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排序方式: 共有298条查询结果,搜索用时 984 毫秒
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VLSI systolic and wavefront array processors' architectures for the block implementation of infinite impulse response digital filters with very high sample rates are presented. The proposed systolic array processor achieves the maximum possible throughput rate and requires only local data transfers. The asynchronous wavefront array processor operates at the same maximum throughput rate and, moreover, it is characterized by a substantial reduced latency. The throughput rate of the proposed array processor structures is a linear function of the block lengthL and theoretically it may be arbitrary high; however, it is limited only by a number of practical implications. 相似文献
63.
Vassilis Konstantinou John Sykes Georgios N. Yannopoulos 《Information & Communications Technology Law》1994,3(1):29-46
The biggest false assumption made when attempting to model automatically acquired legal knowledge is that methodological and procedural legal knowledge is also contained in the text of law. Although the legal profession Intuitively knows the falsity of this assumption, researchers in the area of automatic knowledge acquisition are still confident in implementing systems that use only the text of laws as their main source of knowledge. Knowledge engineers are then forced to make their own interpretations of this knowledge, thus resulting in erroneous and legally unacceptable interpretations of the law. The aim of Nomos (an EC supported project under the ESPRIT II initiative) was to assist the knowledge engineer by providing tools that perform semiautomatic knowledge acquisition from legal texts in Italian and French. This paper uses the implementation of Nomos‐advisor, a legal expert system that uses Nomos's results as an input, as a proof of the falsity of the above assumption and discusses possible solutions. 相似文献
64.
Gad M. Landau Ph.D. Jeanette P. Schmidt Ph.D. Vassilis J. Tsotras Ph.D. 《The VLDB Journal The International Journal on Very Large Data Bases》1995,4(4):703-726
Traditional approaches to addressing historical queries assume asingle line of time evolution; that is, a system (database, relation) evolves over time through a sequence of transactions. Each transaction always applies to the unique, current state of the system, resulting in a new current state. There are, however, complex applications where the system's state evolves intomultiple lines of evolution. In general, this creates a tree (hierarchy) of evolution lines, where each tree node represents the time evolution of a particular subsystem. Multiple lines create novel historical queries, such asvertical orhorizontal historical queries. The key characteristic of these problems is that portions of the history are shared; answering historical queries should not necessitate duplication of shared histories as this could increase the storage requirements dramatically. Both the vertical and horizontal historical queries have two parts: a search part, where the time of interest is located together with the appropriate subsystem, and a reconstruction part, where the subsystem's state is reconstructed for that time. This article focuses on the search part; several reconstruction methods, designed for single evolution lines can be applied once the appropriate time of interest is located. For both the vertical and the horizontal historical queries, we present algorithms that work without duplicating shared histories. Combinations of the vertical and horizontal queries are possible, and enable searching in both dimensions of the tree of evolutions. 相似文献
65.
Simo Hosio Jorge Goncalves Niels van Berkel Simon Klakegg Shin’Ichi Konomi Vassilis Kostakos 《Human-Computer Interaction》2018,33(5-6):335-371
Online crowdsourcing enables the distribution of work to a global labor force as small and often repetitive tasks. Recently, situated crowdsourcing has emerged as a complementary enabler to elicit labor in specific locations and from specific crowds. Teamwork in online crowdsourcing has been recently shown to increase the quality of output, but teamwork in situated crowdsourcing remains unexplored. We set out to fill this gap. We present a generic crowdsourcing platform that supports situated teamwork and provide experiences from a laboratory study that focused on comparing traditional online crowdsourcing to situated team-based crowdsourcing. We built a crowdsourcing desk that hosts three networked terminal displays. The displays run our custom team-driven crowdsourcing platform that was used to investigate collocated crowdsourcing in small teams. In addition to analyzing quantitative data, we provide findings based on questionnaires, interviews, and observations. We highlight 1) emerging differences between traditional and collocated crowdsourcing, 2) the collaboration strategies that teams exhibited in collocated crowdsourcing, and 3) that a priori team familiarity does not significantly affect collocated interaction in crowdsourcing. The approach we introduce is a novel multi-display crowdsourcing setup that supports collocated labor teams and along with the reported study makes specific contributions to situated crowdsourcing research. 相似文献
66.
Vassilis M. Charitopoulos Lazaros G. Papageorgiou Vivek Dua 《American Institute of Chemical Engineers》2017,63(9):3871-3895
Multi‐parametric programming has proven to be an invaluable tool for optimisation under uncertainty. Despite the theoretical developments in this area, the ability to handle uncertain parameters on the left‐hand side remains limited and as a result, hybrid, or approximate solution strategies have been proposed in the literature. In this work, a new algorithm is introduced for the exact solution of multi‐parametric linear programming problems with simultaneous variations in the objective function's coefficients, the right‐hand side and the left‐hand side of the constraints. The proposed methodology is based on the analytical solution of the system of equations derived from the first order Karush–Kuhn–Tucker conditions for general linear programming problems using symbolic manipulation. Emphasis is given on the ability of the proposed methodology to handle efficiently the LHS uncertainty by computing exactly the corresponding nonconvex critical regions while numerical studies underline further the advantages of the proposed methodology, when compared to existing algorithms. © 2017 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 63: 3871–3895, 2017 相似文献
67.
The scope of this article is to present a methodology for the estimation of the uncertainty characterizing the energy performance of solar domestic hot water systems. The work concentrates on the uncertainty characterizing the expected annual energy output, as calculated through tests implemented according to the valid international standards. In order to cope with difficulties related to the algorithmic character of the measurement model, which cannot be explicitly formulated, Monte-Carlo simulation techniques are implemented. The component of uncertainty associated with measurement errors is estimated, on the basis of the metrological quality anticipated by the relevant testing standards. Errors due to imperfections of the energy model used through the test are also counted in, as well as uncertainties attributed to the variability of meteorological conditions. The proposed uncertainty analysis allows the realistic assessment of the actual energy provided to the user by a solar domestic hot water system. Implementation of the proposed methodology for a typical system leads to an expanded uncertainty in the order of 9% for the expected annual energy output. 相似文献
68.
Optical performance and instantaneous efficiency calculation of linear Fresnel solar collectors 下载免费PDF全文
The main objective of this study is the investigation of the effect of the optical path of incident beam solar radiation on the performance of a linear Fresnel concentrating solar collector. The requirements regarding the kinematics of the reflectors are examined, allowing the effective focus of the reflected radiation on the receiver cover. A methodology for the calculation of the reflection angles of the sun rays incident on the mirrors, as well as of the incidence angles of the reflected rays on the cover, as a function of the sun position and the geometry of the collector is proposed. Specific scenarios, describing the effect of the solar radiation optical path on the collected heat, are formulated, each of them leading to a different form for the instantaneous efficiency equation. The evaluation and analysis of these scenarios, on the basis of actual operation conditions, has shown that the effect of the reflection and incidence angles throughout the modeling of the collector and the calculation of the useful thermal power cannot be neglected. 相似文献
69.
Applying configurational analysis to IS behavioural research: a methodological alternative for modelling combinatorial complexities 下载免费PDF全文
An important limitation of regression‐based analysis stems from the assumption of symmetric relationships between variables, which is often violated. To overcome this limitation within IS research, we propose the use of the fuzzy‐set qualitative comparative analysis (FsQCA) method. The paper elaborates on the rationale for applying this approach to IS behavioural research and how to tailor FsQCA for this purpose. A systematic interpretation of the technique covering its mathematical properties and advanced features is provided. Drawing from an illustrative study of mobile government services adoption by residents of rural areas, the paper demonstrates FsQCA's potential to supplement regression‐based IS behavioural research, by (i) examining asymmetric relationships between a set of antecedents and the IS phenomenon of interest, (ii) providing nuanced coverage of necessary and sufficient conditions for emergence of an IS behavioural outcome, and (iii) identifying various configurations of conditions in association with users' demographic characteristics. © 2015 Blackwell Publishing Ltd 相似文献
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