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111.
Performance measurements of 30 mammographic installations were carried out in order to see the current level of image quality and breast doses.The half of the systems tested in this survey indicated automatic exposure control and beam collimation problems. Film processing and dark room conditions were not optimum for the majority of the installations. Image quality phantoms were exposed by the user and team of the survey at each visited center. Lower breast doses were obtained at equal image qualities for the radiographs of the team indicating the importance of adequate handling of some exposure parameters. Corrective actions were suggested to each installation and necessary guidance was advised for the implementation of routine quality control activities.  相似文献   
112.
Due to the great interest in oil‐based polymers, which are prepared from renewable resources, different forms and amounts of soybean oil‐based PLA films were prepared and evaluated for their potential usage as a medical biomaterial. Soybean oil, epoxidized soybean oil and auto‐oxidized soybean oil were blended with PLA and PLA/oil films with appropriate oil amounts [2, 7, 14 and 20% (w/w)] were obtained by solvent casting. Thermal stability and plasticization effect were determined by adjusting oil amounts and type. Epoxidized soybean oil blended films showed the smallest increase in elongation breaks (13–20%) and the highest decrease in thermal decomposition temperatures (364–327 °C) compared to other oil blended films. In vitro quantitative and qualitative cytotoxicity results showed no reactivity (grade 0) for the L929 cells treated with 14% (w/w) oil blended PLA films. In vivo irritation and implantation tests concluded that 14% (w/w) oil blended PLA films were non‐irritant. No erythema, no oedema reactions, no traumatic necrosis and foreign debris were observed. Thus, along with superior biocompatibility, PLA/oil films can replace petroleum‐based products for several biomedical uses.  相似文献   
113.
The influences of lactic acid bacteria and brine solutions on the biogenic amine formation by Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterococus faecalis, Pseudomonas aeruginosa, Listeria monocytogenes, Aeromonas hydrophila and Salmonella paratyphi A in fermented trout fillets were investigated. Fish fillets were divided into four groups, group 1 without any lactic acid bacteria inoculation, group 2 and group 3 with different salt concentration inoculated with lactic acid bacteria and food-borne pathogens, and group 4 inoculated with lactic acid bacteria and food-borne pathogens without a salt solution. The histamine content in trout fillets in group 4 was found to be more than 10 mg/100 g, while the other groups contained less than 7.5 mg/100 g. The highest tyramine production was found for group 1 and group 3, ranging from 3 to 18 mg/100 g. Lactic acid bacteria did not seem to play an important role on biogenic amine production by food borne pathogens, while adding brine solution on fillets has inhibitory effects on some of the biogenic amines.  相似文献   
114.
The effects of gamma radiation on the fecundity, fertility, longevity, development and level of inherited sterility in the Mediterranean flour moth Ephestia kuehniella were determined. Newly emerged virgin Mediterranean flour moth adults were irradiated with 100, 200, 400 and 600 Gy in a 60Co irradiator with a source strength of ca. 3811 Ci and a dose rate of ca. 1 Gy/min. Laboratory studies revealed that radiation did not effect the longevity of irradiated male and female adults. Inherited deleterious effects of gamma radiation were observed in the F1 and F2 generations. Fecundity and the daily egg laying pattern of irradiated and unirradiated females mated to irradiated males was not significantly different from untreated controls. Adverse effects of gamma radiation were observed in the percentage egg hatch and rate of development. Levels of sterility in the P1, F1 and F2 generations were higher than that of untreated controls. The doses of radiation also had a significant effect on the time from oviposition to larval eclosion or adult emergence. Mortality increased with radiation dose. The incidence of larval and pupal mortality was higher in the F2 than in the F1 generation.  相似文献   
115.
Signaling alternatives in a wireless ATM network   总被引:1,自引:0,他引:1  
The world of wireless telecommunications is rapidly changing. The capabilities of wireless networks are improving at a steady pace. This paper presents two possible protocols for implementing mobility for wireless users in an asynchronous transfer mode (ATM) network. The vision of the authors is of one “wireless ATM telecommunications network” that is capable of supporting a variety of today's applications with room to grow for advanced applications of the future. We first visit database architectures that can support mobility in a wireless ATM network. We then discuss one of two signaling architecture alternatives, the “overlay signaling”, for overlay support of mobile users in the ATM-based wireless telecommunications network. “Overlay signaling” aims at minimizing the modification needed to the existing ATM protocols. We then describe a native “migratory signaling” approach that further integrates wireless and wireline users into one global wireless ATM network at the expense of requiring some modifications to the existing ATM protocols. A performance analysis of the proposed signaling architecture alternatives is also presented. We conclude by pointing out some challenges in merging ATM with wireless telecommunications  相似文献   
116.
Ergonomics has been playing an important role in assembly system design (ASD) that contains not only the main assembly line balancing problem but also the subassembly line balancing and assembly layout problem. The ergonomics in ASD has an impact both on productivity and on workers’ health, especially when frequent changes in the product mix occur. In this study, we propose a systematic approach in order to handle ASD, which consists of three subproblems, while considering ergonomic risk factors. The first two subproblems are solved simultaneously using the proposed rule‐based constructive search algorithm, where ergonomic risks are evaluated by OCRA method. Later, layout problem is solved under transportation constraints using local search methods with various neighborhood structures. To provide the applicability and evaluate the performance of the proposed systematic approach, a real‐life case study in a harness manufacturing company is solved and prototype productions are performed.  相似文献   
117.
The literature on transboundary water resources allocation modelling is still short on encompassing and analyzing complex geographic multiparty nature of basins. This study elaborates the Inter Temporal Euphrates and Tigris River Basin Model (ITETRBM), which is a linear programming based transboundary water resources allocation model maximizing net economic benefit from allocation of scarce water resources to energy generation, urban, and agricultural uses. The elaborations can be categorized in two directions: First, agricultural and urban demand nodes are spatially identified with their relative elevations and distances to water resources supplies (dams, reservoirs, and lakes). Digital elevation model (DEM) database are intensely processed in geographic information system (GIS) environment. Second, the agricultural irrigable lands are restructured into a pixel based decision making units (DMUs) in order to be able to see the spatial extent of optimally irrigated land, and then optimization program is converted from linear programming (LP) to a mixed integer programming (MIP). The model applications are designed to cover a series of sensitivity analyses encompassing the various transboundary management, energy and agricultural use value, and transportation cost scenarios over the optimal uses of the Euphrates and Tigris Basin (ETRB) resources. The model results are visually presented via GIS in order to show the transboundary upstream and downstream spatial impacts of these selected parameters. The findings are i) system parameters significantly alter the spatial extent of water resources allocation in the ETRB, and ii) the magnitudes of the parameters also explains the tradeoffs between agriculture and energy sectors as much as upstream and downstream water uses of countries.  相似文献   
118.
A systematic study on the effect of monovalent cation doping on structural, magnetic, and magnetocaloric properties of Pr0.85 A 0.15MnO3 (A = Ag and K) samples synthesized by a sol-gel method has been carried out. The crystal structure and morphology have been worked by X-ray diffraction (XRD) and scanning electron microscopy (SEM) imaging measurements. The XRD results indicate that both samples have orthorhombic structure. Magnetization versus temperature measurements show that our samples display a ferromagnetic-to-paramagnetic phase transition with increasing temperature. The ferromagnetic-to-paramagnetic phase transition temperature (T C) values were found as 74 and 116 K for Pr0.85Ag0.15MnO3 and Pr0.85 K 0.15MnO3, respectively. The magnetic entropy changes were evaluated from isothermal magnetization curves measured at various temperatures near T C by steps of 4 K. The values of the magnetic entropy change were determined as 0.99 and 1.39 J kg ?1 K ?1 for Pr0.85Ag0.15MnO3 and Pr0.85 K 0.15MnO3 under external field changes of 10 kOe, respectively.  相似文献   
119.
In this paper, we present a deep neural network model to enhance the intrusion detection performance. A deep learning architecture combining convolution neural network and long short‐term memory learns spatial‐temporal features of network flows automatically. Flow features are extracted from raw network traffic captures, flows are grouped, and the consecutive N flow records are transformed into a two‐dimensional array like an image. These constructed two‐dimensional feature vectors are normalized and forwarded to the deep learning model. Transformation of flow information assures deep learning in a computationally efficient manner. Overall, convolution neural network learns spatial features, and long short‐term memory learns temporal features from a sequence of network raw data packets. To maximize the detection performance of the deep neural network and to reach at the highest statistical metric values, we apply the tree‐structured Parzen estimator seeking the optimum parameters in the parameter hyper‐plane. Furthermore, we investigate the impact of flow status interval, flow window size, convolution filter size, and long short‐term memory units to the detection performance in terms of level in statistical metric values. The presented flow‐based intrusion method outperforms other publicly available methods, and it detects abnormal traffic with 99.09% accuracy and 0.0227 false alarm rate.  相似文献   
120.
Istanbul is the largest city in Turkey with an area of around 5750 km2 and population of around 10.58 M (2000). The population is increasing because of mass immigration. Planned and unplanned housing are increasing while green areas are decreasing in area. Rapid, uncontrolled and illegal urbanization accompanied by insufficient infrastructure has caused degradation of forest, water basin and barren lands in the metropolitan area, especially within the past two decades. The study includes taking administrative planning decisions about the development of urban sustainability in the metropolitan area of Istanbul, producing rationalist solutions to the problems in environmental and natural resources, and conservation of small-scale (historical, tourist, residential, industrial, etc.) specific urban areas. By the help of this study, settlement suitability analyses have been achieved according to the natural thresholds of the area. Additionally, some kinds of formations, which may limit the development of the metropolitan area of Istanbul, such as natural structures, natural structure, ecological corridors and natural hazard areas, have been defined and developed model on the ArcGIS 9.1 platform. In the light of the policies of the European Union about sustainable cities, environmental impact assessments and sustainability policies have been determined for both the existing settlements and sustainable development areas.  相似文献   
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