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排序方式: 共有317条查询结果,搜索用时 31 毫秒
171.
Aurélie Guyomard Sagrario Pascual Jean-François Bardeau 《European Polymer Journal》2004,40(10):2343-2348
A series of cross-linked porous copolymer supports based on N-(p-vinylbenzoyl)-2-methylalanine (VBM), styrene and divinylbenzene was prepared by aqueous suspension copolymerization in the presence of butan-2-ol used as porogen. The cross-linked copolymer beads were characterized by elemental analysis, scanning electron microscopy (SEM), FT-IR and confocal Raman spectrometries. It was observed that the VBM incorporation was effective and homogeneous within the beads. Those VBM functionalized supports were converted into azlactone functionalized supports using acetic anhydride and their scavenging efficiency towards different amines was measured. It appeared that 90% of benzylamine was quenched after 5 h. 相似文献
172.
2-Bromobenzaldehydes react with an array of suitably functionalized alkenes in the presence of a catalytic amount of a palladium catalyst together with a base to afford the corresponding naphthalenes in moderate to good yields. 相似文献
173.
Krishnavenu Bolla Taejung KimJung Ho Song Seokjoon LeeJungyeob Ham 《Tetrahedron》2011,67(31):5556-5563
In this study, we present a previously unreported method of preparing regiospecific organo-[1,2,3]-triazol-1-aryl-trifluoroborates from haloaryltrifluoroborates via a one-pot 1,3-dipolar cycloaddition reaction. We found that the use of either electron-rich or electron-deficient haloaryltrifluoroborates led to the desired cycloaddition products with good to excellent yields. Furthermore, we successfully carried out the cross-coupling reactions of the obtained triazoles with various aryl halides by means of the Suzuki-Miyaura reaction in the presence of 3 mol % of Pd(PPh3)4 catalyst in a 20% aqueous 1,4-dioxane solution at 100 °C; all these reactions yielded complete conversion to the corresponding products. Besides providing a high level of personnel safety, our highly versatile approach allows the preparation of functionalized organotrifluoborates containing 1,2,3-triazoles with retained functionality. 相似文献
174.
Direct alkenylation of indoles at the 3-position with 1,3-dicarbonyl compounds under Brønsted acidic ionic liquid catalysis has been developed. The yields were excellent, and the catalyst can be reused at least six times without noticeable loss of catalytic activity. 相似文献
175.
Sarita MishraRina Ghosh 《Tetrahedron letters》2011,52(22):2857-2861
A highly efficient diastereoselective one-pot synthesis of functionalized piperidines has been developed based on an aqua-compatible ZrOCl2·8H2O catalyst via tandem reactions of aromatic aldehydes, amines, and acetoacetic esters. 相似文献
176.
Michael Block Martin Bette Christoph Wagner Prof. Dr. Dirk Steinborn 《无机化学与普通化学杂志》2011,637(2):206-210
The reaction of the electronically unsaturated platina‐β‐diketone [Pt2{(COMe)2H}2(μ‐Cl)2] ( 1 ) with Ph2PCH2CH2CH2SPh ( 2 ) leads selectively to the formation of the acetyl(chlorido) platinum(II) complex (SP‐4‐3)‐[Pt(COMe)Cl(Ph2PCH2CH2CH2SPh‐κP,κS)] ( 4 ) having the γ‐phosphinofunctionalized propyl phenyl sulfide coordinated in a bidentate fashion (κP,κS). In boiling benzene complex 4 undergoes decarbonylation yielding the methyl(chlorido) platinum(II) complex (SP‐4‐3)‐[PtMeCl(Ph2PCH2CH2CH2SPh‐κP,κS)] ( 6 ). However, the reaction of 1 with the analogous γ‐diphenylphosphinofunctionalized propyl phenyl sulfone Ph2PCH2CH2CH2SO2Ph ( 3 ) affords the acetyl(chlorido) platinum(II) complex (SP‐4‐4)‐[Pt(COMe)Cl(Ph2PCH2CH2CH2SO2Ph‐κP)2] ( 5 ). In boiling benzene complex 5 undergoes a CO extrusion yielding (SP‐4‐4)‐[PtMeCl(Ph2PCH2CH2CH2SO2Ph‐κP)2] ( 8 ) whereas in presence of 1 the formation of the carbonyl complex (SP‐4‐3)‐[PtMeCl(CO)(Ph2PCH2CH2CH2SO2Ph‐κP)] ( 7 ) is observed. Addition of Ag[BF4] to complex 5 leads to the formation of the cationic methyl(carbonyl) platinum(II) complex (SP‐4‐1)‐[PtMe(CO)(Ph2PCH2CH2CH2SO2Ph‐κP)2][BF4] ( 9 ). All complexes were characterized by microanalysis and NMR spectroscopy (1H, 13C, 31P) and complexes 4 and 6 additionally by single‐crystal X‐ray diffraction analyses. 相似文献
177.
α-Bromo-2-acetylfuran adds oxidatively to elemental tellurium and aryltellurium(II) bromide at ambient temperature to afford (2-furoylmethyl)tellurium(IV) dibromides, (FuCOCH2)2TeBr2 (1b) and Ar(FuCOCH2)TeBr2 (Fu = 2-C4H3O; Ar = 1-C10H7, 2b; 2,4,6-Me3C6H2, 3b). The iodo analogues 1c-3c can be obtained by metathesis of the bromides with an alkali iodide. Condensation reactions of the parent methyl ketone with Te(IV) chlorides results in the corresponding chloro analogues, (FuCOCH2)2TeCl2 (1a) and Ar(FuCOCH2)TeCl2 (2a, 3a and Ar = 4-MeOC6H4 (4a)). These diorganotellurium dihalides are reduced with aqueous bisulfite to diorganotellurides 1-3, which can be oxidized readily with dihalogens to the desired diorganotellurium(IV) dihalides. The tellurated furan derivative, bis(2-furyl)tellurium(II), Fu2Te (5), obtained by detelluration of bis(2-furyl)ditelluride with electrolytic copper, gives crystalline bis(2-furyl)tellurium(IV) dichloride (5a) upon chlorination. Crystal structures of Te(IV) compounds 1a, 1b, 2a-4a, and the telluride 3 together with its thiophene analogue (2,4,6-Me3C6H2)((2-C4H3S)COCH2)Te, 6 have been studied. Among the Te(IV) compounds, the functionalized organic moiety, FuCOCH2-, behaves as a (C, O) chelating ligand, resulting in a intramolecular 1,4-Te?O secondary bonding interaction. Such an interaction is absent in Te(II) compounds 3 and 6, though they differ in the conformation adopted by the organic ligand. The chalcogen atoms in the heteroaroyl moiety are trans in 3 but cis in 6 which also possesses intermolecular Te?O interaction in its lattice. 相似文献
178.
In this study COOH-functionalised silica is synthesised using phosphonateN-(phosphonomethyl)iminodiacetic acid (PMIDA) in an aqueous solution. The presence of PMIDA on the silica particles was verified using Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy and titration. Experimentally, surface concentrations of COOH functional groups of up to about 3 mmol/gsilica were achieved, whereas theoretical calculation of the maximum COOH functional group concentration gave about 1 mmol/gsilica. The discrepancy may be caused by PMIDA multilayer formation on the particle. 相似文献
179.
180.
Il Gu Jung Soo Young Choi Youn K. Kang Young Keun Chung 《Journal of organometallic chemistry》2009,694(2):297-889
In situ generated cationic (η3-substituted allyl) palladium N-heterocyclic carbene (NHC) complexes are air-stable active catalysts for the olefin polymerization of (bicyclo[2.2.1]hept-5-en-2-yl)methyl acetate (5-norbornene-2-methyl acetate) (endo:exo = 7:3). Catalytic activities, polymer yields, molecular weights, and molecular weight distributions of polymers were investigated under various reaction conditions. The catalytic activity was highly dependent not only on the reaction condition such as a solvent or the reaction temperature but also on the structure of the catalyst that include substituents of the allyl group in the catalyst and the counter anion. As the bulkiness of the allyl group increased, the catalytic activity of the catalysts increased. 相似文献