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71.
N. S. Polonik S. G. Polonik V. A. Denisenko O. P. Moiseenko V. F. Anufriev 《Russian Journal of Organic Chemistry》2011,47(7):1045-1049
Chlorination of 2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones with HCl-MnO2 in acetic acid gave a mixture of 7-chloro-2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones and 2,3,7-trichloro-2,3,6-trialkyl-1,2,3,4-tetrahydronaphthalene-1,4-diones,
the latter being formed via addition of the second chlorine molecule to monochloro derivatives. The reduction of 2,3,7-trichloro-2,3,6-trialkyl-1,2,3,4-tetrahydronaphthalene-1,4-diones
with sodium dithionite in alkaline medium resulted in the formation of 7-chloro-2,3,6-trialkyl-5,8-dihydroxy-1,4-naphthoquinones
in high yield. 相似文献
72.
Sergey A. Anufriev Akim V. Shmal’ko Kyrill Yu. Suponitsky Igor B. Sivaev 《Phosphorus, sulfur, and silicon and the related elements》2020,195(11):901-904
AbstractStructure of 3-ammonio derivative of nido-carborane 3-NH3-7,8-C2B9H11 was determined by single crystal X-ray diffraction. The isomeric 10-ammonio derivative 10-NH3-7,8-C2B9H11 was prepared by the treatment of the corresponding ethylnitrilium derivative 10-EtC≡N-7,8-C2B9H11 with hydrazine hydrate in acetonitrile. 相似文献
73.
The nucleophilic substitution of halogen by methoxy groups in 5,8-dihydroxy-2,3-dichloro-1,4-naphthoquinones effected by complex reagent KF-MeOH-Al2O3 is considerably accelerated in the presence of electron-donor solvents. 相似文献
74.
A. Ya. Yakubovskaya N. D. Pokhilo N. P. Mishchenko V. F. Anufriev 《Russian Chemical Bulletin》2007,56(4):819-822
2,3,5,8-Tetrahydroxy-1,4-naphthoquinone (spinazarin) and 6-ethyl-2,3,5,8-tetrahydroxy-1,4-naphthoquinone (ethylspinazarin)
were first isolated from the sea urchin Scaphechinus mirabilis. The structures of spinazarins were established based on analysis of spectroscopic data. A preparative synthetic route to
ethylspinazarin was proposed.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 788–791, April, 2007. 相似文献
75.
76.
N. D. Pokhilo V. A. Denisenko V. F. Anufriev 《Russian Journal of Organic Chemistry》2014,50(5):647-653
Transetherification of naphthazarin methoxy derivatives in basic conditions occurs only with primary monohydric alcohols. 1,3-Butanediol due to the assistance of the hydroxy group at the C1 atom gives rise to a mixture of transetherification products at the primary and secondary hydroxy groups in a ratio 3: 1. The reaction with methyl α-D-glucopyranoside affords predominantly methyl 6-O-(5,8-dihydroxy-1,4-dioxonaphthalen-2-yl)-α-D-glucopyranoside, previously unknown water-soluble naphthoquinone-carbohydrate conjugate. 相似文献
77.
78.
A. Ya. Chizhova T. Yu. Kochergina V. F. Anufriev V. A. Denisenko V. P. Glazunov 《Russian Chemical Bulletin》1999,48(5):938-943
The 7,7′-dideoxy analog of islandoquinone, binaphthazarin of a new structural type, bearing a 2-oxo-2,3-dihydro-1,4-naphthoquinone
moiety was synthesized. The carbonyl group at the C(2) atom of this binaphthazarin easily adds water to give the correspondinggem-diol. Comparison of the spectral characteristics of the prepared diol and islandoquinone made it possible to elucidate more
precisely the structure of the latter. 相似文献
79.
The mass spectra of the residual gas in a metallic vacuum chamber of capacity 3 l are studied with an MI-9303 high-resolution
magnetic resonance mass spectrometer in the mass range 1–140 u. The experiments are carried out under four evacuation conditions
in the pressure range P = 10−8–10−10 Torr, and almost all the mass peaks forming multiplets are resolved. It is shown that the multiplets with mass numbers M≤80 have, as a rule, a multicomponent structure and hydrogen is the basic component responsible for the total pressure in
the chamber irrespective of evacuation conditions. Next in order of intensity in the mass spectra are, CH
4
+
, H2O+, CO+, and CO
2
+
peaks. Other lines in the residual gas spectra are largely due to various C-, H-, N-, and O-based compounds. In addition,
the background mass spectrum involves Cl-and F-based compounds and noble gas isotopes. The multiplets with M > 80 often degenerate into a single hydrocarbon line. 相似文献
80.
V. Ya. Sosnovskikh A. Yu. Sizov B. I. Usachev M. I. Kodess V. A. Anufriev 《Russian Chemical Bulletin》2006,55(3):535-542
Reactions of chromones with methyl ketoximes in the presence of lithium diisopropylamide follow the nucleophilic 1,2-addition
mechanism to give spiro[4H-chromene-4,5′-isoxazolines] in good yields. The isoxazoline ring in spiro[4H-chromene-4,5′-isoxazolines] undergoes opening under the action of conc. H2SO4, yielding α,β-unsaturated oximes. Their nitrosation and bromination lead to the corresponding spiroisoxazolines, while the
Beckmann rearrangement, to α,β-unsaturated amides. The latter are also formed directly from spiro[4H-chromene-4,5′-isoxazolines] under the action of PCl5. N-Substituted acetophenone hydrazones in the presence of lithium diisopropylamide react at the C(4) atom of 2-trifluoromethylchromone,
while acetophenone anil under the same conditions, at the C(2) atom.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 516–522, March, 2006. 相似文献