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排序方式: 共有124条查询结果,搜索用时 78 毫秒
1.
中国蓼科植物化学成分研究进展   总被引:5,自引:0,他引:5  
我国有蓼科植物13属约235种,37变种.通过对已报道的蓼科植物的化学成分综述分析,表明:大黄属、何首乌属、虎杖属与酸模属都含有蒽醌类化合物(如大黄素、大黄酸、大黄酚等);而养麦属与蓼属富含黄酮类化合物,极少有蒽醌类存在.蓼科植物化学成分主要为蒽醌类和黄酮类,鞣质在该科中普遍存在;生物碱很少、有些属还含有芪类.  相似文献   
2.
中国拳参属(蓼科)植物叶脉序式样的研究   总被引:3,自引:0,他引:3  
用清净标本制作法对中国产拳参属(Bistorta)(蓼科)12种1变种植物的叶脉序式样在光镜下进行了比较研究。结果表明,叶脉序式样可分为3种类型:(1)环结曲行羽状脉,边缘末级脉不完全,加粗且外卷;(2)环结曲行荆状脉,二级脉与其余各级脉近等粗,边缘末级脉具边脉,不加粗;(3)直行羽状脉,盲脉无或偶有,边缘末级脉不完全,不加粗。依据叶脉序式样,结合其植物习性及外部形态特征,将拳参属植物划分为3个组:拳参组section Bistortu,乌饭树叶蓼组section Vacciniifolia F.Z.Li,L.X.Liu & Y.T.Hou,sect.nov.和匍枝蓼组section Bambuphyllum F.Z.Li,L.X.Liu & Y.T.Hou,sect.nov.。  相似文献   
3.
Preformation, the initiation of organs one or more years prior to maturation and function, is reported to be common and crucial for plant survival in arctic and alpine environments, yet the phenomenon is remarkably little studied. In order to understand the role of preformation in the ecology and evolution of tundra species, this investigation takes a developmental and architectural approach to the analysis of plant growth and reproduction in the alpine perennial Polygonum viviparam L. Analyses show that the extent and duration of preformation in P. viviparam are extraordinary. Four years are required for each leaf and inflorescence to progress from initiation to functional and structural maturity. This single salient feature of development has profound consequences for basic architecture, dynamics of resource allocation, and the timing of plant responses to environmental variation. As a consequence of the protracted duration of leaf and inflorescence development, five cohorts of primordia, initiated in successive years, are borne simultaneously by an individual plant. In the year prior to maturation leaves reach 30% of their maximum size, and the maximum potential reproductive output of each inflorescence is determined. Thus, developmental processes that affect final morphology and resource allocation occur at least 1 yr before functional maturity. From the developmental and architectural models constructed for P. viviparum, a 1-yr delay in measurable plant responses to environmental variation is predicted. The models also apply generally to arctic and alpine species and provide a mechanistic explanation for observed patterns of productivity at the community and ecosystem scale.  相似文献   
4.
The problem of whether phloroglucinol is a direct biosynthetic precursor of flavonoids was reinvestigated. Phloroglucinol-2,4,6-14C was found to be incorporated into rutin in Buckwheat (Fagopyrum esculentum) but most of the activity was found in the sugar moiety, the remainder being approximately equally distributed among the A- and B-rings of the aglycone, quercetin. This indicates extensive degradation of the added phloroglucinol prior to its utilization in the biosynthesis of the flavonoid. The hypothesis of a bio-Fries rearrangement of phloroglucinyl cinnamate to a chalcone, and hence to flavonoids, was also eliminated by comparing the efficiency of incorporation of 14C-labelled phloroglucinyl cinnamate and those of labelled phloroglucinol and cinnamic acid.  相似文献   
5.
From the methanol extract of the root of Polygonum hydropiper, a novel coumaryl glycoside hydropiperoside was isolated together with anthraquinone, ellagic acid 3,3′-di-O-methyl ether, gallic acid, two quercetin glycosides and an unidentified aromatic δ-lactone possessing antifertility activity. The structure of hydropiperoside was established as β-d-(1,3,6-tri-p-coumaryl)-fructofuranosyl-α-d-glucopyranoside by combination of extensive 1H NMR and 13C NMR spectra, and the FD/MS spectrum.  相似文献   
6.
Recently much attention has been paid to genetic aspects of invasive success in Japanese knotweed s.l. One hypothesis to explain the invasive spread of these species is a multiple introduction, which leads to a higher level of genetic diversity in the invaded range. Fallopia japonica is considered to be genetically uniform in Europe, introduced as a single female clone. However, there is some evidence suggesting that invasion history and dynamics differ between Western and Central-Eastern Europe. We used AFLP markers to characterize genetic diversity of three Fallopia taxa that occur in Poland: F. japonica, F. sachalinensis and their hybrid Fallopia × bohemica, growing in so-called ‘homogeneous’ populations, consisting of one taxon and ‘heterogeneous’ populations, composed of the three taxa cohabiting together. No polymorphism, resp. an insignificantly low variability was observed in the ‘homogeneous’ populations. In the ‘heterogeneous’ stands polymorphism was detected within each taxa, with one exception that concerns individuals of F. sachalinensis from a riparian habitat. The highest level of polymorphism was found among individuals of F. × bohemica. The most striking result of our study is the observation of polymorphism between individuals of F. japonica. The AFLP data also showed that F. × bohemica is most diverse when occurring in a heterogeneous configuration with F. japonica and F. sachalinensis in the same habitat. Our results are the first evidence of genetic diversity in F. japonica populations in Central Europe and can implicate the possibility of its multiple introduction in this region or the existence of sexual reproduction of this species.  相似文献   
7.
通过对广义蓼属及近缘属共32个代表种内转录间隔区ITS序列的分子系统学分析,尝试研究备受争议的广义蓼属及近缘属的物种族、属、组级的划分问题,结果显示,广义蓼属在系统发育树上并不能形成一个单系类群,这些物种共聚为3大支,分别对应春蓼族、蓼族及荞麦族,其中荞麦属与翅果蓼属形成了一支独立于春蓼族及蓼族之外的类群。在春蓼族中,冰岛蓼属与分叉蓼组形成一个单系类群。  相似文献   
8.
Phytochemical investigations on the roots of Fallopia multiflora var. Ciliinerve led to the isolation of eighteen compounds, including six chromones [2-methyl-5- carboxymethyl-7-hydroxychromone (1), 2-methyl-5-methylcarboxymethyl-7- hydroxychromone (2), 2,5-dimethyl-7-hydroxychromone (3), 2-methyl-5-hydroxymeth-yl-7-hydroxychromone (4), 2-methyl-5-carboxylicacid-7-hydroxy-chromone (5), and 2,5-dimethyl-7-hydroxychromone-7-O-β-D-glucopyranoside (6)], three lignans [Isolariciresinol (8), 5-[4-(3,4-dimethoxyphenyl)-2,3-dimethylbutyl]-1,3-benzodioxole (9), and isolariciresinol-9-O-β-D-xylopyranoside (10)], four anthraquinones [physcion-8-O-β-D-glucopyranoside (11), emodin-8-O-β-D-glucopyranoside (12), Rhein (13), and Chrysophanol (14)], three isobenzofurans [5,7-dihydroxy-isobenzofuran (15), 5-methoxy-7-hydroxy-isobenzofuran (16), and 5-methoxy-isobenzofuran-7-O-β-D-glucoside (17)], one phenolic acid [2,5-diacethylhy-droquinone (7)], and one pyran [Zanthopyranone (18)]. Among them, compounds 1, 3, 6, 13 and 14 were reported from F. multiflora var. Ciliinerve for the first time, compounds 2, 8, 10 and 15–17 were isolated from the genus Fallopia for the first time, and compounds 4, 9 and 18 were isolated for the first time from Polygonaceae family. Furthermore, the isolation of compounds 5 and 7 were reported for the first time in plants. Their structures were identified by spectroscopic methods and compared with those previously published. The chemotaxonomic significance of these isolated compounds has also been discussed.  相似文献   
9.
Investigations of rhubarb and the bark of Rhaphiolepis umbellata led to the isolation of new flavan-3-ol glucosides. Their structures were elucidated on the basis of 1H and 13C NMR analysis hydrolytic studies as (+)-catechin 5-O-β-d-glucopyranoside and (?)-catechin 7-O-β-d-glucopyranoside.  相似文献   
10.
The genus Reynoutria is represented by four taxa in the Czech Republic: Reynoutria japonica var. japonica, R. japonica var. compacta, R. sachalinensis and R. xbohemica. By using flow cytometry, cytological variability within the genus is described based on 257 Reynoutria samples. The varieties of R. japonica are cytologically uniform, var. japonica is exclusively octoploid (2n = 8x = 88) and var. compacta occurs only as a tetraploid (2n = 4x = 44), but R. sachalinensis and R. xbohemica exhibit some variation in chromosome numbers. Reynoutria sachalinensis is predominantly tetraploid (2n = 4 x = 44), but also occurs occasionally as hexaploid and octoploid cytotypes. The most common ploidy level in R. xbohemica is hexaploid (2n = 6x = 66), but tetraploid and octoploid clones were also found. The four taxa occurring in the Czech Republic are described briefly and the possible origins of the cytotypes discussed.  相似文献   
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