全文获取类型
收费全文 | 26211篇 |
免费 | 4493篇 |
国内免费 | 3110篇 |
专业分类
化学 | 11543篇 |
晶体学 | 238篇 |
力学 | 2439篇 |
综合类 | 232篇 |
数学 | 4873篇 |
物理学 | 14489篇 |
出版年
2024年 | 41篇 |
2023年 | 243篇 |
2022年 | 758篇 |
2021年 | 797篇 |
2020年 | 910篇 |
2019年 | 810篇 |
2018年 | 794篇 |
2017年 | 949篇 |
2016年 | 1129篇 |
2015年 | 871篇 |
2014年 | 1386篇 |
2013年 | 2378篇 |
2012年 | 1603篇 |
2011年 | 1765篇 |
2010年 | 1449篇 |
2009年 | 1636篇 |
2008年 | 1687篇 |
2007年 | 1653篇 |
2006年 | 1583篇 |
2005年 | 1295篇 |
2004年 | 1180篇 |
2003年 | 1052篇 |
2002年 | 966篇 |
2001年 | 879篇 |
2000年 | 829篇 |
1999年 | 593篇 |
1998年 | 634篇 |
1997年 | 505篇 |
1996年 | 446篇 |
1995年 | 404篇 |
1994年 | 362篇 |
1993年 | 336篇 |
1992年 | 295篇 |
1991年 | 226篇 |
1990年 | 195篇 |
1989年 | 156篇 |
1988年 | 166篇 |
1987年 | 118篇 |
1986年 | 101篇 |
1985年 | 114篇 |
1984年 | 113篇 |
1983年 | 46篇 |
1982年 | 73篇 |
1981年 | 48篇 |
1980年 | 37篇 |
1979年 | 33篇 |
1978年 | 39篇 |
1977年 | 33篇 |
1976年 | 25篇 |
1973年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
171.
Marta Gimnez-Pedrs Ali Aghmiz Carmen Claver Anna M. Masdeu-Bult Denis Sinou 《Journal of molecular catalysis. A, Chemical》2003,200(1-2):157-163
High linear alkenes (1-octene and 1-decene) have been hydroformylated using water-soluble rhodium complexes associated with sulfonated diphosphines in the presence of ionic surfactants or methanol. In all cases, the hydroformylation activities were higher than in experiments without additives. The selectivity in aldehydes was higher when we used cetyltrimethylammonium hydrogensulfate (CTAHSO4) as the surfactant or methanol as the co-solvent. 相似文献
172.
173.
174.
Andreas Rößler 《BIT Numerical Mathematics》2006,46(1):97-110
A general class of stochastic Runge–Kutta methods for Itô stochastic differential equation systems w.r.t. a one-dimensional Wiener process is introduced. The colored rooted tree analysis is applied to derive conditions for the coefficients of the stochastic Runge–Kutta method assuring convergence in the weak sense with a prescribed order. Some coefficients for new stochastic Runge–Kutta schemes of order two are calculated explicitly and a simulation study reveals their good performance. 相似文献
175.
176.
177.
Andreas Rößler 《BIT Numerical Mathematics》2007,47(3):657-680
The weak approximation of the solution of a system of Stratonovich stochastic differential equations with a m–dimensional Wiener process is studied. Therefore, a new class of stochastic Runge–Kutta methods is introduced. As the main
novelty, the number of stages does not depend on the dimension m of the driving Wiener process which reduces the computational effort significantly. The colored rooted tree analysis due
to the author is applied to determine order conditions for the new stochastic Runge–Kutta methods assuring convergence with
order two in the weak sense. Further, some coefficients for second order stochastic Runge–Kutta schemes are calculated explicitly.
AMS subject classification (2000) 65C30, 65L06, 60H35, 60H10 相似文献
178.
We study theoretically a nonlinear response of the planar metal/dielectric nanostructures constituted from periodical array
of ultra thin silver layers and the layers of Kerr-like nonlinear dielectric. We predict hysteresis-type dependences of the
components of the tensor of effective dielectric permittivity on the field intensity allowing the change in material transmission
properties from transparent to opaque and back at extremely low intensities of the light. It makes possible to control the
light by light in all-optical nanoscale devices and circuits. 相似文献
179.
180.
G. K. Shenoy 《Hyperfine Interactions》2006,170(1-3):5-13
Stanley L. Ruby (1924–2004) made major contributions to Mössbauer spectroscopy and was the first to suggest the feasibility of observing the Mössbauer effect using synchrotron radiation. In this article we recall his scientific legacy that have inspired his scientific colleagues. 相似文献