全文获取类型
收费全文 | 329篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
化学 | 128篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 140篇 |
物理学 | 66篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 10篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 14篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 23篇 |
2011年 | 15篇 |
2010年 | 7篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 14篇 |
2006年 | 16篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 14篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有338条查询结果,搜索用时 15 毫秒
1.
2.
3.
Doron Gepner 《Communications in Mathematical Physics》1991,142(3):433-491
InN=2 string theory the chiral algebra expresses the generations and anti-generations of the theory and the Yukawa couplings among them and is thus crucial to the phenomenological properties of the theory. Also the connection with complex geometry is largely through the algebras. These algebras are systematically investigated in this paper. A solution for the algebras is found in the context of rational conformal field theory based on Lie algebras. A statistical mechanics interpretation for the chiral algebra is given for a large family of theories and is used to derive a rich structure of equivalences among the theories (dihedralities). The Poincaré polynomials are shown to obey a resolution series which cast these in a form which is a sum of complete intersection Poincaré polynomials. It is suggested that the resolution series is the proper tool for studying allN=2 string theories and, in particular, exposing their geometrical nature. 相似文献
4.
5.
In his celebrated paper, Polya has considered the random walk in the three-dimensional (cubic) lattice and showed that the probability of return to the origin is less than 1. Subsequent authors have shown that the probability is %34.053.... Here we consider the same random walk, with the restriction that the drunkard is only allowed to stay inxyz. It is shown that his probability of returning to the originand staying in the allowed region is %6.4844.... 相似文献
6.
Elena Levi Eli Lancry Yossi Gofer Doron Aurbach 《Journal of Solid State Electrochemistry》2006,10(3):176-184
A crystallographic approach was applied to elucidate the influence of the nature of the surface films on the electrochemical
behavior of Li and Mg intercalation compounds. This paper presents two examples: (1) protection of graphite electrodes by
Li2CO3 surface films, and (2) the unique electrochemical behavior of Mg-containing Chevrel phases (MgCP) obtained by different synthetic
routes. In the former case, the elucidation of the protection mechanism and the explanation of the high performance of such
protected electrodes are based on the analysis of possible Li-ion motion in the carbonate crystal structure. In the latter
case, a combination of synthesis, electrochemistry and XRD analysis was used to explain an unusual phenomenon: the difference
between the excellent electrochemical behavior of the Chevrel phase (CP) based on Cu-leached Cu2Mo6S8 (CuCP), and the poor electrochemical activity of the high-temperature synthesized MgCP, with the same phase composition.
It is shown that this phenomenon is caused by MgO formation on the surface of the latter material. The different surface chemistry
of the MgCPs obtained by the two different synthetic routes was substantiated by revealing the correlation between the electrochemical
activity and the chemical stability of these materials under ambient atmosphere conditions.
Dedicated to Prof. Mikhail A. Vorotyntsev on the occasion of his 60th birthday. 相似文献
7.
8.
In this paper, we propose a metamaterial film bounded by a nonlinear cover and a dielectric substrate as a THz wave sensor. The dispersion characteristics and magnetic field profiles have been derived, computed and analyzed. Confinement of the light waves was found to increase with both nonlinearity and frequency. We believe our results can be used to design novel tunable future sensors. 相似文献
9.
A. B. Shabat 《JETP Letters》2015,102(9):620-623
The scattering problem for the linear Schrödinger equation on the entire axis has been considered. Conditions under which the knowledge of the discrete spectrum of the Schrödinger operator is sufficient for the reconstruction of the potential have been determined. The main difference from the soliton sector is the self-similarity of the problem under consideration with respect to the extension of the spectral parameter λ. This makes it possible to reduce the inverse scattering problem to the study of the singularity of the Green’s function at λ = 0. 相似文献
10.
Dr. Umesh A. Kshirsagar Regev Parnes Hagit Goldshtein Dr. Rivka Ofir Dr. Raz Zarivach Dr. Doron Pappo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(40):13575-13583
An iron‐based cross‐dehydrogenative coupling (CDC) approach was applied for the diversity‐oriented synthesis of coumestrol‐based selective estrogen receptor modulators (SERMs), representing the first application of CDC chemistry in natural product synthesis. The first stage of the two‐step synthesis of coumestrol involved a modified aerobic oxidative cross‐coupling between ethyl 2‐(2,4‐dimethoxybenzoyl)acetate and 3‐methoxyphenol, with FeCl3 (10 mol %) as the catalyst. The benzofuran coupling product was then subjected to sequential deprotection and lactonization steps, affording the natural product in 59 % overall yield. Based on this new methodology other coumestrol analogues were prepared, and their effects on the proliferation of the estrogen receptor (ER)‐dependent MCF‐7 and of the ER‐independent MDA‐MB‐231 breast cancer cells were tested. As a result, new types of estrogen receptor ligands having an acetamide group instead of the 9‐hydroxyl group of coumestrol were discovered. Both 9‐acetamido‐coumestrol and 8‐acetamidocoumestrol were found more active than the natural product against estrogen‐dependent MCF‐7 breast cancer cells, with IC50 values of 30 and 9 nM , respectively. 相似文献