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51.
Soluble Flavanthrone Derivatives: Synthesis,Characterization, and Application to Organic Light‐Emitting Diodes 下载免费PDF全文
Kamil Kotwica Dr. Piotr Bujak Dr. Przemyslaw Data Wojciech Krzywiec Damian Wamil Dr. Piotr A. Gunka Lukasz Skorka Dr. Tomasz Jaroch Prof. Robert Nowakowski Prof. Adam Pron Prof. Andrew Monkman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7978-7986
Simple modification of benzo[h]benz[5,6]acridino[2,1,9,8‐klmna]acridine‐8,16‐dione, an old and almost‐forgotten vat dye, by reduction of its carbonyl groups and subsequent O‐alkylation, yields solution‐processable, electroactive, conjugated compounds of the periazaacene type, suitable for the use in organic electronics. Their electrochemically determined ionization potential and electron affinity of about 5.2 and ?3.2 eV, respectively, are essentially independent of the length of the alkoxyl substituent and in good agreement with DFT calculations. The crystal structure of 8,16‐dioctyloxybenzo[h]benz[5,6]acridino[2,1,9,8‐klmna]acridine ( FC‐8 ), the most promising compound, was solved. It crystallizes in space group P and forms π‐stacked columns held together in the 3D structure by dispersion forces, mainly between interdigitated alkyl chains. Molecules of FC‐8 have a strong tendency to self‐organize in monolayers deposited on a highly oriented pyrolytic graphite surface, as observed by STM. 8,16‐Dialkoxybenzo[h]benz[5,6]acridino[2,1,9,8‐klmna]acridines are highly luminescent, and all have photoluminescence quantum yields of about 80 %. They show efficient electroluminescence, and can be used as guest molecules with a 4,4′‐bis(N‐carbazolyl)‐1,1′‐biphenyl host in guest/host‐type organic light‐emitting diodes. The best fabricated diodes showed a luminance of about 1900 cd m?12, a luminance efficiency of about 3 cd A?1, and external quantum efficiencies exceeding 0.9 %. 相似文献
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Eric A. Margulies Dr. Yi‐Lin Wu Przemyslaw Gawel Dr. Stephen A. Miller Dr. Leah E. Shoer Prof. Dr. Richard D. Schaller Prof. Dr. François Diederich Prof. Dr. Michael R. Wasielewski 《Angewandte Chemie (International ed. in English)》2015,54(30):8679-8683
Thin films of 5,11‐dicyano‐6,12‐diphenyltetracene ( TcCN ) have been studied for their ability to undergo singlet exciton fission (SF). Functionalization of tetracene with cyano substituents yields a more stable chromophore with favorable energetics for exoergic SF (2E(T1)?E(S1)=?0.17 eV), where S1 and T1 are singlet and triplet excitons, respectively. As a result of tuning the triplet‐state energy, SF is faster in TcCN relative to the corresponding endoergic process in tetracene. SF proceeds with two time constants in the film samples (τ=0.8±0.2 ps and τ=23±3 ps), which is attributed to structural disorder within the film giving rise to one population with a favorable interchromophore geometry, which undergoes rapid SF, and a second population in which the initially formed singlet exciton must diffuse to a site at which this favorable geometry exists. A triplet yield analysis using transient absorption spectra indicates the formation of 1.6±0.3 triplets per initial excited state. 相似文献
53.
Przemyslaw Dera Barbara Lavina Yue Meng Vitali B. Prakapenka 《Journal of solid state chemistry》2011,184(11):3040-3049
Synchrotron single-crystal x-ray diffraction experiments have been performed on corundum-type Cr2O3 up to a pressure of 55 GPa in Ne and He pressure transmitting media. Diffraction experiments were complemented by measurements of optical absorption spectra with single crystal samples up to 60 GPa. Results of the diffraction data analysis rule out the earlier reported monoclinic distortion at 15–30 GPa, but indicate evidence of two discontinuous transitions of electronic or magnetic nature, most likely associated with a change in magnetic ordering and charge transfer. The compression mechanism established from single crystal refinements indicates much smaller distortion of the Cr3+ coordination environment than was previously assumed. 相似文献
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Sakuntala Gupta Tanmay Choudhury Ewelina Dmochowska Przemyslaw Kula Fabio Borbone Roberto Centore 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(11):1459-1464
The title compound, C37H42, is a new mesogenic compound containing the fluorene moiety. It exhibits enantiotropic nematic liquid crystalline behaviour with melting at 125 °C and isotropization at 175 °C. The crystallographically independent unit contains two molecules oriented face‐to‐edge with respect to each other. The two molecules have nearly the same conformation of the bis‐phenyl fluorene moiety. The molecular packing in the crystal phase is nematic‐like. 相似文献
56.
A laser Doppler vibrometer (LDV) is described in which holographic optical elements are used to provide the interferometer reference and object illumination beams. A complementary metal-oxide semiconductor camera, incorporating a digital signal processor, is used to carry out real-time signal processing of the interferometer output to allow multipoint LDV to be implemented. 相似文献
57.
Lorenzo Torrisi Marcin Rosinski Dominika Terwinska Przemyslaw Tchorz Mariapompea Cutroneo Alfio Torrisi 《等离子体物理论文集》2020,60(4):e201900187
Non-equilibrium plasma was obtained by irradiating Al foils in vacuum with a femtosecond (fs) laser at intensities of the order of 1018 W/cm2. Protons and other light ions were accelerated in the forward direction by using the target-normal-sheath acceleration regime. Time-of-flight technique was employed to measure the ions' kinetic energy using SiC detectors placed at known distances and angles. The ion acceleration was monitored under different conditions of laser focal position, laser pulse energy, and laser contrast. The target was irradiated using different thicknesses and anti-reflecting graphene films. By optimizing the laser parameters, irradiation conditions, and target properties, it was possible to accelerate up to 2.3 MeV per charge state, as will be presented and discussed. 相似文献
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