全文获取类型
收费全文 | 3172篇 |
免费 | 195篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 62篇 |
综合类 | 1篇 |
化学工业 | 849篇 |
金属工艺 | 42篇 |
机械仪表 | 72篇 |
建筑科学 | 151篇 |
矿业工程 | 1篇 |
能源动力 | 101篇 |
轻工业 | 243篇 |
水利工程 | 10篇 |
石油天然气 | 3篇 |
武器工业 | 1篇 |
无线电 | 289篇 |
一般工业技术 | 574篇 |
冶金工业 | 124篇 |
原子能技术 | 30篇 |
自动化技术 | 818篇 |
出版年
2024年 | 5篇 |
2023年 | 41篇 |
2022年 | 130篇 |
2021年 | 148篇 |
2020年 | 76篇 |
2019年 | 89篇 |
2018年 | 98篇 |
2017年 | 92篇 |
2016年 | 143篇 |
2015年 | 113篇 |
2014年 | 146篇 |
2013年 | 219篇 |
2012年 | 202篇 |
2011年 | 230篇 |
2010年 | 192篇 |
2009年 | 190篇 |
2008年 | 177篇 |
2007年 | 165篇 |
2006年 | 117篇 |
2005年 | 93篇 |
2004年 | 117篇 |
2003年 | 96篇 |
2002年 | 63篇 |
2001年 | 50篇 |
2000年 | 42篇 |
1999年 | 35篇 |
1998年 | 24篇 |
1997年 | 20篇 |
1996年 | 34篇 |
1995年 | 26篇 |
1994年 | 24篇 |
1993年 | 19篇 |
1992年 | 19篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 2篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 15篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有3371条查询结果,搜索用时 15 毫秒
41.
Paolo Cotogno 《Minds and Machines》2009,19(3):391-405
Hypercomputation—the hypothesis that Turing-incomputable objects can be computed through infinitary means—is ineffective,
as the unsolvability of the halting problem for Turing machines depends just on the absence of a definite value for some paradoxical
construction; nature and quantity of computing resources are immaterial. The assumption that the halting problem is solved
by oracles of higher Turing degree amounts just to postulation; infinite-time oracles are not actually solving paradoxes,
but simply assigning them conventional values. Special values for non-terminating processes are likewise irrelevant, since
diagonalization can cover any amount of value assignments. This should not be construed as a restriction of computing power:
Turing’s uncomputability is not a ‘barrier’ to be broken, but simply an effect of the expressive power of consistent programming
systems. 相似文献
42.
Paolo Vicig 《Minds and Machines》2016,26(3):303-305
Constrained coherence is compared to coherence and its role in the behavioural interpretation of coherence is discussed. The equivalence of these two notions is proven for coherent conditional previsions, showing that the same course of reasoning applies to several similar concepts developed in the realm of imprecise probability theory. 相似文献
43.
A novel frequency–based definition of dynamic compliance is introduced within the framework of H ∞ –norm based structural dynamics in the presence of load uncertainties. The system itself is supposed to depend on a vector of design parameters with respect to which an optimal design is pursued. A three-step worst-case-scenario is then developed that finds the minimum-compliance structure capable of accounting for the entire norm–bounded load sets. Once the problem is initialized, the current worst load is found that is used as input to the minimization of the structural compliance and the procedure is repeated until convergence. Numerical examples are eventually proposed that deal with viscoelastic beams discretized via a truly–mixed finite–element scheme. 相似文献
44.
Contrast-enhanced ultrasound (CEUS) has recently become an important technology for lesion detection and characterization in cancer diagnosis. CEUS is used to investigate the perfusion kinetics in tissue over time, which relates to tissue vascularization. In this paper we present a pipeline that enables interactive visual exploration and semi-automatic segmentation and classification of CEUS data.For the visual analysis of this challenging data, with characteristic noise patterns and residual movements, we propose a robust method to derive expressive enhancement measures from small spatio-temporal neighborhoods. We use this information in a staged visual analysis pipeline that leads from a more local investigation to global results such as the delineation of anatomic regions according to their perfusion properties. To make the visual exploration interactive, we have developed an accelerated framework based on the OpenCL library, that exploits modern many-cores hardware. Using our application, we were able to analyze datasets from CEUS liver examinations, being able to identify several focal liver lesions, segment and analyze them quickly and precisely, and eventually characterize them. 相似文献
45.
Data-Intensive Web Sites: Design and Maintenance 总被引:1,自引:0,他引:1
46.
Seng KY Figueroa-Masot X Folch A Vicini P 《Computer methods and programs in biomedicine》2007,85(3):220-228
A new approach for objectively analyzing the aggregation of acetylcholine receptors (AChRs) through power spectrum analysis derived from fast Fourier transform (FFT) of images has been developed. Presently, detection of AChR aggregates at neuromuscular junctions is not easily accomplished. Though the formation of AChR clusters results in periodic gray-level variations that differ with time, no study reporting their correlation with frequency information in the Fourier domain for aggregates' detection purposes exists. To this end, we processed time-lapse images of AChR aggregates' formation on murine myotubes to extract peak values of power spectra. To validate interpretation of the Fourier spectra analysis, a computer routine was developed to semi-automatically count AChR aggregates. We found: (1) logarithmic maxima of Fourier spectra correlated significantly with experimentation time; (2) cluster count correlated significantly with time only after clusters were discernable from images, signifying that this method heavily depended on definitive growth data and thresholding values; (3) exponents of Fourier maxima versus time and cluster count versus time profiles during this phase compared favorably, indicating that both methods were analyzing identical cluster growth rates. Our observations suggest that analysis via FFT power spectrum is sensitive and robust enough to automatically quantify AChR aggregates. 相似文献
47.
The multimod application framework: a rapid application development tool for computer aided medicine 总被引:1,自引:0,他引:1
Viceconti M Zannoni C Testi D Petrone M Perticoni S Quadrani P Taddei F Imboden S Clapworthy G 《Computer methods and programs in biomedicine》2007,85(2):138-151
This paper describes a new application framework (OpenMAF) for rapid development of multimodal applications in computer-aided medicine. MAF applications are multimodal in data, in representation, and in interaction. The framework supports almost any type of biomedical data, including DICOM datasets, motion-capture recordings, or data from computer simulations (e.g. finite element modeling). The interactive visualization approach (multimodal display) helps the user interpret complex datasets, providing multiple representations of the same data. In addition, the framework allows multimodal interaction by supporting the simultaneous use of different input-output devices like 3D trackers, stereoscopic displays, haptics hardware and speech recognition/synthesis systems. The Framework has been designed to run smoothly even on limited power computers, but it can take advantage of all hardware capabilities. The Framework is based on a collection of portable libraries and it can be compiled on any platform that supports OpenGL, including Windows, MacOS X and any flavor of Unix/linux. 相似文献
48.
Paolo Baldan Fabio Gadducci Ugo Montanari 《Electronic Notes in Theoretical Computer Science》2007,176(1):85
In the theory of graph rewriting, the use of coalescing rules, i.e., of rules which besides deleting and generating graph items, can coalesce some parts of the graph, turns out to be quite useful for modelling purposes, but, at the same time, problematic for the development of a satisfactory partial order concurrent semantics for rewrites. Rewriting over graphs with equivalences, i.e., (typed hyper)-graphs equipped with an equivalence over nodes provides a technically convenient replacement of graph rewriting with coalescing rules, for which a truly concurrent semantics can be easily defined. The expressivity of such a formalism is tested in a setting where coalescing rules typically play a basic role: the encoding of calculi with name passing as graph rewriting systems. Specifically, we show how the (monadic fragment) of the solo calculus, one of the dialect of those calculi whose distinctive feature is name fusion, can be encoded as a rewriting system over graph with equivalences. 相似文献
49.
Tarini M Cignoni P Montani C 《IEEE transactions on visualization and computer graphics》2006,12(5):1237-1244
The paper presents a set of combined techniques to enhance the real-time visualization of simple or complex molecules (up to order of 106 atoms) space fill mode. The proposed approach includes an innovative technique for efficient computation and storage of ambient occlusion terms, a small set of GPU accelerated procedural impostors for space-fill and ball-and-stick rendering, and novel edge-cueing techniques. As a result, the user's understanding of the three-dimensional structure under inspection is strongly increased (even for still images), while the rendering still occurs in real time. 相似文献
50.
Paolo Carraresi Giorgio Gallo Gabriella Rago 《Annals of Mathematics and Artificial Intelligence》1993,8(3-4):247-270
In a previous paper, a hypergraph model for the satisfiability of Datalog formulas was proposed. Here, we extend that approach in order to deal with a class ofconstraint logic programming (CLP) formulas, that is, Datalog formulas in the presence of constraints. A CLP formula is represented by means of a weighted hypergraph and the problem of evaluating this formula is reduced to a sequence of shortest path computations on hypergraphs. To evaluate the performance of this approach, the bus drivers' scheduling problem is formulated as the problem of checking the satisfiability of a CLP formula and it is solved by means of the hypergraph-based algorithm embedded within a local search procedure. Preliminary experimental results are quite encouraging and suggest that the proposed approach may provide an efficient way to tackle hard real-life combinatorial problems.This research was partially supported by the Progetto Finalizzato Trasporti 2 of the Italian National Research Council, under Contract No. 91.02479.PF74. 相似文献