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31.
The use of boric acid as a modifier for the determination of trace amount of indium in high purity antimony by electrothermal atomic absorption is described. It was found that the negative influence of the hydrofluoric acid, used for the digestion could not be eliminated by using stabilized temperature platform furnace (STPF) alone. Due to the high dissociation energy (D0 = 506 kJ mol−1) of indium fluoride, it is difficult to dissociate in the gas phase and hence is lost. In presence of HF (used for the dissolution of antimony), the universal Pd-Mg modifier does not work satisfactorily. Additionally, rising corrosion and reduced tube lifetime were observed when the acid digested (HF-HNO3) antimony solution was injected in to the platform. Improvement in platform life and elimination of interferences were achieved by the addition of boric acid as a chemical modifier together with ruthenium coating of the platform. Corrosive changes of the transversely heated graphite atomizer (THGA) platform surface were examined by scanning electron microscopy. The standard addition method was applied. A characteristic mass of 36 pg was obtained. The detection limit of the proposed method is around 0.04 μg g−1. The developed method was applied to the determination of indium in real samples. The data obtained by this method were in good agreement with those obtained by ICP-MS. 相似文献
32.
The effect of unilamellar vesicles of dipalmitoylphosphotidylcholine (DPPC), both below and above the phase transfer region, on the second-order rate constants for outer-sphere electron transfer between Fe2+ and the surfactant?Ccobalt(III) complexes, cis-[Co(en)2(C12H25NH2)2]3+ and cis-[Co(trien)(C12H25NH2)2]3+ (en?=?ethylenediamine, trien?=?triethylenetetramine, C12H25NH2?=?dodecylamine) was studied by UV?CVis absorption spectroscopy. Below the phase transition temperature of DPPC, the rate decreased with increasing concentration of DPPC, while above the phase transition temperature the rate increased with increasing concentration of DPPC. It is concluded that below the phase transition temperature, there is an accumulation of surfactant?Ccobalt(III) complexes at the interior of the vesicle membrane through hydrophobic effects, and above the phase transition temperature the surfactant?Ccobalt(III) complex is released from the interior to the exterior surface of the vesicle. Through isokinetic plots, we have established that the mechanism of the reaction does not alter during the phase transition of DPPC. 相似文献
33.
Eswaran Chinnaraja Rajendran Arunachalam Renjith S. Pillai Anssi Peuronen Kari Rissanen Palani S. Subramanian 《应用有机金属化学》2020,34(8):e5666
Synthesis of binuclear Cu(II) terminally closed [ 2+2 ]- double-stranded helicate-like macrocycles 1, 1′ , 1″ , 2 , 2′ , 2″ and 2+4- μ4-oxo tetranuclear open frame complexes 3 , 3′ , 3″ , 4 , 4′ , 4″ are established. Adapting one-pot self-assembly technique from simple three components systems: 1,1′-binaphthyl-2,2′-diamine, 4-methyl-2,6-diformyl phenol and cupric salts, the helicate-like [ 2+2 ]- macrocyclic complexes 1–1″, 2–2″ and 2+4- μ4-oxo tetranuclear complexes 3–3″ , 4–4″ were obtained by appropriately altering the reaction condition such as temperature and subcomponent ratio. Density Functional Theory (DFT) calculations were carried out for understanding the structural geometries, intermediates involved in the diverse formation of [ 2+2 ] and 2+4 frameworks. The single crystal X-ray structures obtained for 1′ , 2 and 3 confirms the self-assembly process in line with DFT. This detailed analysis tempted us to derive a plausible mechanism for this long standing challenge in the synthesis of such macrocycles using 1,1′-binaphthyl-2,2′-diamine (BNDA) and aromatic aldehyde. The chiroptical properties of enantiopure complexes and their catalytic applications in asymmetric oxidative coupling of 2-naphthol to chiral 1,1’-Bi-2-naphthol (BINOL) achieved in good yield and ee were discussed. 相似文献
34.
Winaki P. Sohtun Themmila Khamrang Arunachalam Kannan Gowdhami Balakrishnan Dhandayutham Saravanan Mohammad Abdulkader Akhbarsha Marappan Velusamy Mallayan Palaniandavar 《应用有机金属化学》2020,34(5):e5593
A series of iron(III) bis-complexes of the type [FeL2]X 1-4 , X = OH− ( 1 ), Cl¯ ( 3 ), and FeCl4¯ ( 2 , 4 ), where LH is a tridentate (N,N,S) ligands such as N′-(1-pyridin-2-ylethylidene)-hydrazinecarbodithioic acid methyl ester ( HL1 ), N′-(phenylpyridin-2-ylmethylene)-hydrazinecarbodithioic acid methyl ester ( HL2 ), N′-quinolin-2-ylmethylene-hydrazinecarbodithioic acid methyl ester ( HL3 ), or N′-(1-methyl-1H-imidazol-2-yl-methylene)hydrazinecarbodithioic acid methyl ester ( HL4 ) has been isolated in moderate to good yields and completely characterized by elemental analyses, conductivity studies, and infrared and UV-visible spectral measurements. The single crystal X-ray structures of 1 , 2 and 4 revealed that two deprotonated tridentate (NNS) ligands are meridionally coordinated to constitute a distorted octahedral coordination geometry around iron(III). In acetonitrile solution, all the complexes show quasi-reversible Fe(III)/Fe(II) redox behavior. The in vitro cytotoxicity of the ligands HL1–HL4 (IC50: HL1 , 64.5; HL2 , 51.0; HL3 , 124.0; HL4 , 45.0 μM at 24 h) and complexes 1–4 (IC50: 1 , 84.5; 2 , 40.0; 3 , 168.5; 4 , 50.5 μM at 24 h) towards A549 lung cancer cell lines are similar to cisplatin (69.0 μM), revealing that free ligands cause cancer cell death with potency higher than the corresponding iron(III) complexes. Also, both the ligands and the complexes cause cell death mainly through apoptotic mode, as revealed by the observation of a higher percentage of apoptotic cells in acridine orange (AO)/ ethidium bromide (EB), and Annexin V-Cy3 stained cancer cells. 相似文献
35.
The hot rotating compound systems formed in heavy ion collisions are studied using the statistical theory with a view to determine
the spin and temperature dependence of nuclear shapes. Shape transitions are observed for these systems at particular spin
values. The neutron and proton separation energies for heavier high spin systems have been evaluated. Results are presented
for
70
170
Yb and
78
194
Pt. 相似文献
36.
Pamidi V. A. Prasad J. Arunachalam S. Gangadharan 《Fresenius' Journal of Analytical Chemistry》1992,342(4-5):350-351
Summary A sensitive procedure for the determination of cobalt in high-purity aluminium using DPCSV through adsorptive accumulation of Co(DMG)2 on HMDE in triethanolamine + NH4OH buffer is described. Analysis of NBS SRM C-1257 and a reactor grade aluminium sample is reported. Prior to the determination, cobalt was separated from Al and Ni on AG-1 X8 resin in 9 mol/l HCl. The results have been cross-validated by INAA. 相似文献
37.
J. Arunachalam Anna John S. Gangadharan 《Journal of Radioanalytical and Nuclear Chemistry》1991,155(1):33-43
A neutron activation analysis procedure has been developed for the indirect determination of phosphorus as orthophosphate at ppb levels, via the formation of antimonyl phosphomolybdic acid. The complex is adsorbed on Sephadex G-25 resin and the antimony is estimated through NAA, allowing the determination of phosphorus. The procedure provides an easy method to adopt for the routine determination of phosphorus at 10 ng ml–1 levels with good precision, in water samples. 相似文献
38.
D. P. Chowdhury J. Arunachalam Rakesh Verma Sujit Pal S. Gangadharan 《Journal of Radioanalytical and Nuclear Chemistry》1992,158(2):463-470
40 MeV -particles have been used to determine oxygen impurity at ppm levels in silicon, copper, and stainless steel, through the radiochemical separation of18F from the matrix. The separation of18F has been carried out by two techniques, viz.(1) distillation of H2SiF6 and (2) precipitation of KBF4 and some modification has been applied in the separation, depending on the nature of interferences from the matrix. Instrumental approach was also carried out to determine the oxygen impurity at 100 ppm in Si matrix because this approach is not possible in Cu and stainless steel samples due to matrix activity. 相似文献
39.
Kaleeswari Kalairajan Tamil Selvi Arunachalam 《Research on Chemical Intermediates》2022,48(4):1495-1513
Research on Chemical Intermediates - A straightforward and suitable protocol is described for the conversion of substituted styrene to alkylbenzenes in the presence of Al2O3 nanoparticles... 相似文献
40.