全文获取类型
收费全文 | 62篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
64篇 |
出版年
2023年 | 5篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2013年 | 5篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有64条查询结果,搜索用时 0 毫秒
1.
SHOKO YASUKAWA HIDETOSHI KATO RYOHEI YAMAOKA HAJIME TANAKA HIROHITO ARAI SHOICHI KAWANO 《Plant Species Biology》1992,7(2-3):121-140
Abstract Volatile substances emitted from the flowers of eight Magnolia taxa ( M. sieboldii ssp. japonica, M. praecocissima var. praecocissima and var. borealis, M. tomentosa, M. salicifolia, M. obovata, M. denudata, and M. grandiflora ) and one Michelia species ( M. compressa ) (Magnoliaceae) were examined and identified using GC-MS. Volatile substances of these Magnolia and Michelia species consist primarily of monoterpenoids and sesquiterpenoids produced by the mevalonate pathway, acetogenins by the acetate-malonate pathway, and phenyl-propanoids by the shikimate pathway. These Magnolia and Michelia species all possessed various combinations of volatile monoterpenoids, acetogenins, and phenylpropanoids, except for Magnolia obovata , which emitted primarily sesquiterpenoids. Free amino acids in pollen of 12 Magnolia and one Liriodendron species were also analyzed, and their value as food sources for pollinators evaluated.
Pollinators visiting the flowers of five Magnolia species were collected in their native sites and identified. Their behaviors and roles as pollinating agents were assessed. 相似文献
Pollinators visiting the flowers of five Magnolia species were collected in their native sites and identified. Their behaviors and roles as pollinating agents were assessed. 相似文献
2.
The coupling pattern of trichothecin biosynthesized from acetate-[1,2-13C2] is in accord with previous enrichment studies. Multiple labelling was observed. Exogenous acetate has been shown to inhibit the utilization of glucose and the incorporation of radioactivity from pyruvate-[2-14C] and citrate-[1,5-14C] into the metabolites. Two pairs of 13C NMR assignments are interchanged. 相似文献
3.
4.
The conversion of eremoacetal to (?)-1-(furan-3-yl)-4-hydroxy-4,8-dimethylnonane-1,6-dione establishes the configuration of (?)-4-hydroxymyoporone (athanagrandione) as R. 相似文献
5.
Xlao-Ling Wang Suo-Lang Gesang Wei Jiao Xun Liao Li-Sheng Ding 《植物学报(英文版)》2007,49(5):609-614
Two new sesqulterpenoid glucosides, namely α-hydroxycostic acid 6-β-D-glucopyranoside (compound 1) and 11 βH-11,13-dlhydrodehydrocostuslactone 8α-O-(6'-acetyl)-β-D-glucopyranoside (compound 2), along with 11 known sesqulterpenoids (compounds 3-13) were isolated from the aerial parts of Saussurea involucrate (Kar. et Kir.) Sch.- BIp. The structures of the new sesquiterpenoid glucosides were established by one- and two-dimensional nuclear magnetic resonance and mass spectrometry analysis. 相似文献
6.
Two new sesquiterpenoids (1 and 2) and a new ent-pimarane type diterpenoid (3), together with eighteen known compounds (4–21), were isolated from the whole plants of Siegesbeckia pubescens. The structures of the new compounds were determined on the basis of 1D-, 2D NMR and HRESIMS data. All compounds were evaluated for their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages. Of these, highly oxygenated germacrane type sesquiterpenoids (1–2 and 13–14) showed significant inhibitory effects with IC50 values ranging from 3.9 to 16.8 μM. 相似文献
7.
The phytochemical investigation on the stems of Schisandra bicolor led to the isolation of seven cadinane-type sesquiterpenoids, 2-hydroxy-11,12-dehydrocalamenene (1), ent-T-muurolol (2), (+)-ent-epicubenol (3), (1S,4S)-7,8-dihydroxy-11,12-dehydrocalamenene (4), cadinane-T-cadinol (5), (−)-cadin-4,10(15)-dien-11-oic acid (6), and cadina-4,10(15)-dien-3-one (7). Their structures were determined by extensive analysis of their spectroscopic data. All the isolates were isolated from this species for the first time. The chemotaxonomic significance of these compounds was also summarized. 相似文献
8.
Genetic variation in the synthesis of halogenated secondary metabolites in the Japanese marine red alga Laurencia nipponica Yamada (Rhodomelaceae, Ceramiales) has been investigated in laboratory crossing experiments and chemical analyses, F1 tetrasporophytes and F1 gametophytes resulting from crosses within chemical races produced major metabolites characteristic of these races. F1 tetrasporophytes derived from reciprocal interracial crosses produced: (i) both parental types of secondary metabolites; (ii) either of the parental types; or (iii) a further major compound in addition to both parental types or in addition to either of the parental types. The latter cases suggest that hybrid-specific products were formed by the combined enzymatic complements of the parents, as F1 gametophytes derived from these interracial F1 tetrasporophytes yielded one or other of their parental products in an approximate 1:1 ratio. The population structure was analyzed at localities in Hokkaido, where two of the chemical races occur sympatrically. At Usujiri (Minami-kayabe), where the prepacifenol race and the laureatin race were sym-patric, hybrid gametophytes (recombination type) were found in high frequency in addition to hybrid tetra sporophytes, which strongly suggests that a new, pre-pacifenol/laureatm race is beginning to be produced by natural hybridization and recombination. By contrast, at Oshoro Bay, where the laurencin race and the epi-lauraliene race grew together, the interracial hybrids were rare: only a few tetrasporophytes (probably F1 generation) were found, suggesting that racial integrity may be retained by habitat segregation and/or the absence of recombination-type gametophytes. 相似文献
9.
Four isomeric sesquiterpenoid lactones have been isolated from the liverwort Frullania tamarisci They have been identified as the simple eudesmanolides (I–III) and costunolide (IV). 相似文献
10.
Alois A. Bell Robert D. Stipanovic Charles R. Howell Paul A. Fryxell 《Phytochemistry》1975,14(1):225-231
The sesquiterpenoid aldehydes, hemigossypol (1a), 6-methoxyhemigossypol (1b), and 6-deoxyhemigossypol (1c), were isolated and identified from Verticillium-infected stele tissue of Gossypium barbadense. Structures were established by spectral (UV, IR, NMR, MS) evidence and chemical transformations. This is the first report of (1b) and (1c) in nature, and of NMR and m.p. data for crystalline pure (1a). Compound (1a) occurred in diseased stele tissues of all 21 Gossypium species examined and in the genera, Cienfuegosia, Gossypioides, Hampea, and Thespesia; it was absent in three Hibiscus spp. Compound (1b) occurred in the same taxa as (1a), except that it was absent in species of two cytogenetic groups (A and B genome) of Gossypium. Compound (1c) occurred in trace quantities, or was not detected, in most species; however, its distribution appeared to besimilar to that 相似文献