全文获取类型
收费全文 | 7459篇 |
免费 | 335篇 |
国内免费 | 463篇 |
专业分类
化学 | 850篇 |
晶体学 | 21篇 |
力学 | 130篇 |
综合类 | 51篇 |
数学 | 6235篇 |
物理学 | 970篇 |
出版年
2023年 | 65篇 |
2022年 | 67篇 |
2021年 | 98篇 |
2020年 | 99篇 |
2019年 | 203篇 |
2018年 | 200篇 |
2017年 | 142篇 |
2016年 | 127篇 |
2015年 | 161篇 |
2014年 | 270篇 |
2013年 | 542篇 |
2012年 | 323篇 |
2011年 | 421篇 |
2010年 | 365篇 |
2009年 | 550篇 |
2008年 | 618篇 |
2007年 | 475篇 |
2006年 | 430篇 |
2005年 | 306篇 |
2004年 | 259篇 |
2003年 | 253篇 |
2002年 | 263篇 |
2001年 | 212篇 |
2000年 | 188篇 |
1999年 | 235篇 |
1998年 | 194篇 |
1997年 | 149篇 |
1996年 | 156篇 |
1995年 | 124篇 |
1994年 | 138篇 |
1993年 | 93篇 |
1992年 | 68篇 |
1991年 | 53篇 |
1990年 | 41篇 |
1989年 | 43篇 |
1988年 | 30篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 34篇 |
1984年 | 32篇 |
1983年 | 10篇 |
1982年 | 27篇 |
1981年 | 36篇 |
1980年 | 30篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1974年 | 9篇 |
1973年 | 8篇 |
排序方式: 共有8257条查询结果,搜索用时 218 毫秒
71.
Ignacio Villanueva 《Mathematische Nachrichten》2003,250(1):98-103
We clarify and prove in a simpler way a result of Taskinen about symmetric operators on C(Kn), K an uncountable metrizable compact space. To do this we prove that, for any compact space K and any n ∈ ?, the symmetric injective n–tensor product of C(K), , is complemented in C(BC(K)*), a result of independent interest. The techniques we develop allow us to extend the result in several directions. We also show that the hypothesis of metrizability and uncountability cannot be removed. 相似文献
72.
Radu Miron 《Reports on Mathematical Physics》2004,54(2):131-147
The Randers spaces RFn were introduced by R. S. Ingarden. They are considered as Finsler spaces Fn = (M, α + β) equipped with the Cartan nonlinear connection. In the present paper we define and study what we call the Ingarden spaces, I Fn, as Finsler spaces I Fn = (M, α + β) equipped with the Lorentz nonlinear connection. The spaces R Fn and I Fn are completely different. For I Fn we discuss: the variational problem, Lorentz nonlinear connection, canonical N-metrical connection and its structure equations, the Cartan 1-form ω, the electromagnetic 2-form tF and the almost symplectic 2-form 0. The formula dω = F+θ is established. It has as a consequence the generalized Maxwell equations. Finally, the almost Hermitian model of I Fn is constructed. 相似文献
73.
We consider quasi-isometric mappings of domains in multidimensional Euclidean spaces. We establish that a mapping depends continuously in the sense of the topology of Sobolev classes on its metric tensor to within isometry of the space. In the space of metric tensors we take the topology determined by means of almost everywhere convergence. We show that if the metric tensor of a mapping is continuous then the length of the image of a rectifiable curve is determined by the same formula as in the case of mappings with continuous derivatives. (Continuity of the metric tensor of a mapping does not imply continuity of its derivatives.) 相似文献
74.
M.S. Bratiychuk 《Insurance: Mathematics and Economics》2007,41(1):156-162
In this paper, we present the classical risk process with two-step premium function. This means that the gross risk premium rate changes if the insurer’s surplus reaches a certain threshold level. The formula for the infinite-time ruin probability is obtained. The asymptotic behaviour of the ruin probability in the case where the claim size distribution has a light tail is considered as well. 相似文献
75.
76.
In this article,the Hausdorff dimension and exact Hausdorff measure function of any random sub-self-similar set are obtained under some reasonable conditions.Several examples are given at the end. 相似文献
77.
In the present paper the problems of existence and uniqueness of almost periodic solutions for impulsive cellular neural networks with delay are considered. 相似文献
78.
设x:M→S^n+1(n≥23)是n+1-维单位球中的无脐点超曲面,Moebius不变量G,Ф,A和B分别表示x的Moebius度量,Moebius形式,Blaschke形式和Moebius第二基本形式.本文证明了如果x的Moebius形式圣平行,并且A+λG+μB=0,其中λ,μ分别是定义在M上的光滑函数,那么Ф=0,由此及李海中、王长平(2003年)文献中的分类定理给出了眇州中具有平行的Moebius形式及满足A+λG+μB=0的超曲面的分类.此结果推广了他们及张廷枋(2003年)文献中的结果. 相似文献
79.
The Newton filtration and d-determination of bifurcation problems related to C~0 contact equivalence
SU Dan & ZHANG Dunmu School of Mathematics Statistics Wuhan University Wuhan China 《中国科学A辑(英文版)》2006,49(5)
In this paper, from the Newton filtration's point of view, we construct the singular Riemannian metric and use the method in singular theory to study the bifurcation problems, and give the sufficient condition of d-determination of bifurcation problems with respect to C0 contact equivalence. The special cases of the main result in this paper are the results of Sun Weizhi and Zou Jiancheng. 相似文献
80.
We develop the monotone method for impulsive hybrid set integro-differential equations in all its generality. Some interesting observations are presented. 相似文献