全文获取类型
收费全文 | 18151篇 |
免费 | 438篇 |
国内免费 | 382篇 |
专业分类
化学 | 2190篇 |
晶体学 | 66篇 |
力学 | 128篇 |
综合类 | 24篇 |
数学 | 15021篇 |
物理学 | 1542篇 |
出版年
2023年 | 34篇 |
2022年 | 82篇 |
2021年 | 64篇 |
2020年 | 104篇 |
2019年 | 432篇 |
2018年 | 477篇 |
2017年 | 259篇 |
2016年 | 169篇 |
2015年 | 202篇 |
2014年 | 505篇 |
2013年 | 1153篇 |
2012年 | 578篇 |
2011年 | 1074篇 |
2010年 | 993篇 |
2009年 | 1417篇 |
2008年 | 1396篇 |
2007年 | 1396篇 |
2006年 | 1042篇 |
2005年 | 672篇 |
2004年 | 633篇 |
2003年 | 527篇 |
2002年 | 392篇 |
2001年 | 361篇 |
2000年 | 385篇 |
1999年 | 425篇 |
1998年 | 400篇 |
1997年 | 274篇 |
1996年 | 387篇 |
1995年 | 395篇 |
1994年 | 386篇 |
1993年 | 305篇 |
1992年 | 247篇 |
1991年 | 154篇 |
1990年 | 162篇 |
1989年 | 165篇 |
1988年 | 112篇 |
1987年 | 112篇 |
1986年 | 121篇 |
1985年 | 154篇 |
1984年 | 141篇 |
1983年 | 68篇 |
1982年 | 117篇 |
1981年 | 88篇 |
1980年 | 88篇 |
1979年 | 72篇 |
1978年 | 73篇 |
1977年 | 50篇 |
1976年 | 38篇 |
1975年 | 33篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
Peter Imkeller 《Probability Theory and Related Fields》1996,106(1):105-135
Summary. The analytic treatment of problems related to the asymptotic behaviour of random dynamical systems generated by stochastic
differential equations suffers from the presence of non-adapted random invariant measures. Semimartingale theory becomes accessible
if the underlying Wiener filtration is enlarged by the information carried by the orthogonal projectors on the Oseledets spaces
of the (linearized) system.
We study the corresponding problem of preservation of the semimartingale property and the validity of a priori inequalities
between the norms of stochastic integrals in the enlarged filtration and norms of their quadratic variations in case the random
element F enlarging the filtration is real valued and possesses an absolutely continuous law. Applying the tools of Malliavin’s calculus,
we give smoothness conditions on F under which the semimartingale property is preserved and a priori martingale inequalities are valid.
Received: 12 April 1995 / In revised form: 7 March 1996 相似文献
4.
5.
M. Brokate D. Rachinskii 《NoDEA : Nonlinear Differential Equations and Applications》2006,13(4):385-411
The paper is concerned with the study of plasticity models described by differential equations with stop and play operators.
We suggest sufficient conditions for the global stability of a unique periodic solution for the scalar models and for the
vector models with biaxial inputs of a particular form, namely the sum of a uniaxial function and a constant term. For another
class of simple biaxial inputs, we present an example of the existence of unstable periodic solutions.
The paper was written during the research stay of D. Rachinskii at the Technical University Munich supported by the research
fellowship from the Alexander von Humboldt Foundation. His work was partially supported by the Russian Science Support Foundation, Russian Foundation for Basic Research (Grant No. 01-01-00146, 03-01-00258), and the Grants of the President of Russia (Grant No. MD-87.2003.01, NS-1532.2003.1). The support is gratefully acknowledged. 相似文献
6.
Balázs Szendröi 《Mathematische Zeitschrift》2002,240(2):233-241
This note shows that a certain toric quotient of the quintic Calabi-Yau threefold in provides a counterexample to a recent conjecture of Cox and Katz concerning nef cones of toric hypersurfaces.
Received: 8 February 2001; in final form: 17 September 2001 / Published online: 1 February 2002 相似文献
7.
Francis Jordan 《Topology and its Applications》2006,153(14):2386-2412
An abstract scheme using particular types of relations on filters leads to general unifying results on stability under supremum and product of local topological properties. We present applications for Fréchetness, strong Fréchetness, countable tightness and countable fan-tightness, some of which recover or refine classical results, some of which are new. The reader may find other applications as well. 相似文献
8.
9.
A construction for Segal operations for K-theory of categories with cofibrations, weak equivalences and a biexact pairing is given and coherence properties of the operations are studied. The model for K-theory, which is used, allows coherence to be studied by means of (symmetric) monoidal functors. In the case of Waldhausen A-theory it is shown how to recover the operations used in Waldhausen (Lecture Notes in Mathematics, Vol. 967, Springer, Berlin, 1982, pp. 390-409) for the A-theory Kahn-Priddy theorem. The total Segal operation for A-theory, which assembles exterior power operations, is shown to carry a natural infinite loop map structure. The basic input is the un-delooped model for K-theory, which has been developed from a construction by Grayson and Gillet for exact categories in Gunnarsson et al. (J. Pure Appl. Algebra 79 (1992) 255), and Grayson's setup for operations in Grayson (K-theory (1989) 247). The relevant material from these sources is recollected followed by observations on equivariant objects and pairings. Grayson's conditions are then translated to the context of categories with cofibrations and weak equivalences. The power operations are shown to be well behaved w.r.t. suspension and are extended to algebraic K-theory of spaces. Staying close with the philosophy of Waldhausen (1982) Waldhausen's maps are found. The Kahn-Priddy theorem follows from splitting the “free part” off the equivariant theory. The treatment of coherence of the total operation in A-theory involves results from Laplaza (Lecture Notes in Mathematics, Vol. 281, Springer, Berlin, 1972, pp. 29-65) and restriction to spherical objects in the source of the operation. 相似文献
10.
The paper provides significant simplifications and extensions of results obtained by Gorsich, Genton, and Strang (J. Multivariate Anal. 80 (2002) 138) on the structure of spatial design matrices. These are the matrices implicitly defined by quadratic forms that arise naturally in modelling intrinsically stationary and isotropic spatial processes. We give concise structural formulae for these matrices, and simple generating functions for them. The generating functions provide formulae for the cumulants of the quadratic forms of interest when the process is Gaussian, second-order stationary and isotropic. We use these to study the statistical properties of the associated quadratic forms, in particular those of the classical variogram estimator, under several assumptions about the actual variogram. 相似文献