全文获取类型
收费全文 | 4881篇 |
免费 | 132篇 |
国内免费 | 151篇 |
专业分类
化学 | 644篇 |
晶体学 | 83篇 |
力学 | 52篇 |
综合类 | 21篇 |
数学 | 3332篇 |
物理学 | 1032篇 |
出版年
2023年 | 16篇 |
2022年 | 37篇 |
2021年 | 78篇 |
2020年 | 39篇 |
2019年 | 119篇 |
2018年 | 93篇 |
2017年 | 68篇 |
2016年 | 43篇 |
2015年 | 52篇 |
2014年 | 110篇 |
2013年 | 218篇 |
2012年 | 179篇 |
2011年 | 254篇 |
2010年 | 217篇 |
2009年 | 323篇 |
2008年 | 348篇 |
2007年 | 363篇 |
2006年 | 357篇 |
2005年 | 286篇 |
2004年 | 215篇 |
2003年 | 156篇 |
2002年 | 177篇 |
2001年 | 151篇 |
2000年 | 145篇 |
1999年 | 146篇 |
1998年 | 106篇 |
1997年 | 95篇 |
1996年 | 104篇 |
1995年 | 67篇 |
1994年 | 80篇 |
1993年 | 55篇 |
1992年 | 47篇 |
1991年 | 41篇 |
1990年 | 21篇 |
1989年 | 42篇 |
1988年 | 23篇 |
1987年 | 29篇 |
1986年 | 20篇 |
1985年 | 38篇 |
1984年 | 25篇 |
1983年 | 26篇 |
1982年 | 24篇 |
1981年 | 19篇 |
1980年 | 28篇 |
1979年 | 17篇 |
1978年 | 16篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1974年 | 9篇 |
1973年 | 10篇 |
排序方式: 共有5164条查询结果,搜索用时 31 毫秒
81.
Yuval Z. Flicker 《Mathematische Annalen》1993,297(1):199-219
82.
Akihiko Yukie 《Mathematische Annalen》1992,292(1):355-374
Partially supported by NSF Grant DMS-8803085, DMS-8610730 相似文献
83.
84.
We introduce a candidate for the group algebra of a Hausdorff group which plays the same role as the group algebra of a finite group. It allows to define a natural bijection betweenk-continuous representations of the group in a Hilbert space and continuous representations of the group algebra. Such bijections are known, but to our knowledge only for locally compact groups. We can establish such a bijection for more general groups, namely Hausdorff groups, because we replace integration techniques by functorial methods, i.e., by using a duality functor which lives in certain categories of topological Banach balls (resp., unit balls of Saks spaces).This paper was written while the authors were supported by the Swiss National Science Foundation under grant 21-33644.92. 相似文献
85.
ρ混合、φ混合、ψ混合线性模型M估计的强相合性 总被引:5,自引:3,他引:2
研究了 ρ混合、φ混合、ψ混合样本线性模型中回归参数M估计的强相合性 ,在条件不变的情况下 ,获得与独立情形一样的M估计是强相合的充分条件 ,推广了文 [1 ]定理 2 . 相似文献
86.
M. C. Jones 《Annals of the Institute of Statistical Mathematics》2004,56(4):733-742
A simple new family of distributions is proposed which has support the unit disc in two dimensions. The density functions
of the family are unimodal, monotonic or uniantimodal. The bivariate symmetric beta distributions, which include the uniform
distribution, are special cases, but many members of the family are skew. The distributions have three parameters, one controlling
orientation, one controlling degree of concentration and the third controlling skewness, or more precisely off-centredness.
Importantly, these parameters are globally orthogonal. An illustrative example of fitting the model to data is given. Conditional
and marginal distributions are considered. The new distributions are compared favourably with an earlier suggestion of the
same author. 相似文献
87.
Three-dimensional (3-D) ZnO random-wall nanostructures and one-dimensional (1-D) ZnO nanorods were prepared on silicon substrates by a simple solid-vapour phase thermal sublimation technique. Optical pumped random lasing has been observed in the ZnO random-wall arrays with a threshold intensity of 0.38 MW/cm2 in the emission wavelength from 380 to 395 nm. The optical gain was attributed to the closed-loop scattering and light amplification of the ZnO random-wall. The experimental result suggests that the morphology of nanostructure is the key factor to effect random lasing. 相似文献
88.
Chau O. Shillor M. Sofonea M. 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(1):32-47
A model for the dynamic, adhesive, frictionless contact
between a viscoelastic body and a deformable foundation is
described. The adhesion process is modeled by a bonding field on
the contact surface. The contact is described by a modified normal
compliance condition. The tangential shear due to the bonding
field is included. The problem is formulated as a coupled system
of a variational equality for the displacements and a differential
equation for the bonding field. The existence of a unique weak
solution for the problem is established, together with a partial
regularity result. The existence proof proceeds by construction of
an appropriate mapping which is shown to be a contraction on a
Hilbert space. 相似文献
89.
Richard P. Kent IV 《Geometriae Dedicata》2004,106(1):145-159
We answer a question of J. Anderson's by producing infinitely many commensurability classes of fibered hyperbolic 3-manifolds whose fundamental groups contain subgroups that are locally free and not free. These manifolds are obtained by performing 0–surgery on a collection of knots with the same properties. 相似文献
90.
Masaharu Ishikawa 《Topology》2004,43(1):215-232
In the present paper we generalize the divide lying in the unit disk, introduced by A'Campo, to compact, oriented, smooth surfaces, and prove a fibration theorem for generalized divides. As a consequence, we will show that, for any link L in the tangent circle bundle Y to the compact surface, there exists an additional knot K such that the link L∪K is the binding of a “positive” open book decomposition of Y. 相似文献