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11.
The Texas fauna of the genus Anillinus Casey, 1918 includes three previously described species (A. affabilis (Brues), 1902, A. depressus (Jeannel), 1963 and A. sinuatus (Jeannel), 1963) and four new species here described: A. acutipennis Sokolov & Reddell, sp. n. (type locality: Fort Hood area, Bell County, Texas); A. comalensis Sokolov & Kavanaugh, sp. n. (type locality: 7 miles W of New Braunfels, Comal County, Texas); A. forthoodensis Sokolov & Reddell, sp. n. (type locality: Fort Hood area, Bell County, Texas); A. wisemanensis Sokolov & Kavanaugh, sp. n. (type locality: Wiseman Sink, Hays County, Texas). A key for identification of adults of these species is provided. The fauna includes both soil- and cave-inhabiting species restricted to the Balcones Fault Zone and Lampasas Cut Plain and adjacent areas underlain by the Edwards-Trinity Aquifer. Based on morphological and distributional data, we hypothesize that four lineages of endogean Anillinus species extended their geographical ranges from a source area in the Ouachita-Ozark Mountains to the Balconian region in central Texas. There the cavernous Edwards-Trinity aquifer system provided an excellent refugium as the regional climate in the late Tertiary and early Quaternary became increasingly drier, rendering life at the surface nearly impossible for small, litter-inhabiting arthropods. Isolated within the Edwards-Trinity aquifer system, these anilline lineages subsequently differentiated, accounting for the currently known diversity. The paucity of specimens and difficulty in collecting them suggest that additional undiscovered species remain to be found in the region. 相似文献
12.
13.
Maria McNamara Patrick J. Orr Stuart L. Kearns Luis Alcalá Pere Anadón Enrique Pe?alver-Mollá 《Proceedings. Biological sciences / The Royal Society》2010,277(1680):423-427
The very labile (decay-prone), non-biomineralized, tissues of organisms are rarely fossilized. Occurrences thereof are invaluable supplements to a body fossil record dominated by biomineralized tissues, which alone are extremely unrepresentative of diversity in modern and ancient ecosystems. Fossil examples of extremely labile tissues (e.g. muscle) that exhibit a high degree of morphological fidelity are almost invariably replicated by inorganic compounds such as calcium phosphate. There is no consensus as to whether such tissues can be preserved with similar morphological fidelity as organic remains, except when enclosed inside amber. Here, we report fossilized musculature from an approximately 18 Myr old salamander from lacustrine sediments of Ribesalbes, Spain. The muscle is preserved organically, in three dimensions, and with the highest fidelity of morphological preservation yet documented from the fossil record. Preserved ultrastructural details include myofilaments, endomysium, layering within the sarcolemma, and endomysial circulatory vessels infilled with blood. Slight differences between the fossil tissues and their counterparts in extant amphibians reflect limited degradation during fossilization. Our results provide unequivocal evidence that high-fidelity organic preservation of extremely labile tissues is not only feasible, but likely to be common. This is supported by the discovery of similarly preserved tissues in the Eocene Grube Messel biota. 相似文献
14.
Hanneke J. M. Meijer Lars W. van den Hoek Ostende Gert D. van den Bergh John de Vos 《Journal of Biogeography》2010,37(6):995-1006
The Late Pleistocene Flores fauna shows a pattern observed on many other islands. It is neither aberrant nor exclusive, but the result of non‐random selective forces acting upon an impoverished and disharmonic insular fauna. By comparing the Flores vertebrate fauna with other fossil insular biotas, it is apparent that the evolution of Homo floresiensis is part of a general pattern affecting all the inhabitants of Pleistocene Flores. Vertebrate evolution on Flores appears to have been characterized by phylogenetic continuity, low species richness and a disharmonic fauna. All three aspects stem from the isolated position of the island and have resulted in the distinct morphological characteristics of the Flores fauna. Evidence reviewed herein shows that features exhibited by H. floresiensis, such as small stature, a small brain, relatively long arms, robust lower limbs and long feet, are not unique, but are shared by other insular taxa. Therefore, the evolution of H. floresiensis can be explained by existing models of insular evolution and followed evolutionary pathways similar to those of the other terrestrial vertebrates inhabiting Pleistocene Flores. 相似文献
15.
中国中生代晚期及第三纪鱼类区系中的若干分布格局问题 总被引:5,自引:0,他引:5
日本列岛和中国大陆东部的现生淡水鱼类区系存在显著的差异,但这两地上新世和中新世的鱼类区系已发现的组成成分却似乎比现代鱼类区系要接近得多。而在中国东部渤海沿岸发现的早第三纪或始新世的鱼类区系成分则显示出与北美西岸同时代鱼类区系的惊人相似,展现出一个“跨太平洋格局”。中国中生代晚期或早白垩世的鱼类区系从组成和分布上可以划分为两个组合。分布于北部的一个组合中土著类型较多,分布于东南部的组合表现出一些与南美东北部及非洲西部鱼类区系的相似性,这种分布格局涉及到南、北两半球的大陆。 本文对上述分布格局作一简单介绍,并作初步解释: 1)早白垩世的副鲚鱼亚科鱼类在西非、南美洲东北部的分布曾被解释为1)历史上曾存在过一个包括副鲚鱼亚科在内的广布单系类群;2)中国东南部早白垩世鱼类区系起源于冈瓦纳;3)中国东南部早白垩世鱼类区系中至少有某些种类是近岸鱼类。本文倾向于接受后两种建议。 2)始新世渤海沿岸及北美绿河页岩鱼类区系的“跨太平洋”分布格局曾有人用“太平洋洲假说”来说明。本文作者不赞成这种解释,认为这一分布格局的形成有多种原因,如当时宽阔的白令陆桥及露出海面的北极地区可作为两地鱼类的通道;两地的近岸鱼类可沿当时连续的海岸来往, 相似文献
16.
A NEW MIOCENE XENOCYPRININE (CYPRINIDAE) FROM HEILONGJIANG PROVINCE,NORTHEAST CHINA AND SUCCESSION OF LATE CENOZOIC FISH FAUNAS OF EAST ASIA 总被引:1,自引:1,他引:0
AnewgenusandspeciesofXenocyprininae(Eoxenocyprisliui)isdescribedfromaplacergoldminenorthwestofHua'nanCounty,HeilongiiangProvince.ThedistributionoftheextantmembersofthesubfamilyislindtedtotheeasternlowlandsofChinaandHanoiBasin(SongHongValley),northernVetnam.InInteChnozoic,however,inadditiontotheirrecentareaofhabitattheywerealsowidelyspreadinJapan,mainlyinthelacustrinedepositsinthewesternsideoftheislandarchalnal,gaPoblique,lengthofheaongtheSeaofJapan.~~tagen'n0v'DiagnosisXen0cyprininofre… 相似文献
17.
Abstract: Trilobites, a dominant component of marine faunas during the Cambrian and Ordovician and which survived until the end of the Permian (542–251 Ma) have been used in many macroevolutionary analyses. Here, we use a discovery curve to document the sampling history of trilobites, which we consider a proxy for Palaeozoic faunas in general. At higher taxonomic ranks, orders, suborders and superfamilies, the fossil record has been completely sampled, while the family rank also shows a high level of sampling completeness, having reached an asymptote in 1970. Importantly, this levelling-off occurred even though worker effort continued to increase. However, at genus level the sampling record is incomplete, indicating that families should not be used as a proxy for genera. There is little variation among the different subsets of generic data, with the sampling history of different stratigraphic periods and among different orders being very similar. However, there is noticeable variation among geographical regions, caused by variations in worker effort, and this could cause problems when comparing speciation and diversity patterns across faunal provinces. The role of synonyms on sampling history has had little effect. 相似文献
18.
红松阔叶混交林凋落物-土壤动物-土壤系统中N、P、K的动态特征 总被引:20,自引:1,他引:19
根据对小兴安岭凉水国家级自然保护区红松阔叶混交林的凋落物、土壤动物和土壤2a的连续采样及测定主要营养元素N、P、K的含量,研究凋落物-土壤动物-土壤系统中主要营养元素在各分室的动态变化,并通过比较主要营养元素在不同分室中的分异,进而分析了土壤动物在该系统营养循环中的作用。结果表明,研究区内不同凋落叶分解过程中元素含量的动态变化比较复杂,阔叶落叶中营养元素含量的变化大于针叶落叶,但不同凋落叶在分解过程中的元素损失量之间的差异不显著。在研究时段,腐殖土层各种营养元素的含量高于土壤层;蚯蚓、蜈蚣和马陆大型土壤动物体内的营养元素含量之间差别较大,其中蚯蚓体内全N含量最高,而马陆体内全P含量最高,蜈蚣则全K含量最高。土壤动物和土壤中营养元素含量的动态变化和凋落叶中的变化趋势不同。N和P在土壤动物分室中表现出一定的富集,而K的富集不明显。土壤动物可以通过其新陈代谢活动加速凋落物-土壤动物-土壤系统中营养元素的循环速率。不同凋落物分解过程中养分含量变化复杂可能是由于不同凋落物种类特性差异造成的。土壤动物在营养元素循环,尤其是N、P元素循环中具有重要意义。 相似文献
19.
Norman Owen‐Smith 《Journal of Biogeography》2013,40(7):1215-1224
Aim
Africa is renowned for the current abundance and diversity of its large mammals. The aim of this study was to assess distinctions evident in the functional composition of continental large herbivore faunas during the late Pleistocene before extinctions depleted the megafauna outside Africa.Location
The African large herbivore fauna was compared with that formerly inhabiting South America, Australia, North America, Eurasia and tropical Asia during the late Pleistocene.Methods
Pleistocene faunas were reconstructed from the literature in terms of their relative body size composition, grazer/browser contributions and taxonomic representations, omitting forest and island species.Results
Although the three southern continents were closely similar in the overall species richness of large herbivores that they supported during the late Pleistocene, South America had a predominance of very large herbivores, while most of Australia's mammalian herbivores were relatively small and those of Africa were intermediate. Africa had many more grazers, especially in the size range 100–1000 kg, than other continents. The South American pattern resembled that in North America and Eurasia, while Africa and Australia diverged in different ways.Main conclusions
Neither the total extent of savannas in each continent nor the morphological features enabling bovid radiation seemed adequate on their own to explain the greater richness of macrograzers in Africa. Africa is characterized by the widespread occurrence of arid/eutrophic savannas, which are unrepresented in other continents. The prevalence of savanna is partly attributable to the high elevation of interior eastern and southern Africa, associated with relatively low rainfall, and to the comparatively high soil fertility, related to volcanic influences. This promoted an abundance and diversity of medium‐sized grazing ruminants unrivalled elsewhere. Indigenous grasses in South America and Australia are less well adapted to withstand severe grazing than the African grasses introduced to support livestock. The locally high abundance of African ungulates presented conditions that facilitated the adaptive transition by early hominins from plant‐gatherers to meat‐scavengers. 相似文献20.
Abstract: A review on the Oligocene and Miocene stalked barnacles of the Paratethys Sea is presented. The fauna comprises two lepadiform and eight scalpelliform species. Only two species are known from Oligocene deposits, four are documented from Lower Miocene formations, and another four species occur in the Middle Miocene. Only one Oligocene and one Miocene species occur in two different Paratethyan basins in roughly coeval environments, and only a single Middle Miocene species is also known from the adjacent Mediterranean Sea. This low degree of biogeographical similarity is probably a result from the still low number of publications dealing with this group. Stalked barnacles are often indicating bathyal or at least deep sublittoral environments. Especially, the abundance of the benthic deep‐water lepadiform Poecilasma in evaporitic deposits of the Middle Miocene Badenian Salinity Crisis may serve as new evidence for a deeper marine depositional environment. Scalpellum paratethyianum sp. nov. and Lepas sattmanni sp. nov. are described as new species; Arcoscalpellum renevieri (Mayer and Gümbel in Gümbel, 1861) is introduced as new combination. 相似文献