全文获取类型
收费全文 | 7532篇 |
免费 | 294篇 |
国内免费 | 39篇 |
专业分类
化学 | 4913篇 |
晶体学 | 43篇 |
力学 | 248篇 |
数学 | 1244篇 |
物理学 | 1417篇 |
出版年
2021年 | 74篇 |
2020年 | 86篇 |
2019年 | 107篇 |
2018年 | 101篇 |
2017年 | 95篇 |
2016年 | 198篇 |
2015年 | 159篇 |
2014年 | 201篇 |
2013年 | 310篇 |
2012年 | 370篇 |
2011年 | 445篇 |
2010年 | 276篇 |
2009年 | 265篇 |
2008年 | 395篇 |
2007年 | 390篇 |
2006年 | 409篇 |
2005年 | 362篇 |
2004年 | 315篇 |
2003年 | 294篇 |
2002年 | 327篇 |
2001年 | 163篇 |
2000年 | 134篇 |
1999年 | 77篇 |
1998年 | 80篇 |
1997年 | 83篇 |
1996年 | 124篇 |
1995年 | 79篇 |
1994年 | 80篇 |
1993年 | 85篇 |
1992年 | 81篇 |
1991年 | 80篇 |
1990年 | 72篇 |
1989年 | 68篇 |
1988年 | 62篇 |
1987年 | 63篇 |
1986年 | 48篇 |
1985年 | 98篇 |
1984年 | 102篇 |
1983年 | 61篇 |
1982年 | 101篇 |
1981年 | 73篇 |
1980年 | 102篇 |
1979年 | 72篇 |
1978年 | 97篇 |
1977年 | 71篇 |
1976年 | 72篇 |
1975年 | 49篇 |
1974年 | 67篇 |
1973年 | 51篇 |
1972年 | 29篇 |
排序方式: 共有7865条查询结果,搜索用时 46 毫秒
21.
Let Λ be a smooth Lagrangian submanifold of a complex symplectic manifold X. We construct twisted simple holonomic modules along Λ in the stack of deformation-quantization modules on X. 相似文献
22.
We consider Sinai’s random walk in random environment. We prove that infinitely often (i.o.) the size of the concentration neighborhood of this random walk is bounded almost surely. We also get that i.o. the maximal distance between two favorite sites is bounded almost surely. 相似文献
23.
Pierre Crispel Pierre Degond Céline Parzani Marie-Hélène Vignal 《Comptes Rendus Mathematique》2004,338(4):327-332
In this Note, we propose three formulations of a model describing a quasi-neutral plasma with non-vanishing current. In order to study and compare the numerical efficiency of each formulation, two test-problems are implemented in one dimension. The first is a periodic perturbation of a uniform stationary plasma. The second is a case of plasma expansion in vacuum between two electrodes. To cite this article: P. Crispel et al., C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
24.
25.
K. -J. Berg A. Berger H. Hofmeister 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,20(1):309-311
Small spherical silver particles in a surface layer of commercial flat glass were produced by means of sodium-silver ion exchange. In each volume element of the layer there is a Gaussian distribution of the particle diameters. The mean diameter increases with penetration depth. Within one individual sample it can vary from 4.5 nm immediately at the glass surface up to more than 50 nm at the end of the layer. Due to a special preparation technique the results were gained by microspectrophotometric measurements as well as by investigations carried out with the transmission electron microscope and the electron-probe microanalyzer on one and the same sample always as function of the penetration depth. 相似文献
26.
Pierre Antoine Grillet 《Semigroup Forum》1995,50(1):317-326
An explicit upper bound is given for the number of commutative semigroups withn elements. 相似文献
27.
Pierre Antoine Grillet 《Semigroup Forum》2007,74(1):41-54
New precedence results are obtained for finite, not necessarily commutative semigroups, which are used to further sharpen
existing algorithms for the computation of finite semigroups. The results in this first part describe the first row of the
multiplication table in detail and provide a numerical profile with which it can be compared to other rows. 相似文献
28.
A general framework is developed to treat inverse problems with parameters that are random fields. It involves a sampling
method that exploits the sensitivity derivatives of the control variable with respect to the random parameters. As the sensitivity
derivatives are computed only at the mean values of the relevant parameters, the related extra cost of the present method
is a fraction of the total cost of the Monte Carlo method. The effectiveness of the method is demonstrated on an example problem
governed by the Burgers equation with random viscosity. It is specifically shown that this method is two orders of magnitude
more efficient compared to the conventional Monte Carlo method. In other words, for a given number of samples, the present
method yields two orders of magnitude higher accuracy than its conventional counterpart. 相似文献
29.
30.
The determination of the enantiomeric purity of 2 or 3-substituted cyclanones, particularly cyclohexanones, is conveniently achieved by derivatisation into cyclic aminals with commercially available (R, R)-1,2-diphenylethylenediamine. The derivatisation procedure is directly done into the NMR tube, instantaneously, and 13C NMR allows an accurate measure of the ee. 相似文献