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排序方式: 共有846条查询结果,搜索用时 46 毫秒
41.
Dipl. Chem. Keven Muller Dr. Yu Sun Andreas Heimermann Fabian Menges Gereon Niedner‐Schatteburg Christoph van Wüllen Prof. Dr. Werner R. Thiel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(24):7825-7834
Pyridinylazolato (N–N′) ruthenium(II) complexes of the type [(N–N′)RuCl(PMe3)3] have been obtained in high yields by treating the corresponding functionalised azolylpyridines with [RuCl2(PMe3)4] in the presence of a base. 15N NMR spectroscopy was used to elucidate the electronic influence of the substituents attached to the azolyl ring. The findings are in agreement with slight differences in the bond lengths of the ruthenium complexes. Furthermore, the electronic nature of the azolate moiety modulates the catalytic activity of the ruthenium complexes in the hydrogenation of carbon dioxide under supercritical conditions and in the transfer hydrogenation of acetophenone. DFT calculations were performed to shed light on the mechanism of the hydrogenation of carbon dioxide and to clarify the impact of the electronic nature of the pyridinylazolate ligands. 相似文献
42.
In the present work a modular pathway towards the synthesis of a new versatile MRI contrast agent is reported and its physico-chemical properties are described. Two different functional groups were attached on two arms of the gadolinium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA) in order to get a platform able to bind one probe designed to target specific biological marker and a fluorescent molecule likely to be used for optical imaging. The nuclear magnetic relaxation dispersion (NMRD) profile, the oxygen-17 relaxometric NMR study and stability assessment versus transmetalation of the Gd-complex show that this new contrast agent has a relaxivity and transmetalation stability similar to Gd–DOTA. 相似文献
43.
M. Sc. Shih‐Fan Hsu Dipl.‐Chem. Susanne Rommel M. Sc. Philipp Eversfield Dr. Keven Muller Prof. Dr. Elias Klemm Prof. Dr. Werner R. Thiel Prof. Dr. Bernd Plietker 《Angewandte Chemie (International ed. in English)》2014,53(27):7074-7078
Apart from energy generation, the storage and liberation of energy are among the major problems in establishing a sustainable energy supply chain. Herein we report the development of a rechargeable H2 battery which is based on the principle of the Ru‐catalyzed hydrogenation of CO2 to formic acid (charging process) and the Ru‐catalyzed decomposition of formic acid to CO2 and H2 (discharging process). Both processes are driven by the same catalyst at elevated temperature either under pressure (charging process) or pressure‐free conditions (discharging process). Up to five charging–discharging cycles were performed without decrease of storage capacity. The resulting CO2/H2 mixture is free of CO and can be employed directly in fuel‐cell technology. 相似文献
44.
Laurence Muhr Steve Pontvianne Katalin Selmeczi Cdric Paris Sandrine Boschi‐Muller Laetitia Canabady‐Rochelle 《Journal of separation science》2020,43(11):2031-2041
Some metal‐chelating peptides have antioxidant properties, with potential nutrition, health, and cosmetics applications. This study aimed to simulate their separation on immobilized metal ion affinity chromatography from their affinity constant for immobilized metal ion determined in surface plasmon resonance, both technics are based on peptide‐metal ion interactions. In our approach, first, the affinity constant of synthetic peptides was determined by surface plasmon resonance and used as input data to numerically simulate the chromatographic separation with a transport‐dispersive model based on Langmuir adsorption isotherm. Then, chromatographic separation was applied on the same peptides to determine their retention time and compare this experimental tR with the simulated tR obtained from simulation from surface plasmon resonance data. For the investigated peptides, the relative values of tR were comparable. Hence, our study demonstrated the pertinence of such numerical simulation correlating immobilized metal ion affinity chromatography and surface plasmon resonance. 相似文献
45.
We studied the growth of solid anisotropic domains in a monolayer made of pure NBD-stearic acid spread on water. These domains have a needle-like shape. We found that the growth process is limited by the interface kinetics, and not by the diffusion of impurities. Moreover the longitudinal growth velocity of these needles is simply proportional to the overpressure, as for a rough interface. No such law was found for the width of the needles. 相似文献
46.
The anisotropic form factor of polystyrene (PS) chains during tensile and simple shear flows in the melt has been measured by small angle neutron scattering (SANS) on quenched samples containing deuterium labeled chains. For all tensile experiments, carried out in a wide range of strain rates, including linear viscoelastic behaviour, the chain conformation is well predicted by a temporary network model involving the recoverable strain. For binary blends of two PS with different molecular weight, the technique allows to characterize the chain conformation of either species. The scattering patterns of sheared samples show that the principal directions of molecular orientation depend on the magnitude of the scattering vector q: At high q (local level on the chain) the orientation is close to 45° with respect to the shear axis, whereas at low q the chains appear to be almost aligned with the stream lines. 相似文献
47.
48.
Deep level transient spectroscopy has been used to observe the reduced concentrations of vacancy-related defects in γ-irradiated n-type Si containing hydrogen atoms. Data are presented on the efficiency and depth of this damage reduction as a function of the duration and temperature of the exposure to the plasma used to introduce the atomic hydrogen. A 3-hour exposure in an H plasma at 300°C prior to irradiation reduced the concentrations of the O-V, V-V and P-V centres by half or more to a depth of ~20 μm, compared to the control samples. 相似文献
49.
50.
Roger M Guenoun P Muller F Belloni L Delsanti M 《The European physical journal. E, Soft matter》2002,9(4):313-326
The concentration profiles of monomers and counterions in star-branched polyelectrolyte micelles are calculated through Monte
Carlo simulations, using the freely jointed chain model. We have investigated the onset of different regimes corresponding
to the spherical and Manning condensation of counterions as a function of the strength of the Coulomb coupling. The Monte
Carlo results are in fair agreement with the predictions of Self-Consistent-Field analytical models. We have simulated a real
system of diblock copolymer micelles of (sodium-polystyrene-sulfonate)(NaPSS)-(polyethylene-propylene)(PEP) with f = 54 hydrophilic branches of N = 251 monomers at room temperature in salt-free solution. The calculated form factor compares nicely with our neutron scattering
data.
Received 18 July 2002 and Received in final form 11 October 2002
RID="a"
ID="a"e-mail: roger@drecam.saclay.cea.fr 相似文献