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61.
Studies on synthesis, structures, and photophysics have been carried out for a series of luminescent copper(I) halide complexes with the chelating ligand, 1,2-bis[diphenylphosphino]benzene (dppb). The complexes studied are halogen-bridged dinuclear complexes, [Cu(mu-X)dppb]2 (X = I (1), Br (2), Cl (3)), and a mononuclear complex, CuI(dppb)(PPh3) (4). These complexes in the solid state exhibit intense blue-green photoluminescence with microsecond lifetimes (emission peaks, lambdamax = 492-533 nm; quantum yields, Phi = 0.6-0.8; and lifetimes, tau = 4.0-10.4 mus) at 298 K. In 2-methyltetrahydrofuran (2mTHF) solutions at 298 K, only 1 and 4 show weaker emission (Phi = 0.009) with shorter lifetimes (tau = 0.35 and 0.23 mus) and red-shifted spectra (lambdamax = 543 and 546 nm). The emission in the solid state originates from the (M + X)LCT excited state with a distorted-tetrahedral conformation, in which emissive excited states, 1(M + X)LCT and 3(M + X)LCT, are in equilibrium with an energy difference of approximately 2 kcal/mol. On the other hand, the complexes in the 2mTHF solutions emit from the MLCT excited state with an energetically favorable flattened conformation in the temperature range of 298-130 K. The flattened geometry with equilibrated 1MLCT and 3MLCT states has a nonradiative rate at least 2 orders of magnitude larger than that of the distorted-tetrahedral geometry, leading to a much smaller emission quantum yield (Phi = 0.009) at 298 K. Since the flattening motion is markedly suppressed below 130 K, the emission observed in 2mTHF below 130 K is considered to occur principally from the (M + X)LCT state with a distorted-tetrahedral geometry. To interpret the photophysics of 1 and 4 in both the solid and solution states, we have proposed the "2-conformations with 2-spin-states model (2C x 2S model)". The electroluminescence device using (1) as a green emissive dopant showed a moderate EL efficiency; luminous efficiency = 10.4 cd/A, power efficiency = 4.2 lm/W at 93 cd/m(2), and maximum external quantum efficiency = 4.8%. 相似文献
62.
The catalytic activity of a base metal-terpyridine complex immobilized on silica gel ( M(tpy)X2@SiO2/H2O : M=Mn, Fe, Co, Ni, Cu; X=Cl, Br) for hydrosilylation was investigated. Co(tpy)Br2@SiO2/H2O in the presence of NaBHEt3 exhibited the highest catalytic activity for hydrosilylation of 1-octene with diphenylsilane (Ph2SiH2) to form the anti-Markovnikov-type hydrosilylation compound as the main product. The reusability of Co(tpy)Br2@SiO2/H2O activated by NaBHEt3 was examined. It was found that the catalytic activity decreased with repeated use because of the peeling off of the Co complex anchor portion from the silica gel surface upon the attack of NaBHEt3. The introduction of Co(OAc)2 instead of CoBr2 to silica gel formed Co(tpy)(OAc)2- and Co(tpy)(OH)2-immobilized silica gel, which exhibited catalytic activity for the hydrosilylation in the absence of an activator such as NaBHEt3. The glassware in which Co(tpy)(OH)2 was immobilized on the inner wall was prepared. It was found that the hydrosilylation catalytically occurred on the surface of a pretreated glassware and that the catalytic activity did not decrease even after 10 repeated uses. 相似文献
63.
Umeki T Asobe M Nishida Y Tadanaga O Magari K Yanagawa T Suzuki H 《Optics letters》2007,32(9):1129-1131
We achieved apodization in a quasi-phase-matched wavelength converter. The new design yields a large bandwidth and a flat phase-matching response with a high conversion efficiency. Using the method, we demonstrate widely tunable 3.4 microm band difference frequency generation in a LiNbO3 ridge waveguide. 相似文献
64.
Dr. Takashi Fukushima Dr. Ryoichi Fukuda Dr. Katsuaki Kobayashi Prof. Giovanni F. Caramori Prof. Gernot Frenking Prof. Masahiro Ehara Prof. Koji Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):106-110
The proton‐induced Ru?C bond variation, which was previously found to be relevant in the water oxidation, has been investigated by using cyclometalated ruthenium complexes with three phenanthroline (phen) isomers. The designed complexes, [Ru(bpy)2(1,5‐phen)]+ ([ 2 ]+), [Ru(bpy)2(1,6‐phen)]+ ([ 3 ]+), and [Ru(bpy)2(1,7‐phen)]+ ([ 4 ]+) were newly synthesized and their structural and electronic properties were analyzed by various spectroscopy and theoretical protocols. Protonation of [ 4 ]+ triggered profound electronic structural change to form remote N‐heterocyclic carbene (rNHC), whereas protonation of [ 2 ]+ and [ 3 ]+ did not affect their structures. It was found that changes in the electronic structure of phen beyond classical resonance forms control the rNHC behavior. The present study provides new insights into the ligand design of related ruthenium catalysts. 相似文献
65.
Cyclometalated ruthenium(II) complexes having acridine moieties have been synthesized and characterized by spectroscopic methods. Protonation of the acridine nitrogen of the ruthenium(II) complexes not only causes dynamic equilibrium with remote N-heterocyclic carbene Ru═C complexes but also generates the NAD(+)/NADH redox function driven by a proton-coupled two-electron transfer accompanying a reversible C-H bond formation in the pyridinium ring. 相似文献
66.
Bactericidal core-shell paramagnetic nanoparticles functionalized with poly(hexamethylene biguanide)
Bromberg L Chang EP Hatton TA Concheiro A Magariños B Alvarez-Lorenzo C 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):420-429
Bactericidal paramagnetic particles were obtained either through the attachment of a conjugate of poly(ethyleneimine) (PEI) and poly(hexamethylene biguanide) (PHMBG) to the surface of magnetite (Fe(3)O(4)) particles, or via the sol-gel encapsulation of magnetite particles with a functional silane (3-glycidoxypropyl trimethoxysilane) and subsequent binding of the polysiloxane shell by the amine/imine groups of PHMBG. The encapsulated core-shell particles possess a high saturation magnetization, which is preserved for more than 10 months while in contact with air in aqueous suspensions. The minimum inhibitory concentration (MIC) of the encapsulated particles for eight types of bacteria was size-dependent, with polydisperse submillimeter particles possessing a several-fold higher MIC than analogous particles sized below 250 nm. The encapsulated particles are biocompatible and nontoxic to mammalian cells such as mouse fibroblasts. The particles efficiently bind both glycopeptide components mimicking the gram-positive bacteria membranes and whole bacteria, and possess broad-range bactericidal activity. The cell-particle complexes can be captured, manipulated, and removed by means of a magnet. 相似文献
67.
Tokuno T Nogi M Jiu J Sugahara T Suganuma K 《Langmuir : the ACS journal of surfaces and colloids》2012,28(25):9298-9302
To shore up the demand of transparent electrodes for wide applications such as organic light emitting diodes and solar cells, transparent electrodes are required as an alternative for indium tin oxide electrodes. Herein the self-assembly method with a bubble template paves the way for cost-effective fabrication of transparent electrodes with high conductivity and transparency using self-assembly of silver nanowires (AgNWs) in a bubble template. AgNWs were first dispersed in water that was bubbled with a surfactant and a thickening agent. Furthermore, these AgNWs were assembled by lining along the bubble ridges. When the bubbles containing the AgNWs were sandwiched between two glass substrates, the bubble ridges including the AgNWs formed continuous polygonal structures. Mesh structures were formed on both glass substrates after air-drying. The mesh structures evolved into mesh transparent electrodes following heat-treatment. The AgNW mesh structure exhibited a low sheet resistance of 6.2 Ω/square with a transparency of 84% after heat treatment at 200 °C for 20 min. The performance is higher than that of transparent electrodes with random networks of AgNWs. Furthermore, the conductivity and transparency of the mesh transparent electrodes can be adjusted by changing the amount of the AgNW suspension and the space between the two glass substrates. 相似文献
68.
Haruhiko Ito Katsuaki Koshimura Saori Onitsuka Kohtaro Okada Tsuneo Suzuki Hiroki Akasaka Hidetoshi Saitoh 《Plasma Chemistry and Plasma Processing》2012,32(2):231-248
The dissociative excitation reaction of C2H2 with the electron-cyclotron resonance plasma of Ar was investigated based on the electrostatic-probe measurements and on
the optical emission spectroscopy of the CH(A2Δ–X2Π) transition. The density, n
e, and the temperature, T
e, of free electrons were controlled by adding H2O molecules externally into the reaction region, and the dependence of the CH(A2Δ–X2Π) emission intensity on the addition of H2O was observed to compare with the evaluated dependencies based on n
e and T
e. The mechanism of production of CH(A2Δ) was found, predominantly, to be the electron impact with the contribution of 10–20% of the electron-impact dissociation
of C2H radicals; the contribution of the ion–electron recombination was negligible. Hydrogenated amorphous carbon films were fabricated
using the same reaction system. The atomic compositions, Raman spectra, and the hardness of films were discussed in terms
of the variations of n
e and T
e upon the addition of H2O molecules. 相似文献
69.
Pd(OAc)(2)/o-chloranil/M(OTf)(n) can effectively promote the C-H arylation of fluoranthene with arylboron compounds or arylsilanes. The reaction takes place with high regioselectivity at the C3 position of fluoranthene. Moreover, the new catalytic system allows the use of unfunctionalized arenes as coupling partners in the arylation of polycyclic aromatic hydrocarbons. 相似文献
70.
Akira Wada Katsuaki Koshimura Masahito Niibe Hidetoshi Saitoh Kazuhiro Kanda Haruhiko Ito 《Journal of Non》2012,358(1):124-128
Amorphous carbon nitride (a-CNx) films were formed from the decomposition of BrCN in the electron cyclotron resonance plasmas of He, Ne, and Ar. The local structures of these films were investigated by the carbon-K near edge X-ray absorption fine structure. It was found that the density of C=C bond in the film prepared with Ar plasma was 7–9 times larger than that with He or Ne plasmas. The [N]/([C] + [N]) ratios of films were estimated from the X-ray photoelectron spectra as 0.34 ± 0.05, 0.35 ± 0.04, and 0.28 ± 0.05 for the He, Ne, and Ar plasmas, respectively. It was found that C atoms in the sp2-hybridized state were incorporated into the two-dimensional and/or one-dimensional conjugated structures composed of ? C=N? in the cases of the He and Ne plasmas and of ? C=C? in the case of the Ar plasma. The compositions and the local structures of films can be explained in terms of a model based on the cyclazine-like network structures. 相似文献