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61.
The general aim of this study was to test the hypothesis that students belonging to a school online community would show higher levels of both offline bridging and bonding social capital than a control group of students, not using the online community. We further hypothesized that the more students used the online community the higher their level of their offline bonding and bridging social capital. Participants were 264 high school boys and girls, 126, (62 males and 64 females) who had joined the community online Spallanzani shout and 138, (62 males and 76 females) who did not. ANOVAs analysis showed that levels of bridging and bonding social capitals were significantly higher for members. Instead intensity of use was significantly related only to bridging but not to bonding social capital. Implications of the findings and directions for future research are discussed.  相似文献   
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63.
Reports an error in "Measuring search efficiency in complex visual search tasks: Global and local clutter" by Melissa R. Beck, Maura C. Lohrenz and J. Gregory Trafton (Journal of Experimental Psychology: Applied, 2010[Sep], Vol 16[3], 238-250). The copyright for the article was incorrectly listed. The correct copyright information is provided in the erratum. (The following abstract of the original article appeared in record 2010-19027-002.) Set size and crowding affect search efficiency by limiting attention for recognition and attention against competition; however, these factors can be difficult to quantify in complex search tasks. The current experiments use a quantitative measure of the amount and variability of visual information (i.e., clutter) in highly complex stimuli (i.e., digital aeronautical charts) to examine limits of attention in visual search. Undergraduates at a large southern university searched for a target among 4, 8, or 16 distractors in charts with high, medium, or low global clutter. The target was in a high or low local-clutter region of the chart. In Experiment 1, reaction time increased as global clutter increased, particularly when the target was in a high local-clutter region. However, there was no effect of distractor set size, supporting the notion that global clutter is a better measure of attention against competition in complex visual search tasks. As a control, Experiment 2 demonstrated that increasing the number of distractors leads to a typical set size effect when there is no additional clutter (i.e., no chart). In Experiment 3, the effects of global and local clutter were minimized when the target was highly salient. When the target was nonsalient, more fixations were observed in high global clutter charts, indicating that the number of elements competing with the target for attention was also high. The results suggest design techniques that could improve pilots' search performance in aeronautical charts. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
64.
The high volume of information produced in the age of omics was and still is an important step to understanding several pathological processes, providing the enlightenment of complex molecular networks and the identification of molecular targets associated with many diseases. Despite these remarkable scientific advances, the majority of the results are disconnected and divergent, making their use limited. Skin diseases with alterations in the Notch signaling pathway were extensively studied during the omics era. In the GWAS Catalog, considering only studies on genomics association (GWAS), several works were deposited, some of which with divergent results. In addition, there are thousands of scientific articles available about these skin diseases. In our study, we focused our attention on skin diseases characterized by the impairment of Notch signaling, this pathway being of pivotal importance in the context of epithelial disorders. We considered the pathologies of five human skin diseases, Hidradenitis Suppurativa, Dowling Degos Disease, Adams–Oliver Syndrome, Psoriasis, and Atopic Dermatitis, in which the molecular alterations in the Notch signaling pathway have been reported. To this end, we started developing a new multiomics platform, PlatOMICs, to integrate and re-analyze omics information, searching for the molecular interactions involved in the pathogenesis of skin diseases with alterations in the Notch signaling pathway.  相似文献   
65.
Over time, much work has been carried out to ascertain the validity of Grassmann's laws, Abney's law, CIE standard color‐matching functions and, up to now, no definitive answer has been given. Some of the phenomena subject of this debate are considered. An apparatus for color matching in 1.8° visual field has been realized with two sets of primary lights with broad spectral bands. This kind of primaries is the great difference with respect to other laboratories because it allows an indirect check of the Grassmann additivity law on the basis of the spectra and individual color‐matching functions by evaluating: (1) the tristimulus values of the primary lights; (2) the transformation matrices between the two reference frames defined by the two primary sets; and (3) the tristimulus values associated to all the pairs of matching lights in the bipartite field produced in the evaluation of the two sets of color‐matching function. The discrepancies of the data resulting in the check (1) and (2) are all compatible with the range defined by the uncertainty propagation of the individual color‐matching functions. In the check (3) fifteen tristimulus values over 18 have a discrepancy lower than one standard uncertainty. Grassmann's proportionality law is checked directly by reducing the matching lights with a neutral filter and holds true. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 271–281, 2008.  相似文献   
66.
A technique of cross talk mitigation developed for liquid crystal on silicon spatial light modulator based optical interconnects and fiber switches is demonstrated. By purposefully introducing an appropriate aberration into the system, it is possible to reduce the worst-case cross talk by over 10 dB compared to conventional Fourier-transform-based designs. Tests at a wavelength of 674 nm validate this approach, and show that there is no noticeable reduction in diffraction efficiency. A 27% spot increase in beam diameter is observed, which is predicted to reduce at longer datacom and telecom wavelengths.  相似文献   
67.
This paper presents a pilot, proof-of-concept study of robot arm therapy (RT) with a treatment protocol specifically designed for severe hemiparetic patients and integrated with a suitable performance measurement protocol. The robot is a planar haptic manipulandum, with low inertia, low friction and impedance control. The task is reaching, with targets arranged in the horizontal plane, in such a way to induce full extension of the arm. Targets are represented haptically, by means of an attractive force field applied by the manipulandum, and visually, by means of circles on a computer screen. The force field is smoothly activated until it reaches a preset intensity that is maintained until the target is reached. Such level of assistance is selected initially as the minimum level that allows each patient to fulfill the task. In each training session, two blocks of trials are alternated (with open and closed eyes, respectively). In the course of training, the level of assistance is reduced as performance improves. Functional recovery is evaluated by processing the kinematic measurements in order to express in quantitative terms the smoothness of the targeting movements. In particular, we defined four performance indicators or outcome measures: (1) the mean speed of the movements; (2) the number of sub-movements in which reaching is decomposed, (3) the remaining error after the first sub-movement, (4) the relative time of the first sub-movement with respect to the total reaching time. For these indicators we identified a measurement scale from the performance of a population of normal subjects performing the same task. The statistical analysis of the responses shows that the proposed protocol is capable to induce significant improvements in all the patients and the performance indicators are sufficiently stable to be chosen as candidates of future adaptive RT protocols in which the training and measurement protocols are designed in an integrated way.  相似文献   
68.
A methodology to develop a GIS-based system for the surface water risk assessment of agricultural chemicals is described. It is based on the integration of relational and spatial databases, GIS incorporating raster and vector, mass balance models, and pesticide risks indicators. Surface water pollution was modeled by taking into account two main processes: the load due to drift and the load due to a rainfall-runoff event. The former is immediately consequent to pesticide application; the second occurs a short period afterward. Thus two distinct PEC (predicted environmental concentration) values were estimated, differing in time. A pilot approach was applied to the herbicide alachlor on corn in Lombardia region (northern Italy) and represents the first stage of a wider project. Although the resultant alachlor PEC and risk maps represent a static image of a worst-case simulation, the main objective was to provide information for the territory with respect to relative risks at the watershed level, which is important in managing risks to the aquatic environment. The driving forces and spatial variability of the above-mentioned processes were investigated to improve knowledge about the territory and to indicate the need for more detailed site-specific studies.  相似文献   
69.
The present experiments compared the ability of pig oocytes matured either in vivo or in vitro to structurally reorganize the penetrated sperm chromatin into male pronucleus (PN) and to carry out, in parallel, the epigenetic processes of global chromatin methylation and acetylation, 12-14 h after in vitro fertilization (IVF). In addition, PN distribution of histone deacetylase (HDAC), a major enzyme interfacing DNA methylation and histone acetylation, was investigated. The ability of the oocyte to operate an efficient block to polyspermy was markedly affected by maturation. The monospermic fertilization rate was significantly higher for in vivo than for in vitro matured (IVM) oocytes (P < 0.01) which, furthermore, showed a reduced ability to transform the chromatin of penetrated sperm into male PN (P < 0.01). Indirect immunofluorescence analysis of global DNA methylation, histone acetylation and HDAC distribution (HDAC-1, -2 and -3), carried out in monospermic zygotes that reached the late PN stage, showed that IVM oocytes also had a reduced epigenetic competence. In fact, while in about 80% of in vivo matured and IVF oocytes the male PN underwent a process of active demethylation and showed a condition of histone H4 hyperacetylation, only 40% of IVM/IVF zygotes displayed a similar PN remodelling asymmetry. Oocytes that carried out the first part of maturation in vivo (up to germinal vesicle breakdown; GVBD) and then completed the process in vitro, displayed the same PN asymmetry as oocytes matured entirely in vivo. A crucial role of HDAC in the establishment of PN acetylation asymmetry seems to be confirmed by the use of HDAC inhibitors as well as by the abnormal distribution of the enzyme between the two PN in IVM zygotes. Collectively, these data demonstrated that some pig IVM oocytes fail to acquire full remodelling competence which is independent from their ooplasmic ability to morphologically reorganize the sperm nucleus into PN.  相似文献   
70.
Polymer-Brush Lubrication in Oil: Sliding Beyond the Stribeck Curve   总被引:1,自引:0,他引:1  
We report a highly effective macroscopic, non-aqueous lubrication strategy, employing polymer-brush-based surface modification. Poly(alkyl methacrylates) with hexyl, dodecyl and octadecyl side chains have been prepared on both silicon and iron substrates by means of surface-initiated atom-transfer radical polymerisation. Frictional properties of the three polymers have been evaluated in hexadecane, ethanol and toluene. For the case of the poly(dodecyl methacrylate), the study additionally involved nine base lubricating fluids of different chemical natures, with viscosities ranging from 4 to 2,200 cSt at 20 °C. By constructing a set of Stribeck curves at low values of speed × viscosity (at constant load), it was possible to identify an extended hydrodynamic lubrication regime and, for P12MA-based coatings, a low-friction, brush-lubrication regime, reinforced by time-dependant effects, which appeared to replace the mixed and boundary regimes observed for conventional lubricants. Self-mated poly(dodecyl methacrylate) brushes maintained low coefficient-of-friction values (e.g. 0.012 in hexadecane) over thousands of reciprocating cycles (>100 m total distance) under low speed × viscosity conditions (0.1 cm/s and 4 cSt).  相似文献   
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