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81.
The mass transfer kinetics during osmotic dehydration of pomegranate arils in osmotic solution of sucrose was studied to increase palatability and shelf life of arils. The freezing of the whole pomegranate at -18 °C was carried out prior to osmotic dehydration to increase the permeability of the outer cellular layer of the arils. The osmotic solution concentrations used were 40, 50, 60°Bx, osmotic solution temperatures were 35, 45, 55 °C. The fruit to solution ratio was kept 1:4 (w/w) during all the experiments and the process duration varied from 0 to 240 min. Azuara model and Peleg model were the best fitted as compared to other models for water loss and solute gain of pomegranate arils, respectively. Generalized Exponential Model had an excellent fit for water loss ratio and solute gain ratio of pomegranate arils. Effective moisture diffusivity of water as well as solute was estimated using the analytical solution of Fick's law of diffusion. For above conditions of osmotic dehydration, average effective diffusivity of water loss and solute gain varied from 2.718 × 10(-10) to 5.124 × 10(-10) m(2)/s and 1.471 × 10(-10) to 5.147 × 10(-10) m(2)/s, respectively. The final product was successfully utilized in some nutritional formulations such as ice cream and bakery products. 相似文献
82.
Sanghera J.S. Nguyen V.Q. Pureza P.C. Kung F.H. Miklos R. Aggarwal I.D. 《Lightwave Technology, Journal of》1994,12(5):737-741
Improved purification and processing techniques have been utilized to fabricate Ge30As10Se30Te30 glass fibers with a minimum loss of O.11 dB/m at 6.6 μm. This is the lowest loss reported for any telluride glass fiber in the infrared region. Furthermore, the fibers exhibit less than 1 dB/m loss between 5.25 and 9.5 μm 相似文献
83.
Hevea brasiliensis ) esterified with acetic anhydride, maleic anhydride and phthalic anhydride was studied for moisture adsorption behaviour.
FTIR spectroscopic technique was used to analyse the chemical changes in the wood through the correspondent reactions. Spectra
indicated increasing intensity of the C=O and C-O stretching bands, and reduction in O-H stretching vibrations that reflects
formation of less hygroscopic ester bonds with hydroxyl groups of cell wall polymers. Moisture adsorption isotherms show low
equilibrium moisture content in esterified wood at all relative humidity values as compared to a control. The adsorption data
was analysed by applying Hailwood-Horrobin theory which separated the adsorbed water into hydrated water and dissolved water
corresponding to mono-layer and multi-layer adsorption. Curve for Mh and Ms were similar in pattern for esterified wood and control with different magnitude. Low Mh and Ms in esterified wood indicate reduction in moisture adsorption sites. Inaccessible fraction of wood for water vapour was increased
by 43%, 32% and 26% in acetic, maleic and phthalic anhydride treated wood, respectively, compared to the control. Acetic anhydride
treatment was found most effective in reducing hygroscopicity of wood.
Hevea brasiliensis ) wurde verestert mit Anhydriden der Maleins?ure, Essigs?ure und Phtals?ure. Das Adsorptionsverhalten bei verschiedenen Feuchten wurde mit FTIR-Methoden untersucht, um die entsprechenden chemischen Abl?ufe zu erfassen. Intensivere C=O, und -C-O- Streckschwingungen sowie reduzierte OH-Schwingungen reflektieren die neu gebildeten, weniger hygroskopischen Esterbindungen. Bei allen modifizierten Proben ergaben sich niedrigere Gleichgewichtsfeuchten. Die Adsorptions-Isothermen wurden mit Hilfe der Hailwood-Horrobin Theorie analysiert, um adsorbiertes (Mh) und gel?stes (Ms) Wasser zu unterscheiden. Der Kurvenverlauf für Mh und Ms für modifiziertes und unbehandeltes Holz war qualitativ ?hnlich, und unterschied sich nur quantitativ. Geringe Werte für Mh und Ms zeigen eine Verringerung der m?glichen Adsorptionsstellen an. Der nicht zug?ngliche Anteil des Holzes, bezogen auf Kontrollproben, verringerte sich auf 43% (Acetanhydrid), 32% (Maleins?ureanhydrid) und 26% (Phthals?ureanhydrid). Acetanhydrid erwies sich als das effektivste Mittel, um die Hygroskopizit?t zu erniedrigen.相似文献
84.
85.
Redefining clustering for high-dimensional applications 总被引:1,自引:0,他引:1
Clustering problems are well-known in the database literature for their use in numerous applications, such as customer segmentation, classification, and trend analysis. High-dimensional data has always been a challenge for clustering algorithms because of the inherent sparsity of the points. Recent research results indicate that, in high-dimensional data, even the concept of proximity or clustering may not be meaningful. We introduce a very general concept of projected clustering which is able to construct clusters in arbitrarily aligned subspaces of lower dimensionality. The subspaces are specific to the clusters themselves. This definition is substantially more general and realistic than the currently available techniques which limit the method to only projections from the original set of attributes. The generalized projected clustering technique may also be viewed as a way of trying to redefine clustering for high-dimensional applications by searching for hidden subspaces with clusters which are created by interattribute correlations. We provide a new concept of using extended cluster feature vectors in order to make the algorithm scalable for very large databases. The running time and space requirements of the algorithm are adjustable and are likely to trade-off with better accuracy 相似文献
86.
K. K. Aggarwal 《Sadhana》1987,11(1-2):155-165
The complexity of computer communication networks has taken a dramatic upswing, following significant developments in electronic
technology such as medium and large scale integrated circuits and microprocessors. Although components of a computer communication
network are broadly classified into software, hardware and communications, the most important problem is that of ensuring
the reliable flow of information from source to destination.
An important parameter in the analysis of these networks is to find the probability of obtaining a situation in which each
node in the network communicates with all other remaining communication centres (nodes). This probability, termed as overall
reliability, can be determined using the concept of spanning trees.
As the exact reliability evaluation becomes unmanageable even for a reasonable sized system, we present an approximate technique
using clustering methods. It has been shown that when component reliability ⩾ 0.9, the suggested technique gives results quite
close to those obtained by exact methods with an enormous saving in computation time and memory usage.
For still quicker reliability analysis while designing the topological configuration of real-time computer systems, an empirical
form of the reliability index is proposed which serves as a fairly good indicator of overall reliability and can be easily
incorporated in a design procedure, such as local search, to design maximally reliable computer communication network. 相似文献
87.
88.
F. Kochary M. D. Aggarwal A. K. Batra R. Hawrami D. Lianos A. Burger 《Journal of Materials Science: Materials in Electronics》2008,19(11):1058-1063
The lead magnesium niobate-lead titanate is one of the new generations of piezoelectric materials with outstanding properties.
Single crystals of 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT) show superior properties as compared to piezoelectric ceramics and piezoelectric films in device applications. Large
size crystals are required for specific applications. Previously, transparent and high quality PMN-PT single crystals have
been grown in our laboratory using the high temperature flux method. The size of the obtained crystals was small and varied
from 2 to 8 mm3, mostly showing regular prismatic shape. In present attempt, PMN-PT crystals are grown from the vertical gradient freeze
method with no flux using congruent melt. Processing conditions and growth parameters have been optimized to increase the
size and yield of the perovskite crystals including cooling rate, soak time and soak temperature. The size of the grown crystals
obtained by this method is very large relatively and varied from 5 to 30 mm3. The microstructure of the as grown single crystals is investigated by scanning electron microscopy. Piezoelectric properties
of the grown crystals are also investigated. PMN-PT plates show excellent piezoelectric properties. Samples were poled under
an applied electric field of 5 kV/cm. Dielectric properties at a frequency of 1 kHz are examined. Finally, the variation of
pyroelectric coefficient with temperature is studied. The grown PMN-PT crystals show typical relaxor dielectric properties. 相似文献
89.
In this paper, the thermodynamic properties of lithium nitrate-ammonia mixtures are presented. The vapour pressure-temperature correlations are developed by fitting the experimental P-T-x data. The enthalpy of solution, the latent heat of vaporization, the integral heat of solution and the differential heat of solution are presented in appropriate tabular and graphical forms. 相似文献
90.
A differential feeder protection that utilizes voltage and current signals is described. This approach obviates the need for relay bias to compensate for capacitance spill current, thus improving the relay sensitivity. From a practical point of view, the scheme has been designed to simplify the digital hardware requirements and reduce the bandwidth requirements for signal transmission over a fiber-optic link 相似文献