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排序方式: 共有114条查询结果,搜索用时 15 毫秒
1.
Diana C. Skigin Miriam L. Gigli Marina E. Inchaussandague Néstor E. Bonomo Claudio I. Valencia 《International Journal of Infrared and Millimeter Waves》1993,14(6):1323-1339
Theoriginal and theenhanced Maxwell-Garnett estimates for the permittivity of a particulate medium are applied to the reflection of light by a composite dielectric slab. The reflection coefficients for incident s and p polarizations are calculated and some curves are plotted and discussed. 相似文献
2.
G. Balducci L. Bencivenni G. De Rosa R. Gigli B. Martine S.Nunziante Cesaro 《Journal of Molecular Structure》1980
The infrared and Raman spectra of some cyclopentadienyl compounds of the transition metals, namely Ti(C5H5)Cl3 and M(C5H5)2Cl2 (M = Ti, Zr and Hf), are reported and discussed. The infrared spectra of the gaseous species isolated in argon matrices at 10 K provide structural information about the single molecules. Particular attention has been paid to the low-frequency region in order to achieve more reliable assignments for the internal-rotation modes. The structural data and the fundamental frequencies derived from the spectra are employed in a calculation of the thermodynamic functions for these compounds in the ideal gas state. 相似文献
3.
Tedesco E Della F Favaretto L Barbarella G Albesa-Jové D Pisignano D Gigli G Cingolani R Harris KD 《Journal of the American Chemical Society》2003,125(40):12277-12283
The "rigid-core" material 3,5-dimethyl-2,3'-bis(3-methylthiophene)-dithieno[3,2-b:',3'-d]thiophene-4,4-dioxide (DTTOMe4) has the highest photoluminescence ever reported for thiophene-based molecules in the solid state. We report the structure of this material, determined directly from powder X-ray diffraction data using the Genetic Algorithm method for structure solution, followed by Rietveld refinement, and the structural properties are discussed in relation to the structures of the corresponding subsystems DTTO and DTTOMe. While the crystal structures of the latter compounds contain cofacial dimers, the crystal structure of DTTOMe4 comprises layers of molecules aligned in an antiparallel fashion. Intermediate neglect of differential overlap with single configuration interaction (INDO/SCI) calculations on the intermolecular interactions in the three crystal structures show that the different solid-state photoluminescence efficiencies of DTTOMe4, DTTOMe, and DTTO cannot be correlated with the different types of dipole-dipole alignment in the solid state. Instead, photoluminescence efficiencies correlate well with the rate of formation of nonradiatively decaying charge-transfer pairs upon photoexcitation. Because of larger intermolecular distances in DTTOMe4, the photoluminescence is less effectively quenched by charge-transfer processes than in DTTOMe and DTTO. 相似文献
4.
Raganato MF Vitale V Della Sala F Anni M Cingolani R Gigli G Favaretto L Barbarella G Weimer M Görling A 《The Journal of chemical physics》2004,121(8):3784-3791
Modifications of the optical properties of dimethyl-dithienothiophenes due to the oxygen functionalization of the central sulfur atom are investigated. We have measured the absorption, photoluminescence (PL) and PL excitation spectra, the PL quantum efficiencies, and the PL decay times. These experimental results are interpreted and compared with first-principles time-dependent density-functional theory calculations, which predict, for the considered systems, excitation and emission energies with an accuracy of 0.1 eV. It is found that the oxygenation strongly changes optical and photophysical properties. These effects are related to the modifications of the energetically lowest-unoccupied molecular orbital and the energetically second highest occupied one, which change the relative position of the two lowest singlet and triplet excited states. 相似文献
5.
The thermal functions S0T, -(G0T-H0O)/T and (H0T-H0O) have been calculated from structural and spectroscopic data for the gaseous organometallics C5H5BeX (X = Cl, Br and BH4), C5H5MX3 (M = Ti and Ge; X = Cl, Br and I) and CH3TiX3 (X = Cl, Br and I). The rotational barriers of the C5H5 and CH3 groups have been evaluated and discussed. 相似文献
6.
Nicola Gigli 《Geometric And Functional Analysis》2012,22(4):990-999
We prove existence of optimal maps in non branching spaces with Ricci curvature bounded from below. The approach we adopt makes no use of Kantorovich potentials. 相似文献
7.
A. GabrielliI. D?Antone F.M. GiorgiI. Lax M. LolliR. De Leo G. De RobertisM. Foresta F. LoddoA. Ranieri G. CosentinoP. Finocchiaro A.D. PappalardoR. Fonte C. CalviniP. Musico P. OttonelloF. Cusanno F. GaribaldiT. Gigli F. GioveB. Maraviglia F. MeddiA. Rivetti 《Nuclear Physics B - Proceedings Supplements》2011,215(1):165-167
8.
Rendiconti del Circolo Matematico di Palermo Series 1 - 相似文献
9.
Guido Gigli 《Fresenius' Journal of Analytical Chemistry》1902,41(6):366
Ohne Zusammenfassung 相似文献
10.
Buonsanti R Carlino E Giannini C Altamura D De Marco L Giannuzzi R Manca M Gigli G Cozzoli PD 《Journal of the American Chemical Society》2011,133(47):19216-19239
A colloidal crystal-splitting growth regime has been accessed, in which TiO(2) nanocrystals, selectively trapped in the metastable anatase phase, can evolve to anisotropic shapes with tunable hyperbranched topologies over a broad size interval. The synthetic strategy relies on a nonaqueous sol-gel route involving programmed activation of aminolysis and pyrolysis of titanium carboxylate complexes in hot surfactant media via a simple multi-injection reactant delivery technique. Detailed investigations indicate that the branched objects initially formed upon the aminolysis reaction possess a strained monocrystalline skeleton, while their corresponding larger derivatives grown in the subsequent pyrolysis stage accommodate additional arms crystallographically decoupled from the lattice underneath. The complex evolution of the nanoarchitectures is rationalized within the frame of complementary mechanistic arguments. Thermodynamic pathways, determined by the shape-directing effect of the anatase structure and free-energy changes accompanying branching and anisotropic development, are considered to interplay with kinetic processes, related to diffusion-limited, spatially inhomogeneous monomer fluxes, lattice symmetry breaking at transient Ti(5)O(5) domains, and surfactant-induced stabilization. Finally, as a proof of functionality, the fabrication of dye-sensitized solar cells based on thin-film photoelectrodes that incorporate networked branched nanocrystals with intact crystal structure and geometric features is demonstrated. An energy conversion efficiency of 6.2% has been achieved with standard device configuration, which significantly overcomes the best performance ever approached with previously documented prototypes of split TiO(2) nanostructures. Analysis of the relevant photovoltaic parameters reveals that the utilized branched building blocks indeed offer light-harvesting and charge-collecting properties that can overwhelm detrimental electron losses due to recombination and trapping events. 相似文献