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   69篇
  免费   5篇
  国内免费   6篇
化学   71篇
综合类   1篇
数学   1篇
物理学   7篇
  2023年   2篇
  2022年   6篇
  2021年   3篇
  2020年   2篇
  2019年   4篇
  2016年   4篇
  2015年   4篇
  2014年   1篇
  2013年   5篇
  2012年   4篇
  2011年   3篇
  2010年   4篇
  2009年   2篇
  2008年   6篇
  2007年   9篇
  2006年   4篇
  2005年   3篇
  2004年   4篇
  2003年   1篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1996年   3篇
  1992年   1篇
  1990年   1篇
排序方式: 共有80条查询结果,搜索用时 31 毫秒
51.
Angelica sinensis polysaccharide(ASP) was extracted from Angelica sinensis by boiling water. An Angelica sinensis polysaccharide-iron complex(APC) was prepared under the alkaline condition by adding a ferric chloride solution to the ASP solution. Then some identifiable properties of the complex were studied. The content of iron (Ⅲ) in the complex was determined with iodometry. The thermal property, the microscopic structure, the spectral characteristics, and N, C, H contents of the complex were examined by a variety of techniques including DSC, TEM, IR,NMR, and elemental analysis. The content of iron (Ⅲ) in the complex ranges from 10% to 40%. The DSC result shows that the melting point of the complex is about 450 ℃. The TEM result shows that the complex has an iron(Ⅲ)core(β-FeOOH core) linked by hydroxy and oxy bridges, with the polysaccharide chains attached to the surface of the core. The IR and NMR results also show that there is aβ-FeOOH core in the complex. The elemental analysis shows that the contents of N, C , H in the complex are, respectively, lower than those of N, C, H in ASP. All our studies indicate that the APC consists of aβ-FeOOH core surrounded by ASP.  相似文献   
52.
Summary A novel strategy for the screening and analysis of biologically active compounds in traditional Chinese medicine by molecular biochromatography is proposed. Molecular biochromatography with human serum albumin (HSA) immobilized on silica as stationary phase was used to screen and analyse the bioactive compounds in the typical Chinese medicine ofAngelica sinensis (Oliv.) Diels. Ten peaks showed retention on this column, which is based on their affinity for HSA. Ferulic acid and liguistilide were identified as the principal active components, which agrees very well with the results in the literature. A quality control method was also developed based on the simultaneous determination the concentrations of ferulic acid and liguistilide in solutions ofAngelica sinensis (Oliv.) Diels extracted with water and methanol. It was observed that the concentrations of ferulic acid and liguistilide in solution extracted with methanol were 2 and 53 times higher, respectively, than those with water. It was shown that molecular biochromatography is an effective way of analysing and screening biologically active compounds in traditional Chinese medicine.  相似文献   
53.
54.
The roots of Peucedanum japonicum (Apiaceae) have been used as an alternative to the roots of Saposhnikovia divaricata (Apiaceae) to treat common cold-related symptoms in Korea. However, a variety of Peucedanum species, including the roots of P. praeruptorum or Angelica decursiva (=P. decursivum), have been used to treat phlegm–heat-induced symptoms in China. Hence, as there are differences in the medicinal application of P. japonicum roots between Korea and China, chemotaxonomic classification of P. japonicum was evaluated. Sixty samples derived from P. japonicum, P. praeruptorum, A. decursiva, and S. divaricata were phylogenetically identified using DNA barcoding tools, and chemotaxonomic correlations among the samples were evaluated using chromatographic profiling with chemometric analyses. P. japonicum samples were phylogenetically grouped into the same cluster as P. praeruptorum samples, followed by S. divaricata samples at the next cluster level, whereas A. decursiva samples were widely separated from the other species. Moreover, P. japonicum samples showed higher chemical correlations with P. praeruptorum samples or A. decursiva samples, but lower or negative chemical correlations with S. divaricata samples. These results demonstrate that P. japonicum is more genetically and chemically relevant to P. praeruptorum or A. decursiva and, accordingly, the medicinal application of P. japonicum might be closer to the therapeutic category of these two species than that of S. divaricata.  相似文献   
55.
Angelica sinensis is one of the most important traditional Chinese medicines and has antioxidant activities that greatly contribute to its pharmacological action. However, the compounds responsible for its antioxidant activity remain unknown. In this study, the fingerprints of 10 batches of A. sinensis collected from different locations in China were established with HPLC to identify the common peaks. The antioxidant activities of these 10 batches were evaluated with 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, and ferric-reducing antioxidant power assays. The spectrum–effect relationship between HPLC fingerprints and antioxidant effect of A. sinensis was examined by the partial-least-square regression analysis and the variable importance in projection method. Results showed that the antioxidant effect of A. sinensis results from the synergistic effect of various compounds, and peaks X3 and X7–X18 were the main substances responsible for antioxidant efficacy. This study successfully identified the spectrum–effect relationship between HPLC fingerprints and the antioxidant effect of A. sinensis. This relationship can provide methods for establishing the quality standards for A. sinensis and developing new and effective products of A. sinensis based on its antioxidant ingredients.  相似文献   
56.
Metabonomics based on GC‐MS was used to study the possible anti‐inflammatory mechanisms of volatile oils of Angelica sinensis (VOAS) in rats with acute inflammation. Acute inflammation was induced by subcutaneous injection of carrageenan in rats. The levels of prostaglandin E2 (PGE2), histamine (HIS) and 5‐hydroxytryptamine (5‐HT) in the inflammatory fluid were detected. Principal component analysis and orthogonal partial least squares‐discriminant analysis models were performed for pattern recognition analysis. After the administration of VOAS, the levels of PGE2, HIS, and 5‐HT returned to levels observed in normal group. According to GC‐MS analysis, the intervention of VOAS in rats with acute inflammation induced substantial and characteristic changes in their metabolic profiles. Fourteen metabolite biomarkers, namely, lactic acid, malic acid, citric acid, trans‐dehydroandrosterone, aldosterone, linoleic acid, hexadecanoic acid, pregnenolone, octadecenoic acid, myristic acid, l ‐histidine, octadecanoic acid, arachidonic acid (AA) and l ‐tryptophan, were detected in the inflammatory fluid. The levels of all biomarkers either increased or decreased significantly in model groups. VOAS possibly intervened in the metabolic process of inflammation by altering histidine metabolism, tryptophan metabolism, AA metabolism, steroid hormone biosynthesis, fatty acid metabolism and energy metabolism. Metabonomics was used to reflect an organism's physiological and metabolic state comprehensively, and it is a potentially powerful tool that reveals the anti‐acute‐inflammatory mechanism of VOAS. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
57.
Nobuwa Aoki 《Tetrahedron letters》2010,51(26):3449-3450
A new sesquiterpenoid designated ashitabaol A was isolated from seeds of Angelica keiskei. The structure was determined by interpretation of spectroscopic data and was confirmed by X-ray crystallographic analysis. Ashitabaol A exhibited free radical scavenging activity.  相似文献   
58.
独活浸膏的热裂解产物分析   总被引:1,自引:0,他引:1  
采用在线热裂解-气相色谱质谱联用技术(Py-GC-MS),模拟卷烟燃吸状态,对独活浸膏进行热裂解,裂解产物经气相色谱-质谱联用仪分析。结果表明:独活浸膏的热裂解产物中共鉴定出51种成分,主要有5-羟甲基糠醛(29.00%)、甲氧基欧芹酚(18.79%)、(Z,Z)-9,12-亚油酸(5.76%)、(E)-2-甲基-2-丁烯酸(3.64%)、5-甲基糠醛(2.79%)、十六酸(2.67%)、2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮(1.55%)、糠醛(1.29%)等致香物质,该结果为独活浸膏在卷烟中的应用提供理论依据。  相似文献   
59.
目的研究当归提取液在体外诱导人角质形成细胞株HaCaT细胞凋亡的作用及其可能的机制.方法采用MTT法检测不同浓度当归提取液对HaCaT细胞增殖的影响,流式细胞仪FITC-Annexin V/PI双染法检测细胞凋亡情况,分光光度法检测细胞内半胱天冬氨酸蛋白酶9(Caspase-9)活性的改变情况.结果浓度≥10mg/ml的当归提取液处理后HaCaT细胞增殖受到抑制,早期凋亡率显著增高(均P<0.01),细胞内Caspase-9活性明显增加(P<0.05),均呈浓度依赖性.结论在一定浓度范围内,当归提取液可抑制诱导HaCaT细胞凋亡,Caspase-9活性增加可能是其诱导凋亡的机制之一.  相似文献   
60.
6-或8-脂代-7-氧香豆素与二氢呋喃香豆素的NMR,MS研究   总被引:1,自引:0,他引:1  
对从重齿毛当归(Angelica pubescens Maxim f.biserrata Shan et Yuan)根及根茎中分得的12种6-或8-脂代-7-氧-香豆素和8种二氢呋喃香豆素衍生物进行了1H和13C NMR分析研究,结合文献,做出规律性总结.运用2D NMR技术,对文献中当归醇类化合物碳谱中的个别错误归属给予了纠正,并首次探讨了此类化合物的MS裂解途径.  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