 |
2009年 | 177篇 |
2008年 | 210篇 |
2007年 | 201篇 |
2006年 | 209篇 |
2005年 | 128篇 |
2004年 | 132篇 |
2003年 | 151篇 |
2002年 | 127篇 |
2001年 | 114篇 |
2000年 | 106篇 |
1999年 | 102篇 |
1998年 | 111篇 |
1997年 | 81篇 |
1996年 | 70篇 |
1995年 | 56篇 |
1994年 | 51篇 |
1993年 | 28篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 21篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 3篇 |
1984年 | 13篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1936年 | 2篇 |
排序方式: 共有3576条查询结果,搜索用时 15 毫秒
71.
72.
Brahim Alouini 《Mathematical Methods in the Applied Sciences》2021,44(1):91-103
In this article, we present, throughout two basic models of damped nonlinear Schrödinger (NLS)–type equations, a new idea to bound from above the fractal dimension of the global attractors for NLS‐type equations. This could answer the following open issue: consider, for instance, the classical one‐dimensional cubic nonlinear Schrödinger equation “How can we bound the fractal dimension of the associate global attractor without the need to assume that the external forcing term f has some decay at infinity (that is belonging to some weighted Lebesgue space)?” 相似文献
73.
74.
We consider uniform stability to a nontrivial equilibrium of a nonlinear fluid–structure interaction (FSI) defined on a two or three dimensional bounded domain. Stabilization is achieved via boundary and/or interior feedback controls implemented on both the fluid and the structure. The interior damping on the fluid combining with the viscosity effect stabilizes the dynamics of fluid. However, this dissipation propagated from the fluid alone is not sufficient to drive uniformly to equilibrium the entire coupled system. Therefore, additional interior damping on the wave component or boundary porous like damping on the interface is considered. A geometric condition on the interface is needed if only boundary damping on the wave is active. The main technical difficulty is the mismatch of regularity of hyperbolic and parabolic component of the coupled system. This is overcome by considering special multipliers constructed from Stokes solvers. The uniform stabilization result obtained in this article is global for the fully coupled FSI model. 相似文献
75.
Vasudevan Lakshminarayanan Cindhuja Chockalingam Dr. Eduardo Mendes Dr. Prof. Jan H. van Esch 《Chemphyschem》2021,22(21):2256-2261
Properties such as shear modulus, gelation time, structure of supramolecular hydrogels are strongly dependent on self-assembly, gelation triggering mechanism and processes used to form the gel. In our work we extend reported rheology analysis methodologies to pH-triggered supramolecular gels to understand structural insight using a model system based on N−N’ Dibenzoyl-L-Cystine pH-triggered hydrogelator and Glucono-δ-Lactone as the trigger. We observed that Avrami growth model when applied to time-sweep rheological data of gels formed at lower trigger concentrations provide estimates of fractal dimension which agree well compared with visualization of the microstructure as seen via Confocal Laser Scanning Microscopy, for a range of gelator concentrations. 相似文献
76.
This paper aims to determine the minimal dimensions and super-dimensions of faithful representations for Heisenberg Lie superalgebras over an algebraically closed field of characteristic zero. 相似文献
77.
78.
以三线两塔直线段输电塔-线体系为工程对象,应用有限元数值模拟,建立了基于概率密度演化的输电塔-线体系抗风可靠性分析方法。首先,应用谱表示-降维方法模拟结构脉动风场,生成风荷载的代表性样本集合。然后,结合概率密度演化理论,分析了输电塔-线体系考虑气弹效应的随机动力反应。最后,应用等价极值思想构建了风荷载作用下输电塔-线体系失效准则,进而对输电塔-线体系的抗风可靠性进行精细化分析。本文结合谱表示-降维方法与概率密度演化理论,实现了仅用较少数量的代表性样本来精细地分析结构的抗风可靠性,为工程实践提供参考。 相似文献
79.
D. Sternik P. Staszczuk J. Pękalska G. Grodzicka B. Gawdzik J. Osypiuk-Tomasik P. Witer 《Journal of Thermal Analysis and Calorimetry》2006,86(1):85-91
The adsorption of a polar (water)
and a non-polar (n-octane) liquid on silica
gels, modified by adsorption of proteins, has been studied by thermal analysis.
Silica gels with physically adsorbed BSA and ovalbumin layers were used. Thermodesorption
energies were determined from Q-TG and Q-DTG curves recorded under quasi-equilibrium
conditions. Significant differences in liquid desorption were observed from
the surfaces due to heterogeneous changes (energetic and geometrical) as a
result of modification. These results are compared with those obtained for
the samples heated at 160°C for 1 h. 相似文献
80.
P. Staszczuk D. Sternik G. W. Chądzyński E. Robens M. Błachnio 《Journal of Thermal Analysis and Calorimetry》2006,86(1):133-136
Nitrogen
adsorption measured at 77 K was used to characterize the surface heterogeneity
of high-temperature superconductor surfaces. Properties relating to adsorption
and porosity of the solids (adsorption capacity, specific surface area, radii
and volume of the pores, pore-size distribution function) were determined
from nitrogen adsorption–desorption isotherms and atomic force microscopy
(AFM) for a series of oxide superconductors. It is shown that the adsorption
isotherms of all samples are S-shaped and belong to type II according to the
IUPAC classification. On the basis of the nitrogen adsorption isotherms and
AFM data, fractal dimensions were determined and correlations found with adsorption
and porosity parameters. 相似文献