全文获取类型
收费全文 | 7980篇 |
免费 | 277篇 |
国内免费 | 26篇 |
专业分类
化学 | 5615篇 |
晶体学 | 72篇 |
力学 | 124篇 |
数学 | 1030篇 |
物理学 | 1442篇 |
出版年
2023年 | 67篇 |
2022年 | 156篇 |
2021年 | 209篇 |
2020年 | 180篇 |
2019年 | 170篇 |
2018年 | 98篇 |
2017年 | 88篇 |
2016年 | 248篇 |
2015年 | 246篇 |
2014年 | 232篇 |
2013年 | 375篇 |
2012年 | 467篇 |
2011年 | 507篇 |
2010年 | 318篇 |
2009年 | 259篇 |
2008年 | 418篇 |
2007年 | 362篇 |
2006年 | 363篇 |
2005年 | 290篇 |
2004年 | 294篇 |
2003年 | 224篇 |
2002年 | 219篇 |
2001年 | 94篇 |
2000年 | 124篇 |
1999年 | 102篇 |
1998年 | 75篇 |
1997年 | 82篇 |
1996年 | 84篇 |
1995年 | 73篇 |
1994年 | 94篇 |
1993年 | 80篇 |
1992年 | 65篇 |
1991年 | 61篇 |
1990年 | 63篇 |
1989年 | 51篇 |
1987年 | 54篇 |
1986年 | 70篇 |
1985年 | 80篇 |
1984年 | 69篇 |
1983年 | 71篇 |
1982年 | 65篇 |
1981年 | 61篇 |
1980年 | 75篇 |
1979年 | 52篇 |
1978年 | 63篇 |
1977年 | 71篇 |
1976年 | 59篇 |
1975年 | 63篇 |
1974年 | 51篇 |
1973年 | 55篇 |
排序方式: 共有8283条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
We consider solutions bifurcating from a spatially
homogeneous equilibrium under the assumption that the associated
linearization possesses continuous spectrum up to the imaginary
axis, for all values of the bifurcation parameter, and that a real
eigenvalue crosses the imaginary axis. For a model we investigate
the nonlinear stability of the trivial solution with respect to
spatially localized perturbations, prove the occurrence of a
pitchfork bifurcation of equilibria and the nonlinear stability of
the bifurcating equilibria, again with respect to spatially
localized perturbations. 相似文献
25.
Dynamics of Multisection Semiconductor Lasers 总被引:1,自引:0,他引:1
We consider a mathematical model (the so-called traveling-wave system) which describes longitudinal dynamical effects in semiconductor lasers. This model consists of a linear hyperbolic system of PDEs, which is nonlinearly coupled with a slow subsystem of ODEs. We prove that a corresponding initial-boundary value problem is well posed and that it generates a smooth infinite-dimensional dynamical system. Exploiting the particular slow-fast structure, we derive conditions under which there exists a low-dimensional attracting invariant manifold. The flow on this invariant manifold is described by a system of ODEs. Mode approximations of that system are studied by means of bifurcation theory and numerical tools. 相似文献
26.
Dynamic systems described by nonlinear differential equations of the second order are studied. It is assumed that certain
preliminary information on the dissipative or elastic characteristics of systems is known. A new approach is demonstrated
to obtaining full information on unknown or partially known characteristics of a system from measurements of not only displacements
but also velocities and accelerations
__________
Published in Prikladnaya Mekhanika, Vol. 41, No. 6, pp. 139–143, June 2005. 相似文献
27.
28.
29.
P.R. Willmott R. Herger M.C. Falub L. Patthey M. Döbeli C.V. Falub M. Shi M. Schneider 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1199-1201
A new ablation target geometry is presented that was used to produce thin films of La1-xSrxMnO3 grown heteroepitaxially on SrTiO3 by pulsed reactive crossed-beam laser ablation. The films were grown in order to perform angle-resolved photoelectron spectroscopy, which demands that the surface be atomically flat. In situ and ex situ analysis shows that this condition was met, even after depositing to a thickness of over 100 nm. PACS 61.10.-i; 61.18.Bn; 68.47.Gh; 71.27.+a; 81.15.Fg 相似文献
30.