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1.
In a series of 10-day pair feeding experiments it was found that the nutritional value of diets containing beans was essentially the same for rats aged between 30 and 123 days. Thus net protein utilisation (NPU) values of 25–39 on diets containing Processor bean (35 g protein kg?1) + egg albumin (65g protein kg?1) were obtained. As food intakes were considerably reduced when rats were fed diets containing more than 35g protein kg?1 of Processor bean, the measurement of protein utilisation became increasingly more difficult. The severe disruption of the brush borders of duodenal and jejunal enterocytes, originally observed when bean-containing diets were fed to young (30-day-old) rats was also found with rats up to the age of 120 days on similar diets. Similarly, the development of circulating anti-lectin antibodies in the animals showed no age dependence within the age limits investigated. It was also shown that oral immunisation did not protect the rats from the effects of toxicity and that the immune response was a result of continuous absorption of lectin throughout the feeding period. Thus the extent and the mechanism of toxicity of Phaseolus vulgaris bean lectins were found not to be dependent on the age or maturity of the animal.  相似文献   
2.
The challenge of developing gene therapies for genetic forms of blindness is heightened by the heterogeneity of these conditions. However, mechanistic commonalities indicate key pathways that may be targeted in a gene-independent approach. Mitochondrial dysfunction and axon degeneration are common features of many neurodegenerative conditions including retinal degenerations. Here we explore the neuroprotective effect afforded by the absence of sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1), a prodegenerative NADase, in a rotenone-induced mouse model of retinal ganglion cell loss and visual dysfunction. Sarm1 knockout mice retain visual function after rotenone insult, displaying preservation of photopic negative response following rotenone treatment in addition to significantly higher optokinetic response measurements than wild type mice following rotenone. Protection of spatial vision is sustained over time in both sexes and is accompanied by increased RGC survival and additionally preservation of axonal density in optic nerves of Sarm1−/− mice insulted with rotenone. Primary fibroblasts extracted from Sarm1−/− mice demonstrate an increased oxygen consumption rate relative to those from wild type mice, with significantly higher basal, maximal and spare respiratory capacity. Collectively, our data indicate that Sarm1 ablation increases mitochondrial bioenergetics and confers histological and functional protection in vivo in the mouse retina against mitochondrial dysfunction, a hallmark of many neurodegenerative conditions including a variety of ocular disorders.  相似文献   
3.
A photoacoustic spectroscopic (PAS) and a direct optical absorption spectroscopic (OAS) gas sensor, both using continuous-wave room-temperature diode lasers operating at 1531.8 nm, were compared on the basis of ammonia detection. Excellent linear correlation between the detector signals of the two systems was found. Although the physical properties and the mode of operation of both sensors were significantly different, their performances were found to be remarkably similar, with a sub-ppm level minimum detectable concentration of ammonia and a fast response time in the range of a few minutes.  相似文献   
4.
Telework is a growing phenomenon that is thought to save energy and air emissions. This paper applies a systems model to telework and nontelework scenarios in order to quantify greenhouse gas and other air emissions from transportation, heating, cooling, lighting, and electronic and electrical equipment use both at the company and the home office. Using United States data, a WWW-based, scalable decision-support tool was created to evaluate the environmental impacts of teleworkers. For a typical case reflecting United States teleworker patterns, the analysis found that telework has the potential to reduce air emissions. However, Monte Carlo simulation employed to perform a probabilistic analysis over a set of likely parameters has revealed that telework may not affect equally the emissions of all types of pollutants. It may decrease CO2, NOx, SO2, PM10, and CO but not N2O and CH4 emissions. Therefore, the scope and goal of telework programs must be defined early in the implementation process. Work-related transportation (commuting) impacts could be reduced as a result of telework; however, home-related impacts due to an employee spending additional time at home could potentially offset these reductions. Company office-related impacts may not be reduced unless the office space is shared with other employees during telework days or eliminated entirely. In states with high telework potential (California, Georgia, Illinois, New York, Texas), telework could save emissions, but it would depend on commuting and climatic patterns and the electricity mix. Environmentally beneficial telework programs are found to depend mainly on commuting patterns, induced energy usage, and characteristics of the office and home space and equipment use.  相似文献   
5.
The hydrocracked residues were found to be considerably enriched both in total nitrogen and in basic nitrogen relative to total nitrogen with respect to the feed asphalt. The matrix in which these basic nitrogen components are most likely to be found consisted of compact aromatic structures containing relatively few naphthenic and paraffinic moieties

Upon hydrocracking, the basicity of the remaining basic nitrogen increased with the level of conversion. It is this increased nitrogen basicity which most probably accounted for the enhanced anti-stripping properties of the hydrocracked residues.

Hot storage, such as could be expected during the transportation of the paving asphalt, resulted in the apparent loss of approximately 10%, on average, of basic nitrogen without a commensurate decrease in the anti-stripping effectiveness of the additive. Possible explanations lie in the chemical reactivity of the asphaltic binder

Attempts at isolation of a basic nitrogen concentrate have met with a modicum of success. Indications are that the nitrogen compounds extracted depend largely on the method of extraction  相似文献   
6.
Reducing the environmental effects of construction is a continuing professional and social concern to promote sustainable development. In this paper, we estimate the major commodity and service inputs, resource requirements, and environmental emissions and wastes for four major U.S. construction sectors as defined by the Department of Commerce: (1) highway, bridge, and other horizontal construction [0.6% of the 1992 U.S. gross domestic product (GDP)]; (2) industrial facilities and commercial and office buildings (1.5% of GDP); (3) residential one-unit buildings (1.9% of GDP); and (4) other construction (towers, water, sewer and irrigation systems, railroads, etc.) (2.4% of GDP). Our estimates include the entire supply chain of material, energy, and service suppliers for these sectors with the use of a detailed 1992 input-output model of the U.S. economy and publicly available environmental data. We find that in general, the four major U.S. construction sectors appear to use fewer resources and have lower rates of environmental emissions and wastes than their share of the GDP might suggest.  相似文献   
7.
Assessing the end-of-life impacts of buildings   总被引:1,自引:0,他引:1  
This paper builds on previous research on end of life of products by synthesizing some of the theories proposed in the literature and presenting a method for environmental decision-making related to buildings. This is achieved through different solutions, but most significantly through the use of hybrid life-cycle assessment and the definition of allocation boundaries in a way that decreases the uncertainty associated with technologicalforecasting. Results show that there is no significant difference between the results of two major end-of-life assessment approaches (attributional and consequential), and that the choice between the use of one or the other for buildings may not be a critical decision. Assessing the impacts of recycling polices requires accounting for product substitutions, market analysis, and the full supply chain impacts of the recycling chains. Increasing the recycling of concrete from deconstructed buildings from the current 27% rate to 50% could yield a 2-3% (2.7-5.6 million metric tons of CO2 equivalents) reduction in buildings' greenhouse gas emissions, or the equivalent of removing 408,000-847,000 typical cars from U.S. roads.  相似文献   
8.
The paper presents an improved context-based denoising method for gray scale images affected by impulse noise. The proposed algorithm is using Markov chains to replace the detected noise with the intensity having the highest number of occurrences in similar contexts. The context of a noisy pixel consists in its neighbor pixels and is searched in a larger but limited surrounding area. We have analyzed different search methods and different context shapes. The experimental results obtained on the test images have shown that the most efficient model applies the search in form of   “*”  of contexts in form of   “+”. Besides the better denoising performance obtained on all the noise levels, the computational time has been also significantly improved with respect to our previous context-based filter which applied full search of full context. We have also compared this improved Markov filter with other denoising techniques existing in the literature, most of them being significantly outperformed.  相似文献   
9.
The poor nutritional performance of rats fed raw soya-bean-containing diets appeared to be due to reduced apparent digestion and absorption of dietary protein, coupled to changes in systemic metabolism leading to a poor overall nitrogen balance. Aqueous heat treatment greatly reduced but did not eliminate the antinutritional effect. Heat treatment with aqueous ethanol was more effective. The whey protein (pH 4.8 soluble extract) fraction contained the bulk of the trypsin inhibitor and haemagglutination activity and gave the poorest net protein utilisation value. However, an eight-fold increase in trypsin inhibitor content did not significantly effect apparent nitrogen digestibility. Therefore inhibition of gut proteolytic enzyme activity in vivo by soya bean trypsin inhibitors did not account fully for the poor nutritional performance. The problems elicited by soya bean are not transitory and thus there was a cumulative deterioration in overall performance for 16 weeks as a result of continuous exposure to soya bean.  相似文献   
10.
High definition television (HDTV) has become a major world-wide event in the television arena. Since the early 1980s, when HDTV was first demonstrated by Japan, a number of alternative systems have emerged. These systems clearly reflect the business and political objectives of the particular countries or organizations. In North America, which is the largest single consumer market in the world, technical, business and political considerations are shaping the evolution of HDTV. This paper describes a possible advanced television (ATV) architecture for North America and defines its functional modules and corresponding interfaces. The developed model is recommended as a design tool for standardizing ATV in North America and analysing interrelationships of the functional modules on the economic basis. The paper proposes an ‘hierarchical’ ATV emission system with full NTSC compatibility and HDTV quality. Solutions are recommended for terrestrial broadcast, CATV and satellite. This work describes a total systems approach to HDTV called HDS-NA (high definition system for North America). The two emission signals of HDS-NA: HDMAC-60 and HDNTSC are characterized. RF alternatives for the terrestrial broadcast of HDTV are also discussed.  相似文献   
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