全文获取类型
收费全文 | 755篇 |
免费 | 6篇 |
国内免费 | 5篇 |
专业分类
化学 | 522篇 |
晶体学 | 14篇 |
力学 | 12篇 |
数学 | 53篇 |
物理学 | 165篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 13篇 |
2019年 | 17篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 25篇 |
2013年 | 46篇 |
2012年 | 37篇 |
2011年 | 50篇 |
2010年 | 22篇 |
2009年 | 28篇 |
2008年 | 51篇 |
2007年 | 54篇 |
2006年 | 43篇 |
2005年 | 47篇 |
2004年 | 45篇 |
2003年 | 33篇 |
2002年 | 41篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1975年 | 1篇 |
1973年 | 6篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有766条查询结果,搜索用时 15 毫秒
81.
A spin-Peierls system (DMe-DCNQI)2Li is studied with W-band electron paramagnetic resonance (EPR) ( approximately 94 GHz) to unveil a charge transport mechanism in the insulating 4k(F) charge density wave state above T(SP). The electron hopping between the neighbor DCNQI columns provides an additional broadening of the EPR linewidth, since the neighbor columns are generally nonequivalent to each other with respect to g shift. The obtained intercolumn hopping rates lead us to the conclusion that the electron hopping to a hole soliton carrying a fractional charge of e / 2 in the neighbor column dominates the intercolumn charge transport. 相似文献
82.
Excited states of excitonic molecules are found in the study of the two-photon-resonant Raman scattering. These states consist of four levels and have binding energies of 1.0–1.8 meV, which are very small compared with those of the ground states. They are considered to be the rotational and vibrational states of excitonic molecules. 相似文献
83.
84.
Osamu Hatori Kazumi Hino Takeshi Miura Hirokazu Oka 《Mediterranean Journal of Mathematics》2009,6(1):47-59
Let and be uniform algebras and p(z,w) = zmwn a twovariable monomial. We characterize maps T from certain subsets of into such that holds for all f and g in the domain of T; peripherally monomial-preserving maps. Furthermore and are proved to be isometrical isomorphic as Banach algebras. If the greatest common divisor of m and n is 1, then T is extended to an isometrical linear isomorphism; a weighted composition operator. An example of peripherally monomial-preserving
surjections between uniform algebras which is not linear, nor multiplicative, nor injective is given when the greatest common
divisor is strictly greater than 1.
The first, third and fourth authors were partly supported by the Grantsin-Aid for Scientific Research, The Ministry of Education,
Science, Sports and Culture, Japan. 相似文献
85.
Hirokazu Matsumoto 《Optics Communications》1982,44(1):5-7
The group refractive index of air at 3.44 μm is directly measured with an accuracy of 2 × 10-7 using two-wavelength simultaneous interferometry with a 3.51- and 3.37-μm simultaneous operation He-Xe laser. 相似文献
86.
Hirokazu Nishimura 《Journal of Pure and Applied Algebra》2001,160(2-3)
We give a synthetic treatment of the first Bianchi identity both in the style of differential forms and in the style of tensor fields on the lines of Lavendhomme (Basic Concepts of Synthetic Differential Geometry, Kluwer, Dordrecht, 1996). The tensor-field version of the identity is derived from the corresponding one for microcubes, just as we did for the Jacobi identity of vector fields with respect to Lie brackets in our previous paper (J. Theoret. Phys. 36 (1997) 1099–1131). As a by-product we have found out an identity of microcubes corresponding to the classical identityof tensor fields, which has largely simplified Lavendhomme's lengthy proof (Basic Concepts of Synthetic Differential Geometry, Kluwer, Dordrecht, 1996, Section 5.3, Proposition 8, pp. 176–180). 相似文献
R(X,Y,Z)=XYZ−YXZ−[X,Y]Z
87.
A finite element method for treating two-dimensional electron systems with Rashba spin–orbit interaction is developed. The Rashba spin–orbit interaction removes spin degeneracy, so that each spin contributes to the conductance differently. By accounting for the connection between a system and leads, this method yields the conductance of a nanoscale quantum device for each spin state. As an example, this calculation method is applied to a model of a quantum point contact. The results of this calculation indicate conductance quantization and a large spin polarization. We discuss the estimated accuracies of this calculation. 相似文献
88.
Some important classes of optimization problems originating from the optimal design of semiconductor memories such as SRAM,
aiming at boosting the yield rate, are studied. New optimization methods for the classes based on a symbolic algorithm called
quantifier elimination, combined with numerical computation, are proposed. The total efficiency of the design process is improved
by reducing the number of numerical yield-rate evaluations. In addition, useful information such as the explicit relations
among design variables, objective functions, and the yield rate, is provided. 相似文献
89.
Yasutaka Shimada Kazumasa Usuda Hirokazu Okabe Tsuguru Suzuki Kazutsugu Matsumoto 《Tetrahedron: Asymmetry》2009,20(24):2802-2808
The deracemization of 1,2-diol monotosylate derivatives is achieved by the sequential combination of enzymatic hydrolysis and Mitsunobu inversion using a polymer-bound triphenylphosphine. After the lipase-catalysed hydrolysis of the racemic 2-acetoxyhexyl tosylate, the subsequent Mitsunobu reaction without separation causes an inversion of the resulting (R)-alcohol to give the (S)-enantiomer of the acetate as a single product. In particular, the reaction using the polymer-bound triphenylphosphine also proceeds smoothly, and the product is easily separated by filtration from the polymer-bound reagent and its by-products. This deracemization process is applicable to the preparation of several optically active 1,2-diol monotosylates. 相似文献
90.