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91.
ABSTRACT In the present study, Zn1?xNixS (x = 0.0–0.8 mol%) nanoparticles were prepared through the chemical route and the synthesis involved the mixing and drying of zinc acetate and sodium sulphide in an appropriate ratio with the addition of Ni2+ at a proper concentration. The structural and spectroscopic studies are investigated by X-ray diffraction (XRD), absorption spectra, emission and excitation spectra, and Raman spectra. Compared with that of the pristine materials, the absorption band-edge demonstrates an apparently blue shift, which is attributed to the quantum size effect. The average particle size of ZnS nanoparticles is in the range of 2–4 nm deduced from the XRD line broadening. Excited at about 330 nm, a blue emission band at 425 nm can be observed, which corresponds to Ni2+ luminescent center; this result is consistent with the postulation that Ni2+ replaced the Zn2+ ions in the lattice of ZnS nanocrystals. Excitation spectra also confirm the above postulation. The effect of different concentrations of nickel is also studied by Raman spectra. 相似文献
92.
A tripodal receptor bearing catechol groups for the chromogenic sensing of F ions via frozen proton transfer 总被引:1,自引:0,他引:1
A neutral tripodal Schiff base receptor (3) having catechol as end groups has been synthesized and characterized with the help of spectroscopic and single crystal X-ray crystallographic studies. The receptor behaves as a visually detectable optical sensor for F− ions in DMSO, sensitive enough to recognize the ions up to a concentration 1×10−5 M with naked eye. The chromogenic response is based upon the deprotonation of the highly acidic catechol moieties in the presence of highly basic F− ions in a polar solvent like DMSO. 相似文献
93.
The title compound C18H20N2S is monoclinic, witha=10.256(2),b=7.470(4),c=21.377(4) Å,=101.52(2)°,z=4 and space groupP21/n. The structure was solved by direct methods, and refined by weighted full-matrix least squares. The refinement, based on 1373 reflections withI2.5 (I), converged to a finalR of 0.062 (R
w=0.060). The conformation of the thiazine ring is a distorted half chair, and that of the pyrimidine ring is a distorted chair. All nonhydrogen intermolecular distances are greater than 3.5 Å. 相似文献
94.
OsVIII-catalysed oxidation of m-hydroxybenzaldehyde by alkaline Fe(CN)6
3– has been studied in the 0.01–0.05 M [OH–] range. Higher [OH–] concentrations were not possible as the substrate turned yellow at [OH–] > 0.05 M. The very low solubility of the substrate in H2O restricted the kinetic study to [OH–] < 0.01 M. A mechanism, consistent with the results is proposed. 相似文献
95.
The kinetics of the oxidation of PhCHO by OsVIII has been studied in 0.01–0.05 M [OH–] range. Fe(CN)3–
6 was used to regenerate OsVIII. The very low solubility of PhCHO in H2O restricted the study to the 0.0024–0.0036 M [PhCHO] range. A mechanism involving the PhCHO hydrate has been proposed. 相似文献
96.
Reaction of copper(I) chloride with thiophene-2-carbaldehyde thiosemicarbazone (Httsc) in acetonitrile in the presence of Ph3P yielded a sulfur-bridged dimer [Cu2Cl2(μ2-S-Httsc)2(PPh3)2] · 2CH3CN (1), while a similar reaction with isatin-3-thiosemicarbazone (H2itsc) formed a monomer, [CuCl(H2itsc)(Ph3P)2] · 2CH3CN (3). Furan-2-carbaldehyde thiosemicarbazone (Hftsc) also formed a compound of the composition [Cu2Cl2(Hftsc)2(PPh3)2] · 2H2O (2). Complexes 1–3 have been characterized using elemental analysis, IR, 1H and 31P NMR spectroscopy and single crystal X-ray crystallography (1 and 3). Acetonitrile is engaged in hydrogen bonding with the chlorine atom {NCCH2–H?Cl)}, which is necessary for the stabilization of the bridging sulfur in 1. In compound 3, however, acetonitrile is strongly hydrogen bonded to the NH hydrogen of the isatin ring {CH3CN?NH(isatin)} and not to the chlorine atom. The Cu?Cu contact of 2.7719(5) Å in dimer 1 is close to twice the van der Waals radius of the Cu atom (2.80 Å). 相似文献
97.
Patni Kiran Pande Chitra Pande Ashutosh Pratap Tiwari Geeta Joshi Tanuj 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(2):647-660
Journal of Radioanalytical and Nuclear Chemistry - The paper deals with the seasonal variation of physico-chemical parameters in natural spring water sources collected from Pithoragarh city,... 相似文献
98.
Vishal G. More Dinesh N. Nadimetla Geeta A. Zalmi Vilas K. Gawade Ratan W. Jadhav Dr. Yogesh D. Mane Prof. Dr. Sheshanath V. Bhosale 《ChemistryOpen》2022,11(6):e202200060
A new ‘Off–On’ system designed and synthesised by functionalisation of a naphthalene diimide (NDI) core with dimethylamine produces 4,9-bis(dimethylamino)-2,7-dioctylbenzo[lmn][3,8]-phenanthroline-1,3,6,8-(2H,7H)-tetraone, abbreviated as DDPT ( 1 ). DDPT 1 was synthesised using a simple strategy, namely aromatic nucleophilic substitution using Br2-NDI with dimethylamine at 110 °C. DDPT was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and elemental analysis. DDPT 1 was then used for optical studies through protonation of its dimethylamine core with trifluoroacetic acid (TFA), blue-shifting the absorption band from 600 nm to 545 nm in solution. Interestingly, the fluorescence of DDPT 1 is weak in solution with a quantum yield Φ=0.09, which is significantly enhanced to Φ=0.78 upon addition of TFA. The limit of detection (LOD) was determined to 2.77 nm . Furthermore, DDPT 1 can be used for naked eyed detection not only under UV light (365 nm) but also using visible light, as clear changes can be clearly seen upon addition of TFA. The binding constant of DDPT was calculated to 2.1×10−3 m −1. Importantly, DDPT 1 showed reversible switching by alternative addition of acid (TFA) and base (triethylamine) without loss of activity. Immobilised on paper, DDPT 1 can be used for strip-test sensing in which the colour changes from blue to reddish when expose to TFA vapours and reverse in the presence of triethylamine vapours. 相似文献
99.
Photo‐irradiation of 2‐(5‐methylthiophen‐2‐yl)‐3‐[(naphthalen‐2‐yl)methoxy]‐4H‐chromen‐4‐ones yielded the fascinating angular tetracyclic products via cyclization involving both 2‐thienyl ring and naphthylmethoxy group via 1,4‐biradical generated in the Norrish type‐II process. The stereochemical dispositions of the products were determined by MM2 energy minimized programme and spectroscopic analysis. 相似文献
100.
The reaction of (1) and (2) uith (3a)2 2nd (3b)3 under liquid-liquid (L-L) and solid-liquid (3-L) phase transfer (PT) conditions furnish the corresponding (4) and (6) respectively and the reaction of (2) with (5) gives dioxolane derivative (7) 相似文献