全文获取类型
收费全文 | 510篇 |
免费 | 2篇 |
专业分类
化学 | 446篇 |
力学 | 7篇 |
数学 | 4篇 |
物理学 | 55篇 |
出版年
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2014年 | 6篇 |
2013年 | 20篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 9篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 15篇 |
2003年 | 7篇 |
2002年 | 12篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 14篇 |
1998年 | 13篇 |
1997年 | 13篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 12篇 |
1992年 | 16篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 21篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1979年 | 6篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1973年 | 7篇 |
1972年 | 7篇 |
1971年 | 6篇 |
1970年 | 5篇 |
1969年 | 4篇 |
1960年 | 4篇 |
排序方式: 共有512条查询结果,搜索用时 15 毫秒
61.
A. V. Arapova M. P. Bubnov N. N. Smirnova A. V. Markin I. A. Letyanina N. A. Skorodumova A. S. Bogomyakov G. A. Abakumov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(1):1-6
The heat capacity of di-(2-pyridyl)amine-bis-(4-methoxy-3,6-di-tert-butyl-o-benzosemiquinone)cobalt in the temperature range from 7 to 370 K was investigated by means of precise adiabatic vacuum calorimetry. It was established that the phase transition associated with the redox-isomeric transformation of the semiquinone-catecholate form of the complex into the bis-semiquinone form is observed above 260 K; this transition is not completed due to thermal destruction that begins at 367 K. The magnetic moment values in the temperature range from 5 to 350 K and the EPR spectra in the temperature range from 130 to 290 K, which confirm the nature of the phase transition, were obtained for the investigated complex. The standard thermodynamic functions C p pO (T), H○(T)-H○(0), S○(T), and G○(T)-H○(0), were calculated from the data on heat capacity in the temperature range from T → 0 to 260 K. Analysis of the low temperature heat capacity on the basis of Debye’s theory of the heat capacity of solids and the multifractional model testifies to the chain-layered structural topology of the investigated complex. 相似文献
62.
E. S. Denislamova N. V. Bubnov Z. G. Aliev A. N. Maslivets 《Russian Journal of Organic Chemistry》2011,47(9):1362-1365
Methyl 1-aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with 3-methyl-4-phenyl-1H-pyrazol-5-amine to give methyl 7-arylcarbamoyl-6-aroyl-2-methyl-3-phenylpyrazolo[1,5-a]-pyrimidine-5-carboxylates. The molecular and crystalline structures of methyl 6-benzoyl-7-(4-chlorophenylcarbamoyl)-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidine-5-carboxylate were studied by X-ray analysis. 相似文献
63.
M. P. Shurygina N. O. Druzhkov M. V. Arsen’ev M. P. Bubnov G. K. Fukin S. A. Chesnokov V. K. Cherkasov 《Russian Journal of Organic Chemistry》2011,47(4):486-495
Alkoxylation of 3,6-di-tert-butyl-1,2-benzoquinone with a number of diols, including propane-1,3-diol, butane-1,4-diol, di-, and triethylene glycols,
and cyclohexane-1,4-diyldimethanol, was studied. Nine new 4-alkoxy-3,6-di-tert-butyl-1,2-benzoquinones were synthesized, four of which were bis-1,2-benzoquinones with different tethers (6–13 atoms) between
the quinone fragments. Depending on the length of the chain between the hydroxy groups in glycols, bicyclic 4,5-disubstituted
3,6-di-tert-butyl-1,2-benzoquinones were formed or their stepwise alkoxylation occurred. The newly synthesized o-benzoquinone derivatives can be reduced with alkali metals to give radical anions and converted into semiquinone chelates
with manganese carbonyl. 相似文献
64.
Yu. N. Bubnov A. Yu. Zykov I. V. Zhun A. V. Ignatenko 《Russian Chemical Bulletin》1996,45(11):2598-2601
An original method was developed for the synthesis of functional derivatives of triallylmethane (CH2=CH-CH2)3C-X (X = OH, NH2, or SCOPh) based on reactions of triallylborane with the corresponding derivatives of carbonic acid (ethylene carbonate, diethylcyanamide, and 0,S-dimethyidithio carbonate) at 110–120 °C.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp 2739–2742, November, 1996. 相似文献
65.
66.
Using secondary electron emission (SEE) techniques, conditions for the traveling of electrons near a charged surface were studied. A simple analytical expression was found to relate the effective coefficient of secondary electron emission from the charged surface of an organic liquid layer with the primary-electron current. At low currents, the relationship is close to a root law, the pattern of the dependence does not change with the varying conductivity of the liquid, its thickness, and the charge spot area. This finding suggests that the effective secondary electron emission coefficient and, hence, the conditions of electron motion near a surface charge depend on the only parameter, the current density of incident electrons. According to the estimates of the dielectric permittivity of a liquid, its resistivity, and ion mobility, the effective SEE coefficient at low charging currents is formed in the ohmic mode of current flow through the liquid. 相似文献
67.
Yan Z. Voloshin Oleg A. Varzatskii Larisa G. Tomilova Marya O. Breusova Tatiana V. Magdesieva Yurii N. Bubnov Roland Krämer 《Polyhedron》2007
Ditopic oximehydrazonate iron(II) phthalocyaninoclathrochelates were synthesized by a transmetallation (a capping group exchange) reaction of the initial labile triethylantimony-capped clathrochelate iron(II) oximehydrazonates with lutetium(III) phthalocyanine as a Lewis acid. The complexes obtained were characterized using elemental analysis, PD and MALDI-TOF mass spectrometries, IR, UV–Vis, 57Fe Mössbauer, and 1H, 13C{1H} NMR spectroscopies. An encapsulated iron(II) ion was found to be in a low-spin state. The cyclic voltammograms show oxidation and reduction waves assignable to Fe2+/3+ couples of macrobicyclic framework and to phthalocyanine macrocycles. 相似文献
68.
69.
70.