全文获取类型
收费全文 | 10615篇 |
免费 | 1083篇 |
国内免费 | 701篇 |
专业分类
化学 | 2580篇 |
晶体学 | 27篇 |
力学 | 1299篇 |
综合类 | 193篇 |
数学 | 5677篇 |
物理学 | 2623篇 |
出版年
2024年 | 12篇 |
2023年 | 93篇 |
2022年 | 145篇 |
2021年 | 164篇 |
2020年 | 264篇 |
2019年 | 265篇 |
2018年 | 269篇 |
2017年 | 320篇 |
2016年 | 336篇 |
2015年 | 273篇 |
2014年 | 433篇 |
2013年 | 687篇 |
2012年 | 436篇 |
2011年 | 517篇 |
2010年 | 493篇 |
2009年 | 565篇 |
2008年 | 681篇 |
2007年 | 700篇 |
2006年 | 618篇 |
2005年 | 604篇 |
2004年 | 471篇 |
2003年 | 457篇 |
2002年 | 451篇 |
2001年 | 368篇 |
2000年 | 316篇 |
1999年 | 274篇 |
1998年 | 289篇 |
1997年 | 217篇 |
1996年 | 226篇 |
1995年 | 211篇 |
1994年 | 172篇 |
1993年 | 150篇 |
1992年 | 127篇 |
1991年 | 106篇 |
1990年 | 69篇 |
1989年 | 66篇 |
1988年 | 61篇 |
1987年 | 56篇 |
1986年 | 61篇 |
1985年 | 55篇 |
1984年 | 49篇 |
1983年 | 24篇 |
1982年 | 50篇 |
1981年 | 46篇 |
1980年 | 28篇 |
1979年 | 33篇 |
1978年 | 23篇 |
1977年 | 10篇 |
1976年 | 19篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Jose M. Guisan Gloria Fernandez-Lorente Javier Rocha-Martin Daniel Moreno-Gamero 《Current Opinion in Green and Sustainable Chemistry》2022
Different strategies for the preparation of efficient and robust immobilized biocatalysts are here reviewed. Different physico-chemical approaches are discussed.i.- The stabilization of enzyme by any kind of immobilization on pre-existing porous supports.ii.- The stabilization of enzymes by multipoint covalent attachment on support surfaces.iii.- Additional stabilization of immobilized-stabilized enzyme by physical or chemical modification with polymers.These three strategies can be easily developed when enzymes are immobilized in pre-existing porous supports. In addition to that, these immobilized-stabilized derivatives are optimal to develop enzyme reaction engineering and reactor engineering. Stabilizations ranging between 1000 and 100,000 folds regarding diluted soluble enzymes are here reported. 相似文献
2.
3.
《Mathematische Nachrichten》2018,291(8-9):1177-1190
We introduce homogeneous Besov and Triebel–Lizorkin spaces with variable indexes. We show that their study reduces to the study of inhomogeneous variable exponent spaces and homogeneous constant exponent spaces. Corollaries include trace space characterizations and Sobolev embeddings. 相似文献
4.
In this paper we study the domain of the generator of stable processes, stable-like processes and more general pseudo- and integro-differential operators which naturally arise both in analysis and as infinitesimal generators of Lévy- and Lévy-type (Feller) processes. In particular we obtain conditions on the symbol of the operator ensuring that certain (variable order) Hölder and Hölder–Zygmund spaces are in the domain. We use tools from probability theory to investigate the small-time asymptotics of the generalized moments of a Lévy or Lévy-type process , for functions f which are not necessarily bounded or differentiable. The pointwise limit exists for fixed if f satisfies a Hölder condition at x. Moreover, we give sufficient conditions which ensure that the limit exists uniformly in the space of continuous functions vanishing at infinity. As an application we prove that the domain of the generator of contains certain Hölder spaces of variable order. Our results apply, in particular, to stable-like processes, relativistic stable-like processes, solutions of Lévy-driven SDEs and Lévy processes. 相似文献
5.
6.
7.
This article proposes a global, chaos-based procedure for the discretization of functionals of Brownian motion into functionals of a Poisson process with intensity . Under this discretization we study the weak convergence, as the intensity of the underlying Poisson process goes to infinity, of Poisson functionals and their corresponding Malliavin-type derivatives to their Wiener counterparts. In addition, we derive a convergence rate of for the Poisson discretization of Wiener functionals by combining the multivariate Chen–Stein method with the Malliavin calculus. Our proposed sufficient condition for establishing the mentioned convergence rate involves the kernel functions in the Wiener chaos, yet we provide examples, especially the discretization of some common path dependent Wiener functionals, to which our results apply without committing the explicit computations of such kernels. To the best our knowledge, these are the first results in the literature on the universal convergence rate of a global discretization of general Wiener functionals. 相似文献
8.
9.
In the paper mentioned in the title, it is proved the boundedness of the Riesz potential operator of variable order α(x) from variable exponent Morrey space to variable exponent Campanato space, under certain assumptions on the variable exponents p(x) and λ(x) of the Morrey space. Assumptions on the exponents were different depending on whether takes or not the critical values 0 or 1. In this note, we improve those results by unifying all the cases and covering the whole range . We also provide a correction to some minor technicality in the proof of Theorem 2 in the aforementioned paper. 相似文献
10.