全文获取类型
收费全文 | 263篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 150篇 |
晶体学 | 3篇 |
力学 | 2篇 |
数学 | 11篇 |
物理学 | 102篇 |
出版年
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 10篇 |
2011年 | 24篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 15篇 |
2007年 | 10篇 |
2006年 | 18篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 10篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1975年 | 1篇 |
1974年 | 3篇 |
排序方式: 共有268条查询结果,搜索用时 0 毫秒
51.
Eugene V. Tretyakov Svyatoslav E. TolstikovElena V. Gorelik Matvey V. FedinGalina V. Romanenko Artem S. BogomyakovVictor I. Ovcharenko 《Polyhedron》2008
It was established that the reactions of pyrazol-3-yl-substituted nitronyl nitroxide (HL1) and pyrazol-3-yl-substituted imino nitroxide (HL3) with Cu(II) acetate lead to self-assembly of the Cu4(OH)2(OAc)4(DMF)2(L1)2 tetranuclear and Cu2(OAc)2(H2O)2(L3)2 dinuclear complexes, respectively. The reaction of Cu(II) acetate with 5-ethoxycarbonyl-pyrazol-3-yl-substituted nitronyl nitroxide (HL2) gave unexpected solid Cu2(H2O)2(L6)2 · 2DMF, in which L6 is a deprotonated 5-carboxy-pyrazol-3-yl-substituted nitronyl nitroxide, formed as a result of cleavage of an ester bond in the starting HL2. A similar transformation of the paramagnetic ligand was observed in the reaction of Cu(II) acetate with 5-ethoxycarbonyl-pyrazol-3-yl-substituted imino nitroxide (HL4). It led to the formation of Cu2(DMF)2(L7)2, where L7 is deprotonated 2-(5-carboxy-1H-pyrazol-3-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide. An X-ray diffraction study indicated that in Cu4(OH)2(OAc)4(DMF)2(L1)2 and Cu2(OAc)2(H2O)2(L3)2, the L1 and L3 paramagnetic ligands perform the bridging cyclic tridentate function, while in Cu2(H2O)2(L6)2 · 2DMF and Cu2(DMF)2(L7)2, the paramagnetic L6 and diamagnetic L7 are bridging bicyclic tetradentate ligands. The magnetic behavior of complexes with coordinated nitronyl nitroxide – Cu4(OH)2(OAc)4(DMF)2(L1)2 and Cu2(H2O)2(L6)2 · 2DMF is dictated by the dominant antiferromagnetic exchange interactions, which is confirmed by quantum-chemical data. The magnetic susceptibility of Cu2(OAc)2(H2O)2(L3)2 reflects the competition between the antiferromagnetic and ferromagnetic components, of which the latter is due to electron coupling in the Cu(II) ← N=C–N ? O exchange channels. EPR data confirm the results received from static magnetic measurements for multispin solids. 相似文献
52.
53.
In the present paper, we report the results of an experimental study of the interaction region of a planar compression shock
produced by a wedge in stream with the wake formed behind a cocurrent gas jet (H2, air, or Ar) injected into the flow. Depending on the gas jet parameters, three modes of interaction could be distinguished:
a strong interaction, observed when the flow velocity in the wake was subsonic; a moderate interaction, observed when a subsonic
flow region, bounded by a shock of almost conical shape, formed in the vicinity of the compression shock; and a neutral interaction.
Three-dimensional non-stationary Euler equations were solved to numerically examine the interaction of an axisymmetric jet
with an oblique shock wave. The obtained interaction regimes were found to be in a reasonable agreement with experimental
data. 相似文献
54.
V. K. Chaikovskii T. S. Kharlova E. V. Tretyakov S. F. Vasilevsky V. D. Filimonov 《Russian Chemical Bulletin》2000,49(8):1475-1477
The reagent obtained from iodine monochloride and silver sulfate in sulfuric acid easily iodinates I-methyl-3-nitropyrazole
under mild conditions to give 4-iodo or 4,5-diiodo derivatives, 1-Methyl-4-nitropyrazole was also directly iodinated with
this reagent for the first time.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1482–1484, August, 2000. 相似文献
55.
Temperature dependence of pressure broadening of the N = 1− fine structure oxygen line at 118.75 GHz
M.Yu. Tretyakov M.A. Koshelev I.A. Koval V.V. Parshin L.M. Kukin L.I. Fedoseev Yu.A. Dryagin A.F. Andriyanov 《Journal of Molecular Spectroscopy》2007,241(1):109-111
The absorption profile of the N = 1− fine structure line of oxygen was recorded by a resonator spectrometer at a frequency range of 110-130 GHz at atmospheric pressure and different temperatures ranging from −21 °C up to +22 °C. Analysis of the observed line shape allowed determination of the temperature dependence of the line pressure broadening. The measured value of the temperature exponent is n = 0.74(5) for self-broadening. Consistency of the measurements is supported by simultaneous measurements of the line intensity, the line mixing parameter and the line center frequency, and by comparison of obtained values with previously known data. 相似文献
56.
Amelin V. G. Shogah Z. A. C. Bolshakov D. S. Tretyakov A. V. 《Journal of Applied Spectroscopy》2022,89(1):75-83
Journal of Applied Spectroscopy - A combined approach was developed for the identification and determination of quinolone antibiotics in pharmaceuticals using solid-state fluorescence digital... 相似文献
57.
Yu.D. Tretyakov V.V. Sorokin A.R. Kaul A.P. Erastova 《Journal of solid state chemistry》1976,18(3):253-261
In the present work it is shown that in the CeFeO system only one ternary compound with a perovskite structure, the orthoferrite CeFeO3, is formed. We define the crystallographic properties of cerium ferroperovskite more accurately. The thermodynamics of its oxidation and reduction over a temperature range of 900–1200°C are studied using the emf method with a solid electrolyte.It is shown that the free energy of cerium orthoferrite formation from the oxides according to the reaction , derived from data on the equilibrium oxidation of CeFeO3, differs very little from the value of ΔG°, calculated from the magnitude of the equilibrium pressure of oxygen over the orthoferrite and reduction products coexisting with it.Phase equilibria and the thermodynamics of coexisting phases in the CeFeO system have been investigated. Equilibrium diagrams are constructed which define the character of the changes taking place in the CeFeO system during changes in partial oxygen pressure, temperature, and composition of the initial oxide mixture. Thus, we have equilibrium diagrams of the type PO2 = f(composition) with T = constant; with one composition parameter fixed; and T = f(composition) with PO2 = constant. 相似文献
58.
59.
Yu. D. Tretyakov 《Russian Journal of Inorganic Chemistry》2010,55(11):1690-1693
The major milestones in the pedagogic activity of N.S. Kurnakov are listed. The characteristic properties of his teaching
activity, his approaches, methods, and his principal ideas as regards the organization of teaching chemistry at a higher school
are presented with attracting the memoirs of his disciplines and associated. 相似文献
60.
Inui N Kakuno H Tretyakov AY Komatsu G Kameoka K 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,59(6):6513-6516
We study the percolation properties of a random diode network (RDN) which contains two kinds of directed bonds on a square lattice. This network is a special case of the random insulation-resistor-diode network. Both Monte Carlo simulations and series expansion for the percolation probability show that an estimated critical exponent, beta=0.1794+/-0.008, is different from known values for a conventional insulation-resistor-diode network. RDN belongs to neither the isotropic percolation universality class nor to the directed percolation universality, which we attribute to a difference of symmetry breakdown around the critical point. 相似文献