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91.
An integrated optical waveguide refractometer, believed to be novel, is presented. The sensor is based on an antiresonant reflecting optical waveguide and uses the strong attenuation dependence on the refractive index of antiresonant cladding layers as the sensing principle. The theory and the operation of the sensor are discussed in terms of one- and two-dimensional geometry. The theoretical predictions and numerical analysis show that a versatile sensor can be realized. The design trade-offs are discussed, and the sensitivity and measurement range are presented. 相似文献
92.
Luigi Palopoli Domenico Rosaci Giorgio Terracina Domenico Ursino 《Knowledge and Information Systems》2005,8(4):462-497
The problem of handling both the integration and the cooperation of a large number of information sources characterised by
heterogeneous representation formats is a challenging issue. In this context, a central role can be played by the knowledge
about the semantic relationships holding between concepts belonging to different information sources (intersource properties).
In this paper, we propose a semiautomatic approach for extracting two kinds of intersource properties, namely synonymies and
homonymies, from heterogeneous information sources. In order to carry out the extraction task, we introduce both a conceptual
model, for representing involved sources, and a metrics, for measuring the strength of the semantic relationships holding
among concepts represented within the same source. 相似文献
93.
This article addresses the problem of detecting feature interactions in the area of telephony systems design. The proposed approach consists of two phases: filtering and testing. The filtering phase detects possible interactions by identifying incoherencies in a logic specification of the main elements of the features, consisting of preconditions, triggers, results and constraints. If incoherencies are identified, then an interaction is suspected, test cases corresponding to the suspected interaction are generated and testing is applied to see if the interaction actually exists. Two case studies, carried out on established benchmarks, show that this approach gives good results in practice.
Nicolas Gorse received a Master of Computer Science from the University of Ottawa, School of Information Technology and Engineering in 2001.He is currently a Ph.D. candidate in the Département d'Informatique et Recherche Opérationnelle of the Université de Montréal. His research interests relate to formal methods and their application in the design and verification of complex electronic systems at high levels of abstraction.
Luigi Logrippo received a degree in law from the University of Rome (Italy) in 1961, and in the same year he started a career in computing. He worked for several computer companies and in 1969 he obtained a Master of Computer Science from the University of Manitoba, followed by a Ph.D. of Computer Science from the University of Waterloo in 1974.He was with the University of Ottawa for 29 years, where he was Chair of the Computer Science Department for 7 years. In 2002 he moved to the Université du Québec en Outaouais, Département d'Informatique et Ingénierie, while remaining associated with the University of Ottawa as an Adjunct Professor.His interest area is formal and logic-based methods and their applications in the design of communications systems. For a number of years he worked on the development of tools and methods for the language LOTOS. Current research deals with the formal analysis of advanced communications services made possible by internet telephony, of the policies that govern them, and of their interactions, in application areas such as presence features and e-commerce contracts.
Jacques Sincennes is a research programmer/systems analyst at the University of Ottawa, School of Information Technology and Engineering. He has held this position for the past 17 years. He is coauthor of a number of papers and a patent application.An erratum to this article is available at . 相似文献
94.
Paolo Casoli Andrea Vacca Germano Franzoni Gian Luigi Berta 《Simulation Modelling Practice and Theory》2006,14(8):1059
This paper presents a numerical model for the simulation of a swash-plate axial piston pump, focusing on the characterization of fluid properties.As it is well known, the reduction of flow oscillations (which generates pressure ripples and produces vibration and noise in the entire circuit) and the avoidance of cavitation are the major problems in the design of these pumps. Developing a simulation code can be very useful for component optimisation in order to predict and reduce the undesired phenomena. The paper first gives a quick overview on a previously developed pump model; afterwards four different models of the fluid are presented: they take into account cavitation in different ways. Their aim at characterizing as well as possible the unsteady and erratic cavitation features in a simplified manner, in order to apply the models to the simulation of hydraulic components.In the second part of the paper an application is shown of these models to an axial piston pump: a few results are presented and compared with available test data. The effects of the fluid models on the predicted pump performance are shown and commented. 相似文献
95.
96.
Gian Carlo Alfonso Luigi Olivero Antonio Turturro Enrico Pedemonte 《Polymer International》1973,5(2):141-154
The self-seeding crystallisation technique is applied to a dilute solution of polyethylene in xylene containing, in suspension, foreign particles; data concerning some pigments usually employed for colouring the plastics are reported. It is shown that this method allows easy demonstration of the interactions existing between the dissolved polymer and the pigment; at the same time, it is possible to study the morphology which is evolved as a consequence of these interactions under particularly simple conditions as only a small amount of polymer crystallises on the pigment particles. The behaviour of several pigments is consistent with the results obtained by crystallising the bulk polyethylene coloured with the same pigments. Some unusual morphologies are made evident. 相似文献
97.
98.
Leone G Barbucci R Borzacchiello A Ambrosio L Netti PA Migliaresi C 《Journal of materials science. Materials in medicine》2004,15(4):463-467
A new technique to obtain microporous hydrogels was realised. It permits us to obtain a microporous structure directly on the already cross-linked hydrogel. It consists in stratifying the already cross-linked hydrogel on to a filter with known porosity and forcing the CO2 bubbles, derived from the addition of HCl to a porogen salt (NaHCO3), to cross through the filter first and then the matrix. By changing the porosity of the filter, it was possible to modulate the porous morphology of the hydrogels. The polysaccharides selected were hyaluronane, alginate, and carboxymethylcellulose. The influence of the porous morphology on the physico-chemical properties of the gel has been evaluated by FT-IR, FRAP, calorimetric, water uptake, and rheological analysis. 相似文献
99.
Cascone MG Lazzeri L Sparvoli E Scatena M Serino LP Danti S 《Journal of materials science. Materials in medicine》2004,15(12):1309-1313
Poly(vinyl alcohol) hydrogels prepared by freeze-thawing procedure represent synthetic systems widely investigated as non-biodegradable scaffolds for tissue regeneration. In order to improve the biocompatibility properties of pure poly(vinyl alcohol) (PVA) hydrogels, blends of PVA with different biological macromolecules, such hyaluronic acid, dextran, and gelatin were prepared and used to produce bioartificial hydrogels. The porosity characteristics of these hydrogels were investigated by scanning electron microscopy and mercury intrusion porosimetry. The morphology of bioartificial hydrogels was evaluated and compared with that of pure PVA hydrogels. In particular the effect exerted by each biological component on pore size and distribution was investigated. The obtained results indicate that when a natural macromolecule is added to PVA the internal structure of the material changes. A small amount of biopolymer induces the structural elements of PVA matrix to take on a well evident lamellar appearance and an apparent preferential orientation. Comparing the results of SEM and mercury intrusion porosimetry it was concluded that hydrogels containing 20% of biological component have the most regular structure and at the same time the lowest total porosity. On the contrary samples with the highest content of natural polymer (40%) show the less regular structure and the highest total porosity. 相似文献
100.
In this paper a methodological approach is proposed to validate mechanistic modeling for proton binding onto active sites of mineral and soil samples by reducing the uncertainty and arbitrariness of model schematization. This approach is based on the quantitative formulation (X-ray calibration method) of a simulating mineral mixture (SMM) accounting for the main mineral phases in the soil (quartz, goethite, hematite, muscovite, clinochlore). Mineral and organic contributions were separated by comparing titration curves of river sediment and SMM. Specific mineral contributions to the acid properties of SMM were separated by comparing titration models of SMM and single minerals. Different nonelectrostatic models were used for titrations of SMM and single minerals: two-site/three-KH models (one amphoteric plus one monoprotic site) for clay minerals and SMM; one-site/two-KH models (one amphoteric site) for goethite and hematite; and a one-site/one-KH model (one monoprotic site) for quartz. Crossed-comparisons of titration models allow for identifying and quantifying the specific contributions of the distinct edge hydroxyl groups of iron oxides, clay minerals, and quartz in the different pH ranges. In particularthe amphoteric sites of aluminosilicates mainly contribute in the acid-neutral pH range, the amphoteric sites of iron oxides take part in the neutral-basic range, and finally the monoprotic edge hydroxyl groups of quartz react in the upper basic region of pH. The good simulation of the acid-base properties of SMM (according to single mineral titration models and quantitative composition by X-ray) confirms both model schematization and SMM formulation. Speciation diagrams of the active sites of the different mineral components (aluminosilicates, iron oxides, and quartz) were obtained by implementing the database of a dedicated software with the apparent equilibrium constants regressed by titration modeling of single minerals. 相似文献