全文获取类型
收费全文 | 2440篇 |
免费 | 93篇 |
国内免费 | 22篇 |
专业分类
化学 | 1793篇 |
晶体学 | 13篇 |
力学 | 86篇 |
综合类 | 1篇 |
数学 | 347篇 |
物理学 | 315篇 |
出版年
2024年 | 15篇 |
2023年 | 36篇 |
2022年 | 269篇 |
2021年 | 176篇 |
2020年 | 105篇 |
2019年 | 90篇 |
2018年 | 87篇 |
2017年 | 74篇 |
2016年 | 125篇 |
2015年 | 72篇 |
2014年 | 80篇 |
2013年 | 194篇 |
2012年 | 133篇 |
2011年 | 147篇 |
2010年 | 89篇 |
2009年 | 80篇 |
2008年 | 103篇 |
2007年 | 95篇 |
2006年 | 79篇 |
2005年 | 78篇 |
2004年 | 61篇 |
2003年 | 60篇 |
2002年 | 42篇 |
2001年 | 26篇 |
2000年 | 17篇 |
1999年 | 20篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 18篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 13篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1974年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有2555条查询结果,搜索用时 281 毫秒
1.
2.
Unexpected benzimidazole ring formation from a quinoneimide species in the presence of ammonium acetate as supporting electrolyte used in the coupling of electrochemistry with mass spectrometry 下载免费PDF全文
3.
Kacimi Rachid Bourass Mohamed Toupance Thierry Wazzan Nuha Chemek Mourad El Alamy Aziz Bejjit Lahcen Alimi Kamel Bouachrine Mohammed 《Research on Chemical Intermediates》2020,46(6):3247-3262
Research on Chemical Intermediates - A theoretical study on four organic dyes based on bis(4-hexyloxy)triphenylamine as donor and electron acceptor cyanoacrylic acid with a... 相似文献
4.
Nonlinear Dynamics - Introduction of stiffness nonlinearities to broaden the frequency bandwidth of vibratory energy harvesters has the adverse influence of complicating the response behavior of... 相似文献
5.
6.
Mohammed Aassila 《Comptes Rendus Mathematique》2002,334(11):961-966
We study the semilinear wave equation utt?Δu=p?k|u|m in , where p is a conformal factor approaching 0 at infinity. We prove that the solutions blow-up in finite time for small powers m, while having an arbitrarily long life-span for large m. Furthermore, we study the finite time blow-up of solutions for the class of quasilinear wave equations utt?Δu=p?k|Lu|m in . To cite this article: M. Aassila, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 961–966. 相似文献
7.
Let M be a Riemannian m-dimensional manifold with m ≥ 3, endowed with non zero parallel p-form. We prove that there is no minimal isometric immersions of M in a Riemannian manifold N with constant strictly negative sectional curvature. Next we show that, under the conform flatness of the manifold N and some assumptions on the Ricci curvature of N, there is no α-pluriharmonic isometric immersion. 相似文献
8.
Mohammed Ali Faya Ibrahim 《Czechoslovak Mathematical Journal》2004,54(2):303-313
It was shown in [7] that any right reversible, cancellative ordered semigroup can be embedded into an ordered group and as a consequence, it was shown that a commutative ordered semigroup can be embedded into an ordered group if and only if it is cancellative. In this paper we introduce the concept of L-maher and R-maher semigroups and use a technique similar to that used in [7] to show that any left reversible cancellative ordered L or R-maher semigroup can be embedded into an ordered group. 相似文献
9.
This paper presents an approach based on topology for the determination of characteristics and properties of curves used in the trimming of NURBS surfaces. Through discrete subdivision and topological criteria, a method is presented to determine characteristics of the boundary; such as whether the set of trimming curves forms a set of closed loops, whether trimming curves contain singularities or self intersections, and whether the boundary is simply connected. A surface mesh partitionning the parameter space is used, formed of isoparametric lines in both parametric directions. Topological properties of the cells of this mesh and their intersections with the trimming curves allow to localize the boundary. Topological treatment of this localization allows to define the interior and exterior of the face, and to refine the boundary localization. Singularities and self intersections of the boundary as well as voids in the face are investigated through the study of topological properties of neighbors. As an application, an algorithm for point localization is presented that very rapidly allows to determine whether a given point in parameter space lies inside, on the boundary or outside of the trimmed surface. 相似文献
10.
Let be an elliptic curve with complex multiplication, defined over . We consider linear forms on with coefficients in the CM field of . Within this framework, we present a new measure of linear independence for elliptic logarithms in (logb)(loga)n. Like recent advances in this domain (works by Ably, David, Hirata-Kohno), our result is best possible in terms of the height of the linear forms (logb) while providing a better estimate in the height of algebraic points considered (loga), removing a term in logloga. To cite this article: M. Ably, É. Gaudron, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献