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31.
LaF3 pure host, LaF3:Ce, LaF3:Tb as well as LaF3:Ce,Tb phosphors were synthesized by the hydrothermal method. X-ray diffraction measurements were in good agreement with the standard data of LaF3 from JCPDS card No. 32-0483 and indicated that the material was nanocrystalline with an average particle size of about 36 nm. Photoluminescence spectra of co-doped samples revealed that the Ce3+ emission was quenched while Tb3+ emission was enhanced, implying that energy was transferred from Ce3+ (the donor) to Tb3+ (the acceptor) in this system. The luminescence intensities and lifetimes of the donor for different concentrations of the acceptor were fitted to theoretical models in order to investigate the energy transfer mechanism. The quadrupole–quadrupole and exchange interaction mechanisms gave the best fit between the experimental data and the theoretical curves. The effective average Bohr radius from the fit to the exchange model is 0.095 nm. Since this is close to the ionic radii of the Ce3+ and Tb3+ ions, it suggests that the exchange interaction mechanism contributes to the energy transfer. 相似文献
32.
D. Kaczmarek J. Domaradzki R. Wasielewski E.L. Prociow 《Applied Surface Science》2008,254(14):4303-4307
In this work, structural investigations of TiO2 thin films doped with Tb at the amount of 0.4, 2 and 2.6 at.% have been outlined. Thin films were deposited on Si and SiO2 substrates by high energy reactive magnetron sputtering from mosaic Ti-Tb target. The influence of Tb dopant amount, post-annealing treatment and kind of applied substrate on microstructure has been discussed. Thin films were investigated by means of X-ray diffraction (XRD) and atomic force microscopy (AFM). XRD analysis revealed the existence of crystalline TiO2 in anatase and rutile forms, depending on Tb amount in examined samples. AFM images show that as-deposited samples with 0.4 at.% concentration of terbium (anatase structure) have bigger crystallites as compared to 2% and 2.6 at.% of Tb (rutile structure). The additional annealing at 1070 K results in a mixed anatase (77%) and rutile (23%) structure. 相似文献
33.
A robust 4,8-connected Tb-based metal-organic framework (Tb-MOF) with paddle wheel-shaped {Tb2(COO)4} subunits extended by C3-symmetric 3,3',3''-[1,3,5-benzenetriyltris(carbonylimino)]tris-benzoate connector was hydrothermally synthesized, showing highly environmental stability, good dispersion and intense green emission in water system. Resulting critically from the well suppressed absorption towards the excitation energy, the Tb-MOF exhibits rapid and efficient fluorescent response towards nitroimidazole antibiotics with strong quenching constants and low detection limits of 1.59 × 104 m –1 and 2.4 μM for metronidazole as well as 1.62 × 104 m –1 and 2.9 μM for dimetridazole. Moreover, the sensitive and selective identification of the Tb-MOF has strong anti-interference and excellent regeneration ability, which endows the promising applications of the Tb-MOF as fluorescent sensing materials. 相似文献
34.
TbFCl2: The First Fluoride Chloride of the Trivalent Lanthanoids Single crystals of TbFCl2 (monoclinic, C2/c; a = 890.28(5), b = 581.56(3), c = 683.37(4) pm, β = 109.621(4)°; Z = 4) can be obtained by the reaction of TbCl3 and TbF3 under inert‐gas atmosphere in tantalum capsules (900 °C, 10 d) as colourless transparent lath‐shaped blocks. The crystal structure contains only one singular Tb3+ cation which is eightfold coordinated by two F− (d(Tb3+−F−) = 218 pm, 2×) and six Cl− anions (d(Tb3+−Cl−) = 280−287 pm) forming a distorted square antiprism. The F− anions are linear surrounded by two Tb3+ cations while the Cl− anions reside in a quasi‐planar coordination of three Tb3+ cations, therefore the Niggli formula for TbFCl2 has to be . Terbium and fluorine form zigzag chains along the c axis that are not connected to each other and arrange like a hexagonal rod‐packing. These cationic chains are mantled by Cl− anions which take care for the charge balance and the three‐dimensional cross‐linkage. The structural relationship of TbFCl2 with YF3‐type and PuBr3‐type will also be discussed. 相似文献
35.
Nucleotide/Tb coordination polymer nanoparticles as luminescent sensor and scavenger for nitrite ion
Newly emerged metal organic coordination polymers have aroused the great interest in designing tailored functional materials. In this study, multiple functional components, luminescent Tb3+ ion, nucleobase and antenna molecule, were integrated in a single material and prepared into a responsive nanoparticle for nitrite. The terbium coordination polymer nanoparticles made of this kind of material have the dual functions of recognition and transduction and obey a preset sensing mechanism without a post-functionalization of common materials. As the result of the tailored, the terbium coordination polymer nanoparticles are highly sensitive and selective to nitrite by means of Dexter energy transfer between Tb3+ ion and nitrite, and can be used for the scavenger for nitrite in aqueous solution. The detection limit, dynamic range and removal capacity of U–Tb–OBBA CPNPs for nitrite are 0.3 µM, 0.3–470 µM and 4.44 mg per gram of particles, respectively. Metal organic coordination polymers show an attractive potential in constructing smart sensing materials. 相似文献
36.
采用共沉淀法合成了掺杂 L a、 Gd、 Y的 Tb-邻氨基苯甲酸配合物 ,研究其荧光性能 ,结果显示 ,掺杂L a、Gd、Y后 ,对 Tb配合物的发光有增敏作用 ,讨论了不同的掺杂离子 (L a、Gd、Y)及掺杂量对其荧光性能的影响。发现 ,当掺杂离子取代大部分 Tb3+时 ,其发光增强仍十分显著。 相似文献
37.
利用平衡析,原子吸收,荧光滴定和荧光寿命测定等方法确定了皖南尖吻蝮蛇蛇毒纤溶组分中Ca^2+含量,并利用荧光光谱研究了Tb^3+与FP中色氨酸残基之间能量转移和FP中的微区结构。 相似文献
38.
螯合剂对铽(Ⅲ)-转铁蛋白配合物的影响 总被引:3,自引:0,他引:3
在室温及pH7.4下,观察了一些螯合剂对铽(Ⅲ)-转铁蛋白配合物的影响.结果表明,铽(Ⅲ)与人血清脱铁转铁蛋白的结合是可逆的;EDTA和次氮基三乙酸可使铽(Ⅲ)-脱铁转铁蛋白配合物定量释放铽(Ⅲ).用ECCLES程序计算表明,血清中微摩尔数量级的铽(Ⅲ)主要以小分子配合物形式存在,其中铽(Ⅲ)-柠檬酸约占62%,而铽(Ⅲ)-脱铁转铁蛋白配合物约占21% 相似文献
39.
The 2,6-pyridinedicarboxylic acid (PDA) has been shown to efficiently sensitize and enhance the fluorescence of uranium in aqueous medium. Interestingly, this ligand stabilizes the UO22+ species, which without the ligand is known to be in a negligible concentration, in aqueous medium at pH 6. The ligand sensitized enhancement of UO22+ fluorescence by PDA, provides an analytical tool for the determination of uranium at trace levels, in aqueous medium. Furthermore, PDA is also known to enhance the fluorescence of lanthanides; consequently, the simultaneous determination of uranium and lanthanides, using PDA as a fluorescence sensitizing agent, becomes a possibility, which has been demonstrated in this work. We have shown that the use of PDA yields detection limits of 2.2×10−7 M for UO22+, 1×10−8 M for Tb3+ and 5×10−9 M for Eu3+ in the simultaneous determination of these analytes. 相似文献
40.