全文获取类型
收费全文 | 4654篇 |
免费 | 246篇 |
国内免费 | 617篇 |
专业分类
化学 | 32篇 |
力学 | 42篇 |
综合类 | 60篇 |
数学 | 5201篇 |
物理学 | 182篇 |
出版年
2024年 | 9篇 |
2023年 | 91篇 |
2022年 | 43篇 |
2021年 | 64篇 |
2020年 | 93篇 |
2019年 | 147篇 |
2018年 | 146篇 |
2017年 | 144篇 |
2016年 | 135篇 |
2015年 | 106篇 |
2014年 | 206篇 |
2013年 | 377篇 |
2012年 | 139篇 |
2011年 | 212篇 |
2010年 | 218篇 |
2009年 | 318篇 |
2008年 | 338篇 |
2007年 | 355篇 |
2006年 | 320篇 |
2005年 | 288篇 |
2004年 | 236篇 |
2003年 | 210篇 |
2002年 | 202篇 |
2001年 | 149篇 |
2000年 | 161篇 |
1999年 | 148篇 |
1998年 | 136篇 |
1997年 | 134篇 |
1996年 | 84篇 |
1995年 | 47篇 |
1994年 | 36篇 |
1993年 | 19篇 |
1992年 | 17篇 |
1991年 | 14篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 19篇 |
1979年 | 12篇 |
1978年 | 15篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1936年 | 3篇 |
排序方式: 共有5517条查询结果,搜索用时 0 毫秒
941.
Hideaki Matsunaga a & Satoru Murakami 《Journal of Difference Equations and Applications》2013,19(7):661-689
For nonlinear autonomous functional difference equations, the existence of the local stable manifolds, together with the local unstable manifolds and the local center-unstable manifolds, is shown. As an application, the principle of linearization which states that stabilities and instabilities for the zero solution of nonlinear equations can be derived from those of the zero solution of the linearized equations under some circumstances is established for functional difference equations. 相似文献
942.
István Győri 《Journal of Difference Equations and Applications》2013,19(12):1393-1412
Suppose that a pair of sequence spaces is admissible with respect to a discrete linear Volterra operator. This paper gives sufficient conditions for the same pair of spaces to be admissible with respect to the associated resolvent operator. The spaces considered include spaces of weighted bounded and weighted convergent sequences. Classes of discrete kernels are discussed for which the appropriate weight sequences are not purely exponential, but the product of an exponential and a slowly decaying sequence. 相似文献
943.
Manuel Pinto Gonzalo Robledo Victor Torres 《Journal of Difference Equations and Applications》2013,19(5):765-778
The equivalence and asymptotic equivalence between the solutions of a linear difference system and some families of quasi-linear ones are studied by using a Lipschitz component-wise condition combined with a spectrally small dichotomy, which is introduced. The equivalence is described by a homeomorphism and the results also include unbounded solutions. The results show the vectorial attractivity of the solutions of the linear part. 相似文献
944.
The discrete frame and the continuous frame in a Hilbert space are discussed. By the tool excess of a sequence, a sufficient and necessary condition is presented under which a discrete frame is equivalent to a continuous frame with respect to the whole natural numbers with a positive Borel measure. And some examples are given to illuminate the condition. 相似文献
945.
In this article, the estimation of spatiotemporal long-range dependence is formulated in the spectral wavelet domain. Sample information is provided by functional spectral data. Their high local singularity at the origin is captured by the wavelet transform. Weak consistency of the spectral wavelet estimators proposed is derived. Two functional estimation algorithms are implemented. A simulation study is developed to illustrate the efficiency of the computational methods derived. An approximation to the empirical convergence rate of the spectral wavelet periodogram is computed in some simulated examples. 相似文献
946.
The expanded mixed covolume method for the two‐dimensional Sobolev equation with convection term is developed and studied. This method uses the lowest‐order Raviart‐Thomas mixed finite element space as the trial function space. By introducing a transfer operator γh which maps the trial function space into the test function space and combining expanded mixed finite element with mixed covolume method, the continuous‐in‐time, discrete‐in‐time expanded mixed covolume schemes are constructed, and optimal error estimates for these schemes are obtained. Numerical results are given to examine the validity and effectiveness of the proposed schemes.© 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013 相似文献
947.
Motivated by multi-task machine learning with Banach spaces, we propose the notion of vector-valued reproducing kernel Banach spaces (RKBSs). Basic properties of the spaces and the associated reproducing kernels are investigated. We also present feature map constructions and several concrete examples of vector-valued RKBSs. The theory is then applied to multi-task machine learning. Especially, the representer theorem and characterization equations for the minimizer of regularized learning schemes in vector-valued RKBSs are established. 相似文献
948.
《Journal of Nonlinear Mathematical Physics》2013,20(3):293-310
Any locally invertible morphism of a finite-order jet space is either a prolonged point transformation or a prolonged Lie's contact transformation (the Lie–Bäcklund theorem). We recall this classical result with a simple proof and moreover determine explicit formulae even for all (not necessarily invertible) morphisms of finite-order jet spaces. Examples of generalized (higher-order) contact transformations of jets that destroy all finite-order jet subspaces are stated with comments. 相似文献
949.
Marius van der Put 《Journal of Nonlinear Mathematical Physics》2013,20(4):165-177
The methods of [vdP-Sa, vdP1, vdP2] are applied to the fourth Painlevé equation. One obtains a Riemann–Hilbert correspondence between moduli spaces of rank two connections on ?1 and moduli spaces for the monodromy data. The moduli spaces for these connections are identified with Okamoto–Painlevé varieties and the Painlevé property follows. For an explicit computation of the full group of Bäcklund transformations, rank three connections on ?1 are introduced, inspired by the symmetric form for PIV, studied by M. Noumi and Y. Yamada. 相似文献
950.
Paweł Józiak 《Linear and Multilinear Algebra》2013,61(12):2406-2418