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11.
12.
Anja Le Blanc John Brooke Donal Fellows Marco Soldati David Pérez-Suárez Alessandro Marassi Andrej Santin 《Journal of Grid Computing》2013,11(3):481-503
In this paper we describe how we have introduced workflows into the working practices of a community for whom the concept of workflows is very new, namely the heliophysics community. Heliophysics is a branch of astrophysics which studies the Sun and the interactions between the Sun and the planets, by tracking solar events as they travel throughout the Solar system. Heliophysics produces two major challenges for workflow technology. Firstly it is a systems science where research is currently developed by many different communities who need reliable data models and metadata to be able to work together. Thus it has major challenges in the semantics of workflows. Secondly, the problem of time is critical in heliophysics; the workflows must take account of the propagation of events outwards from the sun. They have to address the four dimensional nature of space and time in terms of the indexing of data. We discuss how we have built an environment for Heliophysics workflows building on and extending the Taverna workflow system and utilising the myExperiment site for sharing workflows. We also describe how we have integrated the workflows into the existing practices of the communities involved in Heliophysics by developing a web portal which can hide the technical details from the users, who can concentrate on the data from their scientific point of view rather than on the methods used to integrate and process the data. This work has been developed in the EU Framework 7 project HELIO, and is being disseminated to the worldwide Heliophysics community, since Heliophysics requires integration of effort on a global scale. 相似文献
13.
Real-time inverse dynamics control of parallel manipulators using general-purpose multibody software
This work deals with the problem of computing the inverse dynamics of complex constrained mechanical systems for real-time
control applications. The main goal is the control of robotic systems using model-based schemes in which the inverse model
itself is obtained using a general purpose multibody software, exploiting the redundant coordinate formalism. The resulting
control scheme is essentially equivalent to a classical computed torque control, commonly used in robotics applications. This
work proposes to use modern general-purpose multibody software to compute the inverse dynamics of complex rigid mechanisms
in an efficient way, so that it suits the requirements of realistic real-time applications as well. This task can be very
difficult, since it involves a higher number of equations than the relative coordinates approach. The latter is believed to
be less general, and may suffer from topology limitations. The use of specialized linear algebra solvers makes this kind of
control algorithms usable in real-time for mechanism models of realistic complexity. Numerical results from the simulation
of practical applications are presented, consisting in a “delta” robot and a bio-mimetic 11 degrees of freedom manipulator
controlled using the same software and the same algorithm. 相似文献
14.
Applied Intelligence - Forecasting future heat load in smart district heating networks is a key problem for utility companies that need such predictions for optimizing their operational activities.... 相似文献
15.
16.
Giuseppe Ascia Vincenzo Catania Alessandro G. Di Nuovo Maurizio Palesi Davide Patti 《Applied Soft Computing》2011,11(1):382-398
Multi-objective evolutionary algorithms (MOEAs) have received increasing interest in industry because they have proved to be powerful optimizers. Despite the great success achieved, however, MOEAs have also encountered many challenges in real-world applications. One of the main difficulties in applying MOEAs is the large number of fitness evaluations (objective calculations) that are often needed before an acceptable solution can be found. There are, in fact, several industrial situations in which fitness evaluations are computationally expensive and the time available is very short. In these applications efficient strategies to approximate the fitness function have to be adopted, looking for a trade-off between optimization performance and efficiency. This is the case in designing a complex embedded system, where it is necessary to define an optimal architecture in relation to certain performance indexes while respecting strict time-to-market constraints. This activity, known as design space exploration (DSE), is still a great challenge for the EDA (electronic design automation) community. One of the most important bottlenecks in the overall design flow of an embedded system is due to simulation. Simulation occurs at every phase of the design flow and is used to evaluate a system which is a candidate for implementation. In this paper we focus on system level design, proposing an extensive comparison of the state-of-the-art of MOEA approaches with an approach based on fuzzy approximation to speed up the evaluation of a candidate system configuration. The comparison is performed in a real case study: optimization of the performance and power dissipation of embedded architectures based on a Very Long Instruction Word (VLIW) microprocessor in a mobile multimedia application domain. The results of the comparison demonstrate that the fuzzy approach outperforms in terms of both performance and efficiency the state of the art in MOEA strategies applied to DSE of a parameterized embedded system. 相似文献
17.
In this work we address the tracking control problems for autonomous underwater vehicles (AUVs). The proposed solution is based on the variable structure systems (VSS) theory and, in particular, on the second‐order sliding‐mode (2‐SM) methodology. The tuning of the controller is carried out via black‐box approach, dispensing with the knowledge of the actual AUV parameters, by simply progressively increasing a single gain parameter. The presented stability analysis includes explicitly the unmodelled actuator dynamics and the presence of external uncertain disturbances. The good performance of the proposed scheme is verified by means of simulations on a 6‐DOF AUV. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
In this paper we study parallel batch scheduling problems with bounded batch capacity and equal-length jobs in a single and
parallel machine environment. It is shown that the feasibility problem 1|p-batch,b<n,r
j
,p
j
=p,C
j
≤d
j
|− can be solved in O(n
2) time and that the problem of minimizing the maximum lateness can be solved in O(n
2log n) time. For the parallel machine problem P|p-batch,b<n,r
j
,p
j
=p,C
j
≤d
j
|− an O(n
3log n)-time algorithm is provided, which can also be used to solve the problem of minimizing the maximum lateness in O(n
3log 2
n) time. 相似文献
19.
Alessandro Nordio Carla-Fabiana Chiasserini Armando Muscariello 《Computer Networks》2010,54(6):991-1004
We apply signal processing techniques to the study of wireless sensor networks, whose nodes are deployed over a planar region for environmental monitoring. We address the problem of reconstructing the phenomenon of interest at a sink node, from the samples gathered by the sensors, and we evaluate the system performance in presence of both a flat and a clustered network topology. When the sensors are grouped into (possibly overlapping) clusters, the data collected within each cluster are compressed by the cluster head and sent to the sink node. By representing the compressed data through the Fourier coefficients of the field spectrum, we analyze both the case where the sensor positions are known to the sink, and the case where they are available at the cluster head only. We show that clustering significantly reduces the energy expenditure due to data transmission with respect to the case of a flat network topology, and, most importantly, we derive the possible degradation of the quality of the reconstructed field due to compression. 相似文献
20.
Giorgio Guglieri Valeria Mariano Fulvia Quagliotti Alessandro Scola 《Journal of Intelligent and Robotic Systems》2011,61(1-4):399-421
The Italian SMAT project is a civilian program supported by Piemonte Region developed for the territorial monitoring and surveillance and for the prevention of natural hazards. In a different way from the previous surveillance programs, the SMAT project is based on the use of several unmanned platforms that are able to cooperate through ground coordination and control station. The flight in non-segregated airspace, needed in order to accomplish the territorial monitoring mission, is a main issue to be investigated and defined, because of the current lack of a common consensus and agreement on the regulations of UAS. The present work outlines the international initiatives that deal with the development of the regulatory framework on airworthiness and certification of UAS and their potential impact on the SMAT project. 相似文献