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   149篇
  免费   10篇
  159篇
  2023年   2篇
  2022年   1篇
  2021年   11篇
  2020年   10篇
  2019年   6篇
  2018年   7篇
  2017年   10篇
  2016年   9篇
  2015年   8篇
  2014年   13篇
  2013年   8篇
  2012年   14篇
  2011年   8篇
  2010年   8篇
  2009年   6篇
  2008年   7篇
  2007年   5篇
  2006年   3篇
  2004年   4篇
  2003年   4篇
  2002年   5篇
  2001年   2篇
  2000年   1篇
  1998年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1987年   1篇
  1982年   1篇
  1977年   1篇
排序方式: 共有159条查询结果,搜索用时 0 毫秒
91.
Published data supports the neuroprotective effects of several phenolic-containing natural products, including certain fruit, berries, spices, nuts, green tea, and olive oil. However, limited data are available for phenolic-containing plant-derived natural sweeteners including maple syrup. Herein, we investigated the neuroprotective effects of a chemically standardized phenolic-enriched maple syrup extract (MSX) using a combination of biophysical, in vitro, and in vivo studies. Based on biophysical data (Thioflavin T assay, transmission electron microscopy, circular dichroism, dynamic light scattering, and zeta potential), MSX reduced amyloid β1?42 peptide (Aβ1?42) fibrillation in a concentration-dependent manner (50–500 μg/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5?% at 500 μg/mL vs. 77.3?% at 50 μg/mL, respectively). MSX (100 μg/mL) decreased H2O2-induced oxidative stress (16.1?% decrease in ROS levels compared to control), and down-regulated the production of lipopolysaccharide (LPS)-stimulated inflammatory markers (22.1, 19.9, 74.8, and 87.6?% decrease in NOS, IL-6, PGE2, and TNFα levels, respectively, compared to control) in murine BV-2 microglial cells. Moreover, in a non-contact co-culture cell model, differentiated human SH-SY5Y neuronal cells were exposed to conditioned media from BV-2 cells treated with MSX (100 μg/mL) and LPS or LPS alone. MSX-BV-2 media increased SH-SY5Y cell viability by 13.8?% compared to media collected from LPS-BV-2 treated cells. Also, MSX (10 μg/mL) showed protective effects against Aβ1?42 induced neurotoxicity and paralysis in Caenorhabditis elegans in vivo. These data support the potential neuroprotective effects of MSX warranting further studies on this natural product.  相似文献   
92.
93.
Physiology and Molecular Biology of Plants - Fungicides are widely used for controlling fungi in crop plants. However, their roles in conferring abiotic stress tolerance are still elusive. In this...  相似文献   
94.
Nitric oxide (NO) is dynamic molecule implicated in diverse biological functions demonstrating its protective effect against damages provoked by abiotic stresses. The present study investigated that exogenous NO pretreatment (500?µM sodium nitroprusside, 24?h) prevented the adverse effect of drought stress [induced by 10% and 20% polyethylene glycol (PEG), 48?h] on rapeseed seedlings. Drought stress resulted in reduced relative water content with increased proline (Pro) level. Drought stress insisted high H2O2 generation and consequently increased membrane lipid peroxidation which are clear indications of oxidative damage. Drought stress disrupted the glyoxalase system too. Exogenous NO successfully alleviated oxidative damage effects on rapeseed seedlings through improving the levels of nonenzymatic antioxidant pool and upregulating antioxidant enzymes’ activities. Improvement of glyoxalase system (glyoxalase I and glyoxalase II activities) by exogenous NO was significant to improve plants’ tolerance. Nonetheless, regulation of Pro level and improvement of plant–water status were vital to confer drought stress tolerance.  相似文献   
95.
Abiotic stress is one of the main threats affecting crop growth and production. An understanding of the molecular mechanisms that underpin plant responses against environmental insults will be crucial to help guide the rational design of crop plants to counter these challenges. A key feature during abiotic stress is the production of nitric oxide (NO), an important concentration dependent, redox‐related signalling molecule. NO can directly or indirectly interact with a wide range of targets leading to the modulation of protein function and the reprogramming of gene expression. The transfer of NO bioactivity can occur through a variety of potential mechanisms but chief among these is S‐nitrosylation, a prototypic, redox‐based, post‐translational modification. However, little is known about this pivotal molecular amendment in the regulation of abiotic stress signalling. Here, we describe the emerging knowledge concerning the function of NO and S‐nitrosylation during plant responses to abiotic stress.  相似文献   
96.
Pathogenic bacteria interacting with eukaryotic host express adhesins on their surface. These adhesins aid in bacterial attachment to the host cell receptors during colonization. A few adhesins such as Heparin binding hemagglutinin adhesin (HBHA), Apa, Malate Synthase of M. tuberculosis have been identified using specific experimental interaction models based on the biological knowledge of the pathogen. In the present work, we carried out computational screening for adhesins of M. tuberculosis. We used an integrated computational approach using SPAAN for predicting adhesins, PSORTb, SubLoc and LocTree for extracellular localization, and BLAST for verifying non-similarity to human proteins. These steps are among the first of reverse vaccinology. Multiple claims and attacks from different algorithms were processed through argumentative approach. Additional filtration criteria included selection for proteins with low molecular weights and absence of literature reports. We examined binding potential of the selected proteins using an image based ELISA. The protein Rv2599 (membrane protein) binds to human fibronectin, laminin and collagen. Rv3717 (N-acetylmuramoyl-L-alanine amidase) and Rv0309 (L,D-transpeptidase) bind to fibronectin and laminin. We report Rv2599 (membrane protein), Rv0309 and Rv3717 as novel adhesins of M. tuberculosis H37Rv. Our results expand the number of known adhesins of M. tuberculosis and suggest their regulated expression in different stages.  相似文献   
97.
98.
The reversed-phase (RP) preparative HPLC analyses of the MeOH extract of the aerial parts of Artemisia armeniaca yielded four prenylated coumarins, 7-hydroxy-8-(4-hydroxy-3-methylbutoxy)coumarin (named armenin), 8-hydroxy-7-(4-hydroxy-3-methylbutoxy)coumarin (named isoarmenin), lacarol, and deoxylacarol, together with five other compounds, including three flavonoid glycosides, quercetin 3-O-β-D-glucopyranoside, rutin, and kaempferol 3-O-β-D-glucopyranoside, and chlorogenic acid, and tryptophan. (10E,12Z)-9-Hydroxyoctadeca-10,12-dienoic acid (β-dimorphecolic acid) was isolated from the CH(2)Cl(2) extract. Armenin and isoarmenin were new coumarins. Structures of all compounds were determined by spectroscopic means, including UV, MS, 1D- and 2D-NMR. The in vitro free-radical-scavenging property of the extracts and isolated compounds was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay.  相似文献   
99.
100.

Background

Perinatal common mental disorders (PCMDs) are a major cause of disability among women and disproportionately affect lower income countries. Interventions to address PCMDs are urgently needed in these settings, and group-based and peer-led approaches are potential strategies to increase access to mental health interventions. Participatory women’s health groups led by local women previously reduced postpartum psychological distress in eastern India. We assessed the effect of a similar intervention on postpartum psychological distress in rural Bangladesh.

Method

We conducted a secondary analysis of data from a cluster-randomised controlled trial with 18 clusters and an estimated population of 532,996. Nine clusters received an intervention comprising monthly meetings during which women’s groups worked through a participatory learning and action cycle to develop strategies for improving women’s and children’s health. There was one group for every 309 individuals in the population, 810 groups in total. Mothers in nine control clusters had access to usual perinatal care. Postpartum psychological distress was measured with the 20-item Self Reporting Questionnaire (SRQ-20) between six and 52 weeks after delivery, during the months of January to April, in 2010 and 2011.

Results

We analysed outcomes for 6275 mothers. Although the cluster mean SRQ-20 score was lower in the intervention arm (mean 5.2, standard deviation 1.8) compared to control (5.3, 1.2), the difference was not significant (β 1.44, 95% CI 0.28, 3.08).

Conclusions

Despite promising results in India, participatory women’s groups focused on women’s and children’s health had no significant effect on postpartum psychological distress in rural Bangladesh.  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