全文获取类型
收费全文 | 1002篇 |
免费 | 27篇 |
国内免费 | 8篇 |
专业分类
化学 | 738篇 |
晶体学 | 4篇 |
力学 | 47篇 |
数学 | 64篇 |
物理学 | 141篇 |
无线电 | 43篇 |
出版年
2023年 | 12篇 |
2022年 | 12篇 |
2021年 | 22篇 |
2020年 | 23篇 |
2019年 | 25篇 |
2018年 | 17篇 |
2017年 | 10篇 |
2016年 | 19篇 |
2015年 | 13篇 |
2014年 | 36篇 |
2013年 | 28篇 |
2012年 | 51篇 |
2011年 | 72篇 |
2010年 | 43篇 |
2009年 | 34篇 |
2008年 | 68篇 |
2007年 | 57篇 |
2006年 | 57篇 |
2005年 | 51篇 |
2004年 | 61篇 |
2003年 | 53篇 |
2002年 | 40篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 10篇 |
1995年 | 8篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 11篇 |
1982年 | 5篇 |
1980年 | 7篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1975年 | 8篇 |
1972年 | 4篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 5篇 |
1967年 | 7篇 |
1927年 | 4篇 |
1921年 | 4篇 |
1920年 | 4篇 |
排序方式: 共有1037条查询结果,搜索用时 296 毫秒
1.
Florence Drui Emmanuel Franck Philippe Helluy Laurent Navoret 《Comptes Rendus Mecanique》2019,347(3):259-269
The over-relaxation approach is an alternative to the Jin–Xin relaxation method in order to apply the equilibrium source term in a more precise way. This is also a key ingredient of the lattice Boltzmann method for achieving second-order accuracy. In this work, we provide an analysis of the over-relaxation kinetic scheme. We compute its equivalent equation, which is particularly useful for devising stable boundary conditions for the hidden kinetic variables. 相似文献
2.
Blaise Faugeras Jé rô me Pousin Franck Fontvieille. 《Mathematics of Computation》2006,75(253):209-222
A numerical scheme based on an operator splitting method and a dense output event location algorithm is proposed to integrate a diffusion-dissolution/precipitation chemical initial-boundary value problem with jumping nonlinearities. The numerical analysis of the scheme is carried out and it is proved to be of order 2 in time. This global order estimate is illustrated numerically on a test case.
3.
Franck D'Agosto Marie‐Thrse Charreyre Christian Pichot Robert G. Gilbert 《Journal of polymer science. Part A, Polymer chemistry》2003,41(9):1188-1195
A method is described for synthesizing latex particles with anchored hairs by the grafting of hydrophilic chains, synthesized by reversible addition–fragmentation chain transfer, onto functionalized latex particles. These have the potential to bind biologically active species. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1188–1195, 2003 相似文献
4.
Digital watermarking robust to geometric distortions. 总被引:23,自引:0,他引:23
Ping Dong Jovan G Brankov Nikolas P Galatsanos Yongyi Yang Franck Davoine 《IEEE transactions on image processing》2005,14(12):2140-2150
In this paper, we present two watermarking approaches that are robust to geometric distortions. The first approach is based on image normalization, in which both watermark embedding and extraction are carried out with respect to an image normalized to meet a set of predefined moment criteria. We propose a new normalization procedure, which is invariant to affine transform attacks. The resulting watermarking scheme is suitable for public watermarking applications, where the original image is not available for watermark extraction. The second approach is based on a watermark resynchronization scheme aimed to alleviate the effects of random bending attacks. In this scheme, a deformable mesh is used to correct the distortion caused by the attack. The watermark is then extracted from the corrected image. In contrast to the first scheme, the latter is suitable for private watermarking applications, where the original image is necessary for watermark detection. In both schemes, we employ a direct-sequence code division multiple access approach to embed a multibit watermark in the discrete cosine transform domain of the image. Numerical experiments demonstrate that the proposed watermarking schemes are robust to a wide range of geometric attacks. 相似文献
5.
As pan of a biomimetic approach towards me marine triterpene teurilene (2), the synthesis of the chiral diepoxide 3 is described. Aiming at the synthesis of the squalene tetraepoxide 1, double Sharpless epoxidation led to the intermediate bisglycidic alcohol 7 being subject to a stereochemical analysis. 相似文献
6.
Boris Andreianov Franck Boyer Florence Hubert 《Numerical Methods for Partial Differential Equations》2007,23(1):145-195
Discrete duality finite volume schemes on general meshes, introduced by Hermeline and Domelevo and Omnès for the Laplace equation, are proposed for nonlinear diffusion problems in 2D with nonhomogeneous Dirichlet boundary condition. This approach allows the discretization of non linear fluxes in such a way that the discrete operator inherits the key properties of the continuous one. Furthermore, it is well adapted to very general meshes including the case of nonconformal locally refined meshes. We show that the approximate solution exists and is unique, which is not obvious since the scheme is nonlinear. We prove that, for general W?1,p′(Ω) source term and W1‐(1/p),p(?Ω) boundary data, the approximate solution and its discrete gradient converge strongly towards the exact solution and its gradient, respectively, in appropriate Lebesgue spaces. Finally, error estimates are given in the case where the solution is assumed to be in W2,p(Ω). Numerical examples are given, including those on locally refined meshes. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007 相似文献
7.
8.
A nonlinear regeneration pulsed oscillator driven by a monochromatic source has been built. Subharmonics of the resonance carrier/modulation are measured with an accuracy of 10-10 thanks to the use of a double beats measurement set-up. The multiscale analysis of frequency readings reveals a rich fine structure which is in agreement with the nonlinear topological approach of synchronized states. 相似文献
9.
10.