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81.
A method has been developed for the synthesis of 2-pyridyl-substituted derivatives of 7-benzyl-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine
based on the condensation of ethyl 1-benzyl-3-oxopiperidine-4-carboxylate with pyridyl-2-, pyridyl-3-, and pyridyl-4-carboxamidines
and subsequent reactions of 7-benzyl-2-pyridyl-5,6,7,8-tetrahydro-3H-pyrido[3,4-d]pyrimidin-4-ones with trifluoromethanesulfonic
anhydride and secondary amines.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1556–1561, October, 2007. 相似文献
82.
SongQingWANG LinFANG XiuJieLIU KangZHAO 《中国化学快报》2004,15(8):885-888
On the basis of the Zaleplon structure, novel pyrazolo[1,5-a]pyrimidines were designed and prepared for studies on their hypnotic activity. This paper reported the synthesis of twelve new 5-methyl-7-substituted-pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives by using simple starting materials such as propane dinitrile and triethyl orthoformate. The structures of the derived target compounds were confirmed by their IR and ^1H-NMR spectroscopic data. The preliminary pharmacological evaluations indicated that some compounds showed hypnotic activity, whilc derivative 1c was the most potent one. 相似文献
83.
I. Ravina D. Zicane M. Petrova E. Gudriniece U. Kalejs 《Chemistry of Heterocyclic Compounds》2002,38(7):836-839
2-Pyridylaminomethyleneisopropylidenemalonates, prepared from ethoxymethyleneisopropylidenemalonate and 2-aminopyridines, form 4-oxo-4H-pyrido[1,2-a]pyrimidines at their melting points and are separated from the reaction mixture by sublimation. 相似文献
84.
Summary Syntheses of 11-amino-5,6-dihydronaphtho[1,2:4,5]thieno[2,3-d]pyrimidine (8) and its 10-oxide 7 from 2-amino-1-cyano-4,5-dihydronaphtho[2,1-b]thiophene and its derivatives are described. Several open chain tetrahydronaphthylidene derivatives and a substituted pyrimidine derivative9 were also prepared.Dedicated to Professor Dr. K. Gewald on the occasion of his 60th birthday 相似文献
85.
Krzysztof Bujnowski Ludwik SynoradzkiEckhard Dinjus Thomas ZevacoEwa Augustynowicz-Kope? Zofia Zwolska 《Tetrahedron》2003,59(11):1885-1893
Within the study covering the search for new methods of synthesis of rifamycin antibiotics, the reactions of 3-formylrifamycin SV (2) with primary amines or ammonia were studied. In the reaction of 2 with methylamine, unstable 3-methyliminomethylrifamycin SV (8) was formed, which was further oxidised to stable 3-methyliminomethylrifamycin S (9). In the reaction of 2 with ammonia, N,15-didehydro-15-deoxo-pyrimido-(4,5-b)rifamycin SV (10), a new compound with a chromophore system enlarged by a pyrimidine ring, was obtained. The product of its reduction with sodium borohydride—(11)—was also isolated. The structures of the compounds and an explanation of the synthesis mechanism have been proposed on the basis of mass spectrometry results as well as (1D) and (2D) 1H- and 13C NMR analysis. In vitro antituberculous activity of the new compounds have been investigated. 相似文献
86.
The synthesis of fused pyrimidines from the Schiff bases of aromatic ortho-nitrocarbaldehydes is reported. The Schiff bases after selective reduction of the nitro group on 10% Pd/C, followed by condensation of the amines formed with orthoesters, are transformed to the corresponding imidates. Heating of the latter in a sealed tube with an excess of ammonia (or with ammonia in ethanol) gives fused pyrimidines. The influence of various substituents in the aromatic ring of the imine moiety of the Schiff bases on the overall yield of fused pyrimidine derivatives has been investigated. Moderate electron-withdrawing groups gave the best results.Institute of Organic Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, PL-01-224 Warszawa, PolandTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 799–805, June, 2000. 相似文献
87.
A concise and versatile method for the preparation of 3-aminoindoles from 2-(disubstituted amino)-benzonitriles is described, and in situ functionalizations were illustrated. 相似文献
88.
Julien Verron 《Tetrahedron letters》2007,48(3):377-380
In the course of establishing a flexible synthesis of 2,4,6-substituted pyrimidines, we discovered that 2-hexyl-isothiourea hydrobromide reacts at ambient temperature and in a mildly exothermic fashion with 5,5-diethoxy-pent-3-yn-2-one upon treatment with 2 equiv of triethylamine in tetrahydrofuran to afford 4-diethoxymethyl-2-hexylsulfanyl-6-methyl-pyrimidine in 80% isolated yield. The methodology was developed in the search for an improved synthesis of the GABAB enhancer 4-(2-hexylsulfanyl-6-methyl-pyrimidin-4-ylmethyl)-morpholine. 相似文献
89.
E. V. Vorob’ev M. E. Kletskii V. V. Krasnikov V. V. Mezheritskii D. V. Steglenko 《Russian Chemical Bulletin》2006,55(12):2247-2255
Recyclization of thieno[3,2-e][1,2,4]triazolo[4,3-c]pyrimidines was studied experimentally and theoretically by B3LYP/6-31G** calculations in the gas phase and in solution (EtOH).
The experimentally observed characteristic features of the isomerization (the possibility of the Dimroth rearrangement occurring
by the ANRORC mechanism and high energy barriers in acid-catalyzed reactions) were confirmed by quantum chemical calculations.
Substituents in the triazole ring were found to play the principal role in the rearrangement.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2164–2171, December, 2006. 相似文献
90.
An efficient and operationally simple strategy for the synthesis of differently C-3 monosubstituted (9) and disubstituted (10) monocyclic β-lactams is described. This involves reaction of β-lactam carbocation equivalents (8) with an active aromatic, aliphatic and heterocyclic substrates in the presence of a Lewis acid. 相似文献