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11.
This paper describes an advanced closed loop quality control methodology for reconfigurable manufacturing systems. The methodology enables rapid root-cause diagnostics for faster ramp-up of reconfigurable systems through integration of the Reconfigurable Inspection Machine (RIM) and the Stream of Variations (SoV) methodology. The RIM enables reconfigurable, rapid, and accurate inspection using non-contact sensors while the SoV methodology is used to quickly analyze the measurements and identify the root-cause of the errors produced during machining.The feasibility of the industrial concept was experimentally validated. A machining error was introduced during machining of an engine head. Measurement information collected by the RIM was processed and used to locate the root-cause of the error using the SoV methodology.  相似文献   
12.
Real time discrete shading   总被引:1,自引:1,他引:0  
A shading technique for voxel-based images, termedcongradient shading, is presented. As the surface information is not available in voxel representation, the surface normal must be recovered from the 3D discrete voxel map itself. The technique defines the normal as one of a finite set of neighborhood-estimated gradients and can thus employ precalculated look-up tables. Furthermore, a table-driven mechanism permits changing the light source parameters by merely redefining the look-up table. The technique uses only simple arithmetic operations and is thus suitable for hardware implementation. Since it has been implemented not as a post-processor, but as part of the projection pipeline of the cube architecture, congradient shading can be executed in real time. Two versions of the technique in real time. Two versions of the technique have been conceived and implemented:unidirectional shading, in which the gradient is estimated only from neighborhoods along the scan-lines;bidirectional shading, in which both horizontal and vertical components of the gradient are considered. In spite of the simplicity of the technique, the results are practically indistinguishable from images generated by conventional techniques.This work was supported by the National Science Foundation under grants DCR 8603603, CCR 8743478, CCR 8717016, and MIP 8805130  相似文献   
13.
Herein we report the synthesis and biological evaluation of symmetric and asymmetric analogues of the DNA intercalating drug mitoxantrone (MTX) in which the side chains of the parent drug were modified through glycosylation or methyl etherification. Several analogues with glycosylated side chains exhibited higher DNA affinity than the parent MTX. The most potent in vitro cytotoxicity was observed for MTX analogue 8 (1,4‐dimethoxy‐5,8‐bis[2‐(2‐methoxyethylamino)ethylamino]anthracene‐9,10‐dione) with methoxy ether containing side chains. Treatment of melanoma‐bearing mice with MTX or analogue 8 decreased the intraperitoneal tumor burden relative to untreated mice; the effect of 8 was less pronounced than that of MTX. In vitro metabolism assays of MTX with rabbit liver S9 fraction gave rise to several metabolites; almost no metabolites were detected for MTX analogue 8 . The results presented indicate that derivatization of the MTX side chain primary hydroxy groups may result in a significant improvement in DNA affinity and lower susceptibility to the formation of potentially toxic metabolites.  相似文献   
14.
The many MRP lot-sizing algorithms proposed imply four underlying time-phasing requirements: minimizing inventory, maintaining uniform batch sizes, maintaining regular order cycles, and attaining minimum costs. This study examines the cost behavior of four exact and two classical algorithms addressing these structures. Several parameters, describing the demand profile, planning horizon and component costs enable effective evaluation and prediction of cost behaviour. The study shows that: (1) imposing regularity constraints on an MRP schedule leads to costs 14% above the minimum for fixed batch sizing, and 2% for regular order cycling; (2) fixed order cycle schedules show costs close to the minimum attainable, thus supporting the use of this approach in practice; (3) the classical POQ schedules also show good cost performance (11% above minimum); and (4) the cost behaviour of a wide range of MRP demand profiles and cost components can be fairly well predicted (to 7% on the average) using simplified “ideal” relationships.  相似文献   
15.
In this report, the authors explore the relationships of perceived treatment to outcome in a large, placebo-controlled trial of nicotine replacement treatment for smoking reduction. In the original study (J. F. Etter, E. Laszlo, J. P. Zellweger, C. Perrot, & T. V. Perneger, 2002), which was conducted in French-speaking Switzerland, smokers were randomly assigned to receive nicotine, matching placebo products, or no intervention. At the end of the 6-month study, participants were asked to guess whether they had received nicotine or placebo. In the present analysis, the authors examined the difference in smoking reduction between those who believed they had received nicotine and those who believed they had received placebo. Regardless of actual treatment, smokers who believed they had received nicotine had significantly better outcome than those who believed they had received placebo. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
16.
We present a method to extract the internal effective refractive index of a vertical-cavity surface-emitting laser (VCSEL) from its transverse mode images. High spatial and spectral resolution mode images of an oxide-guided VCSEL were obtained using an etalon filter and an imaging spectrometer. The refractive index and the oxide radius were extracted from the field intensity distribution and the spectral wavelength of the laser modes. The procedure was repeated at two different currents and both gave a refractive index step of 0.046 plusmn 0.006 with a 14.1-mum oxide diameter. With several degrees of freedom for error available in the refractive index extraction, this method may be extended to ion-implanted, photonic crystal, and noncircular devices  相似文献   
17.
Since the elucidation of its chemical structure two decades ago, platelet-activating factor (PAF) has emerged as an important mediator of various cardiovascular stress situations. Most notably, PAF was implicated as a key factor in the septic shock syndrome, based on the similarities between endotoxin and PAF biological effects, the elevation of circulating and tissue levels of PAF during endotoxemia, and the protective effect of PAF antagonists in the septic state. In addition, accumulating data suggest the involvement of PAF in the pathophysiological processes associated with ischemia, hemorrhage and trauma, where PAF exerts its effects directly on cells and blood elements or indirectly through interactions with other mediators such as cytokines and prostaglandins. Nevertheless, the relative contribution of PAF to the pathophysiological processes in endotoxemia is still unknown and should await further investigations. The primary aims of this chapter are: to delineate the effects of PAF on the cardiovascular system, to summarize the data which suggest the involvement of PAF in stress situations of the cardiovascular system, and to identify areas where future experimental efforts should be focused. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.  相似文献   
18.
The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal enterotoxin A (SEA), a single chain protein which consists of 233 amino acid residues with a molecular weight of 27078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, diarrhea, atopic dermatitis, arthritis, and toxic shock) syndromes. Changes in the native structural integrity may inactivate the toxin by preventing molecular interaction with cell membrane receptor sites of their host cells. In the present study, we evaluated the ability of the pure olive compound 4-hydroxytyrosol and a commercial olive powder called Hidrox-12, prepared by freeze-drying olive juice, to inhibit S. aureus bacteria and SEA's biological activity. Dilutions of both test substances inactivated the pathogens. Two independent cell assays (BrdU incorporation into newly synthesized DNA and glycyl-phenylalanyl-aminofluorocoumarin proteolysis) demonstrated that the olive compound 4-hydroxytyrosol also inactivated the biological activity of SEA at concentrations that were not toxic to the spleen cells. However, efforts to determine inhibition of the toxin by Hidrox-12 were not successful because the olive powder was cytotoxic to the spleen cells at concentrations found to be effective against the bacteria. The results suggest that food-compatible and safe antitoxin olive compounds can be used to inactivate both pathogens and toxins produced by the pathogens. Practical Application: The results of this study suggest that food-compatible and safe antitoxin olive compounds can be used to reduce both pathogens and toxins produced by the pathogens in foods.  相似文献   
19.
With the increasing complexity of chemical plants and the growing public concern for the safe manufacture, transport, and disposal of these chemicals, there exist a need to assist decision-makers in project evaluation with regard to risk.

Extensive work has been done in risk analysis area related to nuclear industry. The amount of research and applications of risk analysis methodology in chemical industry is seriously lacking. Direct application of some of the risk analysis techniques used for nuclear risk studies is not always appropriate to the chemical industry.

The use of simulation models to overcome some of the problems of direct application of probabilistic risk assessment (PRA) methodologies is evaluated in this paper. A simulation model is developed for a toxic chemical storage risk analysis problem. The results of the simulation model are compared to the results of using standard fault tree methodology.  相似文献   

20.
Feeding tests with loggerhead shrikes (Lanius ludovicianus) showed this bird to acceptUtetheisa ornatrix, a moth (Arctiidae) protected by pyrrolizidine alkaloids, but to avoidLytta polita, a beetle (Meloidae) containing cantharidin.Paper no. 130 of the series Defense Mechanisms of Arthropods; no. 129 is T. Eisner and J. Meinwald,Proc. Natl. Acad. Sci. U.S.A. 92:50–55, 1995.  相似文献   
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