全文获取类型
收费全文 | 362篇 |
免费 | 2篇 |
专业分类
化学 | 178篇 |
晶体学 | 2篇 |
力学 | 43篇 |
数学 | 58篇 |
物理学 | 83篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 10篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 19篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 20篇 |
2008年 | 7篇 |
2007年 | 14篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 13篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 9篇 |
1993年 | 5篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1970年 | 4篇 |
1968年 | 3篇 |
1967年 | 4篇 |
1966年 | 2篇 |
排序方式: 共有364条查询结果,搜索用时 31 毫秒
41.
The natural convection of fresh water in a square cell is considered at a temperature close to the density inversion temperature for Grashof numbers 2.9 · 104 Gr 106. As a result of the numerical investigation, one steady-state and three self-oscillating regimes are found in addition to the three steady-state flows previously detected earlier and described for low Grashof numbers ( 0 Gr 2 · 105). The basic characteristics of the unsteady flows are analyzed by means of the Fourier method, the fundamental oscillation frequencies are found, and the flow evolution and the variation of the oscillation characteristics with increase in the Gr number are considered. 相似文献
42.
43.
V. A. Pal’chikov S. Yu. Mykolenko A. N. Pugach F. I. Zubkov 《Russian Journal of Organic Chemistry》2017,53(5):656-662
Composition of aminolysis products of phenyl glycidyl ether with benzylamine in various conditions was studied. The ratio of 1-(benzylamino)-3-phenoxypropan-2-ol and 1,1'-(benzylazanediyl)bis(3-phenoxypropan-2-ol) does not considerably depend on the nature of the solvent and is basically determined by ratio of initial reagents. 2,6-Bis(phenoxymethyl)morpholine was obtained by dehydration of aminodiol in conditions of Mitsunobu reaction with subsequent reductive debenzylation. 相似文献
44.
45.
M. D. Anokhin Yu. A. Vinogradov A. I. Zubkov B. E. Lyagushin Yu. A. Panov 《Fluid Dynamics》1998,33(2):186-189
The three-dimensional shape of the shock wave formed ahead of a sonic jet flowing out into a supersonic flow through the surface
of a sharp cone is determined. The shape of the wave in the longitudinal and transverse cross-sections of the model is constructed
using schlieren photographs taken for various angles of rotation and freestream Mach numbers M=1.75–3.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 41–44, March–April, 1998.
This research was carried out with financial support from the Russian Foundation for Basic Research (project No. 95-01-00709a). 相似文献
46.
A. P. Tyutyunnik V. N. Krasil’nikov I. F. Berger V. G. Zubkov L. A. Perelyaeva I. V. Baklanova 《Russian Journal of Inorganic Chemistry》2011,56(8):1168-1177
The vanadium(V) complexes K[VO2(SeO4)(H2O)] and K[VO2(SeO4)(H2O)2] · H2O were synthesized using original procedures; their physicochemical properties were studied, and the crystal structure was
determined on the basis of X-ray diffraction and neutron diffraction data. The structure of K[VO2(SeO4)(H2O)2] · H2O is composed of VO6 octahedra connected to form infinite chains by bridging SeO4 tetrahedra. Each VO6 tetrahedron has short terminal V-O bonds forming the bent dioxovanadium group VO2+ The unit cell parameters of K[VO2(SeO4)(H2O)2] · H2O are a = 6.4045(1) ?, b = 9.9721(2) ?, c = 6.6104(1) ?, β = 107.183(1)°, V = 403.34 ?3, Z = 2, monoclinic system, space group P21. The complex K[VO2(SeO4)(H2O)] forms a two-dimensional layered structure composed of highly distorted VO6 octahedra having two short terminal V-O bonds and SeO4 groups coordinated simultaneously by three vanadium atoms. This compound crystallizes in the monoclinic system (space group
P21/c): a = 7.3783(1) ?, b = 10.5550(2) ?, c = 10.3460(2) ?, β = 131.625(1)°, V = 602.894(5) ?3, Z= 4. The vibrational spectra of the studied compounds are fully consistent with their structural features. 相似文献
47.
48.
The supersonic air flow structure and the pressure distribution in the vicinity of a vertical cylinder suspended over the surface of a plate with a turbulent boundary layer are studied experimentally. The effects of the free-stream Mach number and the width of the clearance between the cylinder base and the surface on the dimensions of the separated flow region and the pressure distribution in the latter are examined. 相似文献
49.
M. V. Ryzhkov D. L. Novikov V. G. Zubkov V. A. Gubanov 《Journal of Structural Chemistry》1989,30(5):713-716
The cluster method of discrete variation was used to study compounds containing chains of plane-coordinated copper ions separating oxygen-copper planes. We also examined real YBa2Cu3O7 and hypothetical MBa3Cu4O9 systems (M is a tetravalent metal ion). A study was carried out on the transformation of the valence band and structure of the molecular orbitals in the Fermi level in going from YBa2Cu3O7 to MBa3Cu4O9. The chemical bonding was analyzed and the role of the interchain interaction in the bonding of the copper and oxygen atoms in different crystallographic positions was determined.Institute of Chemistry, Urals Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 5, pp. 17–20, September–October, 1989. 相似文献
50.
The thermodynamic states of two systems of impact polystyrene based on polybutadiene-styrene rubbers are investigated, without introducing spectrography, in terms of the theory of linear viscoelasticity. The results are confirmed by the considerable difference in physicomechanical properties.Ukrainian Scientific-Research Institute of Plastics, Donetsk. Translated from Mekhanika Polimerov, Vol. 4, No. 4, pp. 595–597, July–August, 1968. 相似文献