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51.
F. J. Sowa V. G. Arcadi und J. A. Nieuwland 《Fresenius' Journal of Analytical Chemistry》1937,109(3-4):138-139
Ohne Zusammenfassung 相似文献
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Photoacoustic spectroscopy is a powerful tool to non-destructively retrieve depth related information with minimal sample preparation from heterogeneous samples. Using a phase modulated step-scan arrangement and digital signal processing a series of spectra with effectively different modulation frequencies, probing different thermal diffusion lengths within a sample, can be collected simultaneously. In this report independent component analysis is used to analyze photoacoustic data acquired from a multilayer sample in an attempt to isolate the spectra of the constituent layers. The ICA findings are compared to the approach of eliciting this information through difference spectroscopy. The results suggest that ICA may offer substantial benefits for segmentation of PAS depth profiles without user intervention. This approach can be useful in analysis of complex heterogeneous samples when one has no prior knowledge of their constituents or their distribution in the sample. 相似文献
54.
Self-diffusion of component atoms and ‘order–order’ relaxations in a B2-ordering binary system AB showing a tendency for triple-defect formation were consistently simulated by means of two Monte Carlo techniques. In view of a strict correlation between antisite-defect and vacancy concentrations the Kinetic Monte Carlo (KMC) simulations were implemented with a temperature-dependent vacancy concentration determined by means of Semi-Grand Canonical Monte Carlo (SGCMC) simulations. The Ising model of the system was completed with local-configuration-dependent saddle-point energy parameters related to vacancy mediated atomic jumps. The simulations elucidated the atomistic origin of the experimentally observed low rate of ‘order–order’ relaxations in NiAl, as well as reproduced the experimental relation between the activation energies for ‘order–order’ kinetics and Ni self-diffusion in NiAl. Higher value of the deduced activation energy for atomic migration with respect to the effective energy barriers related to individual atomic jumps indicated their high correlation. 相似文献
55.
Doyle Britton John R. Sowa Kent R. Mann 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(6):o418-o420
p‐Decylphenyl isocyanide, p‐C10H21–C6H4–NC or C17H25N, and p‐decylbenzonitrile, p‐C10H21–C6H4–CN or C17H25N, are isomorphous. The molecules lie in mirror planes, with the C6 rings perpendicular to the mirror. The packing of both molecules includes an aliphatic region, with close to ideal packing of the C10H21 chains, and an aromatic region, with phenyl ring–CN interactions. In addition, the CN ends of the molecules are also involved in a CN⋯NC dipolar interaction. 相似文献
56.
Shu‐Qin Liu Hisashi Konaka Takayoshi Kuroda‐Sowa Gui‐Ling Ning Megumu Munakata 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):m194-m196
In the title complex, [Ag2(C7H4NO4)2(C16H16S2)], each AgI atom is trigonally coordinated by one S atom of a 2,11‐dithia[3.3]paracyclophane (dtpcp) ligand, and by one N and one O atom of a 6‐carboxypyridine‐2‐carboxylate ligand. Dtpcp acts as a bidentate ligand, bridging two inversion‐related AgI atoms to give a dinuclear silver(I) compound. The dinuclear moieties are interconnected via O—H·O hydrogen bonds to form a two‐dimensional zigzag sheet. Two such sheets are interwoven viaπ–π interactions between pyridine rings, affording an interwoven bilayer network. 相似文献
57.
Alkylated Aromatic Thioethers with Aggregation‐Induced Emission Properties—Assembly and Photophysics
Steffen Riebe Marco Saccone Jacqueline Stelzer Andrea Sowa Christoph Wlper Kateryna Soloviova Cristian A. Strassert Michael Giese Jens Voskuhl 《化学:亚洲杂志》2019,14(6):814-820
In this contribution, we present the synthesis and self‐assembly of alkylated thioethers with interesting photophysical properties. To this end, the emission, absorption and excitation spectra in organic solvents and as aggregates in water were measured as well as the corresponding photoluminescence quantum yields and lifetimes. The aggregates in aqueous media were visualized and measured using transmission electron microscopy. Besides that, crystal structures of selected compounds allowed a detailed discussion of the structure–property relationship. Furthermore, the mesomorphic behavior was investigated using polarized optical microscopy (POM) as well as differential scanning calorimetry (DSC). 相似文献
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59.
In a deuterium plasma with an electron density of 2.8 × 1013 cm-3 and an electron temperature of 1850 K, the n = 2 level is coupled to the n = 6 level by absorption of short-pulsed laser light. Due to inelastic and superelastic electron collisions, the enhanced n = 6 population density is distributed to its neighbouring levels, i.e., n = 5 and n = 7. The laser-resonance fluorescences of the Balmer lines D5, D6, and D7 were measured with time resolution. The transient behaviour of the fluorescence is compared with numerical calculations, which are based on the rate equations for population densities of a system with 5 states. It is observed that the rate coefficients of Johnson cannot explain our experimental data. The coefficients of Vriens and Smeets compare favourably with the measurements within experimental errors. 相似文献
60.
da Costa EC Figueiredo W 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》2000,61(2):1134-1138
We studied in this work a three-monomer reaction model on one- and two-dimensional lattices. We have taken different reactivity rates among pairs of monomers and the reaction between two selected monomers was forbidden. We have employed the mean field and the pair approximation to decouple the equations of motion for the densities of single and pairs of monomers. We found the stationary states and the phase diagram of the model. We have shown that, in two dimensions and within the pair approximation, there is a first-order transition line between active and poisoned steady states. 相似文献