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   77篇
  免费   4篇
化学工业   15篇
机械仪表   1篇
建筑科学   4篇
能源动力   1篇
轻工业   6篇
石油天然气   1篇
一般工业技术   10篇
冶金工业   18篇
自动化技术   25篇
  2019年   3篇
  2017年   2篇
  2016年   3篇
  2014年   2篇
  2012年   3篇
  2011年   8篇
  2010年   3篇
  2009年   3篇
  2008年   5篇
  2007年   3篇
  2006年   2篇
  2005年   1篇
  2004年   3篇
  2003年   4篇
  2002年   4篇
  2001年   1篇
  2000年   3篇
  1999年   4篇
  1998年   5篇
  1997年   5篇
  1996年   6篇
  1995年   2篇
  1993年   1篇
  1990年   1篇
  1986年   1篇
  1985年   2篇
  1981年   1篇
排序方式: 共有81条查询结果,搜索用时 31 毫秒
51.
As tools for mechanistic studies on lipid metabolism, with the long-term goal of developing a drug for the treatment of lipid disorders, thia FA with the sulfur atom inserted at positions 3–9 from the carboxyl group were fed to male Wistar rats for 1 wk to determine their impact on key parameters in lipid metabolism and hepatic levels of thia FA metabolites. Thia FA with the sulfur atom in even positions decreased hepatic and cardiac mitochondrial β-oxidation and profoundly increased hepatic and cardiac TAG levels. The plasma TAG level was unchanged and the hepatic acyl-CoA oxidase activity increased. In contrast, thia FA with the sulfur atom in odd positions, especially 3-thia FA, tended to increase hepatic and cardiac FA oxidation and acyl-CoA oxidase and carnitine palmitoyltransferase-II activities, and decreased the plasma TAG levels. The effects seem to be related to differences in the catabolic rate of the thia FA. Differences between the two groups of acids were also observed with respect to the regulation of genes involved in FA transport and catabolism. Feeding experiments with 3- and 4-thia FA in combination indicated that the 4-thia FA partly attenuated the effects of the 3-thia FA on mitochondrial FA oxidation and the hepatic TAG level. In summary, the position of the sulfur atom in the alkyl chain, especially whether it is placed in the even or odd position, is crucial for the biological effect of the thia FA. The first and second authors contributed equally to the work.  相似文献   
52.
53.
This study examined perceptions of training, supervision, consultation, services provided, and role satisfaction among program personnel (N = 93) providing assistance to children, adults, and families affected by Hurricanes Katrina and Rita through the Louisiana Spirit Specialized Crisis Counseling Services (SCCS) Program. Findings indicated that there was uniform high satisfaction with the training, supervision, and consultation, which included the skills-based intervention, Skills for Psychological Recovery, provided by the SCCS Practice Directorate that included staff from Louisiana State University Health Sciences Center, the National Child Traumatic Stress Network, and the National Center for PTSD. Counselors also made high ratings of their perceptions of the helpfulness of services to survivors and overall satisfaction with their work. The vast majority of counselors, who had themselves been seriously affected by the hurricanes, indicated that their own hurricane-related experiences and losses were extremely helpful to them in relating to survivors and providing services. Fully 90% indicated that they had significantly benefited professionally from their work and would be interested in providing SCCS services in the event of another disaster. Provider perceptions of personal strengths derived from the hurricanes were associated with high levels of SCCS program satisfaction and conversely, difficulties providing SCCS services were associated with lower levels of program satisfaction. Multiple regression analyses indicated that provider's perceived negative impact of the hurricane on survivors predicted increased perceived helpfulness of SCCS provider trainings and services to survivors. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
54.
The plasticity of masticatory muscles was studied by comparing rats that were wearing a protrusive appliance and were kept on a liquid diet with two control groups: (1) pair-fed rats and (2) rats that had free access to ordinary pelleted food. The animals were 45 days old at the beginning of the experiment and were studied for a period of 20 days. Three jaw muscles with different functions were examined: masseter, temporalis, and digastric. Muscle fiber composition was determined (1) by fiber counting after staining with four monoclonal antibodies, which were able to recognize the four major myosin heavy chain (MHC) isoforms and therefore four fiber types (I, IIA, IIX, IIB) and (2) by electrophoresis on 6% polyacrylamide gels. The comparison between free-diet rats and pair-fed rats showed that the change from a hard pelleted diet to a liquid diet caused a shift in fiber type and MHC distribution, characterized by an increase of IIB MHC in temporalis and digastric muscles but not in the masseter muscle. The comparison between pair-fed rats and rats wearing appliances showed on the contrary a decrease in IIB MHC and an increase in IIA and IIX MHC. The results support the conclusions that (1) rat jaw muscles can quickly adapt to functional demand changing their fiber type composition, (2) the changes appear restricted inside the fast fiber population, and (3) fiber-type changes caused by dietary variation are not less than those caused by orthodontic intervention and must be taken into account to assess the effect of the appliance correctly.  相似文献   
55.
We propose a new criterion to characterize hierarchical two-dimensional vortex regions induced by swirling motion. Central to the definition are closed loops that intersect the flow field at a constant angle. The union of loops belonging to the same area of swirling motion defines a vortex region. These regions are disjunct but may be nested, thus introducing a spatial hierarchy of vortex regions. We present a parameter free algorithm for the identification of these regions. Since they are not restricted to star- or convex-shaped geometries, we are able to identify also intricate regions, e.g., of elongated vortices. Computing an integrated value for each loop and mapping these values to a vortex region, introduces new ways for visualizing or filtering the vortex regions. Exemplary, an application based on the Rankine vortex model is presented. We apply our method to several CFD datasets and compare our results to existing approaches.  相似文献   
56.
Genetic and personality trait moderators of tobacco abstinence–symptom trajectories were assessed in a highly controlled study. Based on evidence suggesting their importance in stress reactivity and smoking, moderators studied were serotonin transporter gene (5-HTTLPR) and dopamine D2 receptor gene (DRD2) polymorphisms and personality traits related to negative affect (NA). Smokers were randomly assigned to quit smoking with nicotine or placebo patches. Financial incentives resulted in 80% verified abstinence across the 44-day study. Individuals with 1 or 2 short alleles of 5-HTTLPR (S carriers) experienced larger increases in NA symptoms than did those without a short allele. Nicotine replacement therapy (NRT) alleviated anxiety only in S carriers. NRT reduced NA to a greater extent in DRD2 A1 carriers than in A2A2 individuals during the 1st 2 weeks of treatment (when on the 21-mg patch); however, A1 carriers experienced a renewal of NA symptoms when switched to the 7-mg patch and when off the patch, while A2A2 individuals continued to benefit from NRT. The results suggest that the effects of genotype and treatment may vary across different durations of abstinence, treatment doses, and genotypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
57.
alpha-Mannosidosis is an autosomal recessive disorder caused by deficiency of lysosomal alpha-mannosidase (LAMAN). The resulting intracellular accumulation of mannose-containing oligosaccharides leads to mental retardation, hearing impairment, skeletal changes, and immunodeficiency. Recently, we reported the first alpha-mannosidosis-causing mutation affecting two Palestinian siblings. In the present study 21 novel mutations and four polymorphic amino acid positions were identified by the screening of 43 patients, from 39 families, mainly of European origin. Disease-causing mutations were identified in 72% of the alleles and included eight splicing, six missense, and three nonsense mutations, as well as two small insertions and two small deletions. In addition, Southern blot analysis indicated rearrangements in some alleles. Most mutations were private or occurred in two or three families, except for a missense mutation resulting in an R750W substitution. This mutation was found in 13 patients, from different European countries, and accounted for 21% of the disease alleles. Although there were clinical variations among the patients, no significant LAMAN activity could be detected in any of the fibroblast cultures. In addition, no correlation between the types of mutations and the clinical manifestations was evident.  相似文献   
58.
Exposure of the deck crew to volatile hydrocarbon compounds and polycyclic aromatic hydrocarbon PAH compounds was observed and monitored on two Norwegian product tankers. The tankers were loading their cargo with the hatches open during the monitoring period. One of the tankers loaded gas oil. This type of cargo is not volatile, and very low concentrations of the monitored chemical PAH compounds were found on this tanker. The second tanker loaded gasoline. On this tanker high concentrations of hydrocarbon compounds were found; benzene was as high as 55 ppm, toluene was as high as 34 ppm, hydrocarbon compounds in the C5-C7 range were as high as 570 ppm, n-hexane was as high as 25 ppm. The levels of PAH-compounds were low. None of the seamen working on the deck did use respiratory protective equipment during the work. The exposure of the deck crew to volatile hydrocarbon compounds ought to be reduced on product tankers. Better routines concerning the use of respiratory protective equipment is an immediate action which ought to take place. Loading volatile cargo like gasoline with the hatches open should be avoided.  相似文献   
59.
The administration of tetradecylthioacetic acid (TTA), a hypolipidemic and anti-inflammatory modified bioactive fatty acid, has in several experiments based on high fat diets been shown to improve lipid transport and utilization. It was suggested that increased mitochondrial and peroxisomal fatty acid oxidation in the liver of Wistar rats results in reduced plasma triacylglycerol (TAG) levels. Here we assessed the potential of TTA to prevent tumor necrosis factor (TNF) α-induced lipid modifications in human TNFα (hTNFα) transgenic mice. These mice are characterized by reduced β-oxidation and changed fatty acid composition in the liver. The effect of dietary treatment with TTA on persistent, low-grade hTNFα overexpression in mice showed a beneficial effect through decreasing TAG plasma concentrations and positively affecting saturated and monounsaturated fatty acid proportions in the liver, leading to an increased anti-inflammatory fatty acid index in this group. We also observed an increase of mitochondrial β-oxidation in the livers of TTA treated mice. Concomitantly, there were enhanced plasma levels of carnitine, acetyl carnitine, propionyl carnitine, and octanoyl carnitine, no changed levels in trimethyllysine and palmitoyl carnitine, and a decreased level of the precursor for carnitine, called γ-butyrobetaine. Nevertheless, TTA administration led to increased hepatic TAG levels that warrant further investigations to ascertain that TTA may be a promising candidate for use in the amelioration of inflammatory disorders characterized by changed lipid metabolism due to raised TNFα levels.  相似文献   
60.
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