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51.
During the last decade the spectral vanishing viscosity (SVV) method has been adopted successfully for large-eddy-type simulations (LES) with high-order discretizations in both Cartesian and cylindrical coordinate systems. For the latter case, however, previous studies were confined to annular domains. In the present work, we examine the applicability of SVV in cylindrical coordinates to flows in which the axis region is included, within the setting of an exponentially convergent spectral element–Fourier discretization. In addition to the ‘standard’ SVV viscosity kernel, two modified kernels with enhanced stabilization in the axis region are considered. Three fluid flow examples are considered, including turbulent pipe flow. The results, on the one hand, show a surprisingly small influence of the SVV kernel, while on the other, they reveal the importance of spatial resolution in the axis region. 相似文献
52.
G. Michael Blackburn Terence H. Lilley Peter J. Milburn 《Journal of solution chemistry》1984,13(11):789-803
Enthalpies of dilution both of solutions of N-acetylsarcosinamide and of ternary solutions equimolal in N-acetylsarcosinamide and N-acetylglycinamide, N-acetyl-L-alaninamide, N-acetyl-L-valinamide or N-acetyl-L-leucinamide have been determined by a microcalorimetric method. The results were employed to calculate the pairwise enthalpic coefficients for both homotactic (like-like) and heterotactic (like-unlike) solute interactions. These pairwise interaction coefficients have been analyzed by means of a group additivity approach and some comments on the utility of this, when applied to such systems, are made. 相似文献
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Melanie A. Short J. Miles Blackburn Prof. Dr. Jennifer L. Roizen 《Angewandte Chemie (International ed. in English)》2018,57(1):296-299
Masked alcohols are particularly appealing as directing groups because of the ubiquity of hydroxy groups in organic small molecules. Herein, we disclose a general strategy for aliphatic γ‐C(sp3)?H functionalization guided by a masked alcohol. Specifically, we determine that sulfamate ester derived nitrogen‐centered radicals mediate 1,6‐hydrogen‐atom transfer (HAT) processes to guide γ‐C(sp3)?H chlorination. This reaction proceeds through a light‐initiated radical chain‐propagation process and is capable of installing chlorine atoms at primary, secondary, and tertiary centers. 相似文献
59.
A surface for the capture of biotin-tagged proteins on matrix-assisted laser desorption/ionisation (MALDI) targets has been investigated. Binding of a poly-L-lysine poly(ethylene glycol)-biotin polymer to glass and gold surfaces has been demonstrated using dual wavelength interferometry. Biotinylated proteins were captured onto this surface using tetrameric neutravidin as a multivalent bridging molecule. Biotin tagging of proteins was achieved by chemical biotinylation or by expressing a protein with a biotinylation consensus sequence in E. coli. The specificity of the surface for biotin-tagged proteins allowed the purification of biotin-tagged glutathione-S-transferase from a bacterial lysate directly onto a MALDI target. Subsequently, the protein was digested on the MALDI target and a protein fingerprint analysis confirmed its presence directly, but no E. coli proteins were detected. Therefore, we conclude that this surface is highly specific for the capture of biotin-labelled proteins and has low non-specific binding properties for non-biotinylated proteins. Furthermore, protein-protein interactions using biotinylated lectins were investigated, and the selective capture of the glycoprotein fetuin with wheat germ agglutinin was demonstrated. Also, immobilised Arachis hypogea agglutinin recognised a minor asialo component of this glycoprotein on the array. The high affinity immobilisation of proteins onto this surface allowed effective desalting procedures to be used which improved the desorption of high molecular weight proteins. Another aspect of this surface is that a highly ordered coupling of the analyte can be achieved which eliminates the search for the sweet spot and allows the creation of densely packed protein microarrays for use in mass spectrometry. 相似文献
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S.N. Blackburn R.N. Haszeldine R.V. Parish J.H. Setchfield 《Journal of organometallic chemistry》1980,192(3):329-338
The complexes IrX(CO)L2, IrCl(N2)(PPh3)2, [IrCl(C8H14)2]2, and IrClL2 (X = halide, L = tertiary phosphine or arsine) are excellent catalysts for the reactions of HSiR3 (R = Ph, Et, OEt) with R′OH (R′ = Et, Me). With IrX(CO)L2 the reactionis inhibited by an excess of HSiR3 and by the product, H2. The proposed mechanism involves intermediate formation of ClSiR3 by elimination from the silyl complex IrHX(SiR3)(CO)L2. The iridium(I) complex IrH(CO)L2, also formed in this step, reacts with HCl in the catalytic cycle or with H2 or HSiR3 in the inhibition reactions. The exchange reaction of HSiR3 (R = OEt, Et) with D2 is catalysed by IrCl(CO)(PPh3)2 or IrH3(CO)(PPh3)2, and probably has a similar mechanism. Catalysis of the HSiR3-R′OH reaction by the other iridium(I) complexes probably involves direct attack by the alcohol on the coordinated silyl group of the intermediate IrHCl(SiR3)L2. 相似文献