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161.
Francisco Foubelo 《Tetrahedron letters》2007,48(19):3379-3383
The lithiation of phthalan derivatives 4, 9 and 12 with an excess of lithium in the presence of a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) in THF at −78 °C gives dianionic intermediates 5, 10 and 13, respectively, which by reaction with different electrophiles [H2O, t-BuCHO, Me2CO, (EtO)2CO] at the same temperature, followed by hydrolysis, leads to regioselective functionalised naphthalenes 7, and biphenyls 11 and 14. The reductive opening takes place with high or total regioselectivity and can be explained considering the electron density in the dianion or in the radical anion, which are formed previous to the carbon-oxygen bond excision. The lithiation of the dihydrofurophthalan derivative 18 with the same reaction mixture but at higher temperature (0 °C) leads to intermediates 19 and 20, resulting from a single and a double reductive cleavage, respectively, which after addition of H2O and benzaldehyde as electrophiles gives a mixture of compounds 21 and 22. 相似文献
162.
O. N. Zefirova L. A. Zasurskaya E. V. Nurieva N. V. Zyk N. S. Zefirov 《Structural chemistry》2007,18(4):461-464
Molecular structure of ethylene acetal of 3-trityloxymethylbicyclo[3.3.1]nonane-2-on-7-ol (3) was determined by X-ray investigation. It was revealed that 3 has endo-endo-configuration and adopt chair-boat-conformation. The distortion of rings was evaluated by calculation of the Zefirov–Palyulin and Cremer–Pople puckering parameters.
Failure of esterification of 3 was rationalized in terms of steric hindrance and intramolecular hydrogen bonding.
相似文献
O. N. ZefirovaEmail: |
163.
UshaRani Mandapati Srinivasarao Pinapati RameshRaju Rudraraju 《Tetrahedron letters》2017,58(2):125-128
The cheap, readily available and air stable catalyst was used as the desulfurization agent for the conversion of aniline to isothiocyanates in one pot two step reaction under mild reaction conditions. 相似文献
164.
Synthesis and Antifungal Activity of Novel Furan‐2,4‐dione Derivatives Containing Substituted Phenylhydrazine Moiety
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Ying Hu Li‐Zhi Zhang Zheng‐Jiao Ren Zheng Zhao Wen‐Qin Xu Chun‐Long Yang 《中国化学会会志》2015,62(6):495-500
A series of novel 3‐(2‐(substituted phenyl)hydrazinylmethylidene)furan‐2,4(3H,5H)‐diones were designed and synthesized with ethyl 4‐chloroacetoacetate as the starting material. Their structures were confirmed by FT‐IR, 1H NMR, 13C NMR, EI‐MS and elemental analysis. Bioassay data demonstrated that these compounds exhibited remarkable antifungal activity against Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis and Colletotrichum capsici. Compound 3‐(2‐(4‐bromophenyl)hydrazinylmethylidene)furan‐2,4(3H,5H)‐dione ( 5g ) had excellent bioactivity against Botrytis cinerea with an EC50 value of 0.18 μg/mL ‐ markedly lower than the 0.24 μg/mL of the commercial fungicide procymidone. The result revealed that introducing the halogenated phenylhydrazine at the 3‐position of furan‐2,4(3H, 5H)‐dione was an effective way to design new tetronic acid derivatives as new fungicides. 相似文献
165.
Hai-Feng Yu 《合成通讯》2020,50(8):1133-1140
AbstractCatalyst free cyclocondensation of β-ethylthio-β-indolyl-α,β-unsaturated ketones with hydrazines has been developed, and 3-pyrazolyl indoles were efficiently synthesized in excellent yields. The catalyst free protocol avoids the use of a large excess of catalysts such as acids and bases, eliminating the discharge of harmful chemicals. 相似文献
166.
《Journal of Coordination Chemistry》2012,65(6):917-925
Two new uranyl β-diketonate complexes [UO2(DBM)2(DEDPU)] (1) and [UO2(PMBP)2(DEDPU)](CH3C6H5)0.5 (2), (HDBM?=?dibenzoylmethane, HPMBP?=?1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, DEDPU?=?N,N′-diethyl-N,N′-diphenylurea) were synthesized and characterized. The coordination geometries of the uranyl atoms in 1 and 2 are distorted pentagonal bipyramidal, coordinated by one oxygen atom of DBDPU molecule and four oxygen atoms of two chelating DBM molecules in 1 and PMBP molecules in 2. 相似文献
167.
《Journal of Coordination Chemistry》2012,65(2):227-242
Four new substituted amino acid ligands, N-(3-hydroxybenzyl)-glycine acid (HL1), N-(3-hydroxybenzyl)-alanine acid (HL2), N-(3-hydroxybenzyl)-phenylalanine acid (HL3), and N-(3-hydroxybenzyl)-leucine acid (HL4), were synthesized and characterized on the basis of 1H NMR, IR, ESI-MS, and elemental analyses. The crystal structures of their copper(II) complexes [Cu(L1)2]·2H2O (1), [Cu(L2)2(H2O)] (2), [Cu(L3)2(CH3OH)] (3), and [Cu(L4)2(H2O)]·H2O (4) were determined by X-ray diffraction analysis. The ligands coordinate with copper(II) through secondary amine and carboxylate in all complexes. In 2, 3, and 4, additional water or methanol coordinates, completing a distorted tetragonal pyramidal coordination geometry around copper. Fluorescence titration spectra, electronic absorption titration spectra, and EB displacement indicate that all the complexes bind to CT-DNA. Intrinsic binding constants of the copper(II) complexes with CT-DNA are 1.32?×?106?M?1, 4.32?×?105?M?1, 5.00?×?105?M?1, and 5.70?×?104?M?1 for 1, 2, 3, and 4, respectively. Antioxidant activities of the compounds have been investigated by spectrophotometric measurements. The results show that the Cu(II) complexes have similar superoxide dismutase activity to that of native Cu, Zn-SOD. 相似文献
168.
《Journal of Coordination Chemistry》2012,65(14):1609-1614
Two new uranyl complexes [UO2(DPDPU)2(NO3)2](C6H5CH3) (1) and [UO2(PMBP)2 (DPDPU)](CH3C6H4CH3)0.5 (2), (DPDPU?=?N,N′-dipropyl-N,N′-diphenylurea, HPMBP?= 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5) were synthesized and characterized. The coordination geometry of the uranyl atom in 1 is distorted hexagonal bipyramidal, coordinated by two oxygen atoms of two DPDPU molecules and four oxygen atoms of two bidentate nitrate groups. The coordination geometry of the uranyl atom in 2 is distorted pentagonal bipyramidal, coordinated by one oxygen atom of one DPDPU molecule and four oxygen atoms of two chelating PMBP molecules. 相似文献
169.
《Journal of Coordination Chemistry》2012,65(24):2671-2678
Two ternary copper(II) complexes [Cu(L1)(py)] (1) and [Cu(L2)(Himdz]?·?CH3OH (2) with substituted aroylhydrazones, 5-bromo-salicylaldehyde-3,5-dimethoxy-benzoylhydrazone (H2L1) and 5-bromo-salicylaldehyde-p-methyl-benzoylhydrazone (H2L2), pyridine (py) and imidazole (Himdz), have been synthesized. Their crystal structures and spectroscopic properties have been studied. In each complex, the metal is in a square-planar N2O2 coordination formed by the phenolate-O, the imine-N and the deprotonated amide-O atoms of L2?, and the sp2?N atom of the neutral heterocycle. In the solid state, 1 exists as a centrosymmetric dimer due to very weak apical coordination of the metal bound phenolate-O. Complex 2 has no such apical coordination and exists as a monomer. Self-assembly via C–H?···?O, N–H?···?O and O–H?···?N interaction leads to a one-dimensional chain arrangement; other non-covalent interactions such as C–H?···?π and π?···?π are not involved. 相似文献
170.
《Journal of Coordination Chemistry》2012,65(5):854-862
This article describes a simple method developed for the synthesis of symmetrically substituted 1,8,15,22-tetra-phenylpropene-1-imino phthalocyanines (M-PhproImPcs) of cobalt(II), copper(II), nickel(II) and zinc(II) by condensing 1,8,15,22-tetra amino phthalocyanines with cinnamaldehyde. The dark bluish-green colored tetraimino substituted phthalocyanine derivatives were characterized by elemental analysis, electronic spectra, IR spectra, magnetic susceptibility, powder XRD and thermogravimetric analysis (TGA) to check the structural integrity and purity. The variations of magnetic moment as a function of field strength indicated the presence of intermolecular co-operative interactions. The complexes were also evaluated for their antibacterial activities. 相似文献