全文获取类型
收费全文 | 3794篇 |
免费 | 240篇 |
国内免费 | 481篇 |
专业分类
化学 | 51篇 |
力学 | 47篇 |
综合类 | 49篇 |
数学 | 3923篇 |
物理学 | 445篇 |
出版年
2023年 | 50篇 |
2022年 | 23篇 |
2021年 | 37篇 |
2020年 | 77篇 |
2019年 | 104篇 |
2018年 | 109篇 |
2017年 | 97篇 |
2016年 | 115篇 |
2015年 | 93篇 |
2014年 | 181篇 |
2013年 | 338篇 |
2012年 | 109篇 |
2011年 | 200篇 |
2010年 | 153篇 |
2009年 | 267篇 |
2008年 | 320篇 |
2007年 | 261篇 |
2006年 | 236篇 |
2005年 | 226篇 |
2004年 | 173篇 |
2003年 | 193篇 |
2002年 | 185篇 |
2001年 | 132篇 |
2000年 | 123篇 |
1999年 | 130篇 |
1998年 | 117篇 |
1997年 | 123篇 |
1996年 | 62篇 |
1995年 | 42篇 |
1994年 | 31篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 18篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1973年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有4515条查询结果,搜索用时 15 毫秒
31.
A. E. Mironov 《Functional Analysis and Its Applications》2005,39(3):240-243
We construct commuting rank 2 formally self-adjoint ordinary differential operators corresponding to a curve of genus 2. 相似文献
32.
本文主要讨论了当非负位势 V(x)属于某逆Holder类时,由一致椭圆算子L=-div(A(x))+V(x)所定义的 Riesz变换在 Lp空间的有界性。 相似文献
33.
M. I. Gil' 《Proceedings of the American Mathematical Society》2003,131(12):3737-3746
A linear operator in a separable Hilbert space is called a quasinormal one if it is a sum of a normal operator and a compact one. In the paper, bounds for the spectrum of quasinormal operators are established. In addition, the lower estimate for the spectral radius is derived. Under some restrictions, that estimate improves the well-known results. Applications to integral operators and matrices are discussed. Our results are new even in the finite-dimensional case.
34.
In this paper we give necessary and sufficient conditions for the existence of a C>
0-semigroup in L
1(I) (I real interval) generated by a second-order differential operator when suitable boundary conditions at the endpoints are imposed. 相似文献
35.
用A的不变子空间作参数,给出了算子方程AX=XAX的全部解。当A是单射或稠值域时,或者当A是正规算子时,给出了算子方程AX=XA=XAX的全部解。我们还给出正规算子X是算子方程AX=XZ=XAX的解的充分必要条件。 相似文献
36.
37.
M.K. Gupta Vijay Gupta Manoj Kumar 《Journal of Mathematical Analysis and Applications》2007,330(2):799-816
In the present paper we introduce a new family of linear positive operators and study some direct and inverse results in simultaneous approximation. 相似文献
38.
Mohamed El-Gebeily Donal O'Regan 《Journal of Mathematical Analysis and Applications》2007,334(1):140-156
Existence theory is developed for the equation ?(u)=F(u), where ? is a formally self-adjoint singular second-order differential expression and F is nonlinear. The problem is treated in a Hilbert space and we do not require the operators induced by ? to have completely continuous resolvents. Nonlinear boundary conditions are allowed. Also, F is assumed to be weakly continuous and monotone at one point. Boundary behavior of functions associated with the domains of definitions of the operators associated with ? in the singular case is investigated. A special class of self-adjoint operators associated with ? is obtained. 相似文献
39.
Pseudodifferential operators that are invariant under the action of a discrete subgroup Γ of SL(2,R) correspond to certain sequences of modular forms for Γ. Rankin-Cohen brackets are noncommutative products of modular forms expressed in terms of derivatives of modular forms. We introduce an analog of the heat operator on the space of pseudodifferential operators and use this to construct bilinear operators on that space which may be considered as Rankin-Cohen brackets. We also discuss generalized Rankin-Cohen brackets on modular forms and use these to construct certain types of modular forms. 相似文献
40.
In this note we make a correction in the paper [1] by two of the authors. Specifically we modify an auxiliary localization
result and prove that the applications to the saturation theory of some outstanding conservative operators remain valid. Moreover,
we enrich a corollary dealing with the well-known Szász-Mirakjan operators.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献