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   182篇
  免费   7篇
  189篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   2篇
  2019年   4篇
  2018年   2篇
  2017年   8篇
  2016年   5篇
  2015年   5篇
  2014年   12篇
  2013年   16篇
  2012年   7篇
  2011年   5篇
  2010年   4篇
  2009年   7篇
  2008年   14篇
  2007年   10篇
  2006年   23篇
  2005年   7篇
  2004年   10篇
  2003年   7篇
  2002年   13篇
  2001年   10篇
  2000年   6篇
  1999年   4篇
  1997年   1篇
  1987年   2篇
  1985年   1篇
排序方式: 共有189条查询结果,搜索用时 15 毫秒
1.
The effect of ingestion of water containing 20% ethanol for 1-2 months on lipid peroxide levels of liver, plasma, and erythrocyte was investigated in rats. Our results show that elevated plasma lipid peroxide levels and erythrocyte susceptibility to lipid peroxidation may reflect stimulated lipid peroxidation in rat liver following chronic ethanol ingestion.  相似文献   
2.
3.
Melatonin has recently been suggested as an antioxidant that may protect neurons from oxidative stress. Acute ethanol administration produces both lipid peroxidation as an indicator of oxidative stress in the brain and impairs water-maze performance in spatial learning and memory tasks. The present study investigated the effect of melatonin against ethanol-induced oxidative stress and spatial memory impairment. The Morris water maze was used to evaluate the cognitive functions of rats. Thiobarbituric acid reactive substances (TBARS), which are the indicators of lipid peroxidation, and the activities of antioxidative enzymes (glutathione peroxidase and superoxide dismutase) were measured in the rat hippocampus and prefrontal cortex which form interconnected neural circuits for spatial memory. Acute administration of ethanol significantly increased TBARS levels in the hippocampus. Combined melatonin-ethanol treatment caused a significant increase in glutathione peroxidase activities and a significant decrease of TBARS in the rat hippocampus. In the prefrontal cortex, there was only a significant decrease of TBARS levels in the combined melatonin-ethanol receiving group as compared to the ethanol-treated group. Melatonin did not affect the impairment of spatial memory due to acute ethanol exposure, but melatonin alone had a positive effect on water maze performances. Our study demonstrated that melatonin decreased ethanol-induced lipid peroxidation and increased glutathione peroxidase activity in the rat hippocampus.  相似文献   
4.
Fetuin-A is synthesized in the liver and is secreted into the bloodstream. Clinical studies suggest involvement of fetuin-A in metabolic disorders such as visceral obesity, insulin resistance, diabetes, and fatty liver. Curcumin is extracted from the rhizome Curcuma longa and has been shown to possess potent antioxidant, anticarcinogenic, anti-inflammatory, and hypoglycemic properties. In this study, we investigated the effect of curcumin treatment on serum fetuin-A levels as well as hepatic lipids and prooxidant–antioxidant status in rats fed a high-fat diet (HFD). Male Sprague–Dawley rats were divided into six groups. Group 1 was fed control diet (10 % of total calories from fat). Groups 2 and 3 were given curcumin (100 and 400 mg/kg bw/day, respectively ) by gavage for 8 weeks and were fed control diet. Group 4 was fed with HFD (60 % of total calories from fat). Groups 5 and 6 received HFD together with the two doses of curcumin, respectively. Curcumin treatment appeared to be effective in reducing liver triglycerides and serum fetuin-A levels. These findings suggest that the reduction of fetuin-A may contribute to the beneficial effects of curcumin in the pathogenesis of obesity.  相似文献   
5.
Mara? powder is a kind of smokeless tobacco used in the south-eastern region of Turkey. The present study was carried out to assess possible DNA damage in exfoliated oral cells of Mara? powder users by analysing the frequencies of micronuclei (MN), which is a simple and reliable biomarker for genotoxic damage and to screen for the detection of site-specific differences in the frequencies of MN. The mean (±SD) MN frequency in the inner lip mucosa site was 1.27(±0.55) % for Mara? powder users and 0.88(±0.47) % for non-smoking control subjects (p < 0.05) and 0.82(±0.40) % for the buccal site of Mara? powder users (p < 0.01). There was no significant site-specific difference between the inner lip site and the buccal mucosa site 0.73(±0.43) % in the MN frequency of non-smoking control subjects (p > 0.05). There was no significant effect of daily consumption of Mara? powder, and duration of usage on MN frequencies. The present study suggests that the oral use of smokeless tobacco represents a genotoxic hazard and also that use of MN from a single site may be misleading as a marker of genotoxic exposure. Habitual use of Mara? powder should be taken into account and could be considered unsafe.  相似文献   
6.
Background aimsOne goal of periodontal therapy is to regenerate periodontal tissues. Stem cells, growth factors and scaffolds and biomaterials are vital for the restoration of the architecture and function of complex tissues. Adipose tissue-derived stem cells (ASCs) are an ideal population of stem cells for practical regenerative medicine. In addition, platelet-rich plasma (PRP) can be useful for its ability to stimulate tissue regeneration. PRP contains various growth factors and may be useful as a cell carrier in stem cell therapies. The purpose of this study was to determine whether a mixture of ASCs and PRP promoted periodontal tissue regeneration in a canine model.MethodsAutologous ASCs and PRP were implanted into areas with periodontal tissue defects. Periodontal tissue defects that received PRP alone or non-implantation were also examined. Histologic, immunohistologic and x-ray studies were performed 1 or 2 months after implantation. The amount of newly formed bone and the scale of newly formed cementum in the region of the periodontal tissue defect were analyzed on tissue sections.ResultsThe areas of newly formed bone and cementum were greater 2 months after implantation of ASCs and PRP than at 1 month after implantation, and the radiopacity in the region of the periodontal tissue defect increased markedly by 2 months after implantation. The ASCs and PRP group exhibited periodontal tissue with the correct architecture, including alveolar bone, cementum-like structures and periodontal ligament-like structures, by 2 months after implantation.ConclusionsThese findings suggest that a combination of autologous ASCs and PRP promotes periodontal tissue regeneration that develops the appropriate architecture for this complex tissue.  相似文献   
7.
Turbot, Scophthalmus maximus, is a commercially important demersal flatfish species distributed throughout the Black Sea. Several studies performed locally with a limited number of specimens using both mitochondrial DNA (mtDNA) and microsatellite markers evidenced notable genetic variation among populations. However, comprehensive population genetic studies are required to help management of the species in the Black Sea. In the present study eight microsatellite loci were used to resolve the population structure of 414 turbot samples collected from 12 sites across the Black Sea. Moreover, two mtDNA genes, COI and Cyt-b, were used for taxonomic identification. Microsatellite markers of Smax-04 and B12-I GT14 were excluded from analysis due to scoring issues. Data analysis was performed with the remaining six loci. Loci were highly polymorphic (average of 17.8 alleles per locus), indicating high genetic variability. Locus 3/20CA17, with high null allele frequency (>30%), significantly deviated from HW equilibrium. Pairwise comparison of the FST index showed significant differences between most of the surveyed sampling sites (P < 0.01). Cluster analysis evidenced the presence of three genetic groups among sampling sites. Significant genetic differentiation between Northern (Sea of Azov and Crimea) and Southern (Turkish Black Sea Coast) Black Sea sampling sites were detected. The Mantel test supported an isolation by distance model of population structure. These findings are vital for long-term sustainable management of the species and development of conservation programs. Moreover, generated mtDNA sequences would be useful for the establishment of a database for S. maximus.  相似文献   
8.
Computational enzyme design is an emerging field that has yielded promising success stories, but where numerous challenges remain. Accurate methods to rapidly evaluate possible enzyme design variants could provide significant value when combined with experimental efforts by reducing the number of variants needed to be synthesized and speeding the time to reach the desired endpoint of the design. To that end, extending our computational methods to model the fundamental physical–chemical principles that regulate activity in a protocol that is automated and accessible to a broad population of enzyme design researchers is essential. Here, we apply a physics‐based implicit solvent MM‐GBSA scoring approach to enzyme design and benchmark the computational predictions against experimentally determined activities. Specifically, we evaluate the ability of MM‐GBSA to predict changes in affinity for a steroid binder protein, catalytic turnover for a Kemp eliminase, and catalytic activity for α‐Gliadin peptidase variants. Using the enzyme design framework developed here, we accurately rank the most experimentally active enzyme variants, suggesting that this approach could provide enrichment of active variants in real‐world enzyme design applications. Proteins 2014; 82:3397–3409. © 2014 Wiley Periodicals, Inc.  相似文献   
9.
The antibacterial activity and chemical composition of the essential oils (EOs) isolated from Origanum bilgeri P.H.Davis by two different extraction methods, i.e., hydrodistillation (HD) and solvent-free microwave extraction (SFME), were examined. This endemic Origanum species had shown very good antibacterial activity. The composition of the O. bilgeri EOs obtained by SFME and HD was investigated by GC/MS analysis. The main components of the oils obtained by both methods were carvacrol (90.20-84.30%), p-cymene (3.40-5.85%), γ-terpinene (0.47-1.20%), and thymol (0.69-1.08%). The EO isolation by SFME offered many important advantages, including a higher extraction yield, a shorter extraction time, and a higher content of the active component carvacrol. The carvacrol-rich oils obtained by both HD and SFME showed a good antibacterial activity. The largest inhibition zones were observed for the O. bilgeri EO obtained by SFME. Our study suggests that O. bilgeri EO has the potential to be used as preventative against bacterial contamination in many foods, instead of the common synthetic antimicrobial products.  相似文献   
10.
Fatty acid binding proteins (FABPs) are cytosolic fatty acid chaperones whose biological role and mechanisms of action are not well understood. Here, we developed mice with targeted mutations in two related adipocyte FABPs, aP2 and mal1, to resolve their role in systemic lipid, glucose, and energy metabolism. Mice lacking aP2 and mal1 exhibited a striking phenotype with strong protection from diet-induced obesity, insulin resistance, type 2 diabetes, and fatty liver disease. These mice have altered cellular and systemic lipid transport and composition, leading to enhanced insulin receptor signaling, enhanced muscle AMP-activated kinase (AMP-K) activity, and dramatically reduced liver stearoyl-CoA desaturase-1 (SCD-1) activity underlying their phenotype. Taken together with the previously reported strong protection against atherosclerosis, these results demonstrate that adipocyte/macrophage FABPs have a robust impact on multiple components of metabolic syndrome, integrating metabolic and inflammatory responses in mice and constituting a powerful target for the treatment of these diseases.  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