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   36篇
  免费   1篇
  国内免费   1篇
电工技术   1篇
化学工业   11篇
机械仪表   2篇
建筑科学   5篇
轻工业   9篇
石油天然气   1篇
无线电   1篇
一般工业技术   1篇
冶金工业   4篇
自动化技术   3篇
  2023年   1篇
  2022年   6篇
  2021年   3篇
  2019年   4篇
  2016年   2篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2012年   1篇
  2011年   2篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2006年   4篇
  2005年   1篇
  2004年   2篇
  2003年   3篇
  2001年   1篇
  1996年   1篇
排序方式: 共有38条查询结果,搜索用时 31 毫秒
11.
This longitudinal study investigated whether smoking bans influence passive smoking at work and/or at home in the same subjects. Passive smoking at work and/or at home was investigated in random population samples (European Community Respiratory Health Survey) in 1990‐1995, with follow‐up interviews in 1998‐2003 and 2010‐2014. National smoking bans were classified as partial (restricted to public workplaces) or global (extended to private workplaces). Multivariable analysis was accomplished by three‐level logistic regression models, where level‐1, level‐2, and level‐3 units were, respectively, questionnaire responses, subjects, and centers. Passive smoking at work was reported by 31.9% in 1990‐1995, 17.5% in 1998‐2003, and 2.5% in 2010‐2014. Concurrently, passive smoking at home decreased from 28.9% to 18.2% and 8.8%. When controlling for sex, age, education, smoking status, and ECHRS wave, the odds of passive smoking at work was markedly reduced after global smoking bans (OR = 0.45, 95% CI 0.25‐0.81), particularly among non‐smokers, while the protective effect of global smoking bans on passive smoking at home was only detected in non‐smokers. Smoking bans both in public and private workplaces were effective in reducing passive smoking at work in Europe. However, given the inefficacy of smoking bans in current smokers’ dwellings, better strategies are needed to avoid smoking indoors.  相似文献   
12.
Arabinoxylans and in particular arabinoxylan oligosaccharides (AXOS) from wheat are recognised for their prebiotic potential. A high-yield, non-chemical production of AXOS is therefore of interest when producing functional foods. This study investigated the enzymatic production of AXOS from wheat bran with the aim of establishing the main fraction contributing to production of AXOS. Fractions of wheat bran, outer pericarp and aleurone with two different purities were treated with the cell wall-degrading enzymes: xylanase, cellulase and β-glucanase. The yield of solubilised arabinoxylans upon treatment was greatest in the most pure aleurone fraction (164 g kg−1) and lowest in the outer pericarp fraction (15 g kg−1). The yield was mainly recovered as AXOS rather than soluble arabinoxylans and was negatively related to the arabinose/xylose ratio found in the raw material. In conclusion, wheat aleurone cell walls are the main contributor to the production of AXOS from wheat bran and this seems to depend on the A/X ratio of the raw material.  相似文献   
13.
14.
Thanks to clinically newly introduced inhibitors of the mesenchymal–epithelial transition (MET) receptor tyrosine-kinase, MET-gene copy number gain/amplification (MET-GCNG/GA) and increased expression of the MET protein are considered very promising therapeutic targets in lung cancer and other malignancies. However, to which extent these MET alterations occur in malignant mesothelioma (MM) remains unclear. Thus, we investigated by well-established immunohistochemistry and fluorescence in situ hybridization methods, the frequency of these alterations in specimens from 155 consecutive MMs of different subtypes obtained from pleural or peritoneal biopsies and pleurectomies. Thirty-three benign reactive mesothelial proliferations (RMPs) were used as controls. MET-protein upregulation was observed in 35% of all MM-cases, though restricted to predominantly epithelioid MMs. We detected low-/intermediate-level MET-GCNG/GA in 22.2% of MET-overexpressing MMs (7.8% of whole MM-cohort) and no MET-GCNG/GA in the other 77.8%, suggesting other upregulating mechanisms. In contrast, 100% of RMPs exhibited no MET-upregulation or MET-GCNG/-GA. Neither MET exon 14 skipping mutations nor MET-fusions were detected as mechanisms of MET overexpression in MM using RNA next-generation sequencing. Finally, in two cohorts of 30 MM patients with or without MET overexpression (MET-positive/-negative) that were matched for several variables and received the same standard chemotherapy, the MET-positive cases showed a significantly lower response rate, but no significant difference in progression-free or overall survival. Our results imply that MET overexpression occurs in a substantial fraction of predominantly epithelioid MMs, but correlates poorly with MET-amplification status, and may impact the likelihood of response to mesothelioma standard chemotherapy. The predictive significance of MET-IHC and -FISH for possible MET-targeted therapy of MM remains to be elucidated.  相似文献   
15.
This study investigated changes in student motivation to participate in physical education and some determinants of these changes over a period of 3 years. Measures were taken twice a year, from age 13 until age 15, from a sample of Greek junior high school students. Multilevel modeling analyses showed significant decreases in task-involving teacher climate, relatedness, identified regulation, and intrinsic motivation. In contrast, there were significant increases in ego-involving climate and amotivation. For some of these variables, the observed linear decreases or increases were somewhat reversed by the beginning of the last year of junior high school. No significant changes were observed in competence need satisfaction and in extrinsic and introjected regulations. The authors found substantial between-student variability in the intercepts and growth trajectories of most variables, and therefore they tested a number of theoretical and demographic predictors to partly account for such variations. The results indicate that increases in maladaptive motivation in physical education over time are not uniform across all students and may be partly tackled by facilitating competence need satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
16.
The role of emotions in housing markets has come under scrutiny in the housing market bubble and subsequent dramatic decline from which markets are still recovering. Thus, the performativity of housing markets has become an object for sociological analysis. Using qualitative interview data from 11 Danish first-time home-buying families, this article investigates the relations between emotions and economic behaviour in a market that has become unpredictable because of volatile price developments since the early 2000s. Identifying the relationship between economic behaviour, emotions and the materialities of homes, the article finds that home-buying is intermeshed with emotional attempts at creating or stabilizing the family as a unit. Homeownership therefore is an emotional investment through financial and material means in the future of the family, and the article therefore argues that markets are saturated with love, desire, fear, anxiety and hope.  相似文献   
17.
The phase formation, heat of hydration and dilatation in a blended cement consisting of 50 wt.% calcium aluminate cement, 25 wt.% Portland cement and 25 wt.% calcium sulfate were studied (w/c=1). The calcium sulfate was β-hemihydrate, anhydrite and mixes of the two. Kinetic expressions describing the ettringite formation in the pastes with the pure calcium sulfates were found. Hydration reactions were suggested and the phase development was compared to the hydration heat by mass and heat balances. When the calcium sulfate was 75 and 50 wt.% β-hemihydrate, the systems behaved as a linear combination of the 100 and 0 wt.% blends. At 25 wt.%, the hydration kinetics differed from the other blends. With only β-hemihydrate, the last 50% of ettringite formation was accompanied by expansion, mainly caused by interaction of crystals growing radially on cement grains. In the paste with only anhydrite, ettringite crystals grew in solution and produced no expansion.  相似文献   
18.
Automated Guided Vehicles (AGVs) are among various advanced material handling techniques that are finding increasing applications today. They can be interfaced to various other production and storage equipment and controlled through an intelligent computer control system. Both the scheduling of operations on machine centers as well as the scheduling of AGVs are essential factors contributing to the efficiency of the overall flexible manufacturing system (FMS). An increase in the performance of the FMS under consideration would be expected as a result of making the scheduling of AGVs an integral part of the overall scheduling activity. In this paper, simultaneous scheduling of parts and AGVs is done for a particular type of FMS environment by using a non-traditional optimization technique called the adaptive genetic algorithm (AGA). The problem considered here is a large variety problem (16 machines and 43 parts) and combined objective function (minimizing penalty cost and minimizing machine idle time). If the parts and AGVs are properly scheduled, then the idle time of the machining center can be minimized; as such, their utilization can be maximized. Minimizing the penalty cost for not meeting the delivery date is also considered in this work. Two contradictory objectives are to be achieved simultaneously by scheduling parts and AGVs using the adaptive genetic algorithm. The results are compared to those obtained by conventional genetic algorithm.  相似文献   
19.
Characterisation of the microbiota of Atlantic mackerel (Scomber scombrus)   总被引:1,自引:0,他引:1  
In this study the microbiota of Atlantic mackerel (Scomber scombrus) collected by a commercial purse seiner was examined. Fish were collected directly from the purse seine and from the Refrigerated Sea Water (RSW) transport tank after loading. The culturable microbiota and Specific Spoilage Bacteria (SSB) were quantified on Iron Agar Lyngby (IAL) and identified using commercially available Biochemical API® kits on pure cultured isolates. These kits showed to be sub-optimal in characterising the isolates, since only half of the strains were identified. The same isolates were also identified by a nucleic acid based PCR-DGGE approach, and only half of the sequences gave the same results as the API®. Characterisation by PCR-DGGE was also performed on bacterial DNA from IAL plates (bulk cell samples) and on samples where the bacterial DNA was extracted directly from fish material without any cultivation (direct DNA samples). The microbiota of Atlantic mackerel was dominated by members of the Gram-negative genera as Psychrobacter sp., Proteus sp., Photobacterium sp., Vibrio sp., Shewanella sp., Synechococcus sp., Oceanisphaerae sp., Bizonia sp., Pseudoalteromonas sp., and members of Flavobacteriaceae. Gram-positive bacteria in the genera Vagococcus sp., Bacillus sp., Mycobacterium sp., Staphylococcus sp., Mycoplasma sp. and Clostridia sp. were also found. Examination by PCR-DGGE and sequencing of the bulk cell pellet after cultivation on IAL, gave a higher number of taxa as compared to extraction and examination of bacterial DNA from fish materials without prior cultivation. This shows the benefit of combining both culture dependent and culture independent methods, when studying the microbiota of marine fish. Several Vibrio spp. were found only in gut samples collected from the purse seine, but in all samples including the skin and the gills collected from the RSW tank, indicating microbial contamination by faecal bacteria from the fish under these transport conditions.  相似文献   
20.
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