全文获取类型
收费全文 | 1714篇 |
免费 | 40篇 |
国内免费 | 8篇 |
专业分类
化学 | 1142篇 |
晶体学 | 13篇 |
力学 | 43篇 |
数学 | 261篇 |
物理学 | 303篇 |
出版年
2023年 | 8篇 |
2022年 | 22篇 |
2021年 | 44篇 |
2020年 | 23篇 |
2019年 | 25篇 |
2018年 | 23篇 |
2017年 | 17篇 |
2016年 | 50篇 |
2015年 | 49篇 |
2014年 | 45篇 |
2013年 | 96篇 |
2012年 | 93篇 |
2011年 | 119篇 |
2010年 | 86篇 |
2009年 | 68篇 |
2008年 | 116篇 |
2007年 | 103篇 |
2006年 | 117篇 |
2005年 | 103篇 |
2004年 | 91篇 |
2003年 | 69篇 |
2002年 | 66篇 |
2001年 | 26篇 |
2000年 | 25篇 |
1999年 | 15篇 |
1998年 | 17篇 |
1997年 | 12篇 |
1996年 | 26篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 13篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1975年 | 7篇 |
1970年 | 5篇 |
1969年 | 3篇 |
排序方式: 共有1762条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Nicola Arcozzi Enrico Casadio Tarabusi Fausto Di Biase Massimo A. Picardello 《Transactions of the American Mathematical Society》2006,358(6):2781-2798
We establish a potential theoretic approach to the study of twist points in the boundary of simply connected planar domains.
5.
A. Mahoui J. Lapasset D. G. Sannikov J. Moret P. Saint Grégoire 《Zeitschrift für Physik B Condensed Matter》1995,99(4):543-549
The crystal structure [(C2H5)4N]2CuCl4 has been determined by X-ray diffraction at 243K. The room temperature phase (phase I) belongs to the space group P42/nm [1] whereas the low temperature phase (phase II) is orthorhombic and belongs to the space group Pnna. The phase transition at Tc=258K is of improper ferroelastic type and it is associated with the ordering of the CuCl4 2? and a partial ordering of the [(C2H5)4N]+ ions which are disordered in the high temperature tetragonal phase. At lower temperature, there occurs another instability which could correspond to a complete ordering in the crystal. 相似文献
6.
7.
Massimo Camarda Antonino La Magna Francesco La Via 《Journal of computational physics》2007,227(2):1075-1093
A modified Kinetic Lattice Monte Carlo model has been developed to predict growth rate regimes and defect formation in the case of the homo-epitaxial growth of close packed crystalline structures. The model is an improvement over standard Monte Carlo algorithms, which usually retain fixed atom positions and bond partners indicative of perfect crystal lattices. Indeed, we extend the concepts of Monte Carlo growth simulations on super-lattices containing additional sites (defect sites) with respect to those of the reference material. This extension implies a reconsideration of the energetic mapping, which is extensively presented, and allows to describe a complex phenomenology that is out of accessibility of standard stochastic approaches. Results obtained using the Kawasaki and the Bond-Counting rules for the transition probability of the Monte Carlo event are discussed in details. These results demonstrate how the defect types (local or extended), the formation mechanisms and the defect generation regimes can be characterized using our approach. 相似文献
8.
L. Raimondo M. Campione M. Moret P. Spearman S. Tavazzi 《Applied Surface Science》2006,253(1):271-274
We propose optical absorption technique at oblique incidence as one of the spectroscopic tools that allow experimentally recognizing the macroscopic order and structural features of molecular solids of conjugated molecules, from single crystals to polycrystalline or twinned samples. We apply this spectroscopy to quaterthiophene as representative of a wide class of materials that usually possess optical transitions of Frenkel exciton origin with strong directional dispersion. The comparison between experimental and simulated data gives evidence of the high sensitivity of this technique for determining quantitatively the polycrystallinity of the measured samples, whose domains may show mirror-like orientation of the unit cell with respect to one of its faces.Frenkel exciton; Oligothiophene, Optical properties 相似文献
9.
We prove that Gibbs states for the Hamiltonian
, with thes
x varying on theN-dimensional unit sphere, obtained with nonrandom boundary conditions (in a suitable sense), are almost surely rotationally invariant if
withJ
xy i.i.d. bounded random variables with zero average, 1 in one dimension, and 2 in two dimensions. 相似文献
10.
Giuseppe Bartoli Sandra Giuli Enrico Marcantoni Massimo Massaccesi 《Tetrahedron letters》2006,47(37):6501-6504
The arylidene malonates with two different geminal carboxylate functions, a suitable class of substrates of several synthetic and pharmacological studies, are easily available through Knoevenagel condensation of ethyl tert-butyl malonate and different aromatic aldehydes. The results have increased the potentialities of CeCl3·7H2O-NaI system as a type of water-tolerant green Lewis acid promoter for carbon-carbon bond forming procedures. 相似文献