全文获取类型
收费全文 | 2710篇 |
免费 | 167篇 |
国内免费 | 255篇 |
专业分类
化学 | 112篇 |
晶体学 | 2篇 |
力学 | 270篇 |
综合类 | 62篇 |
数学 | 2261篇 |
物理学 | 425篇 |
出版年
2024年 | 3篇 |
2023年 | 17篇 |
2022年 | 32篇 |
2021年 | 48篇 |
2020年 | 59篇 |
2019年 | 57篇 |
2018年 | 59篇 |
2017年 | 72篇 |
2016年 | 59篇 |
2015年 | 62篇 |
2014年 | 103篇 |
2013年 | 204篇 |
2012年 | 71篇 |
2011年 | 99篇 |
2010年 | 104篇 |
2009年 | 140篇 |
2008年 | 190篇 |
2007年 | 193篇 |
2006年 | 169篇 |
2005年 | 193篇 |
2004年 | 131篇 |
2003年 | 147篇 |
2002年 | 140篇 |
2001年 | 104篇 |
2000年 | 102篇 |
1999年 | 91篇 |
1998年 | 97篇 |
1997年 | 72篇 |
1996年 | 46篇 |
1995年 | 46篇 |
1994年 | 32篇 |
1993年 | 26篇 |
1992年 | 24篇 |
1991年 | 20篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有3132条查询结果,搜索用时 718 毫秒
111.
Coleman Automorphisms of Extensions of Finite Characteristically Simple Groups by Some Finite Groups
Let G be an extension of a finite characteristically simple group by an abelian group or a finite simple group.It is shown that every Coleman automorphism of G is an inner automorphism.Interest in such automorphisms arises from the study of the normalizer problem for integral group rings. 相似文献
112.
In this note, we prove that the CR manifold induced from the canonical parabolic geometry of a quaternionic contact (qc) manifold via a Fefferman-type construction is equivalent to the CR twistor space of the qc manifold defined by O. Biquard. 相似文献
113.
Whether Fittsʼ law, a well-known model of human pointing movement, is a logarithmic law or a power law has remained unclear so far. In two widely cited papers, Meyer et al. have claimed that the power model they derived from their celebrated stochastic optimized-submovement theory encompasses the logarithmic model as a limiting case. We show that Meyer et al.ʼs theory implies in fact a quasi-logarithmic, rather than quasi-power model, the two models being not equivalent. 相似文献
114.
We determine curvature properties of pseudosymmetric type of certain warped product manifolds, and in particular of generalized Robertson–Walker spacetimes, with Einsteinian or quasi-Einsteinian fibre. 相似文献
115.
116.
We introduce a parametrisation of the direct correlation function for the square-shoulder fluid and demonstrate that this parametrisation is in quantitative agreement with the numerical solution of the Ornstein–Zernike equation within the Percus–Yevick approximation. Moreover, the radial distribution function obtained from the parametrisation reproduces quantitatively Monte Carlo simulation data. Our results show that the parametrisation is accurate over a large regime of densities for different interaction ranges and potential strengths. 相似文献
117.
The aim of the present paper is to investigate new classes of symplectically fat fibre bundles. We prove a general existence theorem for fat vectors with respect to the canonical invariant connections. Based on this result we give new proofs of some constructions of symplectic structures. This includes twistor bundles and locally homogeneous complex manifolds. The proofs are conceptually simpler and allow for obtaining more general results. 相似文献
118.
WANG FengYu School of Mathematical Sciences Beijing Normal University Beijing China 《中国科学 数学(英文版)》2010,(4)
By establishing the intrinsic super-Poincar'e inequality,some explicit conditions are presented for diffusion semigroups on a non-compact complete Riemannian manifold to be intrinsically ultracontractive.These conditions,as well as the resulting uniform upper bounds on the intrinsic heat kernels,are sharp for some concrete examples. 相似文献
119.
We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer.The system.whose components are connected via ferrule connector/physical connection(FC/PC)fiber connectors,constitutes all-fiber configuration to generate squeezed soliton.Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level.Optimal squeezing fields in both simple and compact all-fiber configuration are obtained. 相似文献
120.
Simple and robust digital holography for high-resolution imaging 总被引:2,自引:0,他引:2
Based on the point spread function of holographic system,the lateral resolution of digital holographic imaging system without any pre-magnification is studied.The expression of resolution limitation of holographic imaging system is thus presented.We investigate the possibilities to improve the lateral resolution.The simple experimental setup with an off-axis arrangement is built.By using a U.S.Air Force(USAF)test target as microscopic object,the recorded holograms are reconstructed digitally based on the principle of Fresnel diffraction.The lateral resolution of 2.76 μm without any pre-magnification is demonstrated experimentally,which matches the theoretical prediction well. 相似文献