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   122篇
  免费   2篇
  国内免费   7篇
  2021年   6篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   2篇
  2016年   2篇
  2015年   2篇
  2014年   11篇
  2013年   12篇
  2012年   5篇
  2011年   5篇
  2010年   8篇
  2009年   4篇
  2008年   14篇
  2007年   12篇
  2006年   4篇
  2005年   3篇
  2004年   5篇
  2003年   13篇
  2002年   2篇
  2001年   2篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1987年   1篇
  1984年   2篇
  1980年   1篇
排序方式: 共有131条查询结果,搜索用时 17 毫秒
21.
Four anthocyanins, cyanidin 3-O-(2″-(5?-(E-p-coumaroyl)-β-apiofuranosyl)-β-xylopyranoside)-5-O-β-glucopyranoside, cyanidin 3-O-(2″-(5?-(E-p-coumaroyl)-β-apiofuranosyl)-β-xylopyranoside), cyanidin 3-O-(2″-(5?-(E-caffeoyl)-β-apiofuranosyl)-β-xylopyranoside) and cyanidin 3-O-(2″-(5?-(E-feroyl)-β-apiofuranosyl)-β-xylopyranoside) were isolated from leaves of African milk bush, (Synadeniumgrantii Hook, Euphorbiaceae) together with the known cyanidin 3-O-β-xylopyranoside-5-O-β-glucopyranoside and cyanidin 3-O-β-xyloside. The four former pigments are the first reported anthocyanins containing the monosaccharide apiose, and the three 5?-cinnamoyl derivative-2″-(β-apiosyl)-β-xyloside subunits have previously not been reported for any compound.  相似文献   
22.
Red cabbage is a source of health beneficial substances with antioxidant and antigenotoxic properties. HPLC analysis specifying the content of the investigated extract indicated that mainly anthocyanins (ATH) were responsible for its abilities. Cytological research was conducted with two experimental models: plant tissues—meristematic cells of Vicia faba, and animal tissue elements—human lymphocytes. Positive influence of ATH extract on mitotic activity of Vicia cells exposed to Cu2+ stress, and inhibitory effect of ATH on cytotoxic actions of Cu2+ on lymphocytes were demonstrated. In all experimental series with ATH application in combinations with Cu2+, mitotic index (MI) were higher than those obtained for only Cu2+ stressed tissues. Preincubation in ATH before Cu2+ stress had the best effect. Similarly, after ATH applications in all tested series decrease in frequency of micronuclei (MN) appearance was noticed in comparison with only Cu2+ stressed material. In the case of Vicia cells ATH acted effectively even applied after Cu2+ stress. It suggests that this ATH mixture not only prevents and limits but also heals the cytological injury caused by Cu2+ stress.  相似文献   
23.
The study was carried out to determine the responses of two parsley (Petroselinum crispum L.) hybrids; plain and curly- leafed to water stress. Besides the control, three irrigation treatments (10, 30 and 50 % of control water amount) were applied. Plant yield (leaf area, stem length and diameter, number of leaves) and quality (fresh and dry weights and concentrations of chlorophyll, carotenes, anthocyanins and vitamin C) were measured. The responses of plant yield and quality varied according to the hybrid and water treatment. The high quality was observed in curly- leafed parsley if compared to plain- leafed parsley, which had higher yield (stem length and diameter, leaf area). Moreover, water stress improved quality but decreased yield parameters in both hybrids.  相似文献   
24.
The genus Cornus is well known for its medicinal properties. Bioassay-guided isolation and characterization of C. kousa fruits afforded kaempferol 3-O-rhamnoside (1), myricetin 3-O-rhamnoside (2), kaempferol 3-O-glucoside (3), cornin (4) and stenophyllin (5) in addition to ursolic acid and beta-sitosterol. These compounds are isolated for the first time from C. kousa. Compounds 1-5 inhibited Fe(2+) catalyzed lipid peroxidation by 63%, 57%, 61%, 53%, and 51%, at 23, 22, 23, 129, and 108 microM, respectively. Similarly, they inhibited COX-1 and -2 enzymes activities by 24% and 47%, 40% and 37%, 20% and 37%, 52% and 63%, and 48% and 55% respectively, at 231, 215, 226, 258, and 217 microM, respectively. At 129 microM, compound 4 displayed growth inhibition of HCT-116 (colon), MCF-7 (breast), NCI-H460 (lung), SF-268 (central nervous system CNS), and AGS (stomach) human tumor cell lines by 31%, 29%, 40%, 9%, and 28%, respectively. Similarly, compound 5 inhibited the growth of colon, breast, lung, CNS, and stomach tumor cell lines by 0%, 27%, 35%, 16%, and 27%, respectively, at 108 microM.  相似文献   
25.
The present study provides new information about the reproductive biology of Boswellia sacra (Burseraceae), focusing on the nectary and its attractiveness for pollinators. The nectary disc changes its color from yellow to orange and red during the flower development. The colors are related to the main period of the stigmatic receptivity, to the dehiscence of anthers with pollen presentation and the nectar secretion. Pollinators preferentially visit the flowers in the “yellow” phase and neglect the “red phase”. This suggests a sophisticated dialogue between the plant and its pollinators. The color change from yellow to red occurs in a very short time (less than 24 h) and it is due to the accumulation of anthocyanins. Despite this dialogue between plant and pollinators, the number of fruits is often scanty.  相似文献   
26.
花青素及其生物活性的研究进展   总被引:2,自引:0,他引:2  
花青素是存在于自然界中的天然的水溶性色素,它赋予水果、蔬菜和植物鲜艳的颜色,主要来源于蓝莓、樱桃、覆盆子、草 莓、紫葡萄和红酒等。它属于黄酮类化合物,其结构和化学成分使得花青素具有多种生物活性,如:抗氧化、抗炎、抗衰老、抗心血 管、抗癌等,对于人类的健康具有重要作用。花青素对于人类各种疾病的治疗以及作为一种药方都具有积极的效果,花青素通过 抗细胞增殖、诱导凋亡等多种机制来抑制肿瘤的发生;通过清除活性氧自由基等机制来发挥抗氧化作用;通过抑制各种炎症因子 的表达来发挥抗炎效应,这一系列的生物活性都给人们对抗各种疾病带来了无限的希望。本文就花青素的特点、提取及生物活性 进行了总结,重点介绍了花青素的生物活性。  相似文献   
27.
Chalcone synthase (CHS) is involved in the biosynthesis of anthocyanin. In this study, a full-length DNA of CHS gene (named as CsCHS-bo) was cloned from the blood orange, Citrus sinensis (L.) Osbeck cv. Ruby. The gene was 1,512 bp in size containing an open reading frame (1,176 bp) encoding 391 amino acids. Comparative and bioinformatic analyses revealed that the deduced protein of CsCHS-bo was highly homologous to CHS from other plant species. The protein of CsCHS-bo had four CHS-specific conserved motifs and a CHS-family signature sequence GFGPG. Phylogenetic analysis indicated that the protein of CsCHS-bo was in a subgroup with CHS of Ruta Palmatum. The CsCHS-bo was localized to the chromosomes 2p, 4p and 6p by an improved fluorescence in situ hybridization technique, indicating that at least three copies of CsCHS-bo were present in the genome. The novel nucleotide sequence data published here have been deposited in the EMBL/DDBJ/GenBank databases under accession number EU410483.  相似文献   
28.
29.
The production of anthocyanin in Catharanthus roseus flowers from both field-grown and regenerated by somatic embryogenesis plants and cell cultures was described. The anthocyanins were identified as the 3-O-glucosides, and the 3-O-(6-O-p-coumaroyl) glucosides of hirsutidin, malvidin and petunidin, respectively both in vivo and in vitro. The influence of environmental conditions on in vitro anthocyanin accumulation is described. The relationship between in vivo and in vitro anthocyanin production is discussed.  相似文献   
30.
Cyanidin-3-glucoside (C3Ghv) compounds were purified and isolated from the anthocyanins extract of Haematocarpus validus. C3Ghv were studied for antioxidant and cytoprotective properties on pancreatic β-cells of rat insulinoma cells (RINm5F) against the oxidative stress induced by streptozotocin (STZ). The exposure of RINm5F cells to C3Ghv at concentration of 100 and 200 μg/mL for 24 h reduced 10% and 23% cell viability, respectively, as compared to control cells. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) increased the cell viability by 29% as compared to control, on being treated with STZ (10 mM) for 24 h. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) for 24 h followed by exposure to STZ (10 mM) for 1 h decreased the generation of reactive oxygen species (ROS) by 57%, generation of nitric oxide by 22.8%, generation of malondialdehyde (MDA) by 32%, the production of p-ERK ½ by 83%, p-JNK by 82.6%, p-MEK by 57%, and p-p38 MAPK by 64%. The C3Ghv treatment also decreased the ratio of apoptotic proteins Bax to Bcl-2 by 61%, and improved the M2 phase of cell cycle by 75% as compared to STZ treated cells. The overall results suggest that C3Ghv protects pancreatic β-cells against oxidative stress-induced apoptosis, thereby implicating the significant role of C3Ghv as an antidiabetic agent.  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