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   386篇
  免费   31篇
  2023年   6篇
  2022年   2篇
  2021年   7篇
  2020年   3篇
  2019年   12篇
  2018年   12篇
  2017年   14篇
  2016年   12篇
  2015年   14篇
  2014年   17篇
  2013年   25篇
  2012年   10篇
  2011年   10篇
  2010年   9篇
  2009年   25篇
  2008年   31篇
  2007年   28篇
  2006年   18篇
  2005年   22篇
  2004年   15篇
  2003年   13篇
  2002年   15篇
  2001年   15篇
  2000年   7篇
  1999年   13篇
  1998年   5篇
  1997年   5篇
  1996年   6篇
  1995年   5篇
  1993年   5篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1979年   3篇
  1978年   3篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有417条查询结果,搜索用时 15 毫秒
1.
Burials and mummies of dogs from the Arica, Chile, area are described. It is concluded that these dogs were brought to this area 2500 years ago by shepherds from the highlands and are still present, relatively unchanged.  相似文献   
2.
3.
4.
Heterais exul, previously known from Brazil and Argentina, was collected from a number of lakes and streams in the Lakes Region of Chile (between Valdivia and Puerto Montt). It was found in a wide variety of habitats: on leaf litter, detritus, algae, rotting wood, emergent vegetation, and clean sandy bottoms. Heterias, Pseudasellus, and Fritzianira are placed in synonymy, but Fritzianira is maintained as a subgenus of Heterias because of its lack of an antenna) scale. The 3 Australian species of Heterias and H. exul are believed to have evolved from a common freshwater Gondwanaland ancestor.  相似文献   
5.
Avila  Marcela  Otaíza  Ricardo  Norambuena  Ricardo  Nuñez  Mario 《Hydrobiologia》1996,326(1):245-252
The present paper describes growth dynamics in a natural bed of the resource luga negra (Sarcothalia crispata) in Guapilinao, southern Chile (41°57 S, 73°31 W). This resource is currently harvested and exported as raw material for the production of carrageenan. Seasonal variation in biomass, frond size, density and phenology was determined by periodic sampling. Natural recruitment was evaluated on different substrata added to the field; at the same time, substrata were inoculated under greenhouse conditions. Results showed that luga negra has seasonal growth: biomass increased from a minimum in spring to a maximum in mid to late summer. On the other hand, density was minimal in winter (200 ind. m–2) and increased to 2000 ind. m–2 in late spring. Peak abundance of mature tetrasporic fronds occurred in late summer, whereas that of cystocarpic fronds occurred in winter. Recruitment began in summer and extended into winter. Survival on different substrata were compared. Gametophytes had better survival rates on clam shells and 5 mm rope while tetrasporophytes had the best survival rate on clam shells and secondarily on boulders.  相似文献   
6.
The betaine lipid DGTA differentiates between two species of Ectocarpus: it is present in E. fasciculatus Harvey, and lacking in E. siliculosus (Dillwyn) Lyngbye, Two ectocarpoid isolates from the coast of Chile, which could not be identified to species level, were found to belong to opposite DGTA types. Culture experiments showed that these plants were sporophytes. Their meiospores produced gametophytes of the species predicted by the lipid analysis. Promoted by this new approach, a sexual population of Ectocarpus fasciculatus has been detected for the first time in the Pacific Ocean.  相似文献   
7.
13 species of the lichen genusCatapyrenium are reported from South America. Five species (C. analogicum, C. andicolum, C. exaratum, C. lachneoides, andC. podolepis) are described as new. A key to the species known from South America is presented. Remarks on taxonomy, ecology and distribution of the species are given.Studies on the lichen genusCatapyrenium (Verrucariaceae) III. For second part seeBreuss (1991).  相似文献   
8.
The continental coasts and remote islands in the high-latitude Southern Hemisphere, including the subantarctic region, are characterized by many endemic species, high abundance of taxa, and intermediate levels of biodiversity. The macroalgal flora of these locations has received relatively little attention. Filamentous green algae are prolific in the intertidal of southern islands, but the taxonomy, distribution, and evolutionary history of these taxa are yet to be fully explored, mostly due to the difficulty of access to some of these locations. In this study, we examined specimens of the order Cladophorales from various locations in the high-latitude Southern Hemisphere including the subantarctic (the Auckland Islands, Bounty Islands, Campbell Island, Macquarie Island, and Kerguelen Islands), as well as mainland New Zealand, the Chatham Islands, Chile, and Tasmania. The analyses of the rDNA sequences of the samples revealed the existence of two new clades in a phylogeny of the Cladophoraceae. One of these clades is described as the novel genus Vandenhoekia gen. nov., which contains three species that are branched or unbranched. The amended genus Rama is reinstated to accommodate the other clade, and contains four species, including the Northern Hemisphere “Cladophora rupestris.” In Rama both branched and unbranched morphologies are found. It is remarkable that gross morphology is not a predictor for generic affiliations in these algae. This study illustrates that much can still be learned about diversity in the Cladophorales and highlights the importance of new collections, especially in novel locations.  相似文献   
9.
10.
A number of expeditions to the area of Salar de Atacama, Chile, 68° 15'W, 20° 30'S, have involved studies of the biological and chemical features of Lake Tebenquiche, situated in the interior of the salar. Chemically, Tebenquiche is hypersaline, with practically anoxic waters dominated by sodium and chloride ions but with high concentrations of sulphate also. The lake is surrounded and invaded by macrophytes, dominated by Scirpus olmeyi and Juncus, which provide organic material for the formation of bacterial mats. The fauna of limnetic crustaceans is almost exclusively of Artemia salina. The most important genera of bacteria are: Marinomonas, Halobacterium, Acinetobacter and the sulphur reductors Vibrio and Bacillus. The Cyanobacteria are represented exclusively by Oscillatoria.  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