全文获取类型
收费全文 | 217235篇 |
免费 | 965篇 |
国内免费 | 561篇 |
专业分类
化学 | 102989篇 |
晶体学 | 2928篇 |
力学 | 11414篇 |
综合类 | 19篇 |
数学 | 31763篇 |
物理学 | 69648篇 |
出版年
2020年 | 1938篇 |
2019年 | 2389篇 |
2018年 | 5233篇 |
2017年 | 5581篇 |
2016年 | 5192篇 |
2015年 | 2609篇 |
2014年 | 4234篇 |
2013年 | 7936篇 |
2012年 | 9114篇 |
2011年 | 9219篇 |
2010年 | 7344篇 |
2009年 | 7218篇 |
2008年 | 7135篇 |
2007年 | 7120篇 |
2006年 | 6387篇 |
2005年 | 11074篇 |
2004年 | 10625篇 |
2003年 | 7731篇 |
2002年 | 5098篇 |
2001年 | 5296篇 |
2000年 | 3805篇 |
1999年 | 3016篇 |
1998年 | 2742篇 |
1997年 | 2540篇 |
1996年 | 2318篇 |
1995年 | 2103篇 |
1994年 | 2069篇 |
1993年 | 2070篇 |
1992年 | 2234篇 |
1991年 | 2529篇 |
1990年 | 2440篇 |
1989年 | 2488篇 |
1988年 | 2359篇 |
1987年 | 2354篇 |
1986年 | 2167篇 |
1985年 | 2698篇 |
1984年 | 2706篇 |
1983年 | 2348篇 |
1982年 | 2396篇 |
1981年 | 2292篇 |
1980年 | 2096篇 |
1979年 | 2425篇 |
1978年 | 2575篇 |
1977年 | 2662篇 |
1976年 | 2810篇 |
1975年 | 2581篇 |
1974年 | 2507篇 |
1973年 | 2685篇 |
1972年 | 2194篇 |
1971年 | 1999篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
D. N. Karimov E. A. Krivandina Z. I. Zhmurova B. P. Sobolev V. A. Bezhanov S. P. Chernov G. M. Shapochkin 《Crystallography Reports》2006,51(6):1009-1015
Crystalline materials that are transparent in the vacuum UV spectral region and currently used have been reviewed. Transmission of crystals of solid solutions with the fluorite structure Ca1?x R xF2+x (R = Sc, Y, La, Yb, Lu) in the UV and vacuum UV spectral regions has been investigated. It is shown that application of different methods of purification of fluorides from some impurities can significantly improve the optical quality of fluoride multicomponent crystals in the short-wavelength spectral region. 相似文献
102.
103.
O. I. Gyrdasova V. N. Krasil’nikov I. G. Grigorov G. V. Bazuev 《Russian Journal of Inorganic Chemistry》2006,51(6):949-955
The effect of ethylene glycol (EG) on the formation of whiskers and fibers of complex oxides with the general formula MCo2O4 upon the thermolysis of M1/3Co2/3C2O4 (M = Zn, Mn) oxalates has been studied. New compounds (solvates) are formed when powdered oxalates are heated with EG. In the solvates, EG molecules substitute for water molecules according to the reaction M1/3Co2/3C2O4 · 2H2O + HOCH2CH2OH = M1/3Co2/3C2O4(HOCH2CH2OH) + 2H2O. The solvates have been characterized using X-ray powder diffraction, microscopy, IR spectroscopy, thermogravimetry, and chemical analysis. The shape, structure, and particle size of the thermolysis products of EG-modified oxalates have been determined using scanning electron microscopy. 相似文献
104.
105.
106.
In this paper the performances of inhomogeneous dielectric slabs as solar light collectors for both illumination and solar energy applications are analysed. 相似文献
107.
Calculations are performed, using a basis of two-center functions described previously, for excited states of the following three-and four-electron compounds: H2
–, He2
+, He2, Li2
+2. High efficiency is demonstrated for the frozen ionic core approximation and the nonorthogonal orbital method in such calculations. For four-electron systems the practical feasibility of the frozen hybrid core approximation is demonstrated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 53–56, August, 1987. 相似文献
108.
Bogdanovskaya V. A. Grinberg V. A. Krishtalik L. I. Kuznetsov A. M. Pleskov Yu. V. Skundin A. M. Tarasevich M. R. Tsyrlina G. A. 《Russian Journal of Electrochemistry》2003,39(4):441-444
Russian Journal of Electrochemistry - 相似文献
109.
We describe in detail fundamental properties of continuity modules of various orders in the spaces L
p of functions defined on a finite segment. We establish some general estimates of seminorms in terms of continuity modules with the best known constants. An example of application of these results to the best approximations is considered. Bibliography: 32 titles. 相似文献
110.
Photorefractive scattering occurs in rhodium-doped lithium niobate crystals irradiated by coherent light. The photorefractive scattering has both wide-angle and selective components. The results of experimental investigation of selective photorefractive scattering in LiNbO3:Rh crystals and calculation of the spatial structure of scattering are reported. The selective scattering is regarded as a kind of a frequency-degenerate fourwave vector interaction. 相似文献