全文获取类型
收费全文 | 434篇 |
免费 | 21篇 |
学科分类
工业技术 | 455篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 15篇 |
2017年 | 21篇 |
2016年 | 16篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 25篇 |
2012年 | 30篇 |
2011年 | 48篇 |
2010年 | 24篇 |
2009年 | 24篇 |
2008年 | 48篇 |
2007年 | 36篇 |
2006年 | 29篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 2篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有455条查询结果,搜索用时 31 毫秒
81.
Fabien Alibart Stéphane Pleutin Olivier Bichler Christian Gamrat Teresa Serrano‐Gotarredona Bernabe Linares‐Barranco Dominique Vuillaume 《Advanced functional materials》2012,22(3):609-616
A large effort is devoted to the research of new computing paradigms associated with innovative nanotechnologies that should complement and/or propose alternative solutions to the classical Von Neumann/CMOS (complementary metal oxide semiconductor) association. Among various propositions, spiking neural network (SNN) seems a valid candidate. i) In terms of functions, SNN using relative spike timing for information coding are deemed to be the most effective at taking inspiration from the brain to allow fast and efficient processing of information for complex tasks in recognition or classification. ii) In terms of technology, SNN may be able to benefit the most from nanodevices because SNN architectures are intrinsically tolerant to defective devices and performance variability. Here, spike‐timing‐dependent plasticity (STDP), a basic and primordial learning function in the brain, is demonstrated with a new class of synapstor (synapse‐transistor), called nanoparticle organic memory field‐effect transistor (NOMFET). This learning function is obtained with a simple hybrid material made of the self‐assembly of gold nanoparticles and organic semiconductor thin films. Beyond mimicking biological synapses, it is also demonstrated how the shape of the applied spikes can tailor the STDP learning function. Moreover, the experiments and modeling show that this synapstor is a memristive device. Finally, these synapstors are successfully coupled with a CMOS platform emulating the pre‐ and postsynaptic neurons, and a behavioral macromodel is developed on usual device simulator. 相似文献
82.
Regularizing common spatial patterns to improve BCI designs: unified theory and new algorithms 总被引:1,自引:0,他引:1
One of the most popular feature extraction algorithms for brain-computer interfaces (BCI) is common spatial patterns (CSPs). Despite its known efficiency and widespread use, CSP is also known to be very sensitive to noise and prone to overfitting. To address this issue, it has been recently proposed to regularize CSP. In this paper, we present a simple and unifying theoretical framework to design such a regularized CSP (RCSP). We then present a review of existing RCSP algorithms and describe how to cast them in this framework. We also propose four new RCSP algorithms. Finally, we compare the performances of 11 different RCSP (including the four new ones and the original CSP), on electroencephalography data from 17 subjects, from BCI competition datasets. Results showed that the best RCSP methods can outperform CSP by nearly 10% in median classification accuracy and lead to more neurophysiologically relevant spatial filters. They also enable us to perform efficient subject-to-subject transfer. Overall, the best RCSP algorithms were CSP with Tikhonov regularization and weighted Tikhonov regularization, both proposed in this paper. 相似文献
83.
Impact of a thermal treatment on the emulsifying properties of egg yolk. Part 1: Effect of the heating time 总被引:3,自引:0,他引:3
The denaturation degree of egg yolk (EY) protein was determined in dilute EY suspensions containing 20% fresh EY (w/w) as a function of the heating time (0–40 min.) at 74 °C. The impact of such a thermal treatment on the emulsifying properties of the EY was studied in a fluid oil-in-water (O/W) emulsion containing 30% oil (v/v). Heating of the EY prior to emulsification appeared to slightly increase the oil droplet size and to drastically decrease of the level of flocculation. It was also shown that the concentration of proteins in the interfacial film increases with increasing degree of EY protein denaturation, which is thought to be responsible for the change in the colloidal interactions between droplets. The increased steric repulsions due to the increased interfacial protein concentration could explain the decrease of oil droplet flocculation. The impact of such modifications on the rheological properties and creaming stability of the emulsions is discussed. 相似文献
84.
Vaillant N Monnet F Vernay P Sallanon H Coudret A Hitmi A 《Environmental science & technology》2002,36(9):2101-2106
Urban wastewater causes rapid eutrophication of natural waters and requires treatment before discharge. This is expensive and produces huge quantities of sludge. In the European Community, it will no longer be lawful to dispose of this sludge as landfill after 2005 (European Directive 91/271/CEE of May 21, 1991). Wastewater treatment by the Chrysanthemum cinerariaefolium plants in horizontal flow was investigated using the nutrient film technique (NFT), a widely used hydroponic system in the commercial greenhouse industry. After a 48 h plant treatment, the purification efficiency was 95%, 91%, and 99% with respect to suspended solids (SS), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD), and the elimination of nutrients (total nitrogen and total phosphorus) varied between 40% and 80%. SS and thus indirectly BOD5 and COD were removed by filtration and adsorption; the solids trapped in the root systems were then decomposed and mineralized. The system with 25 plants purified 30 L of wastewater in 48 h. One-hundred people communities wastewater could be treated with a 6 m2 area of production. Pyrethrin contents and chlorophyll a fluorescence of plants grown on raw urban waters were not significantly different from those grown on a standard nutrient solution. 相似文献
85.
Roland Oltra Alexandre Zimmer Claire Sorriano Fabien Rechou Céline Borkowski Olivier Néel 《Electrochimica acta》2011,(20):7038
Some constituent intermetallic (IMPs) particles at the surface of aluminium alloys are considered as preferential sites for the initiation of structural corrosion resulting in localized trenching around the particles and the surrounding Al matrix. In this work, a modified scanning electrochemical microscope (SECM) experiment was used to induce such phenomena via a local alcalinisation on 200 nm thick aluminium coatings promoting their local dissolution in an aerated 0.1 M NaCl electrolyte. The local alcalinisation was induced by the oxygen reduction reaction on the tip of a SECM which mimics the surface of an isolated IMP. From a phenomenological point of view, reproducible cylindrical damage develops in front of the platinum ultramicroelectrode (UME). Using a 2D finite element modelling to simulate the SECM experiments, the role of the local alcalinisation was validated and the calculated Al dissolution rate was found in agreement with the experimental evaluation. 相似文献
86.
Fabien Prgaldiny Franois Krummenacher Birahim Diagne Franois Pêcheux Jean‐Michel Sallese Christophe Lallement 《International Journal of Numerical Modelling》2006,19(3):239-256
This paper presents a new compact model for the undoped, long‐channel double‐gate (DG) MOSFET under symmetrical operation. In particular, we propose a robust algorithm for computing the mobile charge density as an explicit function of the terminal voltages. It allows to greatly reduce the computation time without losing any accuracy. In order to validate the analytical model, we have also developed the 2D simulations of a DG MOSFET structure and performed both static and dynamic electrical simulations of the device. Comparisons with the 2D numerical simulations give evidence for the good behaviour and the accuracy of the model. Finally, we present the VHDL‐AMS code of the DG MOSFET model and related simulation results. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
87.
Blandine Ponsard Isabelle Durot Philippe Delerive Fabien Oudot Catherine Cordelet Alain Grynberg Pierre Athias 《Lipids》1999,34(5):457-466
The purpose of the present investigation was to determine whether the beneficial effects of polyunsaturated fatty acids (PUFA)
may influence ischemia-reperfusion-induced alterations of myocardial α- and β-adrenoceptor (α-AR, β-AR) responsiveness. This
study was carried out using monolayer cultures of neonatal rat ventricular myocytes in a substrate-free, hypoxia-reoxygenation
model of ischemia. The cardiomyocytes (CM) were incubated during 4 days in media enriched either with n−6 PUFA (arachidonic
acid, AA) or with n−3 PUFA (eicosapentaenoic acid, EPA, and docosahexaenoic acid, DHA). The n−6/n−3 ratio in n−3 CM was close
to 1.2, compared to 20.1 in n−6 CM. The contractile parameters of n−6 CM and n−3 CM were similar in basal conditions as well
as during hypoxia and reoxygenation. In basal conditions, the phospholipid (PL) enrichment with long chain n−3 PUFA resulted
in an increased chronotropic response to isoproterenol (ISO) and to phenylephrine (PHE). After posthypoxic reoxygenation,
the chronotropic response to β-AR activation in n−6 CM was significantly enhanced as compared with the control response in
normoxia. In opposition, the ISO-induced rise in frequency in n−3 CM in control normoxia and after reoxygenation was similar.
In these n−3 CM, the changes in contractile parameters, which accompanied the chronotropic response, were also similar in
reoxygenation and in normoxic periods, although the rise in shortening velocity was slightly increased after reoxygenation.
In response to PHE addition, only the chronotropic effect of n−6 CM appeared significantly enhanced after hypoxic treatment.
These results suggested that increasing n−3 PUFA in PL reduced the increase in α- and β-AR functional responses observed after
hypoxia-reoxygenation. This effect may partly account for the assumed cardiac protective effect of n−3 PUFA, through the attenuation
of the functional response to catecholamines in the ischemic myocardium. 相似文献
88.
Bruno Legeard Fabien Peureux Mark Utting 《Software Testing, Verification and Reliability》2004,14(2):81-103
BZ‐TESTING‐TOOLS (BZ‐TT) is a tool set for automated test case generation from B and Z specifications. BZ‐TT uses boundary and cause–effect testing on the basis of the formal model. It has been used and validated on several industrial applications in the domain of critical software, particularly smart card and transport systems. This paper presents the test coverage criteria supported by BZ‐TT. On the one hand, these correspond to various classical structural coverage criteria, but specialized to the case of B abstract machines. The paper gives algorithms for these in Prolog. On the other hand, BZ‐TT introduces new coverage criteria for complex data structures, based on boundary analysis: this paper defines weak and strong state‐boundary coverage, input‐boundary coverage and output‐boundary coverage. Finally, the paper describes how BZ‐TT presents a unified view of these criteria to the validation engineer, and allows him or her to control the test case explosion on a coarse basis (choosing from a range of coverage criteria) as well as a fine basis (selecting options for each state or input variable). Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
89.
Alex Hirtz Fabien Rech Hlne Dubois-Pot-Schneider Hlne Dumond 《International journal of molecular sciences》2020,21(23)
Astrocytomas and, in particular, their most severe form, glioblastoma, are the most aggressive primary brain tumors and those with the poorest vital prognosis. Standard treatment only slightly improves patient survival. Therefore, new therapies are needed. Very few risk factors have been clearly identified but many epidemiological studies have reported a higher incidence in men than women with a sex ratio of 1:4. Based on these observations, it has been proposed that the neurosteroids and especially the estrogens found in higher concentrations in women’s brains could, in part, explain this difference. Estrogens can bind to nuclear or membrane receptors and potentially stimulate many different interconnected signaling pathways. The study of these receptors is even more complex since many isoforms are produced from each estrogen receptor encoding gene through alternative promoter usage or splicing, with each of them potentially having a specific role in the cell. The purpose of this review is to discuss recent data supporting the involvement of steroids during gliomagenesis and to focus on the potential neuroprotective role as well as the mechanisms of action of estrogens in gliomas. 相似文献
90.
Xiang Yan Aurélie Cayla Fabien Salaün Eric Devaux Pengqing Liu Jianzhao Mao Tingjian Huang 《应用聚合物科学杂志》2020,137(11):48470
Biphasic polypropylene (PP)-polyvinyl alcohol (PVA) fibers containing silica nanoparticles with various surface hydrophobicity were melt-spun. The localization of nanoparticles relates on the thermodynamic factors, and the design promotes a surface-decorated fibrous scaffold with nanoparticles after selective extraction. The influence of silica nanoparticles on the melt flow index was observed, and the interface-located Aerosil R972 silica nanoparticles lead to an increase in viscosity. The scanning electron microscopy (SEM) demonstrates the preponderant interfacial localization of Aerosil R972 nanoparticles within the biphasic fibers. The porous morphology of the obtained fibers was investigated by SEM, selective extraction experiment, X-ray diffraction analysis, and dynamical mechanical analysis. The specific interface area of PP70-PVA30 fibers with a draw ratio (DR) of 2 is 3.2 m2 g−1 and is further enlarged with the increase of DR. The incorporation of nanoparticles contributes to the increase of interconnectivity of the PVA phase. The further increment of DR modifies the crystalline structure, and results in better mechanical properties. The Aerosil R972-containing fibers with the DR of 3 provide almost completely accessible PVA phase, with enough mechanical strength to be transformed into textile products, and retains a good mechanical property after selective extraction. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48470. 相似文献