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41.
A new switch-mode rectifier (SMR) topology has been developed and presented in this paper. Its advantages over other SMR topologies include: high input power factor, minimum input current distortion, elimination of dc link bus electrolytic capacitors, and minimization of switching stresses of high-frequency inverter stage components. 相似文献
42.
Trinocular Stereo: A Real-Time Algorithm and its Evaluation 总被引:1,自引:0,他引:1
Jane Mulligan Volkan Isler Kostas Daniilidis 《International Journal of Computer Vision》2002,47(1-3):51-61
In telepresence applications each user is immersed in a rendered 3D-world composed from representations transmitted from remote sites. The challenge is to compute dense range data at high frame rates, since participants cannot easily communicate if the processing cycle or network latencies are long. Moreover, errors in new stereoscopic views of the remote 3D-world should be hardly perceptible. To achieve the required speed and accuracy, we use trinocular stereo, a matching algorithm based on the sum of modified normalized cross-correlations, and subpixel disparity interpolation. To increase speed we use Intel IPL functions in the pre-processing steps of background subtraction and image rectification as well as a four-processor parallelization. To evaluate our system we have developed a test-bed which provides a set of registered dense ground-truth laser data and image data from multiple views. 相似文献
43.
44.
Anastasios I Zouboulis Nick K Lazaridis Kostas A Matis 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(8):958-964
Biosorptive flotation was used as a combined operation for the simultaneous abstraction of nickel, copper and zinc ions from aqueous streams. Laboratory‐scale batch experiments, as well as pilot‐scale continuous experiments, have been conducted. Grape stalks, a by‐product of the winery industry, were used as sorbent material. The experimental procedure consisted of two consecutive stages: (i) biosorption, and (ii) flotation. The possibility of reusing biomass, after appropriate elution, was also examined. The main parameters examined were biomass concentration, particle size of sorbent, surfactant concentration, pH and flocculation. Flotation removals, following laboratory‐scale experiments, were found to be in the order of 100, 85 and 70% for copper, zinc and nickel, respectively. In pilot‐scale experiments, biomass sorption capacities were determined as 25 for copper, 81 for zinc and 7 µmol dm?3 for nickel. The order of biomass affinity regarding the studied metals was Cu > Zn > Ni. Short retention time and high effectiveness suggest that biosorptive flotation is a promising treatment process for the removal of toxic metals from contaminated aqueous solutions. © 2002 Society of Chemical Industry 相似文献
45.
Perisinakis K Damilakis J Theocharopoulos N Papadokostakis G Hadjipavlou A Gourtsoyiannis N 《Radiation protection dosimetry》2004,108(1):65-72
The objectives were to assess patient effective radiation dose from fluoroscopically guided surgical reconstruction of femoral fractures and provide normalized data for the estimation of patient effective dose and risks associated with such procedures performed in any laboratory. The fluoroscopic control required during surgical reconstruction of femoral fractures was classified into two types identified by beam orientation, i.e., posterior-anterior (PA) and lateral crosstable (LC) exposures. The duration and the dose area product (DAP) of each exposure were monitored in 24 patients with femoral fractures. Patient dose per DAP unit and per minute of fluoroscopy were measured at 14 radiosensitive organs/tissues using an anthropomorphic phantom and thermoluminescence dosimetry. The typical effective dose to patients with femoral fracture treated surgically in our institution was 11.6-21.7 microSv. This effective dose is estimated to cause an excess of 1.4 fatal cancers per million patients treated, and an excess of 0.4 hereditary disorders per million of births. Induction of deterministic skin injuries to treated patients is highly improbable at the dose levels found in this study. Patient effective dose and associated risks from a typical fluoroscopically guided surgical fixation of femoral fracture are low. However, they may be significantly elevated if treated patients are young individuals and/or the fluoroscopic exposure is prolonged. The present data may be used to determine effective dose to patients undergoing surgical reconstruction of femoral fracture in any institution. 相似文献
46.
George Caridakis Amaryllis Raouzaiou Elisabetta Bevacqua Maurizio Mancini Kostas Karpouzis Lori Malatesta Catherine Pelachaud 《Language Resources and Evaluation》2007,41(3-4):367-388
This work is about multimodal and expressive synthesis on virtual agents, based on the analysis of actions performed by human
users. As input we consider the image sequence of the recorded human behavior. Computer vision and image processing techniques
are incorporated in order to detect cues needed for expressivity features extraction. The multimodality of the approach lies
in the fact that both facial and gestural aspects of the user’s behavior are analyzed and processed. The mimicry consists
of perception, interpretation, planning and animation of the expressions shown by the human, resulting not in an exact duplicate
rather than an expressive model of the user’s original behavior. 相似文献
47.
Kostas G. Anagnostakis Michael B. Greenwald Sotiris Ioannidis Angelos D. Keromytis 《International Journal of Information Security》2007,6(6):361-378
Cooperative defensive systems communicate and cooperate in their response to worm attacks, but determine the presence of a worm attack solely on local information. Distributed worm detection and immunization systems track suspicious behavior at multiple cooperating nodes to determine whether a worm attack is in progress. Earlier work has shown that cooperative systems can respond quickly to day-zero worms, while
distributed detection systems allow detectors to be more conservative (i.e., paranoid) about potential attacks because they
manage false alarms efficiently. In this paper we present our investigation into the complex tradeoffs in such systems between
communication costs, computation overhead, accuracy of the local tests, estimation of viral virulence, and the fraction of
the network infected before the attack crests. We evaluate the effectiveness of different system configurations in various
simulations. Our experiments show that distributed algorithms are better able to balance effectiveness against worms and viruses
with reduced cost in computation and communication when faced with false alarms. Furthermore, cooperative, distributed systems
seem more robust against malicious participants in the immunization system than earlier cooperative but non-distributed approaches. 相似文献
48.
Dimos V. Dimarogonas Kostas J. Kyriakopoulos 《Journal of Intelligent and Robotic Systems》2007,48(3):411-433
The decentralized navigation function methodology, established in our previous work for navigation of multiple holonomic agents
with global sensing capabilities is extended to the case of local sensing capabilities. Each agent plans its actions without
knowing the destinations of the others and the positions of those agents lying outside its sensing neighborhood. The stability
properties of the closed loop system are checked via Lyapunov stability techniques for nonsmooth systems. The collision avoidance
and global convergence properties are verified through simulations.
This work was partially presented in [5]. 相似文献
49.
50.
Stefanos E. Kavargiris Andreas P. Mamolos Constantinos A. Tsatsarelis Anna E. Nikolaidou Kiriaki L. Kalburtji 《Biomass & bioenergy》2009,33(9):1239-1250
An energy analysis, in conventional and organic vineyards, combined with ethanol production and greenhouse gas emissions, is useful in evaluating present situation and deciding best management strategies. The objective of this study was to evaluate the differences in the energy flow between organic and conventional vineyards in three locations, to calculate CO2, CH4 and N2O-emissions based on the used fossil energy and to explore if wine industry wastes can be used to extract bioethanol. The data were collected through personal interviews with farmers during 2004–2005. Eighteen farmers, who owned vineyards about 1 ha each, were randomly selected to participate in this study [(3 conventional and 3 organic) × 3 locations]. The means averaged over all locations for fertilizer application, plant protection products application, transportation, harvesting, labor, machinery, fuels, plant protections products and tools energy inputs, total energy inputs, outputs (grapes), outputs (grapes + shoots), grape yield, man hour, pomace and ethanol from pomace were significantly higher in conventional than in organic vineyards, while the opposite occurred for the pruning. Means averaged over two farming systems for harvesting, tools energy inputs, energy outputs (grapes), grape yield, pomace and ethanol from pomace were significantly higher at location A, followed by location C and location B. Finally, for irrigation, the means averaged over the two farming systems were significantly lower at location C. Greenhouse gas emissions were significant lower in organic than in conventional vineyards. The results show a clear response of energy inputs to energy outputs that resulted from the farming system and location. 相似文献