全文获取类型
收费全文 | 2612篇 |
免费 | 91篇 |
国内免费 | 3篇 |
专业分类
化学 | 1876篇 |
晶体学 | 12篇 |
力学 | 148篇 |
数学 | 204篇 |
物理学 | 466篇 |
出版年
2023年 | 33篇 |
2022年 | 106篇 |
2021年 | 123篇 |
2020年 | 72篇 |
2019年 | 74篇 |
2018年 | 88篇 |
2017年 | 67篇 |
2016年 | 126篇 |
2015年 | 74篇 |
2014年 | 109篇 |
2013年 | 156篇 |
2012年 | 145篇 |
2011年 | 181篇 |
2010年 | 113篇 |
2009年 | 88篇 |
2008年 | 145篇 |
2007年 | 113篇 |
2006年 | 120篇 |
2005年 | 102篇 |
2004年 | 86篇 |
2003年 | 65篇 |
2002年 | 53篇 |
2001年 | 31篇 |
2000年 | 20篇 |
1999年 | 28篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 13篇 |
1991年 | 20篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 18篇 |
1984年 | 14篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1979年 | 9篇 |
1978年 | 17篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1973年 | 11篇 |
1971年 | 11篇 |
1969年 | 11篇 |
排序方式: 共有2706条查询结果,搜索用时 8 毫秒
1.
2.
Natalia L. Calvo Sebastian O. SimonettiRubén M. Maggio Teodoro S. Kaufman 《Analytica chimica acta》2015
Exposure of cimetidine (CIM) to dry heat (160–180 °C) afforded, upon cooling, a glassy solid containing new and hitherto unknown products. The kinetics of this process was studied by a second order chemometrics-assisted multi-spectroscopic approach. Proton and carbon-13 nuclear magnetic resonance (NMR), as well as ultraviolet and infrared spectroscopic data were jointly used, whereas multivariate curve resolution with alternating least squares (MCR-ALS) was employed as the chemometrics method to extract process information. It was established that drug degradation follows a first order kinetics. 相似文献
3.
Formalization for problems of multicriteria decision making under uncertainty is constructed in terms of guaranteed and weak
estimates. A relevant definition of the vector maximinimax value is given. Parameterization and approximation of maximum,
minimax, and maximinimax values based on the inverse logical convolution are suggested. An application for multicommodity
networks is considered.
Received: December 13, 2000 / Accepted: August 21, 2001?Published online May 8, 2002 相似文献
4.
Institute of Mechanics, Ukrainian Academy of Sciences, Kiev. Translated from Prikladnaya Mekhanika, Vol. 28, No. 1, pp. 31–39, January, 1992. 相似文献
5.
The proton-donor properties of 1-(p-chlorobenzoyl)-5-methoxy-2-methylindole-3-acetic acid (indometacin) were studied in emulsions based on different surfactants and their mixtures. A procedure for the alkalimetric titration of indometacin with detecting the titration end-point in the presence of Cresol Red was developed using an emulsion based on dodecylpyridinium chloride. The conditions for determining indometacin in medicinal forms by pH-metric titration were selected. 相似文献
6.
Study of the viscoelastoplastic deformation of an element of a body with a three-branch loading path
Yu. N. Shevchenko R. G. Terekhov N. S. Braikovskaya S. M. Zakharov 《International Applied Mechanics》1991,27(12):1162-1167
Institute of Mechanics, Academy of Sciences of the Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 27, No. 12, pp. 26–33, December, 1991. 相似文献
7.
8.
9.
10.
S. E. Korostova S. G. Shevchenko M. V. Sigalov N. I. Golovanova 《Chemistry of Heterocyclic Compounds》1991,27(4):363-365
The reaction of 1-methyl-2-acetylpyrrole oxime with acetylene at atmospheric and increased pressure can be catalyzed by KOH-DMSO superbase to give 1-methyl-2-(2-pyrrolyl)pyrrole, N-vinyl-2-[1-methyl(2-pyrrolyl)]pyrrole, and the reaction intermediate methyl-2-(1-methylpyrrolyl)-O-vinyloxime.See [1] for Communication 44.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 460–463, April, 1991. 相似文献