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1.
Tertiary N-ethylamines were converted into amide derivatives by reactions with sulfur monochloride and DABCO at 0 °C. Depending on the
nature of the substituents in the amine, the reaction can be accompanied by unexpected transformations.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1135–1140, June, 2007. 相似文献
2.
Z. S. Klemenkova B. V. Lokshin L. I. Strunkina M. Kh. Minacheva 《Russian Chemical Bulletin》1994,43(9):1516-1521
Raman and IR spectra (4000-50 cm–1) of solid cyclopentadienyl zirconium and hafnium hydrides Cp2MH2, Cp2MD2, Cp2Zr(H)X, and Cp2Zr(D)X (Cp = 5-C5H5; M = Zr, Hf; X = Cl, Br) have been studied. The vibrational modes of MH groups, Cp-rings, and metal-ligand bonds are discussed and the band assignments are proposed. In the solid state, these complexes form polymers with linear hydride bridges of the M-H-M type. The force constants of the M-H and M-Cp bonds increase on going from Zr to Hf.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1604–1609, September, 1994. 相似文献
3.
B. G. Bazarov R. F. Klevtsova A. D. Tsyrendorzhieva L. A. Glinaskaya Zh. G. Bazarova 《Journal of Structural Chemistry》2004,45(6):993-998
Physicochemical analysis (XRPA, DTA) was used to study phase equilibria in a ternary salt system Rb2MoO4-Fe2(MoO4)3-Hf(MoO4)2 in the subsolidus region. Ternary molybdates with compositions 5:1:3, 5:1:2, and 1:1:1 have been found and synthesized. Crystal and thermal characteristics have been determined. Single crystals of the ternary molybdate Rb5FeHf(MoO4)6 with a composition of 5:1:2 were grown. The crystal structure of the compound was solved using X-ray diffractometry (CAD-4 automatic diffractometer, MoK
α radiation, 1766 F(hkl), R = 0.0298). Hexagonal crystals with unit cell dimensions: a = b = 10.124(1) Å, c =15.135(3) Å, V = 1343.4(4) Å3, Z = 2, ρcalc = 4.008 g/cm3, space group P63. The mixed three-dimensional framework of the structure is formed from two sorts of MoO4 tetrahedra and Fe and Hf octahedra linked through their common O-vertices. Rubidium atoms of three varieties occupy the large voids of the framework.Original Russian Text Copyright © 2004 by B. G. Bazarov, R. F. Klevtsova, A. D. Tsyrendorzhieva, L. A. Glinaskaya, and Zh. G. Bazarova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1038–1043, November–December, 2004. 相似文献
4.
Synthesis and X-ray structural study of octa-coordinated hexafluoroacetylacetone hafnium(IV) complex
K. V. Zherikova N. B. Morozova I. A. Baidina V. I. Alekseev I. K. Igumenov 《Journal of Structural Chemistry》2006,47(1):82-86
Hexafluoroacetylacetonate hafnium(IV) complex has been synthesized and studied by X-ray structural analysis. Crystal data for C30H8F36Hf2O14 are: a = 12.957(3) Å, b = 16.687(3) Å, c = 12.398(3) Å, β = 108.97°, space group P21/c, Z = 2, d calc = 2.137 g/cm3, R = 0.047. The molecular structure is built from discrete binuclear molecules of Hf2(OH)2(hfac)6 composition; the Hf...Hf distance in dimer is 3.533 Å. The structural units are connected by van der Waals interactions in the crystal. 相似文献
5.
Marina Lulla Jelena Asari Jaan Aarik Kaupo Kukli Raul Rammula Unto Tapper Eero Kauppinen Väino Sammelselg 《Mikrochimica acta》2006,155(1-2):195-198
Quantitative electron probe microanalysis of highly insulating materials is a complicated problem, partially solved by coating
samples with grounded thin conductive layers or using novel scanning electron microscopy (SEM) techniques, such as low-voltage
and/or variable pressure SEM. In this work, some problems of quantitative X-ray microanalysis of thin HfO2 films, in particular the possibility to determine mass thickness correlated to the density of the layer material, are discussed.
For comparison, Al2O3, Ta2O5 and TiO2 films grown onto both semiconductive Si and insulating quartz substrates were also analysed. All the films studied were synthesized
by atomic layer deposition method. 相似文献
6.
The triplet nature of rare long-lived states of d0 metallocenes formed upon ligand-to-metal energy transfer was confirmed by studies of triplet-triplet charge transfer in biscyclopentadienyl
complexes Cp2MCl2 (M = Zr (1), Hf (2)). The interaction between precatalysts and substrates of catalytic polymerization systems, viz., complexes 1 and 2 and unsaturated hydrocarbons (alkenes and dienes), was studied in the region of concentrations close to catalytic values.
For organometallic π-complexes, it has been shown for the first time that, in the case of the unsaturated hydrocarbons, the
efficiency of energy transfer obeys the Perrin equation. The process occurs at distances R
0 close to the diameter of the interacting molecules and is well described by the exchange-resonant mechanism of interaction.
In the case of the cyclopentadiene-Cp2MCl2 (M = Zr, Hf) systems, R
0 = 14.6 Å. A linear relationship between the critical radius of the quenching sphere R
0 and the number of carbon atoms in a linear α-olefin has been revealed for the first time and evidences the formation of a
π-complex between the precatalyst and substrate molecules.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 35–39, January, 2007. 相似文献
7.
Dale F Shellhamer David C Gleason Andrew J Ryan Victor L Heasley 《Journal of fluorine chemistry》2003,123(2):171-176
Ionic and photochemical reaction of chlorine (Cl2), bromine (Br2) and iodine monochloride (ICl) to hexafluoro-1,3-butadiene (1) and 1,3-butadiene (2) were carried out under conditions that would provide product distributions under controlled ionic or free-radical conditions. Product distributions for ionic reaction of Cl2 and Br2 with 1 are similar and suggest a weakly-bridged halonium ion species. Theoretical calculations support weakly-bridged chloronium and bromonium ions for both dienes 1 and 2. There are more of the 1,4-dihalo-2-butene products from ionic halogenation of 1 than 2 which correlates with the greater charge density on carbon-4 of halonium ions from 1. Ionic and free-radical reactions of ICl with 1 give 8 and 2% of 3-chloro-4-iodohexafluoro-1-butene and 4-chloro-3-iodohexafluoro-1-butene, respectively. The minor cis-1,4-dihalo-2-butene products from 1 and 2 are reported when formed. 相似文献
8.
Ling-Tian Tang Yu Wei Yi Wang Shao-Wen Hu Xin-Qi Liu Tai-Wei Chu Xiang-Yun Wang 《Journal of Molecular Structure》2004,686(1-3):25-30
The formation of charge-transfer (CT) complexes between N-methyl-6,7-methylenedioxy-tetrahydro-4-isoquinolone (MMDTIQ, the model molecule of alkaloids) and iodine monochloride has been studied with the density functional B3LYP method. The competition for ICl between n-donor(s) and π-donor in the same molecule has been compared for the first time. The results indicate that the electron-donating ability of various donor sites decreases in the following order: amino nitrogen>carbonyl oxygen>etheric oxygen≈aromatic ring. Complexes with a stoichiometry of 1:1 to 1:5 (MMDTIQ–ICl) might form. Among complexes with a given stoichiometry, the one in which the phenyl ring is involved in the binding is always the least stable. According to these results, in order to ensure an alkaloid iodinated, the amount of ICl should be far beyond that of alkaloids and a low polar solvent should be used, which is quite in agreement with our recent experimental results. 相似文献
9.
B. G. Bazarov R. F. Klevtsova A. E. Sarapulova K. N. Fedorov L. A. Glinskaya Zh. G. Bazarova 《Journal of Structural Chemistry》2005,46(4):756-760
Single crystals of triple molybdate of composition 5:1:3 K5Pb0.5Hf1.5(MoO4)6 have been grown and their crystal structure has been solved from X-ray diffraction data (an automated diffractometer X8 APEX, MoK α -radiation, 2173 F(hkl), R = 0.0321). Trigonal unit cell parameters are: a = b = 10.739(2) Å, c = 37.933(9) Å; V = 3789(1) Å3, Z = 6, ρcalc = 4.014 g/cm3, space group \(R\bar 3\). Three-dimensional mixed framework of the structure is formed by two types of MoO4 tetrahedra and Pb and Hf octahedra linking via common O-vertices. Potassium atoms of three types occupy large vacancies in the framework. 相似文献
10.
Helmut G. Alt 《Russian Chemical Bulletin》1995,44(1):1-8
Ansa metallocene dichloride complexes of titanium, zirconium, and hafnium can be activated by methyl aluminoxane (MAO) to give excellent catalysts for the homogeneous polymerization of ethylene and propylene. The symmetry of the corresponding metaliocene dichloride complexes is essential for the stereospecific polymerization of propylene (isotactic, syndiotactic or atactic). The application of fluorenyl groups instead of cyclopentadienyl groups greatly increases the activity of the catalysts. The first ansa bis(fluorenyl) complexes of zirconium and hafnium, (C13H8-C2H4-C13Hs)MCl2 (M = Zr, Hf), have been prepared. It was found that after the activation by MAO the zirconium derivative demonstrates a very high activity. Several model complexes are presented in order to discuss the mechanism of the polymerization.This paper was presented at the INEOS-94 Workshop The Modern Problems of Organometallic Chemistry (Moscow, May 21–27, 1994).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 7–14, January, 1995. 相似文献