全文获取类型
收费全文 | 4332篇 |
免费 | 571篇 |
国内免费 | 115篇 |
专业分类
化学 | 824篇 |
晶体学 | 38篇 |
力学 | 260篇 |
综合类 | 22篇 |
数学 | 2489篇 |
物理学 | 1385篇 |
出版年
2024年 | 3篇 |
2023年 | 25篇 |
2022年 | 57篇 |
2021年 | 70篇 |
2020年 | 81篇 |
2019年 | 172篇 |
2018年 | 185篇 |
2017年 | 146篇 |
2016年 | 138篇 |
2015年 | 130篇 |
2014年 | 259篇 |
2013年 | 393篇 |
2012年 | 191篇 |
2011年 | 290篇 |
2010年 | 263篇 |
2009年 | 285篇 |
2008年 | 304篇 |
2007年 | 299篇 |
2006年 | 230篇 |
2005年 | 177篇 |
2004年 | 156篇 |
2003年 | 142篇 |
2002年 | 110篇 |
2001年 | 90篇 |
2000年 | 83篇 |
1999年 | 86篇 |
1998年 | 72篇 |
1997年 | 51篇 |
1996年 | 87篇 |
1995年 | 84篇 |
1994年 | 88篇 |
1993年 | 48篇 |
1992年 | 35篇 |
1991年 | 31篇 |
1990年 | 30篇 |
1989年 | 17篇 |
1988年 | 24篇 |
1987年 | 9篇 |
1986年 | 14篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 3篇 |
1982年 | 14篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有5018条查询结果,搜索用时 31 毫秒
91.
I. A. Taimanov 《Acta Appl Math》1994,36(1-2):119-124
The-parametrized family of two-gap elliptic potentials is constructed so that (i) 0<<1, (ii) for rational values of such potentials are elliptic (i.e., double-periodic), (iii) within the limit0 this family degenerates to the soliton potential, (iv) within the limit1 this family degenerates to the one-gap Lamé potential.Dedicated to the memory of J.-L. Verdier 相似文献
92.
Summary We study integral functionals of the formF(u, )=
f(u)dx, defined foru C1(;R
k), R
n
. The functionf is assumed to be polyconvex and to satisfy the inequalityf(A) c0¦(A)¦ for a suitable constant c0 > 0, where (A) is then-vector whose components are the determinants of all minors of thek×n matrixA. We prove thatF is lower semicontinuous onC
1(;R
k) with respect to the strong topology ofL
1(;R
k). Then we consider the relaxed functional , defined as the greatest lower semicontinuous functional onL
1(;R
k
) which is less than or equal toF on C1(;R
k). For everyu BV(;R
k) we prove that (u,)
f(u)dx+c0¦Dsu¦(), whereDu=u dx+Dsu is the Lebesgue decomposition of the Radon measureDu. Moreover, under suitable growth conditions onf, we show that (u,)=
f(u)dx for everyu W1,p(;R
k), withp min{n,k}. We prove also that the functional (u, ) can not be represented by an inte- gral for an arbitrary functionu BVloc(R
n;R
k). In fact, two examples show that, in general, the set function (u, ) is not subadditive whenu BVloc(R
n;R
k), even ifu W
loc
1,p
(R
n;R
k) for everyp < min{n,k}. Finally, we examine in detail the properties of the functionsu BV(;R
k) such that (u, )=
f(u)dx, particularly in the model casef(A)=¦(A)¦. 相似文献
93.
M. Giaquinta G. Modica J. Souček 《Calculus of Variations and Partial Differential Equations》1994,2(1):65-100
On the ground of four axioms we define thekinematics of perfectly elastic bodies and in particular the notion ofweak deformations of a perfectly elastic body. Weak deformations turn out to agree withweak diffeomorphisms introduced in [10], a class of rectifiable currents which enjoys good closure and compactness properties. Defining thedynamics of perfectly elastic bodies in terms of twoconstitutive conditions on the stored energy function, we can therefore prove existence of stable equilibrium weak deformations for mixed boundary value problems, which moreover satisfy equilibrium and conservation equations.This work has been partially supported by the Ministero dell'Universitá e della Ricerca Scientifica, by C.N.R. contract n. 91.01343.CT01, by the European Research Project GADGET, and by Grant n.11957 of the zech Acad. of Sciences.This article was processed by the author using the LaTEX style filepljour1 from Springer-Verlag. 相似文献
94.
Sisto Baldo Giandomenico Orlandi 《Calculus of Variations and Partial Differential Equations》1996,4(4):369-384
We define a class
p
(M,N) of Sobolev maps from a manifoldM into a manifoldN, in such a way that each mapu
p
(M, N) has a well defined [p]-homotopy type, providedN satisfies a topological hypothesis. Using this, we prove the existence of minimizers in [p]-homotopy classes for some polyconvex variational problems. 相似文献
95.
We describe an algorithm for selecting the n-th largest element (where 0<<1), from a totally ordered set ofn elements, using at most (1+(1+o(1))H())·n comparisons whereH() is the binary entropy function and theo(1) stands for a function that tends to 0 as tends to 0. For small values of this is almost the best possible as there is a lower bound of about (1+H())·n comparisons. The algorithm obtained beats the global 3n upper bound of Schönhage, Paterson and Pippenger for <1/3. 相似文献
96.
Ayelet Lindenstrauss 《K-Theory》1996,10(3):239-265
Topological Hochschild homology is calculated for the rings /p[x]/(f(x)) (where p is prime and f(x) /p[x] any polynomial), [x]/(x
n) and [x]/(x
n–1). A spectral sequence argument is used for calculating the homology of the topological Hochschild homology spectrum, from which its stable homotopy structure can be read off since the spectrum is known for a priori reasons to be a restricted product of Eilenberg-MacLane spectra. 相似文献
97.
You-Jin Zhang 《Letters in Mathematical Physics》1996,36(1):1-15
In this Letter, we study the constrained KP hierarchies by employing Segal-Wilson's theory on the -functions of the KP hierarchy. We first describe the elements of the Grassmannian which correspond to solutions of the constrained KP hierarchy, and then we show how to construct its rational and soliton solutions from these elements of the Grassmannian. 相似文献
98.
Bernard Helffer 《Letters in Mathematical Physics》1996,38(3):297-312
This Letter gives detailed proofs concerning the analysis of the pair correlations for a nonconvex model. Using the transfer matrix approach, the problem is reduced to the analysis of the spectral properties of this transfer operator. Although the problem is similar to the semiclassical study of the Kac operator presented in a paper with M. Brunaud, which was devoted to the study of exp-(v/2) exp h
2 exp-(v/2) for h small, new features appear for the model exp-(v/2h) exp h exp-(v/2h). Our principal results concern the splitting of this operator between the two largest eigenvalues. We give an upper and a lower bound for this splitting in the semi-classical regime. As a corollary, we get good control of the decay of the pair correlation. Some of the results were announced in a previous paper. Related WKB constructions will be developed in a later paper.Inspired by papers by M. Kac [15, 16]. 相似文献
99.
David Applebaum 《Letters in Mathematical Physics》1993,28(3):231-237
The index of a Fredholm operator associated to a-summable Fredholm module is expressed in terms of the vacuum expectation value of a unitary operator-valued stochastic process which satisfies a stochastic differential equation with unbounded coefficients driven by fermion noise. 相似文献
100.
Previous results on quasi-classical limit of the KP hierarchy and itsW-infinity symmetries are extended to the Toda hierarchy. The Planck constant now emerges as the spacing unit of difference operators in the Lax formalism. Basic notions, such as dressing operators, Baker-Akhiezer functions, and tau function, are redefined.W
1 + symmetries of the Toda hierarchy are realized by suitable rescaling of the Date-Jimbo-Kashiara-Miwa vertex operators. These symmetries are contracted tow
1 + symmetries of the dispersionless hierarchy through their action on the tau function. 相似文献