全文获取类型
收费全文 | 112篇 |
免费 | 6篇 |
国内免费 | 8篇 |
专业分类
化学 | 108篇 |
综合类 | 10篇 |
数学 | 1篇 |
物理学 | 7篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 13篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有126条查询结果,搜索用时 0 毫秒
11.
12.
《Electroanalysis》2005,17(4):356-362
Capillary electrophoresis with electrochemical detection (CE‐ED) was employed to analyze active ingredients of Lonicera japonica Thumb., an important crude herb frequently used in Chinese medicines. Hyperoside, chlorogenic acid, luteolin and caffeic acid are the major important active ingredients. Operating in a wall‐jet configuration, a 300 μm diameter carbon‐disk electrode was used as the working electrode, which exhibits a good response at +0.90 V (vs. saturated calomel electrode) for four analytes. Under the optimum conditions, the analytes were baseline separated within 20 min in a 50 mmol L?1 borax buffer (pH 8.7). Notably, excellent linearity was obtained over two orders of magnitude with detection limits (S/N=3) ranging from 0.1 to 0.5 mg L?1 for all the analytes. This method was successfully used in the analysis of Lonicera japonica Thumb. with relative simple extraction procedures, and the assay results were satisfactory. 相似文献
13.
从采自西藏的皱叶香茶菜中分离鉴定了3对B-闭联对映贝壳杉烯型二萜化合物:二萜化合物皱叶香茶菜素(Ⅰ)和二氢皱叶香茶菜素(Ⅱ);isodocarpin(Ⅲ)和dihydroisodocarpin(Ⅳ)及Carpalasionin(Ⅴ)和dihydrocarpalasionin(Ⅵ)。(Ⅰ)、(Ⅲ)和(Ⅴ)分别与对应的二氢化合物(Ⅱ)、(Ⅳ)和(Ⅵ)以混合物的形式被分离和鉴定。化合物(Ⅱ)为新化合物,(Ⅰ)、(Ⅳ)和(Ⅵ)首次在自然界发现,(Ⅲ)和(Ⅴ)为已知化合物。 相似文献
14.
FGS was isolated and purified from laminaria japonica by enzymolysis,chromatography methods and so on.The high blood fat model was established by feeding mouse on high fat feedstuff.Compared with control group,the concentration of HDL-C.the ratio of HDL-C.TC increased.while the concentration of TC,LDL-C and TG decreased in experimental groups,Conclusion:FGS was an effective serum lipid regulator and can be developed as medicine and health food. 相似文献
15.
WANG Qilin ZHANG Yinghui QU Aiqin WANG Hairen XU Zhenguo College of Life Science Shandong University Jinan Rongcheng Hongyangshen Group Shandong Province 《Chinese Journal of Reactive Polymers》2001,(2)
1. INTRODUCTION Blood fat primarily contains cholesterol, cholesterol ester, phosphatide, triglyceride and free fatty acid in serum of human being and mammalian. Under physiological conditions, the lipids transport in the form of lipoproteins linked with the proteins. Except for the free fatty acid linked with albumin, the other lipids are linked with the globular proteins into high-density lipoproteins (HDL), low density lipoproteins (LDL), very low density lipoproteins (VLDL) and so… 相似文献
16.
高效液相色谱-电喷雾离子阱质谱联用法测定金银花中绿原酸和咖啡酸 总被引:1,自引:0,他引:1
建立了高效液相色谱-电喷雾离子阱质谱法(HPLC-ESI-ITMSn)同时测定了金银花中绿原酸和咖啡酸活性成分的分析方法。样品用体积分数80%乙醇回流提取,用Zorbax Eclipse XDB-C18柱分离,以体积分数0.5%甲酸的乙腈-甲酸水溶液为梯度流动相,以保留时间和质荷比对分离出的组分予以定性确证,用峰面积进行定量。绿原酸和咖啡酸的线性范围均为10.0~1000.0μg/L,检出限(以信噪比为3计)均为2.0μg/L。样品的加标平均回收率为92.7%~98.7%,相对标准偏差为1.4%~2.7%。该方法适用于其它复杂体系中绿原酸和咖啡酸的分析。 相似文献
17.
TANG Jian MA Rui-li LI Qian-qian JIANG Chun-bao CHEN Rui OUYANG Zhen CHEN Hai-sheng 《高等学校化学研究》2013,(6):1072-1077
For the efficient extraction of kamebakaurin(KA), the ultrasound-assisted extraction(UAE) of KA from Rabdosia excisa(R, excisa) via response surface methodology(RSM) was investigated with high-performance liquid chromatography(HPLC). Effects of the experimental parameters such as extraction solvent, ratio of liquid to plant material, extraction time and extraction temperature on the extracting efficiency of KA from R. excisa were evaluated, and the purity of KA in residual was calculated. The optimized conditions were 65.5%(volume fraction) acetone, 35 ℃, time of 24.6 min with ultrasound of 80 W/L, 40 kHz, ratio of liquid to plant material at 30:1(mL/g). The maximum yield of KA is 0.708 mg/kg, with mean purity of 6.09%, indicating that ultrasound-assisted extraction is a feasible and useful method for extracting KA from R. excisa. 相似文献
18.
Hong Ping HE Yue Mao SHEN Xiao Sheng YANG Bin Gui WANG Ling LI Xiao Jiang HAO * Laboratory of Phytochemistry Kunming Institute of Botany the Chinese Academy of Sciences Kunming . The Key Laboratory of Chemistry for Natural Prod 《中国化学快报》2001,(1)
Spiraea japonica L. (Rosaceae) is widely distributed in Yunnan Provence, P. R. China. Previous chemical investigations on S. japonica and its varieties have led to the report of 7 new atisane-type diterpenoids and 38 new diterpene alkaloids of atisine- and hetisine-type1-11. This paper describes the isolation and structure elucidation of two new diterpene alkaloids named spiratines A and B (1-2). Their structures were elucidated on the basis of 1D and 2D NMR experiments (HMQC, HMBC, 1… 相似文献
19.
Two new homosecoiridoids, named loniaceticiridoside (1) and lonimalondialiridoside (2), were isolated from an aqueous extract of the flower buds of Lonicera japonica. Their structures including the absolute configuration were determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis. A proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1 and 2 are also discussed. 相似文献
20.