全文获取类型
收费全文 | 298060篇 |
免费 | 1347篇 |
国内免费 | 327篇 |
专业分类
化学 | 136817篇 |
晶体学 | 4686篇 |
力学 | 16870篇 |
综合类 | 3篇 |
数学 | 42001篇 |
物理学 | 99357篇 |
出版年
2021年 | 3096篇 |
2020年 | 3415篇 |
2019年 | 4189篇 |
2018年 | 6225篇 |
2017年 | 6439篇 |
2016年 | 7937篇 |
2015年 | 3516篇 |
2014年 | 6871篇 |
2013年 | 12102篇 |
2012年 | 10106篇 |
2011年 | 11772篇 |
2010年 | 9969篇 |
2009年 | 10125篇 |
2008年 | 11394篇 |
2007年 | 11187篇 |
2006年 | 9960篇 |
2005年 | 8593篇 |
2004年 | 8348篇 |
2003年 | 7759篇 |
2002年 | 8046篇 |
2001年 | 7662篇 |
2000年 | 6055篇 |
1999年 | 4486篇 |
1998年 | 4262篇 |
1997年 | 4122篇 |
1996年 | 3733篇 |
1995年 | 3296篇 |
1994年 | 3358篇 |
1993年 | 3374篇 |
1992年 | 3379篇 |
1991年 | 3786篇 |
1990年 | 3787篇 |
1989年 | 3794篇 |
1988年 | 3545篇 |
1987年 | 3628篇 |
1986年 | 3320篇 |
1985年 | 3850篇 |
1984年 | 4083篇 |
1983年 | 3488篇 |
1982年 | 3686篇 |
1981年 | 3372篇 |
1980年 | 3132篇 |
1979年 | 3621篇 |
1978年 | 3686篇 |
1977年 | 3855篇 |
1976年 | 3928篇 |
1975年 | 3671篇 |
1974年 | 3527篇 |
1973年 | 3688篇 |
1972年 | 3177篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
We obtain conditions under which the Morse functions defined on surfaces are smooth equivalent and functions with isolated critical (singular) points are topologically equivalent. 相似文献
72.
Russian Physics Journal - 相似文献
73.
Glezer A.M. Blinova E.N. Pozdnyakov V.A. Shelyakov A.V. 《Journal of nanoparticle research》2003,5(5-6):551-560
Journal of Nanoparticle Research - It was shown that the thermoelastic martensite transformation B2 ? B19 inside nanoparticles surrounded by amorphous matrix in Ni–Ti–Cu alloys as... 相似文献
74.
A. V. Pukhlikov 《Computational Mathematics and Modeling》2004,15(3):223-256
The article develops the principles of optimal control theory for probability distributions on the configuration space of a controlled dynamical system. Necessary conditions of optimality are derived in the form of the Pontryagin principle for various classes of problems. Analytical representations in the space of distributions and observables are considered. Special modes are examined. The relationship between distribution control theory and nonlocal optimization problems is demonstrated. 相似文献
75.
The nonprimary subgroups of the symmetric group S
9 are investigated. Embedding properties of these subgroups are listed in a table. Properties such as abnormality, pronormality, paranormality, weak normality, etc. were checked with the help of a computer. Algorithms and codes of the first author were used for this purpose. The research leans upon the technique of Burnside marks, as well as upon pertinent information on the table of marks of S
9 from the computer algebra package GAP. The subgroups were investigated up to conjugacy; the total number of conjugacy classes of nonprimary subgroups of S
9 is 432. Some subgroups were additionally checked by other programs based on the double coset method. Bibliography: 24 titles. 相似文献
76.
I. V. Bodnar 《Technical Physics》2003,48(5):587-591
The thermal expansion coefficients and the thermal conductivity of Bridgman-grown crystals of CuGa1−x
InxTe2 solid solutions are investigated. It is found that the thermal expansion coefficient varies with x linearly, while the thermal conductivity is minimal when x=0.5. The Debye temperature and the rms dynamic atomic displacements are calculated from experimental data. It is shown that
the Debye temperature decreases and the rms displacements in the crystal lattice sharply increase as the In content in the
solid solutions grows. 相似文献
77.
78.
Russian Journal of General Chemistry - 相似文献
79.
In the present paper, the notion of norm series with respect to the norm residue symbol is generalized to high-dimensional local fields. Necessary and sufficient conditions for the existence of norm series are obtained. Bibliography: 12 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 305, 2003, pp. 60–83. 相似文献
80.
The results of optical study and quantum-chemical simulation of a conjugated organic system, 2-cyclooctylamino-5-nitropyridine (COANP)-fullerene, performed to determine its potential for application as a limiter of visible and near-IR laser radiation and as a material for diffraction elements in systems for reversible recording of optical information, are presented. Complexation between a COANP molecule and fullerene is considered as one of the main mechanisms responsible for the corresponding properties of this system. For the first time, nonlinear optical characteristics of COANP-C60 and COANP-C70 systems are comparatively studied and the intermolecular interaction between a COANP molecule and fullerene is analyzed on the quantum-chemical level. 相似文献