全文获取类型
收费全文 | 3254篇 |
免费 | 129篇 |
国内免费 | 226篇 |
专业分类
化学 | 1157篇 |
晶体学 | 16篇 |
力学 | 202篇 |
综合类 | 5篇 |
数学 | 1640篇 |
物理学 | 589篇 |
出版年
2023年 | 35篇 |
2022年 | 50篇 |
2021年 | 37篇 |
2020年 | 58篇 |
2019年 | 55篇 |
2018年 | 61篇 |
2017年 | 76篇 |
2016年 | 76篇 |
2015年 | 88篇 |
2014年 | 145篇 |
2013年 | 267篇 |
2012年 | 187篇 |
2011年 | 212篇 |
2010年 | 151篇 |
2009年 | 246篇 |
2008年 | 210篇 |
2007年 | 229篇 |
2006年 | 201篇 |
2005年 | 155篇 |
2004年 | 132篇 |
2003年 | 122篇 |
2002年 | 94篇 |
2001年 | 74篇 |
2000年 | 70篇 |
1999年 | 82篇 |
1998年 | 63篇 |
1997年 | 82篇 |
1996年 | 41篇 |
1995年 | 44篇 |
1994年 | 36篇 |
1993年 | 31篇 |
1992年 | 26篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 14篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有3609条查询结果,搜索用时 31 毫秒
31.
Elie Leopold 《Numerical Algorithms》2007,44(4):347-366
In this paper, we give some new explicit relations between two families of polynomials defined by recurrence relations of
all order. These relations allow us to analyze, even in the Sobolev case, how some properties of a family of orthogonal polynomials
are affected when the coefficients of the recurrence relation and the order are perturbed. In a paper we have already given
a method which allows us to study the polynomials defined by a three-term recurrence relation. Also here some generalizations
are given. 相似文献
32.
In this paper a class of impulsive differential inclusions is investigated. The existence of solution bundle is proved. And we also construct a nonlinear semigroup of operators on cb(E) (closed-bounded subset of E) to describe the set of attainable states. 相似文献
33.
Chin-Yuan Hu 《Journal of Mathematical Analysis and Applications》2007,328(1):201-219
Recently we established Matysiak and Szablowski's conjecture [V. Matysiak, P.J. Szablowski, Theory Probab. Appl. 45 (2001) 711-713] about a lower bound of real-valued characteristic functions. In this paper, applying an alternative approach we are able to give explicitly the ranges of argument for which the obtained inequalities hold true for general characteristic functions. 相似文献
34.
This paper deals with a model of time-dependent double diffusive convection in Darcy flow. In particular it is concerned with the spatial decay of solutions when the flow is confined to a semi-infinite cylinder. Decay bounds for an energy expression are derived. 相似文献
35.
Th. Friedrich I. Kath A. Moroianu U. Semmelmann 《Journal of Geometry and Physics》1997,23(3-4):259-286
A nearly parallel G2-structure on a seven-dimensional Riemannian manifold is equivalent to a spin structure with a Killing spinor. We prove general results about the automorphism group of such structures and we construct new examples. We classify all nearly parallel G2-manifolds with large symmetry group and in particular all homogeneous nearly parallel G2-structures. 相似文献
36.
We investigate the propeties of differential algebras generated by an operator d satisfying the property dN = 0 instead of d2 = 0 as in the usual case. Several examples of realizations of such differential algebras are given, either in the context of ZN-graded N × N matrix algebras, or as a generalized differential calculus on manifolds. 相似文献
37.
Alain Lascoux 《Bulletin des Sciences Mathématiques》2006,130(4):354-359
Eliminating the arbitrary coefficients in the equation of a generic plane curve of order n by computing sufficiently many derivatives, one obtains a differential equation. This is a projective invariant. The first one, corresponding to conics, has been obtained by Monge. Sylvester, Halphen, Cartan used invariants of higher order. The expression of these invariants is rather complicated, but becomes much simpler when interpreted in terms of symmetric functions. 相似文献
38.
Aliasing effects are investigated for spherical random fields sampled on a finite grid. Using the spherical harmonics expansion, it is shown that for a band-limited spherical random field its trend and spectrum can be uniquely reconstructed from the sampled field if the sampling points are judiciously designed. Analytical expressions are also obtained for aliasing errors in the trend and the spectrum when the field is not band-limited. 相似文献
39.
S Ponnusamy 《Proceedings Mathematical Sciences》1994,104(2):397-411
Denote byS
* (⌕), (0≤⌕<1), the family consisting of functionsf(z)=z+a
2z2+...+anzn+... that are analytic and starlike of order ⌕, in the unit disc ⋎z⋎<1. In the present article among other things, with very
simple conditions on μ, ⌕ andh(z) we prove the f’(z) (f(z)/z)μ−1<h(z) implies f∈S*(⌕). Our results in this direction then admit new applications in the study of univalent functions. In many cases these results
considerably extend the earlier works of Miller and Mocanu [6] and others. 相似文献
40.
研究了油/水界面电解的示差半微分循环伏安行为。在0.01mol/L LiCl(w)-0.01mol/L TBATCIPB(nb)体系“电位窗”比TBATPB(nb)向正方向扩展约50mV,残余电流基本消除,使“电位窗”内的平台向左右拓宽约50mV。算得界面电容约为16μF/cm~2。考察了琥珀酰胆碱离子在w/nb界面的传递伏安特性,结果与一般半微分循环伏安法相似。但峰形改善,检测限降低一个数量级(1×10~(-6)mol/L),相对标准偏差在5%以内,可用于定量测定琥珀酰胆碱。 相似文献