首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   62篇
  免费   1篇
化学工业   14篇
建筑科学   3篇
能源动力   1篇
轻工业   24篇
水利工程   1篇
无线电   1篇
一般工业技术   7篇
冶金工业   5篇
自动化技术   7篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   6篇
  2017年   3篇
  2016年   3篇
  2015年   1篇
  2014年   3篇
  2013年   5篇
  2012年   4篇
  2011年   4篇
  2010年   4篇
  2009年   3篇
  2008年   2篇
  2007年   6篇
  2006年   3篇
  2005年   1篇
  2004年   1篇
  2003年   2篇
  2001年   1篇
  2000年   1篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1988年   2篇
排序方式: 共有63条查询结果,搜索用时 15 毫秒
11.
The production of Saccharomyces cerevisiae cells enriched with copper and the effects of adding copper ions to different media on yeast cell growth and ethanol production were studied. In the media Cu(2+) concentrations of up to 0.094 mM had no effect on alcoholic fermentation, whereas higher Cu(2+) concentrations markedly decreased yeast cell growth rate and ethanol production. Under static conditions, the maximum amounts of copper uptake (i.e., 1.16 mg/g, 1.2 mg/g and 0.81 mg/g dry matter yeast biomass for glucose, sucrose and molasses media, respectively) were obtained after 8 h of fermentation, whereas under dynamic conditions smaller amounts of copper uptake (i.e., 0.98 mg/g, 1.02 mg/g and 0.7 mg/g dry matter yeast biomass for glucose, sucrose and molasses media, respectively) were obtained after 6 h of fermentation.  相似文献   
12.
Durability of reinforced concrete is primarily influenced by the penetration of aggressive substances into concrete, which are degrading concrete and reinforcement. For structures in marine environment chlorides are the most critical environmental load, which are causing serious corrosion damages. Data collected during the survey of the Krk Bridge, a large reinforced concrete arch bridge structure located on the Adriatic coast, is used as documented reference in this research. The structure has been exposed to the marine environment for over 25 years. Based on collected materials data and the exposure conditions, the service life of this structure is estimated using three currently available prediction models, two deterministic models, the North American Life-365 model and the Croatian CHLODIF model, and the DuraCrete probabilistic method. All these models are based on the chloride diffusion process, but with different detailing of the model parameters. The conclusion is an evaluation of the service life predictive ability of each of these three service life models.  相似文献   
13.
Whole Atlantic mackerel (Scomber scombrus), sardine (Sardina pilchardus) and Mediterranean hake (Merluccius merluccius) from the Croatian Adriatic were stored at 22 °C and changes in histamine, putrescine, tyramine and cadaverine levels were monitored in relation to bacterial endotoxin. After 12 h, histamine levels in sardine were above the legal limit of 50 mg kg?1, set by the US Food and Drug Administration, and an increase in putrescine content preceded the increase in histamine. After 24 h, histamine contents in mackerel and sardine reached 1090 ± 101 and 577 ± 275 mg kg?1, respectively, which exceeded the toxic threshold of 500 mg kg?1. At the same time, the putrescine content was also high in both fish (353–420 mg kg?1). The time-course of endotoxin production was similar in all fish species stored at 22 °C. A high correlation was found between endotoxin and histamine, and between endotoxin and putrescine in mackerel and sardine. On the other hand, high endotoxin levels in hake, after 24 h, were associated with the low histamine and putrescine content (40–60 mg kg?1).  相似文献   
14.
The region of the investigated receptor is situated in the southern part of the Adriatic Sea in the Mediterranean. The measuring station is located on the seashore, which, being considered as a border area, is representative for the qualitative and quantitative estimation of the influence of marine and continental aerosols on the content of major ions in precipitation. In the sampling period, precipitation in the region of the investigated receptor was more abundant during the summer and autumn than during the winter and spring. The most frequent precipitation heights were up to 20 mm, while high precipitation came exclusively from the continental region. The results of the measurements of ions readily soluble in water were used for the differentiation of marine from continental contributions of primary and secondary aerosols to their content in the precipitation. Using PCA, it was shown that main contribution of Cl(-), Na(+) and Mg(2+) came from primary marine aerosols, while the contribution from continental sources was dominant for the content of SO(4)(2-), NO(3)(-), NH(4)(+) and Ca(2+) in the precipitation. The continental origin of Ca(2+) was from a primary source, while SO(4)(2-), NO(3)(-) and NH(4)(+) were representatives of secondary aerosols produced by reactions between acid oxides and alkaline species in the atmosphere, but SO(4)(2-) and NO(3)(-) also exist in the precipitation as free acids. The origin of the trace elements Cd, Cu, Pb and Zn in the precipitation came from anthropogenic emission sources. The results obtained in this work are based on experimental data from 609 samples collected during the period 1995-2000.  相似文献   
15.
Numerous viruses hijack cellular protein trafficking pathways to mediate cell entry or to rearrange membrane structures thereby promoting viral replication and antagonizing the immune response. Adaptor protein complexes (AP), which mediate protein sorting in endocytic and secretory transport pathways, are one of the conserved viral targets with many viruses possessing AP-interacting motifs. We present here different mechanisms of viral interference with AP complexes and the functional consequences that allow for efficient viral propagation and evasion of host immune defense. The ubiquity of this phenomenon is evidenced by the fact that there are representatives for AP interference in all major viral families, covered in this review. The best described examples are interactions of human immunodeficiency virus and human herpesviruses with AP complexes. Several other viruses, like Ebola, Nipah, and SARS-CoV-2, are pointed out as high priority disease-causative agents supporting the need for deeper understanding of virus-AP interplay which can be exploited in the design of novel antiviral therapies.  相似文献   
16.
Standard measurement devices do not normally provide detailed information about flows in porous media because either they are too intrusive (e.g., hot/film wire anemometers) or because the solid phase impedes their physical access to the flow as in the case of laser Doppler anemometers or particle image velocimetry (PIV). In this study, a Metflow ultrasonic velocity profiler (UVP) is used to measure instantaneous velocity fields within porous media composed of plastic balls packed in a cubic pattern. Simple considerations of the ultrasound beam properties and propagation, plus a comparison with measurements performed by a PIV system, demonstrate that UVP devices are suitable for such a purpose.  相似文献   
17.
The meaning of the term the intellectual island effect which was introduced byArunachalam et al. is broadened as to characterize the status of science on the periphery in general. A practical solution is proposed, based on bibliometric data of the research output and relying on two criteria: the extent of coverage by world significant secondary literature and the extent of scatter of that literature. Reliability of the publication data retrieved from the Citation Indexes is discussed; a measure is offered to assess the adequacy of the Citation Indexes as the data sources.Unquestionably, there has been no one like Einstein in physics in this century, but one has to reflect on how easily Einstein might have been lost, particularly if he had been born in a developing country.From C. M. KINNON, (Ed.)The Impact of Modern Scientific Ideas on Society Reidel/UNESCO, 1981, p. 29.  相似文献   
18.
The goal of this paper is to discuss the spatial averaging concept in environmental hydraulics and develop it further by considering transport equations for fluid momentum, passive substances, and suspended sediments. The averaging theorems, the double-averaged (in time and in space) fluid momentum equation, and advection-diffusion equations for a passive substance and suspended sediments are introduced and their limitations and applications for modeling rough-bed flows, experimental design, and data interpretation are discussed. The suggested equations differ from those considered in terrestrial canopy aerodynamics and porous media hydrodynamics by accounting for roughness mobility, change in roughness density in space and time, and particle settling effects for the case of suspended sediments. We show that the form of the double-averaged equations may depend on the type of decomposition of flow variables and that this difference may have important implications for modeling. We also show that the suggested methodology offers better definitions for hydraulic characteristics, variables, and parameters such as flow uniformity, flow two dimensionality, and bed shear stress.  相似文献   
19.
20.
Croatian traditional cheese, which ripens in a lamb skin sack, was studied to determine compositional, biochemical and sensory changes over 60 days of ripening. The ripening time had a significant effect on the chemical, biochemical and sensory parameters, particularly on the medium‐ and long‐chain free fatty acids (< 0.05) and total FFAs (< 0.001). At the end of ripening palmitic, oleic and stearic acids were the predominant FFAs. Cheese ripened for more than 45 days was less acceptable to consumers as a consequence of extensive proteolysis and lipolysis. Therefore, ripening for more than 45 days, which is commonly practised by cheesemakers, is not recommended.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号