全文获取类型
收费全文 | 375篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 196篇 |
力学 | 16篇 |
数学 | 56篇 |
物理学 | 112篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 15篇 |
2012年 | 18篇 |
2011年 | 12篇 |
2010年 | 19篇 |
2009年 | 19篇 |
2008年 | 15篇 |
2007年 | 20篇 |
2006年 | 14篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 4篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 16篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1968年 | 5篇 |
1967年 | 2篇 |
排序方式: 共有380条查询结果,搜索用时 109 毫秒
11.
A. I. Kharlamov Yu. D. Pankratiev N. D. Lemeshko E. M. Malyshev 《Reaction Kinetics and Catalysis Letters》1981,17(3-4):311-314
Adsorption heats of hydrogen, oxygen and carbon monoxide on titanium nitrides have been measured calorimetrically in the temperature range from 473 to 673 K. With increasing Me/N ratio, the adsorption heat of oxygen grows.
, 473–673 . Me/N.相似文献
12.
13.
14.
Mohammad Aghazadeh Meshgi Alexander Pcheim Judith Baumgartner Viatcheslav V. Jouikov Christoph Marschner 《Molecules (Basel, Switzerland)》2021,26(1)
A number of mono- and dioligosilanylated silocanes were prepared. Compounds included silocanes with 1-methyl-1-tris(trimethylsilyl)silyl, 1,1-bis[tris(trimethylsilyl)silyl], and 1,1-bis[tris(trimethylsilyl)germyl] substitution pattern as well as two examples where the silocane silicon atom is part of a cyclosilane or oxacyclosilane ring. The mono-tris(trimethylsilyl)silylated compound could be converted to the respective silocanylbis(trimethylsilyl)silanides by reaction with KOtBu and in similar reactions the cyclosilanes were transformed to oligosilane-1,3-diides. However, the reaction of the 1,1-bis[tris(trimethylsilyl)silylated] silocane with two equivalents of KOtBu leads to the replacement of one tris(trimethylsilyl)silyl unit with a tert-butoxy substituent followed by silanide formation via KOtBu attack at one of the SiMe3 units of remaining tris(trimethylsilyl)silyl group. For none of the silylated silocanes, signs of hypercoordinative interaction between the nitrogen and silicon silocane atoms were detected either in the solid state. by single crystal XRD analysis, nor in solution by 29Si-NMR spectroscopy. This was further confirmed by cyclic voltammetry and a DFT study, which demonstrated that the N-Si distance in silocanes is not only dependent on the energy of a potential N-Si interaction, but also on steric factors and through-space interactions of the neighboring groups at Si and N, imposing the orientation of the pz(N) orbital relative to the N-Si-X axis. 相似文献
15.
16.
A. T. Gubaidullin V. N. Nabiullin S. V. Kharlamov B. I. Buzykin 《Russian Journal of General Chemistry》2014,84(6):1157-1178
5-Methyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one exists as zwitterion with a proton localized on the nitrogen atom of the piperidine ring and negative charge delocalized over the pyrazololate fragment. The compound is stable in crystal but ustable in solution. Its chromatographic purification and attempts to recrystallize or synthesize by condensation of phenylhydrazine with alkyl 1-methyl-4-oxopiperidin-3-carboxylate on heating in alcohols or benzene lead to the formation of a complex mixture of products. Among these products, we isolated and identified 3a,3a′-methylenebis(5-methyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one), 1-methyl-3-(2-phenylhydrazinylidene)pyrrolidin-2-one, and 5-methyl-2-phenyl-3,5,6,7-tetrahydro-2H-pyrazolo[4,3-c]pyridine. The structure of methyl 3-(2-phenylhydrazinylidene)-4,5-dihydro-3H-pyrrole-2-carboxylate and 3a,5-dimethyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one was proved by NMR spectroscopy. 3a,5-Dimethyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one was isolated as hydrochloride hydrate whose structure was determined by X-ray analysis. 相似文献
17.
V. S. Kharlamov D. V. Kulikov Yu. V. Trushin P. Nader P. Mazri Th. Stauden J. Pezoldt 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(2):241-244
Structures grown using the technique of molecular-beam epitaxy during deposition of carbon and/or germanium atoms on an Si(111)
surface were investigated experimentally and theoretically. Experimental profiles of in-depth component distribution were
obtained using SIMS-profiling, whereas a complex technique of computer simulation taking into account diffusion and ballistic
processes was applied for the calculated profiles. 相似文献
18.
M. P. Kharlamov 《Regular and Chaotic Dynamics》2009,14(6):621-634
We continue the analytical solution of the integrable system with two degrees of freedom arising as the generalization of
the 4th Appelrot class of motions of the Kowalevski top for the case of two constant force fields [Kharlamov, RCD, vol. 10,
no. 4]. The separated variables found in [Kharlamov, RCD, vol. 12, no. 3] are complex in the most part of the integral constants
plane. Here we present the real separating variables and obtain the algebraic expressions for the initial Euler-Poisson variables.
The finite algorithm of establishing the topology of regular integral manifolds is described. The article straightforwardly
refers to some formulas from [Kharlamov, RCD, vol. 12, no. 3]. 相似文献
19.
R. Stanoeva D. A. Artemenkov V. Bradnova S. Vokál L. A. Goncharova P. I. Zarubin I. G. Zarubina N. A. Kachalova A. D. Kovalenko D. O. Krivenkov A. I. Malakhov G. I. Orlova N. G. Peresadko N. G. Polukhina P. A. Rukoyatkin V. V. Rusakova M. Haiduc S. P. Kharlamov M. M. Chernyavsky T. V. Shchedrina 《Physics of Atomic Nuclei》2009,72(4):690-701
Experimental data on fragmentation channels in peripheral interactions of 8B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process 8B → 7Be + p and to estimate its cross section. Events of 10C peripheral dissociation that were observed in the same exposure are described. 相似文献
20.
Kharlamov A. I. Loytchenko S. V. Kirillova N. V. Fomenko V. V. 《Theoretical and Experimental Chemistry》2002,38(1):54-58
Study of the heterogeneous reaction of SiO2 with activated carbon fibers has shown that the heterophase reaction (SiO2 (gas), SiO (gas) + C) gave rise to polycrystalline fibers of - and -SiC, whereas the homophase reaction of SiO with CO on a Si cupel led to the growth of filament crystals of -SiC. In agreement with the proposed mechanism for the origin and growth of SiC crystals, the appearance of Si (l) on the surface of the product is connected to the exo-effect of the formation of silicon carbide. 相似文献