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991.
992.
Gerd Herzog 《Numerical Functional Analysis & Optimization》2017,38(8):1008-1013
It is known that vector translations are contractive with respect to Thompson’s part metric. Here, we give a simple proof, based on a representation of Thompson’s metric through positive functionals. Moreover, we use contractivity of translations to prove a fixed point result for mappings that are Lipschitz continuous with respect to Thompson’s metric with Lipschitz constant r>1. The case r = 1 for order preserving or order reversing mappings has been recently studied by Lawson and Lim. We apply our result to a nonlinear boundary value problem. 相似文献
993.
994.
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996.
Natural Abundance 15N NMR by Dynamic Nuclear Polarization: Fast Analysis of Binding Sites of a Novel Amine‐Carboxyl‐Linked Immobilized Dirhodium Catalyst
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Torsten Gutmann Jiquan Liu Niels Rothermel Yeping Xu Eva Jaumann Mayke Werner Hergen Breitzke Snorri T. Sigurdsson Gerd Buntkowsky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3798-3805
A novel heterogeneous dirhodium catalyst has been synthesized. This stable catalyst is constructed from dirhodium acetate dimer (Rh2(OAc)4) units, which are covalently linked to amine‐ and carboxyl‐bifunctionalized mesoporous silica (SBA‐15?NH2?COOH). It shows good efficiency in catalyzing the cyclopropanation reaction of styrene and ethyl diazoacetate (EDA) forming cis‐ and trans‐1‐ethoxycarbonyl‐2‐phenylcyclopropane. To characterize the structure of this catalyst and to confirm the successful immobilization, heteronuclear solid‐state NMR experiments have been performed. The high application potential of dynamic nuclear polarization (DNP) NMR for the analysis of binding sites in this novel catalyst is demonstrated. Signal‐enhanced 13C CP MAS and 15N CP MAS techniques have been employed to detect different carboxyl and amine binding sites in natural abundance on a fast time scale. The interpretation of the experimental chemical shift values for different binding sites has been corroborated by quantum chemical calculations on dirhodium model complexes. 相似文献
997.
Gil M. Barretto Peter J. Collings Dirk Bennemann Detlef Lötzsch Gerd Heppke 《Liquid crystals》2013,40(4):629-635
Optical activity measurements in the isotropic phase of two antiferroelectric liquid crystal systems in which the chirality can be varied reveal unusual behaviour of the short range order. In one system the phase sequence as the chirality is increased is smectic A, smectic C* A, and smectic Q. In the other system the phase sequence is smectic C*, smectic C* A, and smectic Q as the chirality is increased. The short range order of the isotropic phase behaves similarly for these systems, showing mean field behaviour at low chirality and far above the phase transition, but deviating from this behaviour significantly as the chirality is increased and the phase transition is approached. These optical activity results indicate how different is the short range order in the isotropic phase for these antiferroelectric liquid crystal systems and demonstrates the crucial role played by chirality. Past theoretical work that includes smecticlike fluctuations in the calculation of short range order in the isotropic phase is capable of qualitatively explaining these results. 相似文献
998.
Wübbeler G Padilla Víquez GJ Jousten K Werhahn O Elster C 《The Journal of chemical physics》2011,135(20):204304
Recently, results for the CO(2) R(12) line strength parameter have been reported, which differ significantly and are inconsistent with respect to quoted uncertainties. We investigate to what extent this inconsistency might be caused by the chosen data analysis methods. To this end, we assess and compare a parametric fitting procedure and a non-parametric approach. We apply the methods to simulated and measured line spectra, and we specify the conditions required for the safe application of the two procedures. For our present data, the corresponding conditions are satisfied for both methods, and consistent results are obtained. However, the simulations reveal that the fitting procedure can show shortcomings when the uncertainty in the wavenumber is large. 相似文献
999.
Schröder-Turk GE Varslot T de Campo L Kapfer SC Mickel W 《Langmuir : the ACS journal of surfaces and colloids》2011,27(17):10475-10483
We report that a specific realization of Schwarz's triply periodic hexagonal minimal surface is isotropic with respect to the Doi-Ohta interface tensor and simultaneously has minimal packing and stretching frustration similar to those of the commonly found cubic bicontinuous mesophases. This hexagonal surface, of symmetry P6(3)/mmc with a lattice ratio of c/a = 0.832, is therefore a likely candidate geometry for self-assembled lipid/surfactant or copolymer mesophases. Furthermore, both the peak position ratios in its powder diffraction pattern and the elastic moduli closely resemble those of the cubic bicontinuous phases. We therefore argue that a genuine possibility of experimental misidentification exists. 相似文献
1000.
Buffet A Abul Kashem MM Schlage K Couet S Röhlsberger R Rothkirch A Herzog G Metwalli E Meier R Kaune G Rawolle M Müller-Buschbaum P Gehrke R Roth SV 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):343-346
Cobalt (Co) sputter deposition onto a colloidal polymer template is investigated using grazing incidence small-angle X-ray scattering (GISAXS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). SEM and AFM data picture the sample topography, GISAXS the surface and near-surface film structure. A two-phase model is proposed to describe the time evolution of the Co growth. The presence of the colloidal template results in the correlated deposition of an ultrathin Co film on the sample surface and thus in the creation of Co capped polystyrene (PS) colloids. Well below the percolation threshold, the radial growth is restricted and only height growth is observed. 相似文献