全文获取类型
收费全文 | 265424篇 |
免费 | 791篇 |
国内免费 | 285篇 |
专业分类
化学 | 116551篇 |
晶体学 | 3763篇 |
力学 | 15982篇 |
综合类 | 7篇 |
数学 | 43881篇 |
物理学 | 86316篇 |
出版年
2019年 | 2290篇 |
2018年 | 10872篇 |
2017年 | 11630篇 |
2016年 | 7726篇 |
2015年 | 2549篇 |
2014年 | 3693篇 |
2013年 | 7143篇 |
2012年 | 9362篇 |
2011年 | 17669篇 |
2010年 | 11663篇 |
2009年 | 12018篇 |
2008年 | 15704篇 |
2007年 | 18939篇 |
2006年 | 5796篇 |
2005年 | 10450篇 |
2004年 | 7572篇 |
2003年 | 7445篇 |
2002年 | 5842篇 |
2001年 | 5141篇 |
2000年 | 4006篇 |
1999年 | 2865篇 |
1998年 | 2645篇 |
1997年 | 2474篇 |
1996年 | 2441篇 |
1995年 | 2156篇 |
1994年 | 2100篇 |
1993年 | 2122篇 |
1992年 | 2146篇 |
1991年 | 2457篇 |
1990年 | 2387篇 |
1989年 | 2472篇 |
1988年 | 2361篇 |
1987年 | 2387篇 |
1986年 | 2207篇 |
1985年 | 2752篇 |
1984年 | 2783篇 |
1983年 | 2416篇 |
1982年 | 2463篇 |
1981年 | 2369篇 |
1980年 | 2171篇 |
1979年 | 2506篇 |
1978年 | 2668篇 |
1977年 | 2672篇 |
1976年 | 2800篇 |
1975年 | 2591篇 |
1974年 | 2519篇 |
1973年 | 2727篇 |
1972年 | 2192篇 |
1971年 | 2000篇 |
1970年 | 1880篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
L. Ya. Yukel'son I. I. Parilis G. L. Bussel' D. Kh. Khamidov 《Chemistry of Natural Compounds》1989,25(6):698-704
On the basis of a computer analysis of four classes of toxic polypeptides, generalized primary structures of each class have been obtained which can be used for planning the synthesis of biologically active compounds. 相似文献
112.
I. Morgenstern 《Zeitschrift für Physik B Condensed Matter》1987,67(2):265-270
I present an abstraction of the Hopfield-model for neural networks which is suitable for physical chip design using commerically available two-dimensional gate arrays. It can be shown that ±1-bonds combined with a dilution of about 80–90% of the original Hopfield-connections still lead to a comparable performance of the network. Furthermore the learning capability of the chips is discussed. Future extensions concerning programmable designs are outlined. The impact on aspects of brain research is discussed. 相似文献
113.
114.
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
115.
P.A. Grillet 《Acta Mathematica Hungarica》2005,106(4):301-315
Summary Three weak variants of compactness which lie strictly between compactness and quasicompactness, are introduced. Their basic properties are studied. The interplay with mapping and their direct and inverse preservation under mappings are investigated. In the process three decompositions of compactness are observed. 相似文献
116.
117.
118.
A mixed problem is considered for a system of partial differential equations modeling the process of adsorption dynamics. An existence and uniqueness theorem is proved for this problem, and the solution properties are investigated. The inverse problem is posed, involving the determination of the system coefficient given additional information about the solution. A uniqueness theorem is proved for the solution of the inverse problem.__________Translated from Prikladnaya Matematika i Informatika, No. 16, pp. 5 – 14, 2004. 相似文献
119.
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
120.
In this paper we obtain a number of Maharam-type slice integral representations, with respect to scalar measures, for positive
projections in Dedekind complete vector lattices and f-algebras.
AMS Classification: 47B65, 46A40, 06F25 相似文献