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51.
Gregory Chockler Seth Gilbert Vincent Gramoli Peter M. Musial Alex A. Shvartsman 《Journal of Parallel and Distributed Computing》2009
This paper presents a new algorithm for implementing a reconfigurable distributed shared memory in an asynchronous dynamic network. The algorithm guarantees atomic consistency (linearizability) in all executions in the presence of arbitrary crash failures of the processing nodes, message delays, and message loss. The algorithm incorporates a classic quorum-based algorithm for read/write operations, and an optimized consensus protocol, based on Fast Paxos for reconfiguration, and achieves the design goals of: (i) allowing read and write operations to complete rapidly and (ii) providing long-term fault-tolerance through reconfiguration, a process that evolves the quorum configurations used by the read and write operations. The resulting algorithm tolerates dynamism. We formally prove our algorithm to be correct, we present its performance and compare it to existing reconfigurable memories, and we evaluate experimentally the cost of its reconfiguration mechanism. 相似文献
52.
Information estimates such as the direct method of Strong, Koberle, de Ruyter van Steveninck, and Bialek (1998) sidestep the difficult problem of estimating the joint distribution of response and stimulus by instead estimating the difference between the marginal and conditional entropies of the response. While this is an effective estimation strategy, it tempts the practitioner to ignore the role of the stimulus and the meaning of mutual information. We show here that as the number of trials increases indefinitely, the direct (or plug-in) estimate of marginal entropy converges (with probability 1) to the entropy of the time-averaged conditional distribution of the response, and the direct estimate of the conditional entropy converges to the time-averaged entropy of the conditional distribution of the response. Under joint stationarity and ergodicity of the response and stimulus, the difference of these quantities converges to the mutual information. When the stimulus is deterministic or nonstationary the direct estimate of information no longer estimates mutual information, which is no longer meaningful, but it remains a measure of variability of the response distribution across time. 相似文献
53.
Vincent C. Müller 《Minds and Machines》2009,19(4):529-541
The paper presents a paradoxical feature of computational systems that suggests that computationalism cannot explain symbol
grounding. If the mind is a digital computer, as computationalism claims, then it can be computing either over meaningful
symbols or over meaningless symbols. If it is computing over meaningful symbols its functioning presupposes the existence
of meaningful symbols in the system, i.e. it implies semantic nativism. If the mind is computing over meaningless symbols,
no intentional cognitive processes are available prior to symbol grounding. In this case, no symbol grounding could take place
since any grounding presupposes intentional cognitive processes. So, whether computing in the mind is over meaningless or
over meaningful symbols, computationalism implies semantic nativism. 相似文献
54.
Vincent C. Müller 《AI & Society》2009,23(4):529-544
Data mining is not an invasion of privacy because access to data is only by machines, not by people: this is the argument
that is investigated here. The current importance of this problem is developed in a case study of data mining in the USA for
counterterrorism and other surveillance purposes. After a clarification of the relevant nature of privacy, it is argued that
access by machines cannot warrant the access to further information, since the analysis will have to be made either by humans
or by machines that understand. It concludes that the current data mining violates the right to privacy and should be subject
to the standard legal constraints for access to private information by people.
相似文献
Vincent C. MüllerEmail: |
55.
Robots acting in human environments usually need to perform multiple motion and force tasks while respecting a set of constraints. When a physical contact with the environment is established, the newly activated force task or contact constraint may interfere with other tasks. The objective of this paper is to provide a control framework that can achieve real-time control of humanoid robots performing both strict and non strict prioritized motion and force tasks. It is a torque-based quasi-static control framework, which handles a dynamically changing task hierarchy with simultaneous priority transitions as well as activation or deactivation of tasks. A quadratic programming problem is solved to maintain desired task hierarchies, subject to constraints. A generalized projector is used to quantitatively regulate how much a task can influence or be influenced by other tasks through the modulation of a priority matrix. By the smooth variations of the priority matrix, sudden hierarchy rearrangements can be avoided to reduce the risk of instability. The effectiveness of this approach is demonstrated on both a simulated and a real humanoid robot. 相似文献
56.
Gambling versus Designing: Organizing for the Design of the Probability Space in the Energy Sector 下载免费PDF全文
Sophie Hooge Olga Kokshagina Pascal Le Masson Kevin Levillain Benoit Weil Vincent Fabreguettes Nathalie Popiolek 《Creativity & Innovation Management》2016,25(4):464-483
The objective of this paper is to elucidate an organizational process for the design of generic technologies (GTs). While recognizing the success of GTs, the literature on innovation management generally describes their design according to evolutionary strategies featuring multiple and uncertain trials, resulting in the discovery of common features among multiple applications. This random walk depends on multiple market and technological uncertainties that are considered exogenous: as smart as he can be, the ‘gambler’ must play in a given probability space. However, what happens when the innovator is not a gambler but a designer, i.e., when the actor is able to establish new links between previously independent emerging markets and technologies? Formally speaking, the actor designs a new probability space. Building on a case study of two technological development programmes at the French Center for Atomic Energy, we present cases of GTs that correspond to this logic of designing the probability space, i.e. the logic of intentionally designing common features that bridge the gap between a priori heterogeneous applications and technologies. This study provides another example showing that the usual trial‐and‐learning strategy is not the only strategy to design GTs and that these technologies can be designed by intentionally building new interdependences between markets and technologies. Our main result is that building these interdependences requires organizational patterns that correspond to a ‘design of exploration’ phase in which multiple technology suppliers and application providers are involved in designing both the probability space itself and the instruments to explore and benefit from this new space. 相似文献
57.
Road‐Centered Map‐Aided Localization for Driverless Cars Using Single‐Frequency GNSS Receivers 下载免费PDF全文
Zui Tao Philippe Bonnifait Vincent Frémont Javier Ibanez‐Guzman Stéphane Bonnet 《野外机器人技术杂志》2017,34(5):1010-1033
Accurate localization with high availability is a key requirement for autonomous vehicles. It remains a major challenge when using automotive sensors such as single‐frequency Global Navigation Satellite System (GNSS) receivers, a lane detection camera, and proprioceptive sensors. This paper describes a method that enables the estimation of stand‐alone single‐frequency GNSS errors by integrating the measurements from a forward‐looking camera matched with lane markings stored in a digital map. It includes a parameter identification method for a shaping model, which is evaluated using experimental data. An algebraic observability study is then conducted to prove that the proposed state vector is fully observable in a road‐oriented frame. This observability property is the basis to develop a road‐centered Extended Kalman filter (EKF) that can maintain the observability of every component of the state vector on any road, whatever its orientation. To accomplish this, the filter needs to handle road changes, which it does using bijective transformations. The filter was implemented and tested intensely on an experimental vehicle for driverless valet parking services. Field results have shown that the performance of the estimation process is better than solutions based on EKF implemented in a fixed working frame. The proposed filter guarantees that the drift along the road direction remains bounded. This is very important when the vehicle navigates autonomously. Furthermore, the road‐centered modeling improves the accuracy, consistency, and robustness of the localization solver. 相似文献
58.
Ke Zhang Vincent Cocquempot Bin Jiang 《International Journal of Control, Automation and Systems》2017,15(3):1077-1088
This paper addresses an adjustable parameter (AP)-based multi-objective fault estimation design for continuous-time/discrete-time dynamic systems. First, a fault estimation observer with AP is constructed to on-line identify the size of occurred faults. The fault estimation design not only possesses a wider application compared with adaptive observers, but also uses the current output information to enhance fault estimation performance. Then a multi-objective approach is proposed to determine the gain matrices of fault estimation observer. Moreover, fault estimation results with the slack-variable technique are obtained to further reduce the conservatism. Finally, simulation results of an aircraft application are presented to illustrate the effectiveness of our contribution. 相似文献
59.
Raphael M. Jungers Francisca Zamorano Vincent D. Blondel Alain Vande Wouwer Georges BastinAuthor vitae 《Automatica》2011,47(6):1255-1259
The concept of elementary flux vector is valuable in a number of applications of metabolic engineering. For instance, in metabolic flux analysis, each admissible flux vector can be expressed as a non-negative linear combination of a small number of elementary flux vectors. However a critical issue concerns the total number of elementary flux vectors which may be huge because it combinatorially increases with the size of the metabolic network. In this paper we present a fast algorithm that randomly computes a decomposition of admissible flux vectors in a minimal number of elementary flux vectors without explicitly enumerating all of them. 相似文献
60.
A compressible model able to manage incompressible two-phase flows as well as compressible motions is proposed. After a presentation of the multiphase compressible concept, the new model and related numerical methods are detailed on fixed structured grids. The presented model is a 1-fluid model with a reformulated mass conservation equation which takes into account the effects of compressibility. The coupling between pressure and flow velocity is ensured by introducing mass conservation terms in the momentum and energy equations. The numerical model is then validated with four test cases involving the compression of an air bubble by water, the liquid injection in a closed cavity filled with air, a bubble subjected to an ultrasound field and finally the oscillations of a deformed air bubble in melted steel. The numerical results are compared with analytical results and convergence orders in space are provided. 相似文献