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151.
A review of lower actinopterygian phylogeny has led us to the conclusion that the Cladistia are the sister group of Recent actinopterygians (Actinopteri) and that the extinct Palaeonisciformes are a paraphyletic group, comprising stem-group actinopterygians (e.g. Cheirolepis ), stem-group actinopterans (e.g. Moythomasia ) and relatives of higher actinopterans such as Pteronisculus . Our analysis further concluded that the Acipenseriformes formed a clade together with Saurichthys and Birgeria , which was most parsimoniously resolved when the Acipenseriformes and Saurichthys were sister groups.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 144 , 511−525.  相似文献   
152.
Tracheary elements from macerations of roots and stems of one species each of five genera of Araceae subfamily Colocasioideae were studied by means of SEM (scanning electron microscopy). All of the genera have vessel elements not merely in roots, as previously reported for the family as a whole, but also in stems. The vessel elements of stems in all genera other than Syngonium are less specialized than those of roots; stem vessel elements are tracheid-like and have porose pit membrane remnants in perforations. The perforations with pit membrane remnants demonstrate probable early stages in evolution of vessels from tracheids in primary xylem of monocotyledons. The vessel elements with such incipient perforation plates lack differentiation in secondary wall thickenings between perforation plate and lateral wall, and such vessel elements cannot be identified with any reliability by means of light microscopy. The discrepancy in specialization between root and stem vessel elements in genera other than Syngonium is ascribed to probable high conductive rates in roots where soil moisture fluctuates markedly, in contrast with the storage nature of stems, in which selective value for rapid conduction is less. Syngonium stem vessels are considered adapted for rapid conduction because the stems in that genus are scandent. Correlation between vessel element morphology and ecology and habit are supported. Although large porosities in vessel elements facilitate conduction, smaller porosities may merely represent rudimentary pit membrane lysis.  相似文献   
153.
The superfamily Dytiscoidea contains six families with an aquatic lifestyle, with most of its extant diversity in two families: the burrowing water beetles (Noteridae) and the diving beetles (Dytiscidae). The other families have few species (up to six) and generally highly disjunct extant distributions. Aspidytidae currently contains one genus with two species, one in China and one in South Africa. Here we provide the first molecular data for the Chinese species, allowing us to explore the phylogenetic relationships and position of both species of this small family for the first time. Based on a matrix of 11 genes we inferred a phylogenetic hypothesis for Dytiscoidea including all extant families. Unexpectedly, Aspidytidae were consistently recovered as paraphyletic relative to Amphizoidae, despite being well characterized by apparently synapomorphic adult features. A re‐examination of larval characters in the two aspidytid species revealed that the larva of the Chinese species is strikingly similar to that of Amphizoidae. Both share a series of plesiomorphic features but also some potential synapomorphies, including a dense vestiture of short setae on the head capsule, anteriorly shifted posterior tentorial grooves and widely separated labial palps. Arguably these features may belong to the groundplan of the clade Aspidytidae + Amphizoidae, with far‐reaching secondary modifications (including reversals) in the South African Aspidytes niobe. At present we retain the family Aspidytidae, however, due to the strong adult morphological synapomorphies of the two extant species, and the fact that the molecular paraphyly of the family may result from the highly divergent nature of the two extant species. This long evolutionary separation and strong divergence, in terms of gene sequences and larval features, is undeniable, substantial levels of saturation in third codon positions of protein‐coding genes being present between the two taxa. We address this issue taxonomically by introducing the new genus S inaspidytes gen. nov. for the Chinese Aspidytes wrasei. The continued contentious relationships amongst Dytiscidae, Hygrobiidae, Aspidytidae and Amphizoidae highlight the need for more data to address dytiscoid phylogenetics, possibly involving a genomic approach. © 2016 The Linnean Society of London  相似文献   
154.
One new genus and six new species of palaeonemerteans are described and illustrated from Hong Kong and the New Territories; these are Hubrechtella sinimarinus sp. nov. and Parahubrechtia jillae gen. et sp. nov. in the Hubrechtidae, and Callinera bergendali sp. nov., Carinina sinensis sp. nov., Tubulanus hylbomi sp. nov. and Tubulanus longivasculus sp. nov. in the Tubulanidae. These bring the known number of pa-laeonemertean species from Hong Kong to 11; a key to these species, based primarily upon features distinguishable in the living animals, is provided.  相似文献   
155.
Twenty-one species of Stylopoma Levinsen, 1909 are described and illustrated with scanning electron micrographs. S. spongites (Pallas, 1766), the type species, is redescribed from the neotype specimen and included here for completeness. A neotype specimen for S. duboisii (Audouin, 1826) and a lectotype specimen for S. viride (Thornely, 1905) are designated and 14 new species of Stylopoma are described from Indo-West Pacific material in the Recent bryozoan collections of the Natural History Museum, London.  相似文献   
156.
Cladistic analysis of extant mustelids based on a data matrix consisting of 30 characters derived from morphological study of the head skeleton in all 23 genera, and 16 characters gleaned from the literature, yielded 75 most parsimonious trees with a consistency index of 0.487 using PAUP 3.0s. The analysis strongly supports the monophyly of both the Mephitinae (skunks) and Lutrinae (otters). The Mustelinae (weasels, martens, wolverine, etc) is probably paraphyletic, but there is some support for a monophyletic group consisting of the mustelines and the honey badger Mellivora. The Melinae (badgers) is a polyphyletic group; the badger ecomorph probably evolved independently at least three times within the Mustelidae. On consensus trees, there is a lack of resolution concerning the relationships within the Mephitinae and Lutrinae and the positions of Galictis and Mustela. These results are broadly congruent with a cladistic interpretation of Simpson's intent in his influential 1945 classification. Thus, a paraphyletic Mustelinae is consistent with Simpson's conception of a horizontal grouping, whereas the Mephitinae and Lutrinae represent vertical divergent lineages. In contrast, the cladistic status of the Melinae is not consistent with Simpsonian classificatory principles. The status of the monotypic Mellivorinae cannot be evaluated without considering its putative fossil members; however, the clustering of Mellivora with the badger Taxidea is not consistent with Simpson's scheme. Some of the more inclusive clades in the most parsimonious trees are vulnerable to minor changes to the data matrix. The fossil record is consistent with the basic outlines of the cladistic pattern and explains various ostensible biogeographic anomalies. Bootstrap analysis identified marked variation in the support for the components of the cladistic pattern.  相似文献   
157.
Edford Wood, near Holcombe in Somerset, England has a rich and varied flora. Topography and species composition indicate that much of the woodland is of ancient origin. The history of the site is complex, with the woodland long subjected to considerable human disturbance from surface mining of coal, drainage and the felling of larger trees. Documentary and other evidence has revealed that part of the wood has developed from grassland during the present century. This area of secondary woodland illustrates processes of succession as woodland plants invade.  相似文献   
158.
Electrohemiphlebia barucheli gen. et sp. nov. and Jordanhemiphlebia electronica gen. et sp. nov. , two new genera and species are described, based on exceptional inclusions of hemiphlebiid damselflies in Cretaceous amber from France and Jordan. The type specimen of E. barucheli was studied using phase contrast X‐ray synchrotron microtomography, giving exceptional images and detailed information. Its comparison with the recent Hemiphlebia mirabilis confirms the attribution of several Cretaceous damselflies to the Hemiphlebiidae, showing that this particular group was widespread in the Early Cretaceous and probably originated in the Late Jurassic or earlier. The ecological niches today occupied by the small coenagrionoid damselflies were occupied during the Triassic and Jurassic by Protozygoptera, hemiphlebiids during the Early Cretaceous, and modern taxa in the Cenozoic.  相似文献   
159.
Macropora is a distinctive genus of anascan cheilostomes. All species have large zooids with an extensive cryptocystal frontal shield perforated by numerous pores through which parietal muscle strands pass. Also characteristic of Macropora are the calcified opercula closing the d -shaped orifice, avicularia resembling autozooids but having slightly enlarged, typically crenulated opercula/mandibles, and large ovicells that are often costate. This mostly Australasian genus has a documented fossil record stretching back to the Eocene. Here we revise the generic diagnosis of Macropora and describe eight new species from New Zealand (three Recent: M. nodulosa sp. nov. , M. filifera sp. nov. and M. carlosi sp. nov. ; five fossil: M. septispinosa sp. nov. , M. similis sp. nov. , M. pittensis sp. nov. , M. leeae sp. nov. and M. bullata sp. nov. ) and one new species from Japan ( M. mawatariorum sp. nov. ), the only species known with certainty to occur in the northern hemisphere. New observations are given for some previously described species, several of which are illustrated using SEM for the first time. The northern hemisphere Upper Cretaceous species Monoporella exsculpta (Marsson), showing features allowing it to be placed tentatively in the stem-group of Macropora , is redescribed. Attempts to resolve the phylogenetic relationships of species within Macropora were hampered by the relatively few morphological characters compared with the number of species, and it proved impossible to obtain a phylogeny robust to slight changes in taxon and/or character inclusion. The favoured cladogram has poor bootstrap and Bremer support, and its stratigraphical and biogeographical congruences are low.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 153 , 115–146.  相似文献   
160.
Cladistic analyses were conducted using morphological and ITS sequence data to examine phylogenetic relationships within the Schisandraceae. The most parsimonious trees obtained from the morphological data consistently show a dichotomy, with clades corresponding with the two currently accepted genera, Kadsura and Schisandra . In the ITS trees S. propinqua consistently groups with the Kadsura clade, and the position of S. glabra is uncertain. The trees resulting from the analysis of combined data are polytomous, due to the variable positions of K. scandens, K. coccinea and S. propinqua . The monophyletic status of Kadsura subgen. Kadsura sect. Kadsura and Schisandra subgen. Pleiostema are strongly supported, although the monophyly of other supraspecific taxa is unclear. Further studies are required before an unambiguous phylogeny is achieved for the family.  相似文献   
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