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41.
A. Manohar V. Venkatachalam K. Ramalingam S. Thirumaran G. Bocelli A. Cantoni 《Journal of chemical crystallography》1998,28(12):861-866
Synthesis, spectral, and single crystal X-ray structural studies on (2,2-bipyridyl)bis (dimethyldithiocarbamato)zinc(II) (1) and (l,10-phenanthroline)bis(dimethyldithiocarbamato)zinc(II) (2) complexes are reported in this paper. The complex (1) crystallizes in the orthorhombic lattice, space group Pcca, a = 18.456(3), b = 6.529(2), and c = 17.092(2) Å. The complex (2) crystallizes in the monoclinic space group C2/c, a = 13.372(2), b = 13.850(2), c = 24.680(3) Å, and = 102.71(4)°. IR spectra of the complexes (1) and (2) show the thioureide (C-N) bands at 1489 and 1510 cm–1, respectively, which are lower than the value observed for the parent bisdithiocarbamate. Reduction in the thioureide stretching frequency is due to the increase in coordination around the zinc ion and the resultant increase in electron density. Thermal studies indicate that the 1,10-phenanthroline adduct is marginally more stable than the other complex. X-ray crystal structures of the two adducts show them to be octahedrally coordinated and monomeric in nature. The Zn-S distances are longer than those observed in the parent bisdithiocarbamate. The thioureide C-N bond distances in (1) and in (2) indicate the partial double bond character. The most important structural changes as a result of the adduct formation are observed in the Zn-S bond distances and S-Zn-S bond angles, in terms of very significant increases in Zn-S bond distances and reductions in S-Zn-S angles, compared to the parent bisdithiocarbamate. The observed changes are indicative of a strong steric force in operation in the adducts rather than electronic effects. 相似文献
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43.
The novel TiO2 nanopartilces/nanowires (TNPWs) composite with ZrO2 nanoparticles (ZNPs) shell-coated photoanodes were prepared to fabricate high-performance dye-sensitized solar cell (DSSC) based on different types of electrolytes. Hafnium oxide (HfO2) is a new and efficient blocking layer material applied over the TNPWs-ZNPs core-shell photoanode film. TiO2 nanoparticles (TNPs) and TiO2 nanowires (TNWs) were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). DSSCs were fabricated using the novel photoanodes with an organic sensitizer D149 dye and different types of electrolytes namely liquid electrolyte, ionic liquid electrolyte, solid-state electrolyte, and quasi-solid-state electrolyte. The DSSC-4 made through the novel core-shell photoanode using quasi-solid-state electrolyte showed better photocurrent efficiency (PCE) as compared to the other DSSCs. It has such photocurrent-voltage characteristics: short circuit photocurrent (Jsc)?=?19 mA/cm2, the open circuit voltage (Voc)?=?650 mV, fill factor (FF)?=?65 %, and PCE (η)?=?8.03 %. The improved performance of DSSC-4 is ascribed to the core-shell with blocking layer photoanode could increased electron transport and suppressed recombination of charge carriers at the TNPWs-ZNPs/dye/electrolyte interface. 相似文献
44.
John C. Beeson Michael E. Huston Douglas A. Pollard T. K. Venkatachalam Anthony W. Czarnik 《Journal of fluorescence》1993,3(2):65-68
The structure-quenching relationship in 9-aminoalkylanthracenes is examined by the synthesis and fluorescence evaluation of five derivatives; it is observed that benzylic 2° and 3° amines lead to 95% quenching of anthracene fluorescence in water, while other amines afford substantially lower quenching efficiencies. 相似文献
45.
Conformational energy calculations are presented for the head-to-head dimerized β helices for Gramicidin A transmembrane channel structures. The calculations take into account both left- and right-handed β helices, and various side-chain conformations. The energetics of the dimerization is studied by considering various docking geometries. It is concluded from these vacuum-energy calculations that the lowest energy conformation for the channel dimer is that comprised of left-handed β helices. 相似文献
46.
Venkatachalam S. Giri Esahak Ali Satyesh C. Pakrashi 《Journal of heterocyclic chemistry》1980,17(5):1133-1134
Racemic quebrachamine ( 1 ) has been synthesised from 2-hydroxytryptamine and dimethyl 4-ethyl-4-formylpimelate through 1,2-dehydroaspidospermidine ( 8 ), obtained by selective reduction of the carbonyl function of lactam 3. 相似文献
47.
An attempt has been made to fabricate methyl ammonium tin chloride (CH3NH3SnCl3) perovskite-sensitized TiO2 nanostructure photoanode solar cell with hole transport material (HTM) spiro-MeOTAD and graphite-coated counter electrode (CE). The TiO2 nanoparticles (TNPs), TiO2 nanoleaves (TNLs), and TNLs with MgO core/shell photoanodes were prepared to fabricate perovskite-sensitized solar cells (PSSCs). The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photovoltaic characteristics of the PSSCs, photocurrent density (J sc), open-circuit voltage (V oc), fill factor (FF), and power conversion efficiency (PCE) were determined under illumination of AM 1.5 G. Electrochemical impedance spectroscopy (EIS) analysis was carried out to study the charge transport and lifetime of charge carriers at the photoanode–sensitizer–electrolyte interface of the PSSCs. The PSSC made with CH3NH3SnCl3 perovskite-sensitized TNL–MgO core/shell photoanode and spiro-MeOTAD HTM shows an impressive photovoltaic performance, with J sc = 17.24 mA/cm2, V oc = 800 mV, FF = 73 %, and PCE = 9.98 % under 100 mW/cm2 light intensity. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost and high-efficiency solar cells. By the aid of electrochemical impedance spectroscopy, it is revealed that the core/shell structure can increase an interfacial resistance of the photoanode–CH3NH3SnCl3 interface and retard an electron recombination process in the photoanode–sensitizer–HTM interface. 相似文献
48.
49.
T. K. Venkatachalam Gregory K. Pierens Paul V. Bernhardt D. C. Reutens 《Journal of chemical crystallography》2011,41(4):563-569
Abstract
The synthesis of titled compounds were achieved in one step using hydroxyl naphthones and substituted cinnamic acids in the presence of a catalytic amount of phosphorus oxychloride. X-ray crystal studies were undertaken for three compounds and the results are presented. Compounds 1 (C22H15F3O3) and 3 (C21H15BrO3) formed a monoclinic crystals while compound 2 (C22H15F3O3) formed a triclinic crystals. The observed space group of these compounds is P21/c and P[`1] \bar{1} respectively. The 2-substituted compounds showed identical space group and showed a perpendicular arrangements of each of the substituents to the plane of the naphthyl ring. On the contrary, the 1-substituted cinnamoyal compound showed an orthogonal arrangement to naphthyl ring but the acetyl group was almost planar relative to the naphthyl moiety. The characterization of the structures of the compounds was also accomplished using high-resolution NMR spectroscopic techniques. 相似文献50.