全文获取类型
收费全文 | 6266篇 |
免费 | 266篇 |
国内免费 | 32篇 |
专业分类
化学 | 4337篇 |
晶体学 | 21篇 |
力学 | 233篇 |
数学 | 1042篇 |
物理学 | 931篇 |
出版年
2022年 | 35篇 |
2021年 | 62篇 |
2020年 | 66篇 |
2019年 | 83篇 |
2018年 | 87篇 |
2017年 | 81篇 |
2016年 | 158篇 |
2015年 | 148篇 |
2014年 | 174篇 |
2013年 | 269篇 |
2012年 | 346篇 |
2011年 | 380篇 |
2010年 | 248篇 |
2009年 | 237篇 |
2008年 | 346篇 |
2007年 | 333篇 |
2006年 | 341篇 |
2005年 | 313篇 |
2004年 | 275篇 |
2003年 | 252篇 |
2002年 | 297篇 |
2001年 | 111篇 |
2000年 | 108篇 |
1999年 | 65篇 |
1998年 | 62篇 |
1997年 | 69篇 |
1996年 | 79篇 |
1995年 | 56篇 |
1994年 | 69篇 |
1993年 | 53篇 |
1992年 | 56篇 |
1991年 | 60篇 |
1990年 | 50篇 |
1989年 | 44篇 |
1988年 | 42篇 |
1987年 | 45篇 |
1986年 | 41篇 |
1985年 | 93篇 |
1984年 | 87篇 |
1983年 | 57篇 |
1982年 | 92篇 |
1981年 | 60篇 |
1980年 | 87篇 |
1979年 | 61篇 |
1978年 | 77篇 |
1977年 | 64篇 |
1976年 | 64篇 |
1975年 | 42篇 |
1974年 | 51篇 |
1973年 | 38篇 |
排序方式: 共有6564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.
Manfred Brun Peter Hubner Dieter Oelkrug 《Fresenius' Journal of Analytical Chemistry》1992,344(4-5):209-213
Summary A theoretical model is derived that describes the influence of lateral light diffusion in a scattering medium on the absorptivity of an absorber spot on top of the substrate. The model uses the lateral resolved reflectivity under point irradiation that has been analyzed experimentally with a scanning-micro-laser-reflectometer. The model allows quantification of the absorptivity by one single equation that contains only the mean radial diffusion length of light and the spot area. Experiment and theory are applied to typical substrates for thin layer chromatography (alumina, silica, cellulose). The diffusion lengths in these substrates are given and the absorptivities of the spots are calculated as a function of the spot area. 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