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荧光光度法直接测定高纯氧化钕中的痕量镨和铈 总被引:2,自引:0,他引:2
李义久 《理化检验(化学分册)》1998,34(5):198-199,201
使用P-ELS50荧光光谱仪,在盐酸介质中,用同一激发波长激发,分别测定Pr(Ⅲ)(nm)和Ce(Ⅲ)(356nm)发射峰强度。 相似文献
3.
Keggin结构钨磷酸稀土镨盐杂多蓝的合成及抗艾滋病病毒(HIV-1)活性的研究 总被引:9,自引:0,他引:9
Keggin结构钨磷酸稀土镨盐杂多蓝的合成及抗艾滋病病毒(HIV-1)活性的研究刘术侠,刘彦勇,王恩波,曾毅,李泽琳(东北师范大学化学系,长春,130024)(中国预防医学科学院,北京)关键词稀土,钨磷杂多蓝,合成,抗艾滋病病毒(HIV-1)活性杂多... 相似文献
4.
During attempts to synthesize rare‐earth nitride tellurides black and bead‐shaped single crystals of the title compound sodium praseodymium(III) ditelluride (NaPrTe2) were obtained as a by‐product by reacting a mixture of praseodymium, sodium azide (NaN3) and tellurium at 900 °C for seven days in evacuated torch‐sealed silica vessels. NaPrTe2 crystallizes cubic (space group: Fd3¯m, Z = 16; a = 1285.51(9) pm, Vm = 79.96(1) cm3/mol, R1 = 0.028 for 146 unique reflections) and exhibits the Na+ and Pr3+ cations in slightly distorted octahedra of six telluride anions (d(Na—Te) = 325 pm, d(Pr—Te) = 317 pm) each. The main characteristics of this new structure type for alkali‐metal rare‐earth(III) dichalcogenides can be derived from the rock‐salt type structure (NaCl, cubic closest‐packed Te2— arrangement, all octahedral voids occupied with Na+ and Pr3+) with alternating layers consisting of Na+ and Pr3+ cations in a ratio of 3:1 and 1:3, respectively, piled along the [111] direction. 相似文献
5.
本文用导数分光光度沾测定了镧系(Pr~(3+))、Ho~(3+))与8-羟基喹啉-5-磺酸及氯化十六烷基吡啶体系的零阶及三阶导数吸收光谱,并计算了它们的摩尔吸光系数及摩尔导数吸光系数。提出了一个混合稀土中直接测定镨的方法,该方法的准确度及选择性较好。 相似文献
6.
Rare‐Earth‐Metal Coordination Polymers: Syntheses and Crystal Structures of Three New Glutarates, [Pr2(Glu)3(H2O)4] · 10.5H2O, [Pr(Glu)(H2O)2]Cl, and [Er(Glu)(GluH)(H2O)2] The new rare‐earth dicarboxylates [Pr2(Glu)3(H2O)4] · 10.5H2O ( 1 ), [Pr(Glu)(H2O)2]Cl ( 2 ) and [Er(Glu)(GluH)(H2O)2] ( 3 ) were obtained from the reactions of glutaric acid with PrCl3·6H2O and Er(OH)3, respectively. The crystal structures were determined by single‐crystal X‐ray diffraction. [Pr2(Glu)3(H2O)4] · 10,5H2O crystallizes in the orthorhombic space group Pnma (no. 62) with a = 871.7(4), b = 3105.0(9), c = 1308.3(9) pm and Z = 4. The crystals of [Pr(Glu)(H2O)2]Cl are monoclinic (I2/a; no. 15) with a = 786.2(1), b = 1527.6(2) c = 801.2(1) pm, β = 99.78(1)° and Z = 4. [Er(Glu)(GluH)(H2O)2] crystallizes in the monoclinic space group P21/a (no. 14) with lattice parameters of a = 882.4(1), b = 1375.3(2), c = 1267.4(2) pm, β = 107.13(1)° and Z = 4. The rare‐earth cations have the coordination numbers 10 ( 1 ), 8 + 1 ( 2 ) and 9 ( 3 ). The individual polyhedra are connected to chains and further to sheets in 1 and 2 and to double chains in 3 . Only in the water‐rich compound 1 there are channels that contain crystal water molecules. It, therefore, has a considerably lower density than 2 and 3 . 相似文献
7.
M. Shamshi HassanYoung-Sic Kang Byoung-Suhk KimIck-Soo Kim Hak-Yong KimMyung-Seob Khil 《Superlattices and Microstructures》2011,50(2):139-144
Well-defined and uniform Pr6O11 nanofibers were synthesized by electrospinning of an aqueous sol-gel consisting of praseodymium nitrate hexa-hydrate and polyvinyl acetate. The synthesized Pr6O11 nanofibers mat was dried at 80 °C for 24 h under vacuum and finally annealed at 600 °C for 2 h in static air furnace. From crystalline properties, the synthesized Pr6O11 nanofibers XRD analysis revealed the typical cubic structure. The morphological observation showed that the synthesized Pr6O11 nanofibers composed of fibers length in several 100 nm and diameter of ∼20 nm. Similarly, transmission electron microscope (TEM) measurement revealed the good crystalline nature of the synthesized Pr6O11 nanofibers with the average diameter of ∼20 nm. Photoluminescence (PL) demonstrated a strong green-blue emission peak at 521 nm, suggesting that the Pr6O11 nanofiber exhibited good crystal quality with very less structural defects. 相似文献
8.
Yizhe An 《Journal of luminescence》2005,111(3):131-138
The time dependence of thermalization between the 3P0 and 3P1 electronic states of Pr3+ in symmetrical Pr3+-Gd3+ pairs in CsCdBr3, following pulsed laser excitation into either state, is reflected in the time dependence of the luminescence from both states. The 3P0 and 3P1 states achieve thermal equilibrium in the microsecond time domain over the temperature range of study (215-340 K). Because the 3P0-3P1 energy gap is larger than the phonon cutoff in CsCdBr3, thermalization occurs via multiphonon processes. A rate-equation model for the thermalization process is presented, and the temperature dependence of the rate constants for 3P1←3P0 multiphonon absorption and 3P1→3P0 multiphonon emission is reported from 215-340 K. In contrast to CsCdBr3, the analogous thermalization kinetics in Pr3+-Gd3+ pairs in isostructural CsMgCl3 is not discernable in the 3P0 and 3P1 luminescence, because thermalization is instantaneous within the time resolution of our experiments (∼20 ns). The difference in the thermalization kinetics in the two lattices is attributed to the difference in the number of phonons required to bridge the 3P0-3P1 energy gap. 相似文献
9.
Konstantina E. Chrysomallidou Spyros P. Perlepes Aris Terzis Catherine P. Raptopoulou 《Polyhedron》2010
Reactions of malonic acid (H2mal) with PrCl3·6H2O afforded the known complex [Pr2(mal)3(H2O)6]n (1), and compounds [Pr2(mal)3(H2O)6]n·2nH2O (2·2nH2O), [PrCl(mal)(H2O)3]n·0.5nH2O (3·0.5nH2O) and [Pr(mal)(Hmal)(H2O)3]n·nH2O (4·nH2O) using various reaction ratios, reaction media (H2O, MeOH) and pH values. Analogous reactions with CeCl3·7H2O afforded compounds [Ce2(mal)3(H2O)6]n (5), [CeCl(mal)(H2O)3]n·nH2O (6·nH2O) and [Ce(mal)(Hmal)(H2O)3]n·nH2O (7·nH2O). Compounds 2·2nH2O and 3·0.5nH2O were characterized by X-ray crystallography, and 4–7 by microanalytical and spectroscopic data. The malonate(-2) ligand adopts three different coordination modes in the structures of 1–3, i.e., the μ2-κO:κO′:κO″ and the μ4-κ2O:κO′:κ2O″:κO? in 1 and 2 leading to a 3D network structure, and the μ3-κ2O:κO′:κ2O″:κO? in 3 promoting an 1D structure. The thermal decomposition of 1 and 3·0.5nH2O was monitored by TG/DTA and TG/DTG measurements. The structural features of 1–3 are discussed in terms of known malonato(-2) LnIII and CaII complexes. The bioinorganic chemistry relevance of our results is discussed. 相似文献
10.
Emiliana Fabbri Isaac Markus Lei BiDaniele Pergolesi Enrico Traversa 《Solid State Ionics》2011,202(1):30-35
BaZr0.8 − xPrxY0.2O3 − δ (BZPYx, 0.1 ≤ x ≤ 0.4) perovskite oxides were investigated for application as cathode materials for intermediate temperature solid oxide fuel cells based on proton conducting electrolytes (protonic-SOFCs). The BZPYx reactivity with CO2 and water vapor was evaluated by thermogravimetric and X-ray diffraction analyses, and good chemical stability was observed for each BZPYx composition. Conductivity measurements of BZPYx sintered pellets were performed as a function of temperature and pO2 in humidified atmospheres, corresponding to cathode operating condition in protonic-SOFCs. Different conductivity values and activation energies were measured depending on the Pr content, suggesting the presence of different charge carriers. For all the compositions, the partial electronic conductivity, calculated from conductivity measurements at different pO2, increased with increasing the temperature from 500 to 700 °C. Furthermore, the larger the Pr content, the larger the electronic conductivity. BaZr0.7Pr0.1Y0.2O3 − δ and BaZr0.4Pr0.4Y0.2O3 − δ showed mostly pure proton and electron conductivity, respectively, whereas the intermediate compositions showed mixed proton/electronic conductivity. Among the two mixed proton/electronic conductors, BaZr0.6Pr0.3Y0.2O3 − δ presented the larger conductivity, which coupled with its good chemical stability, makes this perovskite oxide a candidate cathode materials for protonic-SOFCs. 相似文献