全文获取类型
收费全文 | 11959篇 |
免费 | 319篇 |
国内免费 | 307篇 |
专业分类
化学 | 1145篇 |
晶体学 | 46篇 |
力学 | 85篇 |
综合类 | 16篇 |
数学 | 10281篇 |
物理学 | 1012篇 |
出版年
2023年 | 20篇 |
2022年 | 26篇 |
2021年 | 28篇 |
2020年 | 54篇 |
2019年 | 328篇 |
2018年 | 368篇 |
2017年 | 195篇 |
2016年 | 117篇 |
2015年 | 133篇 |
2014年 | 370篇 |
2013年 | 821篇 |
2012年 | 470篇 |
2011年 | 794篇 |
2010年 | 684篇 |
2009年 | 875篇 |
2008年 | 903篇 |
2007年 | 845篇 |
2006年 | 660篇 |
2005年 | 439篇 |
2004年 | 366篇 |
2003年 | 351篇 |
2002年 | 261篇 |
2001年 | 266篇 |
2000年 | 263篇 |
1999年 | 306篇 |
1998年 | 274篇 |
1997年 | 224篇 |
1996年 | 288篇 |
1995年 | 284篇 |
1994年 | 266篇 |
1993年 | 228篇 |
1992年 | 141篇 |
1991年 | 68篇 |
1990年 | 43篇 |
1989年 | 47篇 |
1988年 | 53篇 |
1987年 | 49篇 |
1986年 | 41篇 |
1985年 | 73篇 |
1984年 | 82篇 |
1983年 | 56篇 |
1982年 | 65篇 |
1981年 | 72篇 |
1980年 | 54篇 |
1979年 | 46篇 |
1978年 | 52篇 |
1977年 | 40篇 |
1976年 | 30篇 |
1975年 | 25篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
21.
Abstract. We propose a general approach to deal with nonlinear, nonconvex variational problems based on a reformulation of the problem
resulting in an optimization problem with linear cost functional and convex constraints. As a first step we explicitly explore
these ideas to some one-dimensional variational problems and obtain specific conclusions of an analytical and numerical nature. 相似文献
22.
富勒烯 (C60 /C70 )与N ,N ,N′ ,N′ 四 (对甲苯基 ) 4,4′ 二胺 1,1′ 二苯硒醚 (TPDASe)间在激光光诱导条件下 ,发生了分子间的电子转移过程 .在可见 -近红外区 ( 60 0~ 12 0 0nm) ,观测到了TPDASe阳离子自由基、富勒烯 (C60 /C70 )激发三线态和阴离子自由基 ,在苯腈溶液中 ,观测瞬态谱测定了电子从TPDASe转移到富勒烯 (C60 /C70 )激发三线态的量子转化产率(ΦTet)和电子转移常数 (Ket) . 相似文献
23.
M Gubinelli 《Journal of Functional Analysis》2004,216(1):86-140
We formulate indefinite integration with respect to an irregular function as an algebraic problem which has a unique solution under some analytic constraints. This allows us to define a good notion of integral with respect to irregular paths with Hölder exponent greater than 1/3 (e.g. samples of Brownian motion) and study the problem of the existence, uniqueness and continuity of solution of differential equations driven by such paths. We recover Young's theory of integration and the main results of Lyons’ theory of rough paths in Hölder topology. 相似文献
24.
Marco Biroli Silvia Mataloni Michele Matzeu 《NoDEA : Nonlinear Differential Equations and Applications》2005,12(3):295-321
Some stability results for Mountain Pass and Linking type solutions of semilinear problems involving a very general class
of Dirichlet forms are stated. The non linear terms are supposed to have a suitable superlinear growth and the family of Dirichlet
forms is required to be dominated from below and from above by a fixed diffusion type form. Some concrete examples are also
given. 相似文献
25.
Michael T. Anderson 《Advances in Mathematics》2003,179(2):205-249
This paper studies several aspects of asymptotically hyperbolic (AH) Einstein metrics, mostly on 4-manifolds. We prove boundary regularity (at infinity) for such metrics and establish uniqueness under natural conditions on the boundary data. By examination of explicit black hole metrics, it is shown that neither uniqueness nor finiteness holds in general for AH Einstein metrics with a prescribed conformal infinity. We then describe natural conditions which are sufficient to ensure finiteness. 相似文献
26.
Operators on manifolds with corners that have base configurations with geometric singularities can be analysed in the frame of a conormal symbolic structure which is in spirit similar to the one for conical singularities of Kondrat'ev's work. Solvability of elliptic equations and asymptotics of solutions are determined by meromorphic conormal symbols. We study the case when the base has edge singularities which is a natural assumption in a number of applications. There are new phenomena, caused by a specific kind of higher degeneracy of the underlying symbols. We introduce an algebra of meromorphic edge operators that depend on complex parameters and investigate meromorphic inverses in the parameter-dependent elliptic case. Among the examples are resolvents of elliptic differential operators on manifolds with edges. 相似文献
27.
Zhaoyang Yin 《Monatshefte für Mathematik》2004,141(4):337-344
We prove under quite general assumptions the existence of a bounded positive solution to the semilinear Schrödinger equation in a two-dimensional exterior domain. 相似文献
28.
We prove the existence of solutions to nonlinear free boundary problem with singularities at given points. 相似文献
29.
On a Definitizable Analog of the Trigonometric Moment Problem Generating an Indefinite Toeplitz Form
We prove the existence of an integro-polynomial representation for a sequence of numbers such that there exists a difference operator mapping this sequence to a sequence that generates the solvable trigonometric moment problem. A similar result related to the power moment problem was given in [12]. 相似文献
30.
Victor Bondarenko 《Bulletin des Sciences Mathématiques》2003,127(3):191-206
In present paper the parabolic equation solution is built. The construction is reduced to iterative procedure. And convergence of the latter is proven. 相似文献