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661.
Ionic Fragmentation Mechanisms of 2,2,2‐Trifluoroethanol Following Excitation with Synchrotron Radiation 下载免费PDF全文
Yanina B. Bava Yanina Berrueta Martínez Dr. Angélica Moreno Betancourt Prof. Dr. Mauricio F. Erben Prof. Dr. Reinaldo L. Cavasso Filho Prof. Dr. Dr. Carlos O. Della Védova Prof. Dr. Rosana M. Romano 《Chemphyschem》2015,16(2):322-330
Gaseous 2,2,2‐trifluoroethanol (TFE) is excited with synchrotron radiation between 10 and 1000 eV and the ejected electrons and positive ions are detected in coincidence. In the valence‐electron energy region, the most abundant species is CH2OH+. Other fragments, including ions produced by atomic rearrangements, are also detected; the most abundant are COH+, CFH2+ and CF2H2+. The energies of electronic transitions from C 1 s, O 1 s and F 1 s orbitals to vacant molecular orbitals are determined. A site‐specific C 1 s excitation is observed. The photofragmentation mechanisms after the excitation of core‐shell electrons are inferred from analysis of the shape and slope of the coincidence between two charged fragments in the bi‐dimensional coincidence spectra. The spectra are dominated by islands that correspond to the coincidence of H+ with several charged fragments. One of the most important channels leads to the formation of CH2OH+ and CF3+ in a concerted mechanism. 相似文献
662.
Manuel Piacenza Dr. Davide Comoretto Dr. Martin Burger Dr. Valentina Morandi Dr. Franco Marabelli Prof. Dr. Carmella Martinelli Dr. Gianluca M. Farinola Prof. Dr. Antonio Cardone Dr. Giuseppe Gigli Prof. Dr. Fabio Della Sala Dr. 《Chemphyschem》2009,10(8):1284-1290
Ring the changes : Experimental Raman spectra of fluorinated and non‐fluorinated polyphenylenevinylenes are assigned according to quantum chemical calculations for oligomer model systems (see picture). Characteristic differences in the spectra can be traced back to strong inter‐ring distortion of the fluorinated compounds.
663.
Nicolas G. Martinelli Yoann Olivier Dr. Stavros Athanasopoulos Dr. Mari‐Carmen Ruiz Delgado Dr. Kathryn R. Pigg Demétrio A. da Silva Filho Dr. Roel S. Sánchez‐Carrera Dr. Elisabetta Venuti Raffaele G. Della Valle Prof. Jean‐Luc Brédas Prof. David Beljonne Dr. Jérôme Cornil Dr. 《Chemphyschem》2009,10(13):2265-2273
We have performed classical molecular dynamics simulations and quantum‐chemical calculations on molecular crystals of anthracene and perfluoropentacene. Our goal is to characterize the amplitudes of the room‐temperature molecular displacements and the corresponding thermal fluctuations in electronic transfer integrals, which constitute a key parameter for charge transport in organic semiconductors. Our calculations show that the thermal fluctuations lead to Gaussian‐like distributions of the transfer integrals centered around the values obtained for the equilibrium crystal geometry. The calculated distributions have been plugged into Monte‐Carlo simulations of hopping transport, which show that lattice vibrations impact charge transport properties to various degrees depending on the actual crystal structure. 相似文献
664.
Spectroscopic and theoretical studies were carried out for O,O,O-trimethyl selenophosphate molecule. DFT structural and vibrational calculations were performed at 6-311++G∗∗ level. Ar/matrix-FTIR spectra were recorded. A coexistence of different conformers with C3 and C1 symmetries was detected at different temperatures. Spectral evidence of a lower energy Cs conformer was found. These conclusions are consistent with the results from DFT calculations. A tentative assignment of the features observed in the Ar/matrix-FTIR spectra is proposed. 相似文献
665.
Michael Wilms Lesly V. Melendez Dr. Rohan J. Hudson Dr. Christopher R. Hall Samantha Prabath Ratnayake Prof. Dr. Trevor Smith Prof. Dr. Enrico Della Gaspera Prof. Dr. Gary Bryant Dr. Timothy U. Connell Prof. Dr. Daniel E. Gómez 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303501
We report a new composite material consisting of silver nanoparticles decorated with three-dimensional molecular organic cages based on light-absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano-resonant interaction between the porphyrin Soret band and the nanoparticle-localised surface-plasmon resonance. Time-resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited-state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2-fold current increase in photoelectrochemical water-splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications. 相似文献
666.
Structural, conformational, and configurational properties of the gaseous molecule ((fluoroformyl)imido)sulfuryl difluoride, FC(O)N=S(O)F(2), have been studied by vibrational spectroscopy (IR (gas) and Raman (liquid)) and quantum chemical calculations (HF, MP2, and B3LYP with 6-31+G* and 6-311+G* basis sets); in addition, the solid-state structure has been determined by X-ray crystallography. FC(O)N=S(O)F(2) exists in the gas phase as a mixture of a favored antiperiplanar-synperiplanar form (the S=O double bond antiperiplanar with respect to the C-N single bond, and the C=O group synperiplanar with respect to the S=N double bond) in equilibrium with less abundant antiperiplanar-antiperiplanar, synclinal-synperiplanar, and synclinal-antiperiplanar structures. The crystalline solid at 163 K (monoclinic, P2(1)/c, a = 5.1323(7) A, b = 15.942(2) A, c = 16.798(2) A, beta = 95.974(3) degrees , Z = 12) consists of three similar antiperiplanar-synperiplanar forms. 相似文献
667.
Fabiano E Sala FD Cingolani R Weimer M Görling A 《The journal of physical chemistry. A》2005,109(13):3078-3085
We have analyzed singlet and triplet excitation energies in oligothiophenes (up to five rings) using time-dependent density-functional theory (TD-DFT) with different exchange-correlation functionals and compared them with results from the approximate coupled-cluster singles and doubles model (CC2) and experimental data. The excitation energies have been calculated in geometries obtained by TD-DFT optimization of the lowest excited singlet state and in the ground-state geometries of the neutral and anionic systems. TD-DFT methods underestimate photoluminescence energies but the energy difference between singlet and triplet states shows trends with the chain-length similar to CC2. We find that the second triplet excited state is below the first singlet excited state for long oligomers in contrast with the previous assignment of Rentsch et al. (Phys.Chem. Chem. Phys. 1999, 1, 1707). Their photodetachment photoelectron spectroscopy measurements are better described by considering higher triplet excited states. 相似文献
668.
Giuseppina Costabile Giuseppe Della Pepa Claudia Vetrani Paola Vitaglione Ettore Griffo Rosalba Giacco Marilena Vitale Dominic Salamone Angela Albarosa Rivellese Giovanni Annuzzi Lutgarda Bozzetto 《Molecules (Basel, Switzerland)》2021,26(11)
Interest has arisen on the anti-inflammatory action of dietary components, including long-chain n-3 fatty acids (LCn3) and polyphenols (PP). The aim of this study was to evaluate the effects of diets rich in PP and oily fish (high-LCn3 diets) on markers of subclinical inflammation and growth factors in people at high cardiometabolic risk. Individuals with high waist circumference and one more component of metabolic syndrome were randomized to one of the following isoenergetic diets: low LCn3&PP, high LCn3, high PP, high LCn3&PP. Before and after 8 weeks, fasting and postprandial plasma concentrations of hs-CRP and fasting serum concentrations of IL-1β, IL-4, IL-6, IL-10, IL-17, INF-γ, TNF-α, FGF, VEGF, PDGF-ββ, G-CSF, and GM-CSF were determined. An oily fish diet reduced fasting plasma hs-CRP (1.28 ± 12.0, −12.5 ± 6.9, 22.5 ± 33.6, −12.2 ± 11.9; 8-week percent change, Mean ± SEM; low LCn3&PP, high LCn3, high PP, high LCn3&PP group, respectively), postprandial 6h-AUC hs-CRP (4.6 ± 16.3, −18.2 ± 7.2, 26.9 ± 35.1, −11.5 ± 11.8, 8-week percent change) and fasting IL-6 (20.8 ± 18.7, −2.44 ± 12.4, 28.1 ± 17.4, −9.6 ± 10.2), IL-17 (2.40 ± 4.9, −13.3 ± 4.9, 3.8 ± 4.43, −11.5 ± 4.7), and VEGF (−5.7 ± 5.8, −5.6 ± 7.5, 3.5 ± 5.8, −11.1 ± 5.5) (8-week percent change; p < 0.05 for LCn3 effect for all; no significant effect for PP; 2-factor ANOVA). An oily fish diet improved subclinical inflammation, while no significant effect was observed for dietary polyphenols. 相似文献
669.
C. Della Casa A. Fraleoni P. Costa Bizzarri M. Lanzi L. Paganin 《Macromolecular Symposia》2002,180(1):217-222
Polythiophene copolymers containing alkyl side chains of different length and partially functionalized with chromophoric groups have been synthesized by FeCl3 oxidative coupling of 3-alkylthiophenes and functionalized 3-alkylthiophenes. Composition, molecular weigth and configuration of the soluble fraction of the copolymers have been investigated and some structure-property correlations have been evidenced. 相似文献
670.