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101.
Topoglidis E Campbell CJ Palomares E Durrant JR 《Chemical communications (Cambridge, England)》2002,(14):1518-1519
Transient optical spectroscopies and photocurrent action spectra are used to demonstrate photoinduced charge separation between zinc-substituted cytochrome c and a nanocrystalline TiO2 electrode. 相似文献
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103.
Ferrando-Soria J Pardo E Ruiz-García R Cano J Lloret F Julve M Journaux Y Pasán J Ruiz-Pérez C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(7):2176-2188
A series of neutral oxamato‐bridged heterobimetallic chains of general formula [MCu(Lx)2(S)2] ? p S ? q H2O [p=0–1, q=0–2.5; L1=N‐2,6‐dimethylphenyloxamate, S=DMF with M=Mn ( 1 a ) and Co ( 1 b ); L2=N‐2,6‐diethylphenyloxamate, S=DMF with M=Mn ( 2 a ) and Co ( 2 b ) or S=DMSO with M=Mn ( 2 c ) and Co ( 2 d ); L3=N‐2,6‐diisopropylphenyloxamate, S=DMF with M=Mn ( 3 a ) and Co ( 3 b ) or S=DMSO with M=Mn ( 3 c ) and Co ( 3 d )] were prepared by treating the corresponding anionic oxamatocopper(II) complexes [Cu(Lx)2]2? (x=1–3) with M2+ cations (M=Mn and Co) in DMF or DMSO as the solvent. The single‐crystal X‐ray structures of 2 a and 3 a reveal the occurrence of well‐isolated, zigzag, oxamato‐bridged manganese(II)–copper(II) chains. The intrachain Cu ??? Mn distances across the oxamato bridge are 5.3761(7) and 5.4002(17) Å for 2 a and 3 a , respectively, whereas the shortest interchain Mn ??? Mn distances are 9.4475(16) and 8.1649(14) Å for 2 a and 3 a , respectively. All of these MIICuII chains (M=Mn and Co) exhibit 1D ferrimagnetic behaviour with moderately strong intrachain antiferromagnetic coupling between the square‐planar CuII and octahedral high‐spin MII ions across the oxamato bridge [?J=31.4–35.2 and 33.4–44.8 cm?1, respectively; H =∑i?J S M,i( S Cu,i+ S Cu,i?1)]. Only the CoIICuII chains show slow magnetic relaxation effects characteristic of single‐chain magnets (SCMs). Analysis of the magnetic relaxation dynamics of 3 d shows a thermally activated mechanism (Arrhenius law dependence) with values of the pre‐exponential factor (τ0=2.6×10?9 s) and activation energy (Ea=7.7 cm?1) that are typical of SCMs. In contrast, two relaxation regimes are observed for 2 d in different temperature regions (τ0=3.2×10?10 s and Ea=24.7 cm?1 for T<4.5 K and τ0=3.2×10?14 s and Ea=37.5 cm?1 for T>4.5 K). 相似文献
104.
Alvaro M Formentín P García H Palomares E Sabater MJ 《The Journal of organic chemistry》2002,67(15):5184-5189
Three N-alkylpyridinium photosensitizers having chiral alkyl groups have been prepared by reacting 2,4,6-triphenylpyrylium tetrafluoroborate ion with (1R,2S)-(-)-norephedrine, (S)-(+)-2-(aminomethyl)pyrrolidine, and (R)-(-)-1-cyclohexylethylamine. Laser flash photolysis allows detection of the corresponding triplet excited states that are quenched by hydrogen atom donors and electron donors. Asymmetric quenching of the chiral triplet excited state was observed using enantiomerically pure 1,2-diamino cyclohexane as quencher. Low enantiomeric excess values (up to 7%) were measured for the photochemical cyclization of 5-methyl-4-hexenoic acid to its corresponding gamma-lactone using these chiral N-alkylpyridinium as photosensitizers. 相似文献
105.
Emilio San-Fabián José Pérez-Jordá Federico Moscardó 《Theoretical chemistry accounts》1990,77(3):207-212
Summary The correlation energy of two- and four-isoelectronic series, a representative example for which the existing spin-density functionals fails, is calculated using the Colle and Salvetti method, considering mono- and multideterminantal wave functions. The results are in agreement with experimental data, and show the potentiality of this method when it is applied to wave functions including the most relevant configurational features. Also, results for the ionization energies and electron affinities of first- and second-row atoms are reported. 相似文献
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108.
Roberta Cavalli Emilio Marengo Otto Caputo Elena Ugazio Maria Rosa Gasco 《Journal of Dispersion Science and Technology》2013,34(7):717-734
The influence of twenty five different alcohols on the formation of warm oil-in-water (O/W) microemulsions was investigated. Selected concentrations of each alcohol were added to fixed amounts of stearic acid, Tween 20 and water at 65 ° C. Fifteen alcohols formed microemulsions, at least at one of the concentrations. A pattern recognition study was performed to elucidate the activities of the alcohols by Principal Component Analysis (PCA). Linear Discriminant Analysis (LDA) was used to classify them. Two classification functions, obtained for alcohols forming / not forming microemulsions, suggest that the formation of warm O/W microemulsion is linked to the nature and the dimension/lipophilicity of the alcohol. 相似文献
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110.
Catalytic Asymmetric Reactions of 4‐Substituted Indoles with Nitroethene: A Direct Entry to Ergot Alkaloid Structures 下载免费PDF全文
Simone Romanini Emilio Galletti Dr. Lorenzo Caruana Prof. Andrea Mazzanti Prof. Fahmi Himo Dr. Stefano Santoro Prof. Mariafrancesca Fochi Prof. Luca Bernardi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17578-17582
A domino Friedel–Crafts/nitro‐Michael reaction between 4‐substituted indoles and nitroethene is presented. The reaction is catalyzed by BINOL‐derived phosphoric acid catalysts, and delivers the corresponding 3,4‐ring‐fused indoles with very good results in terms of yields and diastereo‐ and enantioselectivities. The tricyclic benzo[cd]indole products bear a nitro group at the right position to serve as precursors of ergot alkaloids, as demonstrated by the formal synthesis of 6,7‐secoagroclavine from one of the adducts. DFT calculations suggest that the outcome of the reaction stems from the preferential evolution of a key nitronic acid intermediate through a nucleophilic addition pathway, rather than to the expected “quenching” through protonation. 相似文献