全文获取类型
收费全文 | 1801篇 |
免费 | 82篇 |
国内免费 | 74篇 |
专业分类
化学 | 423篇 |
晶体学 | 7篇 |
力学 | 326篇 |
综合类 | 20篇 |
数学 | 614篇 |
物理学 | 567篇 |
出版年
2023年 | 10篇 |
2022年 | 19篇 |
2021年 | 29篇 |
2020年 | 21篇 |
2019年 | 72篇 |
2018年 | 66篇 |
2017年 | 51篇 |
2016年 | 67篇 |
2015年 | 63篇 |
2014年 | 69篇 |
2013年 | 104篇 |
2012年 | 57篇 |
2011年 | 67篇 |
2010年 | 66篇 |
2009年 | 105篇 |
2008年 | 129篇 |
2007年 | 81篇 |
2006年 | 124篇 |
2005年 | 125篇 |
2004年 | 118篇 |
2003年 | 104篇 |
2002年 | 110篇 |
2001年 | 29篇 |
2000年 | 29篇 |
1999年 | 29篇 |
1998年 | 28篇 |
1997年 | 19篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 10篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1957年 | 2篇 |
排序方式: 共有1957条查询结果,搜索用时 15 毫秒
1.
《Indagationes Mathematicae》2021,32(1):55-85
We show that the differential structure of the orbit space of a proper action of a Lie group on a smooth manifold is weakly reflexive. This implies that the orbit space is a differentiable space in the sense of Smith, which ensures that the orbit space has an exterior algebra of differential forms, that satisfies Smith’s version of de Rham’s theorem. Because the orbit space is a locally closed subcartesian space, it has vector fields and their flows. 相似文献
2.
3.
《Comptes Rendus Physique》2015,16(2):193-203
The field of multiferroics has experienced a rapid progress resulting in the discovery of many new physical phenomena. BiFeO3 (BFO) compound, which is one of the few room-temperature single-phase multiferroics, has contributed subsequently to this progress. As a result, significant review articles have been devoted specifically to this famous system. This chapter is dedicated to the strain effects on the structure stability and property changes of BFO thin films. It is a short and non-exhaustive topical overview that may be seen as an invitation for interested readers to go beyond. There is a very active and prolific research in this field and we apologize to the authors whose relevant work is not cited here. After a short introduction, we will thus review the effect of strain on BFO films by describing the consequences on the structure and the phase transitions as well as on polar, magnetic and magnetoelectric properties. 相似文献
4.
《Comptes Rendus Mecanique》2019,347(4):318-331
In this essay we explore analogies between macroscopic patterns, which result from a sequence of phase transitions/instabilities starting from a homogeneous state, and similar phenomena in cosmology, where a sequence of phase transitions in the early universe is believed to have separated the fundamental forces from each other, and also shaped the structure and distribution of matter in the universe. We discuss three distinct aspects of this analogy: (i) Defects and topological charges in macroscopic patterns are analogous to spins and charges of quarks and leptons; (ii) Defects in generic 3+1 stripe patterns carry an energy density that accounts for phenomena that are currently attributed to dark matter; (iii) Space-time patterns of interacting nonlinear waves display behaviors reminiscent of quantum phenomena including inflation, entanglement and dark energy. 相似文献
5.
《Comptes Rendus Mecanique》2019,347(4):287-293
I will shortly review the history of experimental and theoretical findings on period doubling until the discovery of the quantitative universal properties of the infinite period-doubling cascade. 相似文献
6.
本文定义了二阶微分方程的弱 Carathéodory解 ,在不涉及紧型条件的情形下 ,直接用迭代法证明了 Banach空间二阶非线性常微分方程两点边值问题存在唯一解 ,并给出逼近解迭代序列的误差估计 ,对周期边值问题得到类似的结果 相似文献
7.
The aim of this article is to give some property of continued fraction with matrices arguments, about their convergence and
others applications. At the end of this work, we present a resolution of the Algebraic Riccati Equation by giving an explicit
continued fraction development of its solution.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
Ph. Batchelor 《Commentarii Mathematici Helvetici》1998,73(3):337-352
On estime la dérivée des petites valeurs propres du Laplacien sur une famille de surfaces de Riemann. Ces valeurs propres
sont considérées comme des fonctions sur l'espace de Teichmüller, et l'estimation des dérivées peut s'exprimer dans ce contexte.
Received: December 21, 1995 相似文献
9.
C. P. Massarolo G. P. Menzala A. F. Pazoto 《Mathematical Methods in the Applied Sciences》2007,30(12):1419-1435
The aim of this work is to consider the Korteweg–de Vries equation in a finite interval with a very weak localized dissipation namely the H?1‐norm. Our main result says that the total energy decays locally uniform at an exponential rate. Our analysis improves earlier works on the subject (Q. Appl. Math. 2002; LX (1):111–129; ESAIM Control Optim. Calculus Variations 2005; 11 (3):473–486) and gives a satisfactory answer to a problem suggested in (Q. Appl. Math. 2002; LX (1):111–129). Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
10.
The Rio de la Plata is a large and shallow water body that discharges onto the Atlantic Ocean. The main driving forces for the river flow are the bathymetry, tides, the outflow from the Paraná and Uruguay rivers and the winds. A numerical model covering the entire river was set up with the objective of increasing our understanding of the hydrographical features and morphological dynamics in the Estuary. The simulations revealed a counter-clockwise residual circulation in the Samborombón Bay and an eastward net flow near the Uruguayan coast. The residual flow is forced by both the tides and the bathymetry. The residence time for the entire river ranges from 40 to 80 days. However, residence times above 120 days was found in the Samborombón Bay. Three corridors of flow have been identified. 相似文献