全文获取类型
收费全文 | 10621篇 |
免费 | 193篇 |
国内免费 | 45篇 |
专业分类
化学 | 6016篇 |
晶体学 | 89篇 |
力学 | 372篇 |
数学 | 1820篇 |
物理学 | 2562篇 |
出版年
2022年 | 105篇 |
2021年 | 126篇 |
2020年 | 138篇 |
2019年 | 140篇 |
2018年 | 137篇 |
2017年 | 126篇 |
2016年 | 201篇 |
2015年 | 175篇 |
2014年 | 185篇 |
2013年 | 596篇 |
2012年 | 386篇 |
2011年 | 469篇 |
2010年 | 343篇 |
2009年 | 298篇 |
2008年 | 416篇 |
2007年 | 373篇 |
2006年 | 359篇 |
2005年 | 341篇 |
2004年 | 350篇 |
2003年 | 280篇 |
2002年 | 294篇 |
2001年 | 197篇 |
2000年 | 186篇 |
1999年 | 145篇 |
1998年 | 120篇 |
1997年 | 135篇 |
1996年 | 175篇 |
1995年 | 130篇 |
1994年 | 133篇 |
1993年 | 156篇 |
1992年 | 163篇 |
1991年 | 162篇 |
1990年 | 120篇 |
1989年 | 123篇 |
1988年 | 139篇 |
1987年 | 183篇 |
1986年 | 151篇 |
1985年 | 202篇 |
1984年 | 191篇 |
1983年 | 150篇 |
1982年 | 169篇 |
1981年 | 179篇 |
1980年 | 172篇 |
1979年 | 171篇 |
1978年 | 165篇 |
1977年 | 167篇 |
1976年 | 151篇 |
1975年 | 160篇 |
1974年 | 130篇 |
1973年 | 127篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
61.
62.
The generator coordinate approximation is a non-adiabatic theory of molecular systems. Its fundamental outlines were developed during the 1970's. A further analysis and first applications were published during the 1980's. In this paper, we review the present status of the theory. 相似文献
63.
64.
For a real Enriques surface Y we prove that every homology class in H1(Y (R), Z/2) can be represented by a real algebraic curve if and only if all connected components of Y(R) are orientable. Furthermore, we give a characterization of real Enriques surfaces which are Galois-Maximal and/or Z-Galois-Maximal and we determine the Brauer group of any real Enriques surface Y. 相似文献
65.
Tetsuya Okuyama Masaru Nakayama Yoshitsugu Tomokiyo Omer Van Der Biest 《Microscopy and microanalysis》2002,8(1):11-15
Lattice strains around a platelet oxygen precipitate in Si wafer is studied by energy filtering convergent-beam electron diffraction (CBED) and calculations based on the finite element method (FEM). Local lattice strains are measured from CBD patterns obtained with a probe size less than 2 nm in a specimen thicker than 450 nm. Strains measured are compressive along a direction normal to a plate of the precipitation and tensile along a direction parallel to the plate. Two-dimensional stress fields near the precipitate are obtained with FEM computer analyses by fitting the measured strains. It appears that shear stresses are concentrated at the end of the precipitate edge and the maximum shear stress at an interface between the precipitate and the Si-matrix is 1.9 GPa. It is demonstrated that a combination of the energy filtering CBED and FEM is very useful for the study of local strains near interfaces in semiconductor devices, in particular for the study of stress fields that are too steep for application of the conventional CBED technique. 相似文献
66.
Supported by a Heisenberg-scholarship of the DFG 相似文献
67.
68.
Asymptotic expansions for the exponential growth rate, known as the Lyapunov exponent, and rotation numbers for two coupled oscillators driven by real noise are constructed. Such systems arise naturally in the investigation of the stability of steady-state motions of nonlinear dynamical systems and in parametrically excited linear mechanical systems. Almost-sure stability or instability of dynamical systems depends on the sign of the maximal Lyapunov exponent. Stability conditions are obtained under various assumptions on the infinitesimal generator associated with real noise provided that the natural frequencies are noncommensurable. The results presented here for the case of the infinitesimal generator having a simple zero eigenvalue agree with recent results obtained by stochastic averaging, where approximate ItÔ equations in amplitudes and phases are obtained in the sense of weak convergence.Dedicated to Thomas K. Caughey on the occasion of his 65th birthday. 相似文献
69.
70.