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61.
The rate constants for the reaction of NO3· with sulfur compounds in acetonitrile have been determined by the flash photolysis method. The rate constant for dimethyl sulfone (2.7 × 104 M?1s?1 at ?10°C) is larger than that of the deuterium derivative, indicating that NO3· abstracts the hydrogen atom from dimethyl sulfone. In the case of dimethyl sulfide, the rate constant was evaluated to be 1.5 × 109 M?1 s?1 at ?10°C; the transient absorption band attributable to the cation radical was observed after the decay of NO3·, suggesting the electron transfer reaction from the sulfide to NO3·. For diphenyl sulfide and dimethyl disulfide, the electron transfer reactions were also confirmed. For dimethyl sulfoxide, the reaction rate constant of 1.2 × 109 M?1 s?1 (at ?10°C) was not practically affected by the deuterium substitution, suggesting that NO3· adds to sulfur atom forming (CH3)2?(O)-ONO2. On the other hand, for diphenyl sulfoxide, the electron transfer reaction occurs. By the comparison of these rate constants in acetonitrile solution with the reported rate constants in the gas phase, the change of the reaction paths was revealed. 相似文献
62.
N. U. Zhanpeisov W. S. Ju K. Iino M. Matsuoka M. Anpo 《Research on Chemical Intermediates》2003,29(4):407-416
XAFS (both XANES and FT-EXAFS) measurements revealed that the Pb2+ /ZSM-5 catalyst prepared from precursor H-ZSM-5 by a conventional ion-exchange method includes a highly dispersed 3-fold coordinated Pb2+ ion species within the zeolite framework. UV-irradiation of Pb2+ /ZSM-5 led to effective decomposition of NO and N2O producing N2. The photocatalytic decomposition of NO is found to be slightly preferable than that of N2O. The isolated Pb2+ ions play a significant role in the decomposition of pollutant NO
x
. Ab initio and DFT quantum chemical studies at the HF/Lanl2dz and B3PW91/Lanl2dz levels further shed light on local structures of the Pb2+ active site of lead-containing zeolites, as well as on their interactions with pollutant NO and N2O molecules. In agreement with experiments, 3-fold coordination was found to be the most favorable state for the Pb2+ site within the zeolite framework. 相似文献
63.
K. Masumoto M. Hara D. Hasegawa E. Iino M. Yagi 《Journal of Radioanalytical and Nuclear Chemistry》1997,217(2):247-253
The internal standard method coupled with the standard addition method has been applied to photon activation analysis and proton activation analysis of minor elements and trace impurities in various types of iron and steel samples issued by the Iron and Steel Institute of Japan (ISIJ). Samples and standard addition samples were once dissolved to mix homogeneously, an internal standard and elements to be determined and solidified as a silica-gel to make a similar matrix composition and geometry. Cerium and yttrium were used as an internal standard in photon and proton activation, respectively. In photon activation, 20 MeV electron beam was used for bremsstrahlung irradiation to reduce matrix activity and nuclear interference reactions, and the results were compared with those of 30 MeV irradiation. In proton activation, iron was removed by the MIBK extraction method after dissolving samples to reduce the radioactivity of56Co from iron via56Fe(p,n)56Co reaction. The results of proton and photon activation analysis were in good agreement with the standard values of ISIJ. 相似文献
64.
Abstract Phototropism is a common property of plants, but it is not known if different species use the same photoreceptor for their response. We have determined fluence-response relations for phototropism in response to brief, broad-band blue irradiation for four plant species grown under red light (Amaranthus paniculatus, Linum usitatissimum, Vigna radiata and Medicago sativa) and compared these to ones previously obtained for Pisum sativum and Zea mays, grown under similar conditions. Curves for all species showed a bell-shaped dependence on fluence, a characteristic of first positive curvature as originally defined for the Avena coleoptile, and had a similar optimal fluence, near 3 H.mol m?2. We have obtained an action spectrum in the blue and UV spectral regions for first positive phototropism of the hypocotyl of alfalfa grown under red light. Fluence-response curves at wavelengths between 300 and 500 nm were nearly identical in shape and magnitude; whereas below 300 nm, their slopes and maximum curvatures were reduced. The action spectrum showed that activity rose sharply at wavelengths below 500 nm, peaked at 450 nm with shoulders on either side of that peak, and had lesser peaks at 380 and, in the far ultraviolet, at 280 nm. This action spectrum was very similar to ones in the literature (obtained between 350 and 500 nm) for first and second positive phototropism of oat coleoptiles. We conclude that the same photoreceptor mediates phototropism in oat and alfalfa. 相似文献
65.
Redox-photosensitized aminations of 1,2-benzo-1,3-cycloalkadienes, arylcyclopropanes, and quadricyclane with ammonia 总被引:1,自引:0,他引:1
Yasuda M Kojima R Tsutsui H Utsunomiya D Ishii K Jinnouchi K Shiragami T Yamashita T 《The Journal of organic chemistry》2003,68(20):7618-7624
1,2,4-Triphenylbenzene and 2,2'-methylenedioxy-1,1'-binaphthalene successfully photosensitized the aminations of 1,2-benzo-1,3-cycloalkadienes, arylcyclopropanes, and quadricyclane with ammonia and primary amines in the presence of m- or p-dicyanobenzene, which gave the 4-amino-1,2-benzocycloalkenes, 3-amino-1-arylpropanes, and 7-amino-5-(p-cyanophenyl)bicyclo[2.2.1]hept-2-ene, respectively. A key pathway for the photosensitized amination is the hole transfer from the cation radicals of the sensitizers that were generated by photoinduced electron transfer to the electron acceptors to the substrates. Therefore, it was found that the relationships in oxidation potentials between the sensitizers and the substrates and the positive charge distribution of the cation radicals of the substrates were important factors for the efficient amination. 相似文献
66.
Ryuji Furuta Shunsuke Naruto Atsushi Tamura Kanae Yokogawa 《Tetrahedron letters》1979,20(19):1701-1704
A new indole-N-glycoside, neosidomycin (I), is produced by a strain belonging to Streptomyces hygroscopicus. The structure of I has been deduced from physico-chemical data obtained using the natural compound, its derivatives and products of degradation reactions. 相似文献
67.
Koomen JM Zhao H Li D Nasser W Hawke DH Abbruzzese JL Baggerly KA Kobayashi R 《Rapid communications in mass spectrometry : RCM》2005,19(12):1624-1636
A peptide targeting method has been developed for diagnostic protein discovery, which combines proteolytic digestion of fractionated plasma proteins and liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC/ESI-TOFMS) profiling. Proteolysis prior to profiling overcomes molecular weight limitations and compensates for the poor sensitivity of matrix-assisted laser desorption/ionization (MALDI) protein profiling. LC/MS increases the peak capacity compared to crude fractionation techniques or single sample MALDI analysis. Differentially expressed peptides are targeted in the mass chromatograms using bioinformatic techniques and subsequently sequenced with MALDI tandem MS. In a model study comparing pancreatic cancer patients to controls, 74% of the peptide targets were successfully sequenced. This profiling method was superior to previous experiments using single sample MALDI analysis for protein profiling or proteolytic peptide profiling, because more potential protein markers were identified. 相似文献
68.
Two new series of each of four Cr(III) and Ni(II) imino nitroxide complexes with various kinds of beta-diketonates, [Cr(beta-diketonato)(2)(IM2py)]PF(6), and [Ni(beta-diketonato)(2)(IM2py)] (IM2py = 2-(2'-(pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy)) have been synthesized, and their structures and magnetic and optical properties have been examined. The X-ray analysis demonstrated that a IM2py ligand coordinated to Cr(III) and Ni(II) acts as a five-membered bidentate chelate. The variable-temperature magnetic susceptibility measurements indicated the antiferromagnetic and ferromagnetic interaction of Cr(III) and Ni(II) with IM2py, respectively, giving a variety of the magnetic coupling constant J values with varying the beta-diketonato ligands. The UV-vis shoulders around (19-20) x 10(3) and (17-18) x 10(3) cm(-)(1) for the Cr(III) and Ni(II) complexes, respectively, characteristic of the IM2py complexes were assigned to the metal-ligand charge-transfer transitions, Cr(t(2g))-SOMO(pi*) and Ni(e(g))-SOMO(pi*) MLCT in terms of the resonance Raman spectra and the variable-temperature absorption spectra. The absorption components centered around (13-14) x 10(3) cm(-1) for the Cr(III) and Ni(II) complexes were due to the formally spin-forbidden d-d transition within the t(2g) and e(g) subshells, associated with the intensity enhancement. The spectroscopic behavior with varying the beta-diketonato ligands is discussed in connection with the antiferromagnetic or ferromagnetic coupling constant J values on the basis of the exchange mechanism along with the coligand effect. 相似文献
69.
Moriyuki Sato Ryuji Ishii Shinji Nakashima Koichiro Yonetake Junji Kido 《Liquid crystals》2013,40(8):1211-1214
Thermotropic liquid crystalline quaterphenyl analogues constituting a central 2,2'-bi-1,3,4- thiadiazole ring, the compounds 5,5'-bis(4-methoxy- and 4-octyloxy-phenyl)-1,3,4-thiadiazole, have been prepared and their photoluminescent (PL) and electroluminescent (EL) properties evaluated. The materials form enantiotropic smectic and nematic phases. The PL spectra showed that they emit blue and green fluorescence in the solid state. The octyloxy compound exhibited an EL spectrum with blue emission and is a candidate for organic EL applications. 相似文献
70.
Ryuji Nakao Kenji Furutsuka Toshimitsu Fukumura Masatoshi Yamaguchi Kazutoshi Suzuki 《Biomedical chromatography : BMC》2010,24(2):202-208
A highly sensitive reversed‐phase liquid chromatographic (HPLC) method was investigated to analyze a range of positron emission tomography (PET) radiopharmaceuticals using electrogenerated chemiluminescence (ECL) detection. ECL is based on the reaction of PET molecules with tris(2,2′‐bipyridyl)ruthenium(III) [Ru(bpy)33+], which is generated through the on‐line electro‐oxidation of Ru(bpy)32+. In 21 different radiopharmaceuticals studied, 18 compounds could be detected with detection limits (signal‐to‐noise ratio = 3) of 0.12–72 ng/mL per 20 μL injection. Sufficient reproducibility and linearity were obtained for the quantitative determination of PET molecules in pharmaceutical fluid. This method could be successfully applied to quality control tests of PET radiopharmaceuticals with ultra‐high specific radioactivity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献