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51.
A theoretical study on the reaction mechanism of methyl salicylate (MeSA), a green leaf volatile organic compound with OH radical and ozone, has been carried out using density functional theory methods using B3LYP, M06‐2X and MPW1K functionals with 6‐311++G(d,p) basis set. The atmospheric degradation pathways of MeSA with OH radical are studied under two different pathways, viz. H‐atom abstraction and electrophilic addition of OH radical. The hydrogen abstraction from –OH group is found to be the dominant reaction channel with small barrier height. Likewise, the electrophilic addition of OH radicals at the para position of MeSA is found to be favourable rather than the ortho and meta positions because of the small barrier height. However, the reaction of MeSA with respect to the addition of O3 is initiated only through the cycloaddition to the C?C bond, resulting in primary ozonide. The Arrhenius plot for most of the addition reaction shows positive temperature dependence, while for the abstraction reaction, it exhibits negative temperature dependence over the temperature range of 278–350 K. The calculated theoretical rate constants are in good agreement with available experimental data. Overall, the addition of both OH radical and ozone possesses ability to degrade MeSA, but slower when compared with the Cl radical. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
52.
Vibrational circular dichroism (VCD) spectra were measured on the chloroform solutions of a series of mixed-ligand diamagnetic Co(III) complexes, [Co(tfac)(n)(acac)(3-n)] (n = 0-3, tfac = 1,1,1-trifluoro-2,4-pentanedionato; acac = acetylacetonato). Distinct differences were observed in the VCD spectra among the geometrical isomers of the same ligand composition. Such differentiation was hardly possible by their infra-red spectra alone. The structural identification of these isomers was performed in conjunction with DFT calculations. 相似文献
53.
Prof. Dr. Akira Watanabe Dr. Hisako Tamai Mrs. Kyoko Hayashi 《Colloid and polymer science》1977,255(8):773-781
Summary The adsorption of ionic dyes, the builder effect, and the interaction between ionic dyes and surface active agents were investigated by using the electrocapillarity at oil/water interfaces. The oil phase was the solution of tetra-butylammonium chloride, sodium cetylsulphate, cetylpyridinium chloride or stearylamine in methylisobutylketone, and the water phase contained various dyes in addition to the inorganic electrolyte. The interfacial tension decreased over the anodic (or cathodic) polarization range, when anionic (or cationic) dyes were added to the water phase, thus indicating the dye adsorption at the interface. The interfacial excess of dye ions was found to increase linearly with the cubic roots of dye concentration and of ionic strength of the water phase. The counterion binding took place at the oil/water interface between anionic (or cationic) dyes and positive (or negative) head groups of surface active agent ions adsorbed at the interface. It was found that the equilibrium constants of binding between anionic dyes and cationic surface active agents at the oil/water interface were of the same order of magnitude as, and a little larger than, those obtained at the water bulk phase.
With 12 figures and 2 tables 相似文献
Zusammenfassung An Öl-Wasser-Grenzflächen wurde die Adsorption ionischer Farbstoffe, die Füllerwirkung und die Wechselwirkung zwischen ionischen Farbstoffen und grenzflächenaktiven Verbindungen mit Hilfe der Elektrokapillarität untersucht. Die Ölphase bestand aus einer Lösung von Tetrabutylammoniumchlorid, Natriumcetylsulfat und Cetylpyridiniumchlorid oder Stearylamin in Methylisobutylketon. Die wässerige Phase enthielt verschiedene Farbstoffe und anorganische Elektrolyte. Die Grenzflächenspannung wurde durch anodische (bzw. kathodische) Polarisation erniedrigt, wenn anionischer (bzw. kationischer) Farbstoff zur Wasserphase gegeben wurde. Dies zeigt an, daß Farbstoff an der Grenzfläche adsorbiert wird. Die Grenzflächenkonzentration des Farbstoffions nimmt linear mit der Kubikwurzel der Farbstoffkonzentration und mit der Ionenstärke zu. Als Gegenionen für die anionischen (bzw. kationischen) Farbstoffe an der Grenzfläche wirken die positiven (bzw. negativen) Endgruppen der Tenside, die ebenfalls in der Grenzschicht adsorbiert sind. Die Gleichgewichtskonstanten für die Wechselwirkung zwischen den ionischen Farbstoffen und den grenzflächenaktiven Verbindungen sind an der Öl-Wasser-Grenzfläche von der gleichen Größenordnung bzw. geringfügig größer als in der wässerigen Volumenphase.
With 12 figures and 2 tables 相似文献
54.
Kazuaki Sakoda Takashi Kuroda NaokiI keda Takaaki Mano Yoshimasa Sugimoto Tetsuyuki Ochiai Keiji Kuroda Shunsuke Ohkouchi Nobuyuki Koguchi Kiyoshi Asakawa 《中国光学快报(英文版)》2009,7(10):879-881
We fabricate photonic crystal slab microcavities embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of the quantum dots is confirmed by the micro photoluminescence measurement. The resonance wavelengths, widths, and polarization are consistent with numerical simulation results. 相似文献
55.
Masakatsu Matsumoto Kazutaka Yamada Harumi Ishikawa Naoyuki Hoshiya Nobuko Watanabe Hisako K. Ijuin 《Tetrahedron letters》2006,47(47):8407-8411
Bicyclic dioxetanes 2a, 2b, and 3, bearing a 3-hydroxy-5-naphthylphenyl moiety underwent charge-transfer-induced decomposition with accompanying emission of light, the color of which changed from red to blue responding to a complex of crown ether with potassium t-butoxide used as a base. Furthermore, they afforded unusual chemiluminescence, the spectra of which displayed two peaks in some cases. It was observed for chemiluminescences in the coordination sphere with crown ether that their spectra did not coincide with the spectra of authentic emitters. 相似文献
56.
M. Fernandes F. A. Almeida Paz J. F. Mano V. de Zea Bermudez 《Crystal Research and Technology》2014,49(6):418-430
The influence of myristyl alcohol (CH3(CH2)13OH), cetyl alcohol (CH3(CH2)15OH) and behenyl alcohol (CH3(CH2)21OH) on the structure, morphology, size and surface properties of calcium carbonate (CaCO3) has been investigated. Changes in the nature of the washing solvent, in the CnOH/Ca2+ and CO32−/Ca2+ molar ratios and in temperature have been also evaluated. The sole polymorph produced was rhombohedral calcite. At room temperature, while microspheres composed of submicrocubes were produced at a high molar ratio CO32−/Ca2+ and low CH3(CH2)15OH concentration, a stoichiometric molar ratio CO32−/Ca2+ and high CH3(CH2)15OH concentration induced the formation of microcubes and microboxes. In the presence of this alkanol (12 % molar) a significant enhancement of the water contact angle (ca. 40 °) resulted in a sample obtained with a stoichiometric CO32−/Ca2+ ratio. These results emphasize the key role played by the three non‐ionic surfactants in the formation of materials with variable crystal shape and wettability and thus technological interest for a range of applications. 相似文献
57.
Shaji Varghese Samuthira Nagarajan Mercy R. Benzigar Ajayan Mano Zeid A. ALOthman George Allen Gnana Raj Ajayan Vinu 《Tetrahedron letters》2012,53(12):1485-1489
A novel bimetallic nanoporous FeAl-KIT-5 catalyst with a cage type porous structure and a high surface area has been prepared for the hydroarylation of styrene and arylacetylenes to afford 1,1-diarylalkanes and 1,1-diarylalkenes, respectively. The catalyst was found to be highly active, and selective, affording a high yield of substituted alkanes and alkenes. The catalyst also showed much higher activity as compared to those of other nanoporous catalysts such as AlSBA-15, AlKIT-5, and FeKIT-5, and can be reused several times without much loss of its activity. 相似文献
58.
Madalena Dionísio María Teresa Viciosa Yaming Wang Joo F. Mano 《Macromolecular rapid communications》2005,26(17):1423-1427
Summary: Dielectric relaxation spectroscopy was used to monitor the development of crystallinity in poly(L ‐lactic acid) (PLLA) at 80 °C. The continuous shifting of the main loss peak towards lower frequencies was modelled considering the evolution of three relaxation processes: the α‐process of the bulk‐like (non‐restricted) amorphous phase, the α‐process of the amorphous fraction influenced by the crystalline structure and the β‐relaxation. It was found that the shape parameters and the position of the loss peaks are essentially constants during crystallisation, just with their dielectric strengths varying. This indicates that (i) the two segmental dynamics process develops independently and (ii) the dynamics features of the (slower) confined amorphous phase do not change during crystallisation. Optical microscopy results showed that a correlation exists between the evolution of the spherulitic morphology and the dielectric strength of the α‐processes.
59.
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