全文获取类型
收费全文 | 472篇 |
免费 | 0篇 |
专业分类
化学 | 359篇 |
晶体学 | 4篇 |
力学 | 5篇 |
数学 | 18篇 |
物理学 | 86篇 |
出版年
2021年 | 10篇 |
2020年 | 5篇 |
2019年 | 14篇 |
2018年 | 18篇 |
2017年 | 16篇 |
2016年 | 15篇 |
2014年 | 12篇 |
2013年 | 20篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 27篇 |
2007年 | 22篇 |
2006年 | 27篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 21篇 |
2002年 | 24篇 |
2001年 | 20篇 |
2000年 | 3篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1994年 | 5篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1963年 | 3篇 |
排序方式: 共有472条查询结果,搜索用时 234 毫秒
1.
Doklady Mathematics - A one-parameter family of global solutions of a two-dimensional hyperbolic differential-difference equation with an operator acting with respect to a space variable is... 相似文献
2.
Kirill V. Zaitsev Yulia A. Piskun Yuri F. Oprunenko Sergey S. Karlov Galina S. Zaitseva Irina V. Vasilenko Andrei V. Churakov Sergei V. Kostjuk 《Journal of polymer science. Part A, Polymer chemistry》2014,52(9):1237-1250
The aluminum complexes containing two iminophenolate ligands of the type (p‐XC6H4NCHC6H4O‐o)2AlR' (R′=Me ( 3, 4 ) or R′=O(CH2)4OCH=CH2 ( 5, 6 ), X=H ( 3, 5 ), F( 4, 6 )) were synthesized and characterized by 1H, 13C NMR spectroscopy, and X‐ray crystallography. The reaction of AlMe3 with two equivalents of substituted iminophenols gave five‐coordinated {ONR}2AlMe ( 3, 4 ) complexes. Subsequent reaction of these methyl complexes with unsaturated alcohol, HO(CH2)4OCH=CH2, resulted in target compounds 5 and 6 in a good yield. It was shown that the complexes ( 3 ‐ 6 ) are monomeric in solution (NMR) and in solid state (X‐ray analysis). The catalytic activity of the complexes 5 and 6 towards ring‐opening polymerization (ROP) of ?‐caprolactone and d,l ‐lactide was assessed. Complex 5 showed higher activity as compared with 6 , while both of these catalysts induced controlled homo‐ and copolymerization to afford the macromonomers with high content of vinyl ether end groups (Fn > 80%) in a broad range of molecular weights (Mn = 4000–30,000 g mol?1) with relatively narrow MWD (Mw/Mn = 1.1–1.5). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1237–1250 相似文献
3.
V. V. Lemanov V. K. Yarmarkin V. M. Egorov G. A. Pankova N. V. Zaitseva L. A. Markova 《Physics of the Solid State》2012,54(2):346-349
It has been shown that the phase transitions observed at temperatures of about 250 K in crystals of protein amino acids and
of their compounds grown from water solutions are related to drops of these solutions trapped by crystals in their growth. 相似文献
4.
H. T. Hoang A. A. Sertsova S. I. Marakulin E. N. Subcheva M. P. Zaitseva E. V. Yurtov 《Russian Journal of Inorganic Chemistry》2018,63(11):1414-1418
MgO@SiO2 core–shell nanoparticles were manufactured, and a synthetic protocol was developed to prepare MgO nanoparticles where the SiO2 shell thickness was less than 10 nm. The influence of synthesis parameters on the formation of MgO@SiO2 nanoparticles was studied. The fact of a SiO2 shell being formed on the MgO surface was established and the sizes of the thus-prepared MgO@SiO2 nanoparticles were determined by TEM and Fourier-transform IR spectroscopy. 相似文献
5.
N. A. Zaitseva V. V. Goidin V. V. Molchanov V. V. Chesnokov R. A. Buyanov V. A. Utkin 《Kinetics and Catalysis》2011,52(5):770-773
In order to extend the area of application of the base catalytic system metal-filamentous carbon, the catalytic properties
of Ni-filamentous carbon catalysts have been tested in the hydrogenation of aromatic compounds (benzene, benzyl cyanide, benzophenone,
and nitrobenzene). The selectivity of the catalysts depends on the outer faceting of the active metal particles. The benzene
ring is hydrogenated on the (111) face of the metal nanoparticles, whereas the selective hydrogenation of functional groups
in substituted aromatic compounds occurs on the surface of active component nanoparticles in which the (111) face is blocked. 相似文献
6.
G. V. Girichev V. V. Rybkin V. V. Tyunina A. V. Krasnov N. V. Tverdova N. P. Kuz’mina I. G. Zaitseva 《Russian Journal of Inorganic Chemistry》2011,56(1):99-103
A mass spectrometric study of the saturated vapor over ytterbium tris(hexafluoroacetylacetonate) Yb(hfa)3 (hfa = CF3-C(O)-CH-C(O)-CF3) and of the vapor overheated up to the thermal decomposition temperature of the complex is presented. The vapor composition
changes markedly with increasing temperature. At T ≈ 370 K, the mass spectrum of the vapor over Yb(hfa)3 indicates the presence of ions containing one to three metal atoms. As the temperature is raised, the ion currents due to
oligomer ions decrease. The oligomers are not detected at T > 440 K. The total decomposition temperature of Yb(hfa)3 is 663(9) K. The second-law enthalpy of sublimation (ΔH
so (380 K)) is 134 ± 7 kJ/mol for the monomer and 138 ± 10 kJ/mol for the dimer. The enthalpy of dissociation of the dimer into
monomer molecules is nearly equal to the enthalpy of sublimation of the monomer and dimer: ΔH
dis(380 K) = 130 ± 15 kJ/mol. 相似文献
7.
T. G. Tyurina O. M. Zarechnaya V. V. Zaitseva S. Yu. Zaitsev 《Russian Journal of General Chemistry》2020,90(5):773-781
Spectrophotometry studies have shown that N-vinylpyrrolidone and/or maleic anhydride interact with 2,2-diphenyl-1-picrylhydrazyl radical in a solution. Thermochemical parameters of the most probable reactions involving these compounds have been estimated by means of the PM6 and B3LYP/6-31+G(d) (gas phase) density functional theory methods. It has been suggested that the stable radical is attached to the monomer molecule, the resulting radical being involved in the chain growth reactions. Termination via the oligomeric radicals recombination is the most probable. 相似文献
8.
T. N. Lomova M. E. Klyueva E. G. Mozhzhukhina E. Yu. Tyulyaeva N. G. Bichan S. V. Zaitseva S. A. Zdanovich 《Journal of Structural Chemistry》2014,55(1):180-190
A new form of MP...H solv + metalloporphyrins is found and studied in the strong acid medium, the conditions of its formation and the qualitative reaction of its determination are established. It is shown that the same form has the H4TPP2+ dication (TPP is the 5,10,15,20-tetraphenyl-21H,23H-porphyrine dianion). The stability in different acid media and in the isolated state, spectral properties and the structure of H+-associates of porphyrins are analyzed in detail by UV-visible and 1H NMR spectroscopy and quantum chemical calculations. It is shown that they have a unique two-band visible electronic spectrum with the bands near 540 nm and 700 nm, which weakly depend on the type of the central atom in the complex and noticeably change when the chromophore is functionally substituted. The proton location the ion-molecular associate and the cases of the formation of H+-associates with higher stoichiometry are revealed. 相似文献
9.
F. M. Fomin K. S. Zaitseva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(3):466-470
A new effect was recorded during the studies of the mechanism of ferrocene oxidation with hydrogen peroxide, namely, a shift of λmax of the absorption band of the ferricinium cation (ABFC) toward the long-wave region and its broadening during the reaction. The shiftΔλmax increased with the excess of the H2O2 concentration with respect to the ferrocene concentration and reached 90 nm and more at H2O2/Fc ≈ 80–100. Similar changes in ABFC took place during the oxidation of a series of ferrocene derivatives. A shift of ABFC was not revealed at comparable concentrations of the metal complex and H2O2. During the oxidation of ferrocene with other peroxides (t-C4H9OOH or (PhCOO)2), there were no changes in the spectrum of the ferricinium cation at any ratios of reagent concentrations. The observed effect is based on the formation of a {ferricinium cation + .OH} radical pair during the primary interaction of the metallocomplex with H2O2 and subsequent reaction between the radicals of the radical pair according to the radical substitution mechanism, which leads to the formation of the hydroxy derivatives of ferrocene and their cations. Sequential accumulation of OH substituents in the metallocomplex and the corresponding ferricinium cations caused a continuous shift of ABFC toward the long-wave region. 相似文献
10.
E. Kh. Lermontova A. V. Churakov M. Quan Yu. F. Oprunenko S. S. Karlov G. S. Zaitseva 《Russian Journal of Inorganic Chemistry》2009,54(2):211-218
The reaction of dialkanolamines RN(CH2CH2O)(CHR’CHR’OH) (R = Me, Ph, PhCH2; R’ = H, Ph) with tetraethoxygermane gives either 2,2-diethoxy-1,3,6,2-dioxazagermocanes RN(CH2CH2O)(CHR’CHR’O)Ge(OEt)2 or 1,7,9,15-tetraoxa-4,12-diaza-8-germaspiro[7.7]pentadecanes [RN(CH2CH2O) (CHR’CHR’O)]2Ge depending on the reactant ratio. The chemical behavior of the obtained compounds in substitution reactions at germanium was studied. The product structure was confirmed by elemental analysis data and 1H, 13C, and 19F NMR spectroscopy. The cyclotrigermanoxane [MeN(CH2CH2O)2GeO]3 was studied by X-ray diffraction. 相似文献