首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   116篇
  免费   7篇
  国内免费   20篇
  2023年   1篇
  2022年   2篇
  2021年   4篇
  2020年   1篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2015年   2篇
  2014年   8篇
  2013年   3篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2009年   3篇
  2008年   2篇
  2007年   4篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2002年   10篇
  2001年   6篇
  2000年   6篇
  1999年   7篇
  1998年   12篇
  1997年   2篇
  1996年   7篇
  1995年   10篇
  1994年   7篇
  1993年   5篇
  1992年   7篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1985年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
排序方式: 共有143条查询结果,搜索用时 31 毫秒
111.
Kengyilia Yen et J L Yang is a recently established genus in trib. Tritieeae of Poaceae. In this paper, this genus is taxonomically revised, and a new taxonomic system is presented. The new system includes 3 sections, 26 species and 6 varieties, of which 3 sections and 1 species are described as new, 7 taxa are treated respectively in the ways of new status or combination and reduction. Three new sections, sect. Kengyilia, sect. Stenachyra L. B. Cai and sect. Hyalolepis (Nevski) L. B. Cai, are differentiated by the length and width of spike, the growing position of spikelet, the relative length of glume, the colour of anther and so on. The sect. Kengyilia contains 9 species, distributed in northwestern China, extending westward to Kazakhstan, Kirghizia, Tadzhikistan, Afghanistan and Iran; the sect. Stenachyra L. B. Cai comprises 10 species and 3 verieties, distributed in western China, mainly in the Qinghai-Xizang Plateau; and the sect. Hyalolepis (Nevski) L. B. Cai consists of about 7 species and 3 varieties, distributed in western China, extending westward to Kirghizia and Tadzhikistan. Twenty-six species of Kengyilia are recognized on the basis of the same criterion of specific concept, and the other taxa below the rank of species are also checked in terms of their external morphology. As a result, Kengyilia pen~ dula L. B. Cai is reported as a new species; K. hirsuta var. obviaristata L. B. Cai is raised to a species; K. melanthera (Keng) J. L. Yang, Yen et Baum is reduced to a variety under K. thoroldiana (Oliver) J. L. Yang, Yen et Baum; Roegneria hirsuta var. leiophylla Keng et S. L. Chen is reduced as a synonym of K. hirsuta var. hirsuta; Agropyron thoroldianum var. lasciusculum Melderis is reduced to K. grandiglumis (Keng et S. L. Chen) J. L. Yang, Yen et Baum; Roegneria rigidula var. intermedia Keng et S. L. Chen to K. rigidula (Keng et S. L. Chen) J. L. Yang, Yen et Baum; R. hirsuta var. variabilis Keng et S. L. Chen and R. rnelanthera var. tahopaica Keng et S. L. Chen to K. hirsuta (Keng et S. L. Chen)J. L. Yang, Yen et Baum. In addition, new records onthe geographical distributions of some taxa are also reported in this paper.  相似文献   
112.
杉科植物的分类学研究   总被引:10,自引:0,他引:10  
于永福 《植物研究》1994,14(4):369-384
本文对杉科植物的研究历史作了回顾,根据分支分类结果和表征分类结果,提出了一个新的分类系统.以形态学为依据,结合其他学科的研究成果,对杉科的分类作了订正。作者承认杉科植物共9属、12种及3变种,将杉木、厚皮杉木、德昌杉木和米德杉木归并,支持柳杉作为日本柳杉的变种、台湾杉木作为杉木的变种、秃杉和台湾杉归并的观点。  相似文献   
113.
在查阅猕猴桃属植物标本时,发现了伞花猕猴桃(Actinidia umbelloidesC.F.Liang)的新分布点,分布地点位于西藏和云南,补充了其花部特征的描述,并将扇叶猕猴桃(Actinidia umbelloidesC.F.Liang var.flabellifoliaC.F.Liang)作为伞花猕猴桃的异名处理。  相似文献   
114.
115.
在查阅猕猴桃属植物标本时,发现了伞花猕猴桃(Actinidia umbelloides C.F.Liang)的新分布点,分布地点位于西藏和云南,补充了其花部特征的描述,并将扇叶猕猴桃(Actinidia umbelloides C.F.Liang var.flabellifolia C.F.Liang)作为伞花猕猴桃的异名处理。  相似文献   
116.
属的分类概述1753年,C. Linnaeus建立了猪屎豆属(Crotalaria),一共记载了该属植物13种。Linnaeus关于该属的基本概念是:"Carina acuminata, longitudine alatum. Filamenta decem, connata, assurgentia. Antherae simplices. Style simplex, infrac-  相似文献   
117.
草苁蓉属(列当科)分类的研究   总被引:1,自引:0,他引:1  
本文详细比较了草苁蓉属和丁座草属(Xylanche)植物的形态特征,并在扫描电镜下观察了它们的种皮纹饰。发现G.Beck(1890)建立丁座草属时所依据的花部性状并不可靠,这些性状,尤其是花萼分裂度和心皮数目,本身就有变异。因此,作者将丁座草属归并入草苁蓉属(Boschniakia)中。  相似文献   
118.
The study of some recently sampled specimens of «Pecten galloprovincialis var. baranensisAlmera & Bofill, from the type-locality Bará (Tarragona), leads to rise this variety to a specific level. Amussiopecten baranensis (Almera & Bofill, 1897) is a senior synonym of Amussiopecten destefanii (Ugolini, 1903). The distinction between this species and Amusium cristatum (Bronn), which have been often confused, is more precisely defined. A. baranensis is polytypic, as proved by some morphotypes from other European localities (Gard and Landes in France, Sardinia). Its stratigraphic distribution is mainly Helvetian sensu lato or Middle Miocene.Signification and affinities of the genusAmussiopecten are also discussed. As a transitional form to Amusium, A. baranensis may contribute to clarify its taxinomic position, specially by means of microsculptural characteristics: a completed diagnosis is provisionally proposed.  相似文献   
119.
西藏壳斗科订正   总被引:4,自引:0,他引:4  
在野外观察和前人工作的基础上,对西藏壳斗科植物进行了详细的订正,描述了1个新种,报道1个中国新记录种,4个西藏新记录种,归并11种和2变种,排除无标本记录的2种。确认西藏壳斗科植物共3属32种,2变种。  相似文献   
120.
Shre.  KK 《植物分类学报》1997,35(5):396-433
Cyananthus Wallich ex Bentham, the only genus of Campanulaceae with superior ovary, is revised to clarify infrageneric relationships and phylogeny of the genus. Evidence obtained from the comparative gross morphology, anatomy, palynology, and karyomorpho-logy recommends a new infrageneric classification of the genus, recognizing 23 species, belonging to two subgenera, four sections and four subsections. One subgenus(Subgen. Mi-cranthus), one section(Sect. Suffruticulosi) and two subsections(Subsect. Flavi and Sub-sect. Lichiangenses)are described as new taxa. New combinations at sectional (Sect. Annui) and subsectional(Subsect. Stenolobi) ranks are also proposed. The genus Cyananthus is strictly distributed in the high mountains of China(Xizang, Yunnan and Sichuan), extending to Bhutan, Nepal and India (Kumaon-Garhwal, Assam and Sikkim), with altitudinal ranges from 2500 ~ 5300 m. It is observed that 13 species are endemic to SW China and only three species are endemic to the Himalayas( two species in Ne  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号