全文获取类型
收费全文 | 10792篇 |
免费 | 957篇 |
国内免费 | 1328篇 |
专业分类
化学 | 725篇 |
晶体学 | 16篇 |
力学 | 639篇 |
综合类 | 283篇 |
数学 | 9387篇 |
物理学 | 2027篇 |
出版年
2024年 | 17篇 |
2023年 | 125篇 |
2022年 | 139篇 |
2021年 | 181篇 |
2020年 | 207篇 |
2019年 | 261篇 |
2018年 | 242篇 |
2017年 | 283篇 |
2016年 | 301篇 |
2015年 | 244篇 |
2014年 | 477篇 |
2013年 | 712篇 |
2012年 | 425篇 |
2011年 | 625篇 |
2010年 | 582篇 |
2009年 | 766篇 |
2008年 | 833篇 |
2007年 | 888篇 |
2006年 | 711篇 |
2005年 | 662篇 |
2004年 | 495篇 |
2003年 | 568篇 |
2002年 | 483篇 |
2001年 | 387篇 |
2000年 | 440篇 |
1999年 | 387篇 |
1998年 | 363篇 |
1997年 | 291篇 |
1996年 | 214篇 |
1995年 | 114篇 |
1994年 | 123篇 |
1993年 | 75篇 |
1992年 | 56篇 |
1991年 | 52篇 |
1990年 | 41篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 36篇 |
1984年 | 32篇 |
1983年 | 13篇 |
1982年 | 28篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 19篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Let Top
0
be the category of topological T
0-spaces, QU
0
the category of quasi-uniform T
0-spaces, T : QU
0
→ Top
0
the usual forgetful functor and K : QU
0
→ QU
0
the bicompletion reflector with unit k : 1 → K. Any T-section F : Top
0
→ QU
0
is called K-true if KF = FTKF, and upper (lower)
K-true if KF is finer (coarser) than FTKF. The literature considers important T-sections F that enjoy all three, or just one, or none of these properties. It is known that T(K,k)F is well-pointed if and only if F is upper K-true. We prove the surprising fact that T(K,k)F is the reflection to Fix(TkF) whenever it is idempotent. We also prove a new characterization of upper K-trueness. We construct examples to set apart some natural cases. In particular we present an upper K-true F for which T(K,k)F is not idempotent, and a K-true F for which the coarsest associated T-preserving coreflector in QU
0
is not stable under K.
We dedicate this paper to the memory of Sérgio de Ornelas Salbany (1941–2005). 相似文献
992.
S. Ramasubramanian 《Applied Mathematics and Optimization》2007,56(3):312-342
We consider a network of d companies (insurance companies, for example) operating under a treaty to diversify risk. Internal and external borrowing
are allowed to avert ruin of any member of the network. The amount borrowed to prevent ruin is viewed upon as control. Repayment
of these loans entails a control cost in addition to the usual costs. Each company tries to minimize its repayment liability.
This leads to a d -person differential game with state space constraints. If the companies are also in possible competition a Nash equilibrium
is sought. Otherwise a utopian equilibrium is more appropriate. The corresponding systems of HJB equations and boundary conditions
are derived. In the case of Nash equilibrium, the Hamiltonian can be discontinuous; there are d interlinked control problems with state constraints; each value function is a constrained viscosity solution to the appropriate
discontinuous HJB equation. Uniqueness does not hold in general in this case. In the case of utopian equilibrium, each value
function turns out to be the unique constrained viscosity solution to the appropriate HJB equation. Connection with Skorokhod
problem is briefly discussed. 相似文献
993.
V. S. Klimov 《Mathematical Notes》2007,81(1-2):61-71
We study homology characteristics of critical values and extremals of Lipschitz functionals defined on bounded closed convex subsets of a reflexive space that are invariant under deformations. Sufficient conditions for the existence of a bifurcation point of a multivalued potential operator (the switch principle for the typical number of an extremal) are established. 相似文献
994.
Bernardo Lafuerza-Guillén Donal O’regan Reza Saadati 《Proceedings Mathematical Sciences》2007,117(1):61-70
We introduce the concept of quotient in PN spaces and give some examples. We prove some theorems with regard to the completeness
of a quotient. 相似文献
995.
J. -R. Chazottes P. Collet C. Külske F. Redig 《Probability Theory and Related Fields》2007,137(1-2):201-225
We present a new and simple approach to concentration inequalities in the context of dependent random processes and random
fields. Our method is based on coupling and does not use information inequalities. In case one has a uniform control on the
coupling, one obtains exponential concentration inequalities. If such a uniform control is no more possible, then one obtains
polynomial or stretched-exponential concentration inequalities. Our abstract results apply to Gibbs random fields, both at
high and low temperatures and in particular to the low-temperature Ising model which is a concrete example of non-uniformity
of the coupling.
相似文献
996.
Gui-xiang Xu Institute of Applied Physics Computational Mathematics P.O.Box Beijing China 《应用数学学报(英文版)》2007,(4)
In this paper,we consider the local and global solution for the nonlinear Schrdinger equationwith data in the homogeneous and nonhomogeneous Besov space and the scattering result for small data.Thetechniques to be used are adapted from the Strichartz type estimate,Kato's smoothing effect and the maximalfunction(in time)estimate for the free Schrdinger operator. 相似文献
997.
998.
999.
On the harmonic Bergman space of the half-space, we give characterizations for an arbitrary positive Toeplitz operator to
be a Schatten (or Schatten-Herz) class operator in terms of averaging functions and Berezin transforms. Examples are provided
to show that various results are sharp.
This research was supported by KOSEF(R01-2003-000-10243-0). 相似文献
1000.
主要在自反和严格凸的且具有一致G(a)teaux可微范数的Banach空间中研究了非扩张非自映射的粘滞迭代逼近过程,证明了此映射的隐格式与显格式粘滞迭代序列均强收敛到它的某个不动点. 相似文献