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31.
32.
M. Portaccio B. Della Ventura D. G. Mita N. Manolova O. Stoilova I. Rashkov M. Lepore 《Journal of Sol-Gel Science and Technology》2011,57(2):204-211
Micro-Attenuated Total Reflection (ATR) Fourier Transform Infrared spectroscopy was used to investigate sol–gel layers for
biosensing applications prior and after glucose oxidase (GOD) immobilization. The changes occurring in sol–gel infrared spectrum
after GOD immobilization were clearly evidenced confirming the retaining of the enzyme activity. Moreover, micro-ATR experimental
technique allowed us to investigate the spatial distribution of enzyme concentration. The non-destructive nature of our approach
also enabled to monitor the time stability of sol–gel layers and of embedded GOD. The temporal evolution of some peaks in
infrared spectra of these sol–gel layers was compared with absorption and steady-state fluorescence measurements. The results
reported here confirm that micro-ATR infrared spectroscopy can be usefully employed for a non- or minimally invasive detailed
characterization of supports for enzyme immobilization. 相似文献
33.
The shear adhesive force of four non-climbing cockroaches (Blatta orientalis Linnaeus, 1758) was investigated by the use of a centrifugal machine, evaluating the shear safety factor (adhesion force divided by body weight) on six surfaces (steel, aluminium, copper, two sandpapers and a common paper sheet) having different roughness. The adhesive system of Blatta orientalis was characterized by means of a field emission scanning electron microscope and the surface roughness was determined by an atomic force microscope. The cockroach maximum shear safety factor, or apparent friction coefficient, is determined to be 12.1 on the less rough of the two sandpapers, while its minimum value is equal to 1.9 on the steel surface. A two-sample Student t analysis has been conducted in order to evaluate the significance of the differences among the obtained shear safety factors due to both roughness and chemistry. An interesting correlation between cockroach shear adhesion and surface roughness emerges with a threshold mechanism dictated by the competition between claw tip radius and roughness, indicating that the best adhesion is obtained for roughness larger than the claw tip radius. 相似文献
34.
M. Portaccio M. Lepore B. Della Ventura O. Stoilova N. Manolova I. Rashkov D. G. Mita 《Journal of Sol-Gel Science and Technology》2009,50(3):437-448
A monolithic silica gel matrix with entrapped glucose oxidase was constructed as a bioactive element in an optical biosensor
for glucose determination. Physicochemical and biochemical characterizations of the catalytic matrix were performed, and the
intrinsic fluorescence of immobilised glucose oxidase (GOD) was investigated in the UV and visible range by performing steady
state and time course measurements. In all cases, the silica gel matrix proved to be a suitable support for optical biosensing
owing to its superior optical properties (e.g., high transmittance and reliable fluorescence and GOD absorption spectra after
immobilisation). From steady state measurements, calibration curves were obtained as a function of glucose concentration.
When time course measurements were performed, the silica gel support displayed a larger linear calibration range and higher
sensitivity than other immobilisation systems. In addition, a glucose optical biosensor was developed and characterised using
as catalytic element GOD immobilised on a gel disk bound to a bundle of optical fibres. 相似文献
35.
J. R. Croca A. Garuccio V. L. Lepore R. N. Moreira 《Foundations of Physics Letters》1990,3(6):557-564
An experimental apparatus to detect de Broglie waves is discussed. The wave packets of two photons generated in the parametric-down conversion are overlapped in a modified Mach-Zehnder interferometer. The coincidence photodetection rate of photon pairs is evaluated, as a function of path-length of two interferometer arms, both by using the de Broglie concept of a real quantum wave and by the quantum optical approach. The different results of these two theories are compared, and it is shown that the proposed experiment can disprove either the theories. 相似文献
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In both solution and the solid phase, a variety of ketone oxime anions have been treated with 4-substituted-2-fluorobenzonitriles to give the corresponding nucleophilic aromatic substitution aryloxime adducts. Under aqueous acidic conditions, these adducts underwent cyclization to give the corresponding ketones. Suzuki and amide coupling reactions were also successfully performed on two resin-bound oximes followed by subsequent cyclorelease to give ketone product in good yields and purities. [reaction--see text] 相似文献
38.
[Chemical reaction: see text] We report the first examples of a Michael-Stork enamine addition to allenyl esters and ketones. Studies reveal that 2 equivalents of enamine are required for optimal yields. In the case of an allenyl methyl ketone, cyclopentyl enamine addition led to 8-oxobicyclo[3.2.1]octane formation, providing evidence for the in situ formation of an enamine intermediate following the initial Michael-Stork reaction. 相似文献
39.
E. Cortizo A. Moreno Yeras J. R. Lepore M. Garavaglia 《Optics and Lasers in Engineering》2003,40(1-2):117-132
The structured illumination technique consists of projecting a fringe system onto a 3D object from a well defined space point, which results in a pattern that depends on the characteristic of the projected fringes, the viewpoint and the illuminated object morphology. Therefore, the structured illumination method enables to determine the topography of 3D objects. To implement this technique we set up an optoelectronic array that allows studying the sole of the foot during a walk. The method consists of projecting a Ronchi grid and capturing the images generated on the foot by a CCD camera. These obtained images are graphically processed and fringes converted into vectors. A depending algorithm on the experimental setup allows obtaining, from those vectors data, cotes for a discrete profile plotting of the studied object. The method enables the quantitative determination of the sole topography during the walk. Qualitatively, it can be used for diagnosis and control of deformation and injuries caused by accidents or illnesses. It can be introduced in the primary attention health system to study a great number of patients, due to its simplicity and low cost installation, and for being a non-invasive technique. 相似文献
40.