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101.
Reactions of alkyl halides with azines of p-nitrobenzaldehyde, benzaldehyde, and p-methoxybenzaldehyde at a high pressure (10 kbar) were studied. Hydrolysis of the reaction mixtures gives pure N-monoalkyl- or N,N"-dialkylhydrazines in high yields, depending on the structure of the starting azine and the solvent nature. It was found that non-symmetrical N,N"-dialkylhydrazines can be synthesized without isolating intermediate N-monoquaternary immonium salts. The effect of the phase transition of the solvent on the direction of the alkylation is discussed. 相似文献
102.
Mario Merslavič Branko Stanovnik Miha Tišler 《Monatshefte für Chemie / Chemical Monthly》1985,116(12):1447-1458
New syntheses of oxazolo[4,5—d]pyridazine derivatives7 and11 were achieved by the cyclization of substituted N-pyridazin-5-ylformamide oximes6 and10. Under mild reaction conditions the transformations of the substituted amino group at position 2 of the oxazolo[4,5—d]pyridazine system7 occured to produce the compounds11, 14, and15, while under more drastic reaction conditions the nucleophilic attack at carbon at position 2 followed by the ring opening of the oxazole part of the molecule was observed to give the compounds13, 16, 17 and18.
Transformationen von N-Heteroarylformamidinen und N-Heteroarylformamidinoximen. Neue Synthesen und Transformationen von Oxazolo[4,5—d]pyridazinen
Zusammenfassung Mittels Cyclisierung substituierter N-Pyridazin-5-ylformamidoxime6 und10 wurden neue Synthesemöglichkeiten von Oxazolo[4,5—d]pyridazinderivaten erschlossen. Bei milden Reaktionsbedingungen trat Transformation der substituierten Aminogruppe an Position 2 des Oxazolo[4,5—d]pyridazin-Systems unter Bildung der Verbindungen11, 14 und15 ein, währenddessen unter drastischeren Reaktionsbedingungen ein nucleophiler Angriff am Kohlenstoff-2, gefolgt von einer Ringöffnung unter Bildung der Verbindungen13, 16, 17 und18 eintrat.相似文献
103.
Infrared spectra and theoretical study of the conformations of substituted benzoylketene-S,S-acetals
A. Perjéssy W. -D. Rudorf D. Loos Z. Šusteková 《Monatshefte für Chemie / Chemical Monthly》1994,125(12):1389-1396
Summary The C=O stretching frequencies of substituted benzoylketene-S,S-dimethylacetals (1a–1o) and benzoylketene-S,S-ethyleneacetals (2a–2m) were measured in CHCl3 and CCl4 and correlated with theHammett substituent constants. The correlations were split into two different and well separated lines for compounds containing electron donor and electron acceptor substituents, which were assigned tos-trans ands-cis quasiplanar conformations. The correlations of carbonyl stretching frequencies with C=O bond orders and oxygen atom charge densities calculated using the semiempirical AM1 method reveal similar results consistent with assignments of structures1 and2 to two quasiplanar conformations. The preparation of some new benzoylketene-S,S-acetals is reported as well.
Infrarotspektroskopische und theoretische Untersuchung der Konformationen substituierter Benzoylketen-S,S-acetale
Zusammenfassung Die C=O-Streckfrequenzen substituierter Benzoylketen-S,S-dimethylacetale (1a–1o) und Benzoylketen-S,S-ethylenacetale (2a–2m) wurden in CHCl3 und CCl4 gemessen und mit denHammet-Konstanten in Beziehung gesetzt. Es ergaben sich zwei deutlich unterschiedliche Gerade für Verbindungen mit Elektronenakzeptoren und mit Elektronendonatoren als Substituenten, die dens-trans- unds-cis-quasiplanaren Konformationen zugeordnet wurden. Die mittels der semiempirischen AM1 — Methode berechneten Korrelationen zwischen C=O-Streckfrequenzen und C=O-Bindungsordnungen bzw. Ladungsdichten am Sauerstoffatom ergeben ebenfalls eine Zuordnung der Verbindungen1 und2 zu zwei quasiplanaren Konformationen. Die Herstellung einiger neuer Benzoylketen-S,S-acetale wird ebenfalls beschrieben.相似文献
104.
Duy H. Hua Kaiyan Lou Elisabeth M. Perchellet Jean-Pierre Perchellet 《Tetrahedron》2004,60(45):10155-10163
Based on a rational approach, 6-substituted 1,4-anthracenediones were synthesized and found to exhibit potent cytotoxic activity against murine and human leukemic cells. The synthetic sequence includes a double Friedel-Crafts reaction, reductive quinone formation, and selective bromination of the alkyl side chain. A key intermediate, 6-bromomethyl-1,4-anthracenedione (10), was synthesized and converted to various active antitumor agents, including a water-soluble phosphate ester pro-drug. The interconversion reactions include displacement of the bromide with various nucleophiles and basic hydrolysis to the alcohol and subsequent oxidation to provide the aldehyde. Based on their ability to decrease L1210 and HL-60 tumor cell viability, 1,4-dihydroxyanthraquinones are inactive but 1,4-anthracenediones have interesting antitumor activity, which may be abolished by modification of the A-ring and improved by substitution of the C-ring. The cytostatic and cytotoxic activity of the representative compound 10 was verified at the National Cancer Institute in studies on the 60-human tumor cell line panel in the in vitro antitumor screening. A wide spectrum of tumor cells are sensitive to 10 inhibition, and concentrations required to inhibit tumor cell growth by 50% (GI50) at 48 h are <10 nM in HL-60 and MOLT-4 and 37.1 nM in SR leukemia. Preliminary studies suggest that the molecular targets and mechanisms of action of 10 may be different from those of daunomycin. 相似文献
105.
TongKuanXU XingHaiSHEN HongChengGAO 《中国化学快报》2004,15(1):26-28
Two substituted 3H-indole quaternary ammonium molecules were designed andsynthesized using hexamethylphosphoramide (HMPA) as a solvent. The products were purified and characterized by IR, ^1H NMR, MS and elemental analysis. 相似文献
106.
Michael addition of lithium enolates of γ-butyrolactone 1 and α-methyl-γ-butyrolactone 1′ to (E)-1-nitropropene 2, (E)-β-nitrostyrene 3 and (E)-2-nitro-1-phenylpropene 4 is described. Reactions of the lithium enolate of 1′ with 2 and 4 occurred with high diasteroselectivity (80 and 92% d.e., respectively). Reactions of the zinc enolate of 1′ with two β-nitroenamines and two methylthio-substituted 1-amino-2-nitro-1,3-dienes were also examined. Catalytic reduction of the nitroalkylated and nitroalkenylated products allowed the achievement of functionalized γ-lactams and/or cyclic hydroxamic acids. 相似文献
107.
2-Polyfluoroalkylchromene-4(4H)-thiones, synthesized from 2-polyfluoroalkylchromones and P2S5, react with aniline, phenylhydrazines, and hydroxylamine at the C(4) atom and afford corresponding anils, phenylhydrazones, and oximes of chromones. On heating in alcohol in the presence of concentrated HCl, chromone phenylhydrazones and oximes undergo ring closure to form 3-(2-hydroxyaryl)-1-phenyl-5-polyfluoroalkylpyrazoles and 5-hydroxy-3-(2-hydroxyaryl)-5-polyfluoroalkyl-Δ2-isoxazolines.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2188–2195, October, 2004. 相似文献
108.
Palaniswamy Suresh 《Tetrahedron》2007,63(23):4959-4967
Cyclodextrin acts as a restricting nanovessel to enhance regioselectivity in bromination of substituted phenols such as 3-nitrophenol, 2-chlorophenol, 3-chlorophenol, and 4-chlorophenol. In contrast to solution bromination, cyclodextrin facilitates regioselective monobromination and formation of polybrominated products are substantially reduced. Selectivities in brominations are also observed in water and in the solid state. The observed results are rationalized on the basis of specific modes of inclusion of substituted phenols inside the cyclodextrin cavity and find strong support from energy minimization studies and 1H-1H NOESY. 相似文献
109.
M. Romero 《Tetrahedron》2006,62(38):9010-9016
Aryl bromides are coupled with N-compounds to give the corresponding arylamines in the presence of a palladium catalyst, a suitable ligand, and a weak base. The catalysts perform well for a large number of different starting material combinations at 100-150 °C with drops of toluene or without solvent, and with low catalyst levels (0.12 mol % Pd). The low catalyst amount makes the process environment friendly. 相似文献
110.
Janet E. Del Bene Guy T. Worth Francis T. Marchese Michael E. Conrad 《Theoretical chemistry accounts》1975,36(3):195-206
Ab initio SCF calculations with a minimal STO-3G basis set have been performed to determine the equilibrium geometries of two series of carbonyl compounds, RCHO and R2 CO. For the mono-substituted compounds, R may be CH3, NH2, OH, F, CHO, and C2 H3. In the disubstituted compounds, R has been restricted to the isoelectronic saturated groups. The computed equilibrium geometries of these compounds are in satisfactory agreement with the experimentally-determined geometries, with an average difference of 0.021 Å between computed and experimental bond lengths, and 1.9 ° in corresponding bond angles. An analysis of the effect of the substituent on the electronic structure of the carbonyl group has also been made. The saturated groups are found to be electron-withdrawing groups relative to H, with the electron withdrawing ability increasing in the order CH3 2 2H2 are also electron withdrawing relative to H, and comparable to CH3 in acetaldehyde. Vertical ionization potentials andn* transition energies have also been calculated for these molecules at their optimized geometries, experimental geometries, and geometries given by a standard model. The effect of changes in molecular geometry on these computed properties has been analyzed. 相似文献