全文获取类型
收费全文 | 321835篇 |
免费 | 5055篇 |
国内免费 | 2847篇 |
专业分类
化学 | 150442篇 |
晶体学 | 4915篇 |
力学 | 18061篇 |
综合类 | 73篇 |
数学 | 58003篇 |
物理学 | 98243篇 |
出版年
2021年 | 2087篇 |
2020年 | 2401篇 |
2019年 | 2666篇 |
2018年 | 13245篇 |
2017年 | 12951篇 |
2016年 | 10437篇 |
2015年 | 3923篇 |
2014年 | 5170篇 |
2013年 | 11508篇 |
2012年 | 12459篇 |
2011年 | 20820篇 |
2010年 | 13099篇 |
2009年 | 13324篇 |
2008年 | 16000篇 |
2007年 | 17996篇 |
2006年 | 9263篇 |
2005年 | 9407篇 |
2004年 | 8876篇 |
2003年 | 8436篇 |
2002年 | 7420篇 |
2001年 | 7596篇 |
2000年 | 5929篇 |
1999年 | 4612篇 |
1998年 | 3950篇 |
1997年 | 3792篇 |
1996年 | 3663篇 |
1995年 | 3265篇 |
1994年 | 3207篇 |
1993年 | 3255篇 |
1992年 | 3323篇 |
1991年 | 3488篇 |
1990年 | 3220篇 |
1989年 | 3165篇 |
1988年 | 3168篇 |
1987年 | 3041篇 |
1986年 | 2890篇 |
1985年 | 3881篇 |
1984年 | 4069篇 |
1983年 | 3243篇 |
1982年 | 3466篇 |
1981年 | 3380篇 |
1980年 | 3292篇 |
1979年 | 3382篇 |
1978年 | 3460篇 |
1977年 | 3370篇 |
1976年 | 3470篇 |
1975年 | 3162篇 |
1974年 | 3166篇 |
1973年 | 3225篇 |
1972年 | 2253篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
A New Cohomology Theory of Orbifold 总被引:7,自引:0,他引:7
Based on the orbifold string theory model in physics, we construct a new cohomology ring for any almost complex orbifold. The key theorem is the associativity of this new ring. Some examples are computed.Both authors partially supported by the National Science Foundation 相似文献
992.
993.
Gábor Házi 《Central European Journal of Physics》2003,1(3):453-462
A general class of analytical solutions of the lattice Boltzmann equation is derived for two-dimensional, steady-state unidirectional
flows. A subset of the solutions that verifies the corresponding Navier-Stokes equations is given. It is pointed out that
this class includes, e.g., the Couette and the Poiseuille flow but not, e.g., the basic Kolmogorov flow. For steady-state
non-unidirectional flows, first and second order solutions of the lattice Boltzmann equation are derived. Practical consequences of the analysis
are mentioned. Differences between the technique applied here and those used in some earlier works are emphasized. 相似文献
994.
Adrian Vasiu 《Central European Journal of Mathematics》2005,3(1):14-25
We include short and elementary proofs of two theorems that characterize reductive group schemes over a discrete valuation
ring, in a slightly more general context. 相似文献
995.
Low-loss and rugged distal tips for CO2 laser have been proposed and fabricated based on a commercially available stainless steel (St) pipe. A method of smoothening the inner surface of the St pipe with a rough inner surface is put forward. Fabrication parameters, transmission properties, and mechanical strength of the cyclic olefin polymer-coated silver hollow St distal tip are experimentally discussed. 相似文献
996.
We suggest a new, more global, approach to the study of geodesically equivalent metrics which is based on application of the theory of integrable geodesic flows. Bibliography: 17 titles. 相似文献
997.
998.
Data on the proteinase complex from Carica papaya latex were reviewed. The properties and applications of the domestic preparation cucumazyme and known medicinal preparations based on papaya proteinases (caripazyme, lecozyme, lecopain) were compared. 相似文献
999.
M. De Falco F. De Giovanni C. Musella R. Schmidt 《Rendiconti del Circolo Matematico di Palermo》2003,52(1):70-76
A subgroupH of a groupG is said to bepermutable ifHX=XH for every subgroupX ofG. In this paper the structure of groups in which every subgroup either is abelian or permutable is investigated.
This work was done while the last author was visiting the University of Napoli Federico II. He thanks the “Dipartimento di
Matematica e Applicazioni” for its financial support. 相似文献
1000.
P. V. Yagodovskii 《Journal of Mathematical Sciences》2003,113(5):728-730
A linear deformation of a discrete group G is a special deformation of the group algebra of G resulting in the group algebra of a multivalued group. Basic results on linear deformations are presented. Bibliography: 5 titles. 相似文献