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31.
Gargi Dutta 《Journal of organometallic chemistry》2011,696(14):2693-2701
Ten mixed dioxime complexes RCo(L)(dmgH)Py [R = Cl, Me, Et, Bu, Benzyl] [L = dSPhgH (1-5) and dSEtgH (6-10)] have been synthesized and characterized by NMR. Formation of 1 and 6 is very fast and takes only 5 and 15 min in ethanol. Molecular oxygen insertion in 5 and 10 is monitored and forms mixture of products within 5 min. The crystal structure of 1, 4, 5, 6, 8 and 10 is reported. Benzyl ring is oriented over dmgH wing in both 5 and 10 and has a weak C-H…π interaction (3.33 Å and 3.22 Å) and this causes high upfield shift of the dmgH protons. Electrochemical study on 1, 4, 5, 6, 8 and 10 is also reported. Because of increased electron donation by SEt group, 6 is more difficult to reduce than 1. 相似文献
32.
A new method for the detection of low oxygen concentration is proposed here. The system is based on the principle of enhancement of fluorescence yield of tetraphenylporphine (TPP) dye at λ=656 nm when excited by He-Cd laser at λ =441 nm in the presence of oxygen. The sensor head was fabricated by cladding the ARTON fiber core with the poly-4-methy1-1-pentene polymer matrix doped with TPP. The experimental results obtained indicate a good enhancement in the fluorescence when the sensor head is exposed to oxygen. The response was found to be linear and stable in the range of (100 ppm-1%) with the resolution of 0.01%. The sensor response was characterized by studying its response for change in temperature and is discussed below. 相似文献
33.
B.K. Agarwal C.B. Bhargava A.N. Vishnoi V.P. Seth 《Journal of Physics and Chemistry of Solids》1976,37(7):725-728
The K absorption edges of copper in the metal, cuprous oxide and cupric oxide are presented. The extended fine structure has been recorded in all the three substances. 相似文献
34.
Basu Ray G Chakraborty I Ghosh S Moulik SP 《Journal of colloid and interface science》2007,307(2):543-553
Self-aggregation of mixed binary nonionic and ionic surfactants comprising N-methyl-N-decanoyl glucamide (MEGA 10) and alkyltrimethylammonium bromides (C(12)-, C(14)-, and C(16)TAB) has been investigated in detail by different physical methods. The counter-ion binding, aggregation number, and polarity of the mixed micelles have been determined. The results have been analyzed in the light of the theories of Rubingh and Maeda. The thermodynamic parameters of the micellization process have been evaluated and discussed. The interfacial adsorptions of the mixed amphiphiles including their surface excesses and head-group areas have also been evaluated. Based on the head-group areas, the overall shapes of the mixed micelles have been predicted from the estimation of the amphiphile packing parameters. 相似文献
35.
Alpha toxin is a common virulent factor of Staphylococcus aureus and is believed to play crucial roles in pathogenicity induced by S. aureus. Alpha toxin is also known to induce permeability to endothelial cell monolayers in vitro due to the formation of interendothelial
gaps. The present study is directed towards measuring alpha toxin using a whole-cell-based biosensor. The biosensor, consisting
of a confluent monolayer of human umbilical vein endothelial cells (HUVECs) on a potassium ion-selective electrode, takes
advantage of cell permeability dysfunction to detect the presence of small quantities of alpha toxin. When a confluent monolayer
of cells was formed on the membrane surface, the response of the electrode toward the marker ion, potassium, was inhibited.
Upon exposing this sensor to varying concentrations of alpha toxin for 20 min, an increase in sensor response to potassium
was observed. The response thus obtained was indirectly related to the concentration of alpha toxin. The detection limit of
this sensor for alpha toxin was found to be 0.1 ng/ml. Cell monolayers were stained with silver nitrate to quantify the formation
of intercellular gaps as well as to study the effect of this toxin on HUVECs morphology. A strong positive correlation was
observed between the response obtained from the biosensor and the area of the intercellular gaps. Silver staining also revealed
the tendency of cells to round up upon being exposed to alpha toxin.
Figure Measuring alpha toxin using a whole-cell-based biosensor 相似文献
36.
R. Vishnoi R. Singhal K. Asokan D. Kanjilal D. Kaur 《Applied Physics A: Materials Science & Processing》2012,107(4):925-934
The effects of 200 MeV Au ions irradiation on the structural and magnetic properties of Ni–Mn–Sn ferromagnetic shape memory alloy (FSMA) thin films have been systematically investigated. In order to understand the role of initial microstructure and phase of the film with respect to high energy irradiation, the two types of Ni–Mn–Sn FSMA films having different phases at room temperature were irradiated, one in martensite phase (Ni58.9Mn28.0Sn13.1) and other in austenite phase (Ni50Mn35.6Sn14.4). Transmission electron microscope (TEM) and scanning electron microscope (SEM) images along with the diffraction patterns of X-rays and electrons confirm that martensite phase transforms to austenite phase at a fluence of 6×1012 ions/cm2 and a complete amorphization occurs at a fluence of 3×1013 ions/cm2, whereas ion irradiation has a minimal effect on the austenitic structure (Ni50Mn35.6Sn14.4). Thermo-magnetic measurements also support the above mentioned behaviour of Ni–Mn–Sn FSMA films with increasing fluence of 200 MeV Au ions. The results are explained on the basis of thermal spike model considering the core and halo regions of ion tracks in FSMA materials. 相似文献
37.
Sen Pratik K. Mukhopadhyay Gargi Gani Nasimul Sen Gupta Kalyan K. 《Transition Metal Chemistry》2001,26(4-5):451-456
The oxidative behaviour of the 1,2-dicarbonyl compounds, viz., glyoxal, biacetyl and benzil, towards permanganate in ethanoic acid medium in the presence of HClO4 has been investigated. The reaction is first order with respect to MnO–
4, substrate, as well as H+. The rate decreases with an increase in ionic strength. Different thermodynamic parameters have been evaluated. The protonated dialdehyde or diketone reacts with permanganate ion to form an intermediate ester which decomposes in a slow step to produce the corresponding carboxylic acid via C—C bond cleavage. 相似文献
38.
A new tailor-made colorimetric chemosensor 1, containing pyridine and benzothiazole moieties connected through an azo (–N = N–) linkage has been synthesised. In 9:1 (v/v) aqueous THF (pH 7.0 HEPES buffer), it showed a conspicuous naked-eye colour change upon binding to Ni2+ (colourless to light green) and AcO? (colourless to orange) resulting in their ratiometric sensing. The cation and anion recognition property of the chemosensor 1 was monitored by UV–vis spectral analysis and 1H NMR titrations. 相似文献
39.
Gargi Dutta 《Journal of organometallic chemistry》2011,696(4):892-3791
Five benzyl cobaloximes with different thiodioximes, BnCo[d(SR)gH]2Py, have been synthesized and four of these complexes have been characterized by X-ray. The reactivity of these complexes towards molecular oxygen has been studied. The puckering of the Co(dioxime)2 unit, caused by dioxime side chain, the SR group, significantly influences the Co-C bond reactivity. Structural features in one of the oxygen inserted cobaloximes have been studied to confirm if puckering of dioxime is the guiding factor. The reactivity is also affected, to some extent, by the C-H…π interaction between the benzyl and the dioxime moiety. 相似文献
40.
Gargi Bhattacharyya John Hegeman Joohyung Kim Jeff Langford Sung Y. Song 《European Journal of Combinatorics》2008,29(6):1396
This paper revisits the existence and construction problems for polygonal designs (a special class of partially balanced incomplete block designs associated with regular polygons). We present new polygonal designs with various parameter sets by explicit construction. In doing so we employ several construction methods — some conventional and some new. We also establish a link between a class of polygonal designs of block size 3 and the cyclically generated ‘λ-fold triple systems’. Finally, we show that the existence question for a certain class of polygonal designs is equivalent to the existence question for ‘perfect grouping systems’ which we introduce. 相似文献