全文获取类型
收费全文 | 20371篇 |
免费 | 493篇 |
国内免费 | 291篇 |
专业分类
化学 | 1380篇 |
晶体学 | 81篇 |
力学 | 242篇 |
综合类 | 31篇 |
数学 | 17925篇 |
物理学 | 1496篇 |
出版年
2023年 | 38篇 |
2022年 | 48篇 |
2021年 | 74篇 |
2020年 | 111篇 |
2019年 | 575篇 |
2018年 | 634篇 |
2017年 | 349篇 |
2016年 | 259篇 |
2015年 | 258篇 |
2014年 | 581篇 |
2013年 | 1216篇 |
2012年 | 659篇 |
2011年 | 1186篇 |
2010年 | 1029篇 |
2009年 | 1420篇 |
2008年 | 1584篇 |
2007年 | 1575篇 |
2006年 | 1238篇 |
2005年 | 803篇 |
2004年 | 749篇 |
2003年 | 640篇 |
2002年 | 490篇 |
2001年 | 407篇 |
2000年 | 390篇 |
1999年 | 467篇 |
1998年 | 440篇 |
1997年 | 326篇 |
1996年 | 477篇 |
1995年 | 461篇 |
1994年 | 430篇 |
1993年 | 331篇 |
1992年 | 244篇 |
1991年 | 170篇 |
1990年 | 127篇 |
1989年 | 150篇 |
1988年 | 92篇 |
1987年 | 94篇 |
1986年 | 91篇 |
1985年 | 142篇 |
1984年 | 106篇 |
1983年 | 85篇 |
1982年 | 114篇 |
1981年 | 101篇 |
1980年 | 82篇 |
1979年 | 58篇 |
1978年 | 69篇 |
1977年 | 60篇 |
1976年 | 58篇 |
1975年 | 22篇 |
1974年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
一阶形式系统K~*及其完备性 总被引:2,自引:0,他引:2
裴道武 《数学年刊A辑(中文版)》2002,(6)
模糊命题演算的形式系统L*已经在模糊逻辑与模糊推理的结合研究中得到了成功的应用.本文考虑与系统L*相应的一阶逻辑理论,建立了一阶形式系统K*,并证明了这个系统的完备性. 相似文献
32.
Nicolas Bergeron 《Mathematische Zeitschrift》2002,241(1):101-125
Let M be an arithmetic hyperbolic manifold and be a codimension 1 geodesic cycle. In this paper, we study the asymptotic growth of the -norm of the lifts of F in the congruence tower above M. We obtain an explicit value for the growth rate of this norm. In particular, we provide a new proof of a celebrated result
of Millson [Mi] on the homology of the arithmetic hyperbolic manifolds. The method is quite general and gives a new way of
getting non zero homology classes in certain locally symmetric spaces.
Received: 20 April 2001; in final form: 26 September 2001 / Published online: 28 February 2002 相似文献
33.
Kunyu Guo 《Journal of Functional Analysis》2004,213(2):380-411
This paper mainly concerns defect operators and defect functions of Hardy submodules, Bergman submodules over the unit ball, and Hardy submodules over the polydisk. The defect operator (function) carries key information about operator theory (function theory) and structure of analytic submodules. The problem when a submodule has finite defect is attacked for both Hardy submodules and Bergman submodules. Our interest will be in submodules generated by polynomials. The reason for choosing such submodules is to understand the interaction of operator theory, function theory and algebraic geometry. 相似文献
34.
We show that there are close relations between extremal problems in dual Brunn-Minkowski theory and isotropic-type properties for some Borel measures on the sphere. The methods we use allow us to obtain similar results in the context of Firey-Brunn-Minkowski theory. We also study reverse inequalities for dual mixed volumes which are related with classical positions, such as ?-position or isotropic position. 相似文献
35.
Sauer, Shelah, Vapnik and Chervonenkis proved that if a set system on n vertices contains many sets, then the set system has full trace on a large set. Although the restriction on the size of the
groundset cannot be lifted, Frankl and Pach found a trace structure that is guaranteed to occur in uniform set systems even
if we do not bound the size of the groundset. In this note we shall give three sequences of structures such that every set
system consisting of sufficiently many sets contains at least one of these structures with many sets. 相似文献
36.
Andrei K. Lerner 《Archiv der Mathematik》2005,85(6):538-543
We show that the Hardy-Littlewood maximal operator and a class of Calderón-Zygmund singular integrals satisfy the strong type
modular inequality in variable Lp spaces if and only if the variable exponent p(x) ∼ const.
Received: 15 September 2004 相似文献
37.
38.
Satyanad Kichenassamy 《Advances in Mathematics》2004,184(2):268-288
In 1985, Fefferman and Graham have constructed a local embedding of an arbitrary real-analytic manifold, of odd dimension n, into a Ricci-flat manifold of dimension n+2 admitting a homothety. They conjectured that their result remains valid in even dimensions, if logarithms are allowed in the expansion of the metric. In this paper, we (i) prove that such expansions exist and converge and (ii) establish the degree of non-uniqueness of the solution in terms of the coefficients in the expansion. 相似文献
39.
We investigate heteroclinic orbits between equilibria and rotating waves for scalar semilinear parabolic reaction-advection-diffusion equations with periodic boundary conditions. Using zero number properties of the solutions and the phase shift equivariance of the equation, we establish a necessary and sufficient condition for the existence of a heteroclinic connection between any pair of hyperbolic equilibria or rotating waves. 相似文献
40.
Dmitri I. Panyushev 《Advances in Mathematics》2004,186(2):307-316
We study Abelian ideals of a Borel subalgebra consisting of long roots. It is shown that methods of Cellini and Papi can be extended to this situation. A uniform expression for the number of long Abelian ideals is given. We also show that there is a one-to-one correspondence between the long Abelian ideals and B-stable commutative subalgebras in the little adjoint representation of the Langlands dual Lie algebra. 相似文献