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101.
Eduardo Sáenz-de-Cabezón L. Javier HernándezM. Teresa Rivas Esteban García-RuizVicente Marco Ignacio Pérez-MorenoF. Javier Sáenz-de-Cabezón 《Mathematics and computers in simulation》2011,82(1):2-14
This paper presents a new procedure to construct families of spatial approximation-prediction functions which depend on several parameters. The method is based on partitions of the unity. In order to find optimal functions in these families we introduce a Vietoris simplicial set associated to an influence radius. We consider error estimators induced by these Vietoris simplicial sets. A computational implementation of these mathematical models has been developed to be applied to any kind of finite discrete data. Our methods provide a useful tool for the analysis of the spatial distribution of species, which is imperative for developing accurate and efficient management of endangered and invasive species, biological conservation programs, etc. We demonstrate the application of our method to the analysis of the spatial distribution of the grape moth Lobesia botrana (Lepidoptera: Tortricidae) in the vineyards of La Rioja obtaining useful results for the management of this pest. 相似文献
102.
Oresti Banos Miguel Damas Hector Pomares Alberto Prieto Ignacio Rojas 《Expert systems with applications》2012,39(9):8013-8021
The benefits arising from proactive conduct and subject-specialized healthcare have driven e-health and e-monitoring into the forefront of research, in which the recognition of motion, postures and physical exercise is one of the main subjects. We propose here a multidisciplinary method for the recognition of physical activity with the emphasis on feature extraction and selection processes, which are considered to be the most critical stages in identifying the main unknown activity discriminant elements. Efficient feature selection processes are particularly necessary when dealing with huge training datasets in a multidimensional space, where conventional feature selection procedures based on wrapper methods or ‘branch and bound’ are highly expensive in computational terms. We propose an alternative filter method using a feature quality group ranking via a couple of two statistical criteria. Satisfactory results are achieved in both laboratory and semi-naturalistic activity living datasets for real problems using several classification models, thus proving that any body sensor location can be suitable to define a simple one-feature-based recognition system, with particularly remarkable accuracy and applicability in the case of the wrist. 相似文献
103.
Daniel R. BortzCésar Merino Ignacio Martin-Gullon 《Composites Science and Technology》2011,71(1):31-38
This study investigates the monotonic and dynamic fracture characteristics of a discontinuous fiber reinforced polymer matrix. Specifically, small amounts (0-1 wt.%) of a helical-ribbon carbon nanofiber (CNF) were added to an amine cured epoxy system. The resulting nanocomposites were tested to failure in two modes of testing; Mode I fracture toughness and constant amplitude of stress tension-tension fatigue. Fracture toughness testing revealed that adding 0.5 and 1.0 wt.% CNFs to the epoxy matrix enhanced the resistance to fracture by 66% and 78%, respectively. Fatigue testing at 20 MPa peak stress showed a median increase in fatigue life of 180% and 365% over the control by the addition of 0.5 and 1.0 wt.% CNF, respectively. These results clearly demonstrate the addition of small weight fractions of CNFs to significantly enhance the monotonic fracture behavior and long-term fatigue performance of this polymer. A discussion is presented linking the two behaviors indicating their interdependence and reliance upon the stress intensity factor, K. 相似文献
104.
Ignacio Moreno-Villoslada Felipe González Luis Arias José Miguel Villatoro Ricardo Ugarte Susan Hess Hiroyuki Nishide 《Dyes and Pigments》2009,82(3):401-408
The aggregation behavior of C.I. Basic Violet 10 in the presence of poly(sodium 4-styrenesulfonate) was modified, as a consequence of short-range interactions. In aqueous acidic media, the cationic dye forms hydrophobic ion pairs with polymeric benzene sulfonate groups which tend to aggregate in H-contacts, this tendency being readily influenced by the relative concentration of the macromolecule with respect to that of the dye. In the case of dilute aqueous dye solutions (≤10?4 M), for which the probability of dye self-aggregation is small, C.I. Basic Violet 10 self-contacts are forced in the presence of a moderate excess of poly(sodium 4-styrenesulfonate). At dye concentrations >10?4 M, for which the probability of dye self-aggregation increases, dye-dye contacts are minimized in the presence of a large excess of the polymer. Hence, the luminescence of dye solutions can be tuned insorar as, that of dilute dye solutions is quenched whilst that of concentrated dye solutions can be enhanced. This behavior was not observed for other polyelectrolytes such as poly(sodium vinylsulfonate), or the more hydrophobic poly(sodium 2-(N-acrylamido)-2-methyl-propanesulfonate). 相似文献
105.
The advent of multicore systems, joined to the potential acceleration of the graphics processing units, has given us a low cost computation capability unprecedented. The new systems alleviate some well-known important architectural problems at the expense of a considerable increment of the programmability wall. Heterogeneity, at both the architectural and programming levels, poses a great challenge to programmers. As a contribution, we propose a development methodology for the automatic source-to-source transformation on specific domains. This methodology is successfully instantiated as a framework to solve Dynamic Programming problems. As a result of applying our framework, the end user (a physicist, a mathematician or a biologist) can express her problem through a latex equation and automatically derive efficient parallel codes for current homogeneous or heterogeneous architectures. The approach allows an easy portability to new emergent architectures. 相似文献
106.
107.
Ignacio Garcia 《Machine Translation》2007,21(1):55-68
Web-based translation memory (TM) is a recent and little-studied development that is changing the way localisation projects
are conducted. This article looks at the technology that allows for the sharing of TM databases over the internet to find
out how it shapes the translator’s working environment. It shows that so-called pre-translation—until now the standard way
for clients to manage translation tasks with freelancers—is giving way to web-interactive translation. Thus, rather than interacting
with their own desktop databases as before, translators now interface with each other through server-based translation memories,
so that a newly entered term or segment can be retrieved moments later by another translator working at a remote site. The
study finds that, while the interests of most stakeholders in the localisation process are well served by this web-based arrangement,
it can involve drawbacks for freelancers. Once an added value, technical expertise becomes less of a determining factor in
employability, while translators lose autonomy through an inability to retain the linguistic assets they generate. Web-based
TM is, therefore, seen to risk disempowering and de-skilling freelancers, relegating them from valued localisation partners
to mere servants of the new technology. 相似文献
108.
Alicia López María Ángeles Losada Ignacio Garcés Ignacio de Miguel 《Photonic Network Communications》2006,11(1):111-121
We present a novel CWDM metropolitan multiple-access ring network based on optical switching of packets according to their
wavelength. Each node within the MAN is identified by a combination of wavelength and numerical address. Hence, nodes are
able to drop packets presenting a particular wavelength and numerical address, but can insert packets in any wavelength into
the ring. This configuration allows wavelength sharing, as several nodes are identified by the same wavelength (but different
numerical addresses), and simplifies switching requirements since the set of numerical addresses is reduced. We analyze the
viability and scalability of such a network, determining the number of nodes supported by the network under different traffic
scenarios and wavelength resources. The impact of switching time on network performance is also analyzed in order to determine
which switching technology should be employed when implementing the network.
An erratum to this article is available at . 相似文献
109.
110.
Inmaculada Romero-Cascales José Ignacio Fernández-Fernández José María Ros-García José María López-Roca & Encarna Gómez-Plaza 《International Journal of Food Science & Technology》2008,43(7):1295-1305
Numerous studies have reported on the use of enzymes in wineries to facilitate the extraction of grape phenolics and to aid colour stability, although no clear conclusions were reached. Information concerning the enzymatic activities of industrial preparations is very difficult to obtain despite its importance. The aim of this work was to characterise and quantify the activities of six macerating enzyme preparations to optimise their use, and to study their effect on the chromatic characteristics of a Monastrell wine. The results indicate that differences exist in the type of enzymatic activities present in the preparations and in their concentration. The chromatic characteristics of the resulting wines, both at the end of alcoholic fermentation and after 12 months of storage in stainless steel tanks, showed differences with the use of the different maceration enzymes when comparing with control wine, although very little differences were observed between the different enzyme treatments. The enzyme-treated wines showed, at the end of alcoholic fermentation, a higher OD280 and tannin content, and after 12 months, a higher colour intensity too. The main effect of all the preparations was an increase in the total phenol content, probably by facilitating the release of skin tannins. 相似文献