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   72篇
  免费   14篇
  2021年   1篇
  2018年   2篇
  2017年   4篇
  2016年   2篇
  2015年   6篇
  2014年   4篇
  2013年   6篇
  2012年   9篇
  2011年   7篇
  2010年   10篇
  2009年   7篇
  2008年   1篇
  2007年   2篇
  2006年   1篇
  2005年   3篇
  2004年   1篇
  2003年   1篇
  1999年   1篇
  1998年   2篇
  1996年   1篇
  1990年   1篇
  1988年   1篇
  1984年   1篇
  1979年   2篇
  1977年   1篇
  1976年   2篇
  1972年   1篇
  1971年   2篇
  1970年   1篇
  1967年   1篇
  1954年   1篇
  1951年   1篇
排序方式: 共有86条查询结果,搜索用时 15 毫秒
81.
The fossil species Architipula fragmentosa (Bode) comb. nov. (Diptera: Nematocera: Limoniidae) from the German Upper Lias (Lower Jurassic) is redescribed. This species was originally described by Bode (1953) in a new monotypic genus as Eoasilidea fragmentosa and placed in the Brachycera, with Eoasilidea as the type-genus of a new family Eoasilidae. This family is here synonymized with the Limoniidae (Nematocera), and the genus Eoasilidea is synonymized with Architipula Handlirsch .  相似文献   
82.
Effects of Anti-inflammatory Drugs on Prostaglandin Biosynthesis   总被引:30,自引:0,他引:30  
Comparison of the anti-inflammatory activities of several aspirin-like drugs with the inhibition of prostaglandin synthetase which they produce supports this as their mechanism of action.  相似文献   
83.
Abstract Phylogenetic relationships within the family Corylophidae were investigated. Twenty ingroup taxa and six outgroups were included in a cladistic analysis, based on 48 characters derived from adult and larval morphology. Phylogenetic analysis confirms that Corylophidae are monophyletic within the superfamily Cucujoidea and may be subdivided into two subfamilies: the Australian Periptycinae and the cosmopolitan Corylophinae containing 10 tribes: Foadiini trib.n. , Cleidostethini, Aenigmaticini, Parmulini, Sericoderini, Peltinodini, Orthoperini, Corylophini, Teplinini and Rypobiini. All currently recognized family‐group taxa are thoroughly diagnosed, and keys to their identification based on adults and larvae are provided. Two new genera and three species are described: Weirus gen.n ., containing only W. tozer sp . n . (Australia: Queensland), and Stanus gen.n. , with the two species S. bowesteadi sp.n . (New Zealand) and S. tasmanicus sp.n. (Tasmania). The larvae of Pakalukodes bimaculatus?lipiński et al. from Queensland and of Stanus bowesteadi sp.n. from New Zealand are described and illustrated for the first time.  相似文献   
84.
Fossil Artematopodidae are rarely collected and previously confined to middle Eocene Baltic amber. Here we report the first definitive artematopodid, Sinobrevipogon jurassicus gen. et sp.n. , from the Middle Jurassic Daohugou beds (c. 165 Ma) in Inner Mongolia, northeastern China. It exhibits a number of defining features of Artematopodidae, including paired carinae on prosternum and an internal apical interlocking tongue on the ventral side of each elytron. However, it differs from any modern Artematopodidae by having the mesocoxal cavitiy closed by the mesepimeron and the anterolateral edge of metanepisternum. The discovery of this new genus represents the earliest fossil record for Artematopodidae, highlighting the antiquity of the family. The systematic positions of Forticatinius Tan & Ren and Tarsomegamerus Zhang are discussed, and the latter is formally transferred to Artematopodidae. Phylogenetic relationships within Artematopodidae were investigated to elucidate the relationships between the two Jurassic genera and Recent genera. Eleven in‐group taxa and two out‐groups were included in a cladistic analysis based on 30 adult characters; the resulting tree recovered the family Artematopodidae in three clades: (i) Electribius authority, (ii) Ctesibius authority + Brevipogon authority + Sinobrevipogon + Tarsomegamerus and (iii) the remaining Recent genera, including Allopogonia authority.  相似文献   
85.
86.
1. This study reports the discovery of sympatric populations of antlions (Neuroptera: Myrmeleontidae) and wormlions (Diptera: Vermileonidae) in a unique system of sandy microhabitats in the lowland rainforest of Borneo. The two species convergently evolved sit‐and‐wait predatory larvae, which construct pitfall traps to hunt insects. Despite similar specialised foraging strategies, the two species coexist in the competitive environment of small, isolated sandy patches in the rainforest, which begs the question: what biological characteristics allow their coexistence? 2. Based on larval morphology alone, it was predicted that antlions would build larger traps, which would allow them to efficiently hunt larger prey. Addressing this hypothesis, this study compared the volumes of traps constructed by the two species under field and laboratory conditions. A laboratory experiment compared their efficiency of capture of three ant species that differed in body size. 3. The results show that antlions constructed larger traps and captured prey more efficiently. The difference between the species could not be explained by trap size alone. The findings demonstrate that the overlap in resource use in these two species was low, and it is suggested that there is a separation in prey utility between them, allowing their coexistence in the space‐limited habitat of the tropical rainforest.  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