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991.
992.
Barsi Ferruccio Bertossi Alan A. Betti Sorbelli Francesco Ciotti Roberto Olariu Stephan Pinotti M. Cristina 《Parallel and Distributed Systems, IEEE Transactions on》2009,20(8):1216-1230
Scalable energy-efficient training protocols are proposed for wireless networks consisting of sensors and a single actor, where the sensors are initially anonymous and unaware of their location. The protocols are based on an intuitive coordinate system imposed onto the deployment area, which partitions the sensors into clusters. The protocols are asynchronous, in the sense that the sensors wake up for the first time at random, then alternate between sleep and awake periods both of fixed length, and no explicit synchronization is performed between them and the actor. Theoretical properties are stated under which the training of all the sensors is possible. Moreover, both worst-case and average case analyses of the performance, as well as an experimental evaluation, are presented showing that the protocols are lightweight and flexible. 相似文献
993.
An analytical isotherm equation that can be applied to water vapor-biopolymer systems, was developed. The model describes the multilayer adsorption on fractal surfaces with energetic interactions adsorbate-adsorbate (measure in terms of free energy) different from that of bulk water. Assuming explicit mathematical functionalities for the variation of the free energy with the number of adsorbed layers, it is possible to evaluate the effect of the adsorbate-adsorbate interactions on the adsorption capacity of solids of high degree of surface irregularity. For those surfaces with relatively low degree of irregularity (D values slightly larger than 2) it results that the free energy variation with the layer number in the multilayer region affects considerably the sorption capacity of the adsorbent, even for water activities lower than those corresponding to the monolayer moisture content. This effect becomes less marked as the fractal dimension increases (D approaching to 3), being relevant for water activities much larger than those corresponding to the monolayer value, only. The isotherm was tested, using published experimental equilibrium data of various biopolymers. 相似文献
994.
Here we test if playing video-games require intelligence. Twenty-seven university undergraduate students were trained on three games from Big Brain Academy (Wii): Calculus, Backward Memory and Train. Participants did not have any previous experience with these games. General intelligence was measured by five ability tests before the training session. Training comprised 10 blocks of trials (10 trials per block). Ackerman’s (Ackerman, P. L. (1988). Individual differences and skill acquisition. In P. L. Ackerman, R. J. Sernberg, & R. Glaser (Eds.), Learning and individual differences: Advances in theory and practice (pp. 165–217). New York: W.H. Freeman and Company) theory of skill learning was used as a framework for the present study. Results show that playing the Train game increases the correlation with general intelligence across blocks of trials. This is not the case for Calculus and Backward Memory. These findings suggest strategies for designing video-games presumably appropriate to stimulate our core cognitive abilities. 相似文献
995.
Passerone Roberto Hafaiedh Imene Ben Graf Susanne Benveniste Albert Cancila Daniela Cuccuru Arnaud Gerard Sebastien Terrier Francois Damm Werner Ferrari Alberto Mangeruca Leonardo Josko Bernhard Peikenkamp Thomas Sangiovanni-Vincentelli Alberto 《Design & Test of Computers, IEEE》2009,26(3):38-53
Editor's note:This article provides an overview of current efforts in Europe for using metamodeling in the integrated development of critical systems such as automotive electronics. It distinguishes between lightweight versus heavyweight approaches, surveys a number of related current European projects, and gives details about the Speeds project to illustrate the role of metamodeling-driven system engineering.—Sandeep Shukla, Virginia Tech 相似文献
997.
Eugenia Rubín Pilar Rodríguez Roberto Herrero Manuel E. Sastre de Vicente 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(7):1093-1099
Phenol, 2‐chlorophenol (2‐CP), and 4‐chlorophenol (4‐CP) biosorption on Sargassum muticum, an invasive macroalga in Europe, has been investigated. The efficiency of this biosorbent was studied measuring the equilibrium uptake using the batch technique. A chemical pre‐treatment with CaCl2 has been employed in this study in order to improve the stability as well as the sorption capacity of the algal biomass. The influence of pH on the equilibrium binding and the effect of the algal dose were evaluated. The experimental data at pH = 1 have been analysed using Langmuir and Freundlich isotherms. It was found that the maximum sorption capacity of chlorophenols, qmax = 251 mg g?1 for 4‐CP and qmax = 79 mg g?1 for 2‐CP, as well as that of a binary mixture of both chlorophenols, qmax = 108 mg g?1, is much higher than that of phenol, qmax = 4.6 mg g?1. Moreover, sorption kinetics have been performed and it was observed that the equilibrium was reached in less than 10 h. Kinetic data have been fitted to the first order Lagergren model, from which the rate constant and the sorption capacity were determined. Finally, biosorption of the phenolic compounds examined in the present study on Sargassum muticum biomass was observed to be correlated with the octanol‐water partitioning coefficients of the phenols. This result allows us to postulate that hydrophobic interactions are the main responsible for the sorption equilibrium binding. Copyright © 2006 Society of Chemical Industry 相似文献
998.
Claudio Fontanesi Roberto Giovanardi Maria Cannio Ercole Soragni 《Journal of Applied Electrochemistry》2008,38(4):425-436
This work presents a study of a hard chromium plating process using low concentration H2CrO4 baths. In particular, the effect of different values of CrO3/H2SO4 ratio on coating properties such as adhesion, hardness, surface roughness, apparent density and microstructure were considered.
To increase the solution conductivity, avoiding long deposition times and low throwing power typical of dilute solutions,
the behaviour of various inorganic compounds was investigated. Specifically, the compounds suitable for obtaining brighter
coatings with lower surface roughness values than those obtained using Fink’s solutions were Na2SO4 and Al2(SO4)3 × 18H2O. A bath composition was identified, with a limited use of Cr(VI) in a solution able to produce coatings with a better surface
roughness than those of conventional industrial baths. 相似文献
999.
Roberto Baldoni Ricardo Jiménez-Peris Marta Patiño-Martínez Leonardo Querzoni Antonino Virgillito 《Journal of Parallel and Distributed Computing》2008
Peer-to-peer systems (P2P) have become a popular technique to design large-scale distributed applications in unmanaged inter-domain settings, such as file sharing or chat systems, thanks to their capabilities to self-organize and evenly split the load among peers. Recently, enterprises owning a large IT hardware and software infrastructure started looking at these P2P technologies as a means both to reduce costs and to help their technical divisions to manage huge number of devices characterized by a high level of cooperation and a relatively low churn. Gaining a quick exclusive access to the system for maintenance or auditing purposes in these enterprise infrastructures is a fundamental operation to be implemented. Conversely, this kind of operation is usually not an issue in the previously mentioned inter-domain setting, where peers are inherently independent and cannot be managed. 相似文献
1000.
Sally Meiners Ijaz Ahmed Abdul S Ponery Nathan Amor Suzan L Harris Virginia Ayres Yuan Fan Qian Chen Roberto Delgado‐Rivera Ashwin N Babu 《Polymer International》2007,56(11):1340-1348
BACKGROUND: The design of implants comprised of biodegradable electrospun nanofibers for the purpose of bridging injuries in damaged spinal cord is discussed. Electrospun nanofibers structurally mimic the extracellular matrix on which neurons and other cell types grow in vivo. This property has created great interest for their use in tissue engineering applications. However, their employment as biomimetic surfaces for such in vivo applications is still in its infancy. RESULTS: A nonwoven fabric comprised of electrospun polyamide nanofibers supported modest axonal regeneration in injured adult rat spinal cord. Covalent modification of the nanofibers with a bioactive peptide derived from the neuroregulatory extracellular matrix molecule tenascin‐C enhanced the ability of the nanofibers to facilitate axonal regrowth. However, the random orientation of the nanofibrillar fabric folds was an impediment to the forward movement of axons. CONCLUSIONS: Polyamide nanofibers covalently modified with neuroactive molecules provide a promising material for grafts to promote spinal cord regeneration. However, for the proper guidance of regrowing axons, attention must be paid to the engineering of ordered nanofibrillar structures. Copyright © 2007 Society of Chemical Industry 相似文献