全文获取类型
收费全文 | 3625篇 |
免费 | 262篇 |
国内免费 | 307篇 |
专业分类
化学 | 340篇 |
晶体学 | 17篇 |
力学 | 345篇 |
综合类 | 66篇 |
数学 | 2674篇 |
物理学 | 752篇 |
出版年
2024年 | 4篇 |
2023年 | 36篇 |
2022年 | 49篇 |
2021年 | 46篇 |
2020年 | 66篇 |
2019年 | 81篇 |
2018年 | 76篇 |
2017年 | 78篇 |
2016年 | 91篇 |
2015年 | 79篇 |
2014年 | 139篇 |
2013年 | 330篇 |
2012年 | 144篇 |
2011年 | 157篇 |
2010年 | 210篇 |
2009年 | 275篇 |
2008年 | 250篇 |
2007年 | 261篇 |
2006年 | 189篇 |
2005年 | 197篇 |
2004年 | 190篇 |
2003年 | 169篇 |
2002年 | 155篇 |
2001年 | 116篇 |
2000年 | 115篇 |
1999年 | 103篇 |
1998年 | 110篇 |
1997年 | 99篇 |
1996年 | 72篇 |
1995年 | 53篇 |
1994年 | 63篇 |
1993年 | 27篇 |
1992年 | 31篇 |
1991年 | 18篇 |
1990年 | 17篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有4194条查询结果,搜索用时 36 毫秒
41.
Djavvat Khadjiev 《Journal of Mathematical Analysis and Applications》2007,326(2):1101-1115
An approach to a definition of an integral, which differs from definitions of Lebesgue and Henstock-Kurzweil integrals, is considered. We use trigonometrical polynomials instead of simple functions. Let V be the space of all complex trigonometrical polynomials without the free term. The definition of a continuous integral on the space V is introduced. All continuous integrals are described in terms of norms on V. The existence of the widest continuous integral is proved, the explicit form of its norm is obtained and it is proved that this norm is equivalent to the Alexiewicz norm. It is shown that the widest continuous integral is wider than the Lebesgue integral. An analog of the fundamental theorem of calculus for the widest continuous integral is given. 相似文献
42.
We study the properties of multifunction operators that are contractive in the Covitz-Nadler sense. In this situation, such operators T possess fixed points satisfying the relation x∈Tx. We introduce an iterative method involving projections that guarantees convergence from any starting point x0∈X to a point x∈XT, the set of all fixed points of a multifunction operator T. We also prove a continuity result for fixed point sets XT as well as a “generalized collage theorem” for contractive multifunctions. These results can then be used to solve inverse problems involving contractive multifunctions. Two applications of contractive multifunctions are introduced: (i) integral inclusions and (ii) iterated multifunction systems. 相似文献
43.
Shan He Wu 《Journal of Mathematical Analysis and Applications》2007,332(1):741-750
In this paper, we generalize Hu Ke's sharpness of Hölder's inequality. As application, the obtained result is used to improve the well-known Opial-Olech inequality. 相似文献
44.
45.
在研究排队网络的文献中,G-网络(即推广的排队网络)最近受到了国际学者广泛的关注,它的研究在一定程度上丰富了排队网络的内容.正因为有很多学者投入到此项研究中,新的结果是层出不穷的.本文简短地介绍G-网络近年来的发展. 相似文献
46.
47.
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
48.
Summary Thermopiezoelastic materials have recently attracted considerable attention because of their potential use in intelligent
or smart structural systems. The governing equations of a thermopiezoelastic medium are more complex due to the intrinsic
coupling effects that take place among mechanical, electrical and thermal fields. In this analysis, we deal with the problem
of a crack in a semi-infinite, transversely isotropic, thermopiezoelastic material by means of potential functions and Fourier
transforms under steady heat-flux loading conditions. The problem is reduced to a singular integral equation that is solved.
The thermal stress intensity factor for a crack situated in a cadmium selenide material is calculated.
Received 20 March 2001; accepted for publication 18 October 2001 相似文献
49.
Daniel Quillen 《K-Theory》1989,3(3):205-246
We construct a spectral sequence to study cyclic cohomology for an extension A = R/I of algebras. When R is a free algebra we describe the cyclic cohomology of A in terms of traces defined on R or powers of I. Explicit cyclic cocycles representing the cyclic cohomology class belonging to the trace are constructed as analogues of Chern character and Chern-Simons forms.Dedicated to Alexander Grothendieck 相似文献
50.
Certain condition on the second fundamental form of CR submanifolds of maximal CR dimension of complex Euclidean space 总被引:1,自引:0,他引:1
We treat m-dimensional real submanifolds M of complex space forms ̿M when the maximal holomorphic tangent subspace is (m−1)-dimensional. On these manifolds there exists an almost contact structure F which is naturally induced from the ambient space and in this paper we study the condition h(FX,Y)−h(X,FY) = g(FX,Y)η, η∊ T⊥(M), on the structure F and on the second fundamental form h of these submanifolds. Especially when the ambient space ̿M is a complex Euclidean space, we obtain a complete classification of submanifolds M which satisfy these conditions.Mathematics Subject Classifications (2000): 53C15, 53C40, 53B20. 相似文献