全文获取类型
收费全文 | 204篇 |
免费 | 6篇 |
国内免费 | 7篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 2篇 |
2017年 | 8篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 12篇 |
2012年 | 1篇 |
2011年 | 9篇 |
2010年 | 2篇 |
2009年 | 10篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 16篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1976年 | 10篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 7篇 |
排序方式: 共有217条查询结果,搜索用时 15 毫秒
81.
灵芝三萜类成分与药理学研究进展 总被引:28,自引:0,他引:28
灵芝的化学成分有三萜类、多糖、生物碱、有机酸、核苷、氨基酸、酶类及微量元素等 ,其主要成分是三萜类化合物中的灵芝酸。由于灵芝化学成分的多样性 ,使灵芝具有较广泛的药理活性 ,主要包括抗肿瘤作用 ;调节免疫系统、心血管系统、神经系统、呼吸系统的作用 ;保肝、抗衰老、抗病毒、消炎抗菌、放射保护作用 ;清除氧自由基和抗氧化、致突变、活血化淤作用 ;对学习和增强记忆有良好的影响。 相似文献
82.
Suan Zau Ren (the seeds of Zizyphus spinosus Hu) is a widely used chinese traditional drag for treatment of insomnia, neurasthenia and sometimes for sleepiness caused by physical emaciation in chinese traditional medicine. Its dichloromethane extract afforded four pentacyclic triterpenes of the lup-20(29)-en group, namely betulin (Ⅱ), betulinic acid(Ⅰ), ceanothic acid(Ⅲ), and alphitolic acid (Ⅳ), and one sterol, daucosterol (Ⅴ). Their structures were identified by the spectroscopic analysis. The later three compounds were isolated from Suan Zau Ren for the first time. 相似文献
83.
Chromatographic separation of the chloroform-soluble part of the methanol extract from Phytolacca esculenta seeds resulted in the isolation of acetylaleuritolic acid, 3-acetylmyricadiol, α-spinasterol and stigmast-7-en-3β-ol. 相似文献
84.
Ferdinand Bohlmann Michael Wallmeyer Jasmin Jakupovic Jürgen Ziesche 《Phytochemistry》1983,22(7):1645-1651
The investigation of several Osteospermum species afforded in addition to known compounds three diterpenes from the rare cassane type, two further sandaracopimarene derivatives, two 6-desoxyglucosides of cubebol and 13-hydroxycaryophyllene, respectively, an isomer of 7-hydroxycalamenene, two p-hydroxyacetophenone derivatives derived from toxol, a thymol derivative and the palmitates of lupeol, taraxasterol and 3β,20-dihydroxydammarene. The structures were elucidated by spectroscopic methods. The chemotaxonomy of the genus is discussed briefly. 相似文献
85.
Thomas G. Waddell Mark H. Thomasson Michael W. Moore Houston W. White Dorothy Swanson-Bean Margaret E. Green Gene S. Van Horn Henry M. Fales 《Phytochemistry》1982,21(7):1631-1633
The hexane extract of Wyethia mollis contains the n-alkanes C15-C18, C20-C25, C27 and C29. Linoleic acid was the only detectable acidic component. A mass spectral analysis of the wax ester fraction indicated that it was a mixture of homologues, the saturated even-carbon acids n-C16-C30 esterfield with the saturated even-carbon alcohols n-C18-C26. The chloroform extract yielded the known isoflavones santal and 3′-O-methylorobol along with a new lanostane-type triterpene, 22,25-epoxy-lanosta-7:9(11)-dien-3-one. The wide distribution of n-alkanes and the decreased odd-even carbon ratio are consistent with the proposed primitive nature of this plant. 相似文献
86.
The distribution of the triterpene mono- and dihydroxy alcohols was investigated in the subcellular fractions of the flowers of Calendula officinalis. The triterpene monols were found mainly in the chromoplast fraction (68% of total) with smaller amounts in the cell debris, microsomal and supernatant fractions, the mitochondrial fraction was almost devoid of these compounds. Triterpene diols were present exclusively in the chromoplast fraction, 98% in the form of the 3-monoesters and 2% in the form of diesters. It is suggested that the hydroxylation of the triterpene monols to the corresponding diols proceeds in the chromoplasts and the esterified form of the monols is probably the substrate for this reaction. 相似文献
87.
A.K. Barua P. Chakrabarti A.S.Dutta Gupta S.K. Pal A. Basak S.K. Banerjee K. Basu 《Phytochemistry》1976,15(11):1780-1781
A new triterpene acid, barrigenic acid, was isolated from the fruits of Barringtonia acutangula. Its structure was established as 2α,3β,19β-trihydroxyolean-12-en-23,28-dioic acid. 相似文献
88.
89.
90.