全文获取类型
收费全文 | 1199篇 |
免费 | 61篇 |
出版年
2022年 | 5篇 |
2021年 | 8篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2016年 | 10篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 41篇 |
2012年 | 45篇 |
2011年 | 35篇 |
2010年 | 36篇 |
2009年 | 15篇 |
2008年 | 23篇 |
2007年 | 25篇 |
2006年 | 38篇 |
2005年 | 28篇 |
2004年 | 34篇 |
2003年 | 21篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 15篇 |
1999年 | 19篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 14篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1989年 | 8篇 |
1985年 | 42篇 |
1984年 | 41篇 |
1983年 | 22篇 |
1982年 | 84篇 |
1981年 | 87篇 |
1980年 | 74篇 |
1979年 | 90篇 |
1978年 | 50篇 |
1977年 | 37篇 |
1976年 | 9篇 |
1973年 | 5篇 |
1966年 | 4篇 |
1960年 | 4篇 |
1933年 | 4篇 |
1870年 | 5篇 |
1869年 | 6篇 |
1868年 | 10篇 |
1864年 | 8篇 |
1853年 | 5篇 |
排序方式: 共有1260条查询结果,搜索用时 515 毫秒
31.
Ferdinand Bohlmann Maniruddin Ahmed Harold Robinson Robert M. King 《Phytochemistry》1982,21(7):1675-1678
The investigation of the aerial parts of a variety of Enhydra fluctuans afforded in addition to 4-hydroxyfarnesyl acetate and fluctuadin five new melampolides elucidated by high field 1H NMR spectroscopy. The chemotaxonomic situation is discussed briefly. 相似文献
32.
Ferdinand Bohlmann Naleen Borthakur Robert M. King Harold Robinson 《Phytochemistry》1982,21(7):1793-1794
Calea reticulata afforded in addition to known compounds two new sesquiterpenes. These were germacrane and eudesmane derivatives, identified as germacra-4(15),5,10(14)-trien-1-one and 6-epi-β-verbesinol coumarate, respectively. 相似文献
33.
Ferdinand Bohlmann Rajinder K. Gupta Robert M.^King Harold Robinson 《Phytochemistry》1982,21(10):2593-2595
Calea villosa afforded three new sesquiterpene lactones, two furanoheliangolides and an epoxy- germacranolide, as well as several known compounds. The structures were elucidated by spectroscopic methods. 相似文献
34.
Ferdinand Bohlmann Maniruddin Ahmed Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1982,21(3):691-694
An investigation of Brickellia diffusa afforded three new dehydronerolidol derivatives and five new labdane derivatives, all highly oxygenated. The structures were elucidated by spectroscopic methods and a few chemical transformations. The compounds isolated showed close relationships to those isolated from Brickellia sp. 相似文献
35.
Ferdinand Bohlmann Alfons Adler Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1982,21(6):1349-1355
The investigation of two Mikania species, both previously placed in the genus Kanimia, afforded in addition to known compounds several new germ 相似文献
36.
Ferdinand Bohlmann Naleen Borthakur Jasmin Jakupovic Joachim Pickard 《Phytochemistry》1982,21(6):1357-1360
An investigation of Ursinia saxatilis afforded in addition to known compounds a new eudesmanolide derived from ursialpinolide, a germacranolide rel 相似文献
37.
Hypochoeris cretensis afforded, in addition to triterpenes and isoalantolactone, a new guaian-5, 12-olide and the corresponding precursor. 相似文献
38.
Ferdinand Bohlmann Nezhun Ates Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1982,21(11):2691-2697
Artemisia douglasiana afforded, in addition to known compounds, two new C14-acetylenes, five longipinene derivatives, three nerolidol derivatives, a lactone and a ketone with a new carbon skeleton and lavendulol-2-methylbutyrate. The structures were elucidated by spectroscopic methods and some chemical transformations. The configurations of several oxo longipinene-7, 9-di- and 7, 8, 9-triesters isolated previously were corrected. The biogenesis of the new lactones is discussed briefly. 相似文献
39.
The investigation of some Heterotheca species afforded three new cadinane angelicates, in addition to several known compounds. The structures are elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly. 相似文献
40.