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151.
Markarian SA Gabrielian LS Bonora S Fagnano C 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(3):575-588
FT IR and Raman spectroscopic studies of pure diethylsulfoxide (DESO) in the liquid and in the solid states and its solutions in various solvents have been performed. Analysis of SO- and CH-stretching regions in a wide range of concentration shows that the bands may be fitted satisfactorily by considering seven components. In addition, fundamental frequencies have been assigned using ab initio calculations at the RHF/3-21G* levels. The results obtained confirm a viewpoint on a self-associative structure of DESO, and support the hypothesis of the existence of different types of intermolecular associates including both dipole-dipole and hydrogen bonding mechanisms. 相似文献
152.
Stepan M. Yayloyan Liana S. Bezhanova Ashot M. Yayloyan 《Molecular Crystals and Liquid Crystals》2013,570(1):747-754
Abstract A theoretical investigation of molecular ordering of smectic C liquuid crystals C8H17O-C6H4-C6H 4-COO-C6H4-OC8H17 { A }, C9H19O-C6H4-COO- C6H4-COO-C6H4-NO2 { B } and its binary mixtures { A+B } has been carried out by the method based on the Rayleigth-Schrodinger perturbation theory. The mutual arrangement of two molecules corresponding to the minimum of the total interaction energy between them Upair has been established. The curves of the dependence of Upair and its various contributions on displacement of molecules from each other along the molecular long X-axis and angle θ between molecules' long axes has been also computed in the minimum point vicinity. The obtained results make it possible to determine the peculiarities of the structural organization of molecules, as well as to construct a model of the structure of A and B compounds in different phases taking into account the most probable packing of molecules. 相似文献
153.
Thorsten M Bernhardt Jan Hagen Liana D Socaciu Roland Mitri? Andreas Heidenreich Jér?me Le Roux Denisia Popolan Mihai Vaida Ludger W?ste Vlasta Bonaci?-Koutecky Joshua Jortner 《Chemphyschem》2005,6(2):243-253
The ultrafast dynamics of the bimetallic cluster Ag2Au is investigated by pump-probe negative ion-to-neutral-to-positive ion (NeNePo) spectroscopy. Preparation of the neutral cluster in a highly nonequilibrium state by electron detachment from the mass-selected anion, and subsequent probing of the neutral nuclear dynamics through two-photon ionization to the cationic state, leads to strongly probe-energy-dependent transient cation-abundance signals. The origin of this pronounced time and wavelength dependence of the ionization probability on the femtosecond scale is revealed by ab initio theoretical simulations of the transient spectra. Based on the analysis of underlying dynamics, two fundamental processes involving geometry relaxation from linear to triangular structure followed by ultrafast intramolecular vibrational energy redistribution (IVR) have been identified and for the first time experimentally observed in the frame of NeNePo spectroscopy under conditions close to zero electron kinetic energy. 相似文献
154.
155.
Liana David 《Differential Geometry and its Applications》2006,24(5):542-553
We introduce and study the notion of Sasaki-Weyl manifold, which is a natural generalization of the notion of Sasaki manifold. We construct a reduction of Sasaki-Weyl manifolds and we show that it commutes with several reductions already existing in the literature. 相似文献
156.
We announce the existence of metrics of positive sectional curvature onthe 3-Sasakian reductions of S11 by an isometric circleaction. 相似文献
157.
Aglaia Raluca Deac Cristina Morar Graziella Liana Turdean Mircea Darabantu Emese Gál Attila Bende Liana Maria Muresan 《Journal of Solid State Electrochemistry》2016,20(11):3071-3081
In an attempt to increase the stability and efficiency of hemin-modified electrodes, the present work reports the preparation of a new modified glassy carbon electrode obtained by immobilization of hemin (Hm) on the electrode surface together with a new N-substituted melamine (2,4,6-triamino-1,3,5-triazine) based G-2 dendrimer comprising p-aminophenol as peripheral unit (Den) or with one of its analogues, a melamine G-0 dimer (Dim). Basic structural features, able to determine intimate relationships between Hm and Dim (or Den) at room temperature in solid state, were evidenced with the use of vibrational analysis carried out by FT-IR. This method revealed contacts between Hm and Dim or Den respectively as H-bond interactions, proton-interchange, and π-π stacking interactions. The new modified electrodes were characterized by cyclic voltammetry and electrochemical impedance spectroscopy and tested for amperometric detection of H2O2. In this purpose, GC/Hm-Dim electrode exhibited better catalytic properties than GC/Hm-Den electrode, but lower stability. 相似文献
158.
Ivan Mosiagin Dr. Anthony J. Fernandes Alena Budinská Liana Hayriyan Prof. Dr. Kai E. O. Ylijoki Prof. Dr. Dmitry Katayev 《Angewandte Chemie (International ed. in English)》2023,62(41):e202310851
Nitroaromatic compounds represent one of the essential classes of molecules that are widely used as feedstock for the synthesis of intermediates, the preparation of nitro-derived pharmaceuticals, agrochemicals, and materials on both laboratory and industrial scales. We herein disclose the efficient, mild, and catalytic ipso-nitration of organotrimethylsilanes, enabled by an electrophilic N-nitrosaccharin reagent and allows chemoselective nitration under mild reaction conditions, while exhibiting remarkable substrate generality and functional group compatibility. Additionally, the reaction conditions proved to be orthogonal to other common functionalities, allowing programming of molecular complexity via successive transformations or late-stage nitration. Detailed mechanistic investigation by experimental and computational approaches strongly supported a classical electrophilic aromatic substitution (SEAr) mechanism, which was found to proceed through a highly ordered transition state. 相似文献
159.
Nilo Zanatta Claudia C. Madruga Patricia C. Marisco Luciana S. Da Rosa Liana Da S. Fernandes Darlene C. Flores Alex F. C. Flores Robert A. Burrow Helio G. Bonacorso Marcos A P. Martins 《Journal of heterocyclic chemistry》2008,45(1):221-227
160.