全文获取类型
收费全文 | 362篇 |
免费 | 14篇 |
国内免费 | 7篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 19篇 |
2012年 | 8篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 12篇 |
2004年 | 22篇 |
2003年 | 13篇 |
2002年 | 14篇 |
2001年 | 16篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 20篇 |
1997年 | 19篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1980年 | 6篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有383条查询结果,搜索用时 15 毫秒
1.
The Bryopsidales contains some of the most species rich and ecologically dominant algae in tropical ecosystems. However, the evolutionary relationships among the 29 genera and several hundred species of this order remain poorly resolved. Because of a lack of known reproductive characters for many taxa, evolutionary hypotheses grouped genera by similarities in morphological characters. To apply standard cladistical analyses to further our understanding of this group, this study presents the first comprehensive compilation of reported morphological, reproductive, and subcellular characteristics for genera in the Bryopsidales. Computer-assisted cladistical analyses ultimately identified phylogenetically informative and uninformative characters. Although the topology of the trees generated in this study is expected to change as additional data are added to this matrix, many traditional groupings and recent groupings based on molecular data were supported. 相似文献
2.
A comparison of phenetic and phylogenetic methods applied to the systematics of Oligochaeta 总被引:1,自引:1,他引:0
A comparative study of naidid subfamilies shows that a combination of ordination, Jaccard/Average Linkage cluster analysis and Wagner parsimony provides a useful basis for a rational phylogeny but that this does not differ markedly from the original proposed by Sperber nearly four decades ago. Hennig rules, modified by Wiley, permit a preliminary phylogeny and classification of the Annelida to be made by hand. An error in earlier versions suggested that the Dorydrilidae lacked prostate glands, and this is corrected. 相似文献
3.
G. R. Guerin 《Plant Systematics and Evolution》2005,254(1-2):49-68
Nutlets of Hemigenia R.Br. and Microcorys R.Br. were examined using SEM. Significant variation, mainly useful at the infrageneric level, was found in nutlet shape, nature of the attachment scar, nature of surface sculpturing, exocarp cell shape and sculpturing, and nature of the indumentum. Typical nutlets are ovoidal, strongly reticulate or rugose. The exocarp cells are isodiametric and convex to papillate. Also common are cylindrical nutlets, often with longitudinal ridging and papillate exocarp cells. Surface pitting and concave exocarp cells are rare. A cladistic analysis of nutlet characters suggests both Hemigenia and Microcorys are polyphyletic, and Microcorys paraphyletic with respect to Westringia Sm. Notwithstanding that, the infrageneric classification of Hemigenia was largely supported, while in Microcorys, there was support for sect. Hemigenioides, but sects Anisandra and Microcorys were not resolved as distinct. 相似文献
4.
P.Mick Richardson 《Biochemical Systematics and Ecology》1982,10(2):197-199
Published results of the distribution of anthocyanins in the Sterculiaceae have been re-interpreted on the basis of the phylogenetic status of the compounds present. A flavonoid score system was less useful than a cladistic interpretation based on Hennigian arguments. 相似文献
5.
N. MØLLER ANDERSEN 《Zoological Journal of the Linnean Society》1991,103(1):21-60
Five species of sea skaters, genus Halobates Eschscholtz, are the only insects to have successfully colonized the open ocean. In addition, 36 species are found in sheltered coastal waters throughout tropical Indo-Pacific. The taxonomy of the genus is relatively well known, but reliable hypotheses about phylogenetic relationships are required if the biogeography and evolution of sea skaters is to be discussed in a meaningful way. This work presents the results of a study of new characters from the genital segments, especially those of the male phallus and the female gynatrial complex, and a reinterpretation for several other characters. In total 64 characters were scored for 26 species of Halobates , two species ofAsclepios and one species of Metrocoris. With Asclepios and Metrocoris species as outgroups, the character state sets were analysed cladistically using the computer program Hennig86. After critical evaluations of both characters and clades, a phylogeny for Halobates is presented and its taxonomic implications are discussed. A number of monophyletic species groups are delimited. One genus-level synonymy and three species-level synonymies are suggested. The evolution of Halobates is discussed in the light of the reconstructed phylogeny and present knowledge of the ecology and behaviour of sea skaters. A hypothesis of ecological evolution in halobatine water striders is proposed and tested. 相似文献
6.
Variation of 80 multistate morphological characters and isozymes encoded by 13 loci among 23 vetch species of the type subgenus
of the genus Vicia in comparison with V. dumetorum,
V. pisiformis and V. sylvatica of the subgenus Cracca is described and analyzed with cladistic parsimony and phenetic neighbour-joining methods by using two different ways of
coding. Morphological analyses showed the subgenus Vicia monophyletic and revealed subgroups in a general agreement with traditionally recognized sections, except showing V. faba nested within section Narbonensis and ambiguity in the position of V. lathyroides and V. bithynica. Parsimony analysis of orthozymes as presence/absence characters revealed in the subgenus two basic monophyletic clades:
1) V. faba and three species of the section Peregrinae, V. michauxii, V. aintabensis and V. peregrina, in one subclade linked with species of the Narbonensis and Hyperchusa sections together with V. pisiformis of subgenus Cracca in a second subclade; 2) species belonging to sections Vicia, Sepium, Pseudolathyrus and Lathyroides together with V. sylvatica of the subgenus Cracca. Neighbour-joining analysis of orthozymes revealed the same two basic groups, differing only in the relative position of some
species in subclusters. Both isozyme analyses showed paraphyly of the subgenera Vicia and Cracca. Parsimony analysis of orthozymes as character states of isozymes yielded a largely unresolved strict consensus cladogram
of 209 most parsimonious trees, and reweighting of characters failed to produce a stable tree. Phylogenetic congruence and
discordance among morphological and isozyme analyses, coding ways, homoplasy and weighting of characters are discussed.
Received November 20, 2001 Accepted January 31, 2002 相似文献
7.
PAULO ANDREAS BUCKUP 《Zoological Journal of the Linnean Society》1993,108(3):225-245
Although virtually no phylogenetic evidence (in the sense advocated by Hennig, 1966) had been previously presented to support the monophyly of the Characidiinae, and most 'diagnostic' characters used by previous authors were found to be unacceptable in a cladistic classification, i t is still possible to diagnose the Characidiinae in a phylogenetic sense. This study revealed the existence of 13 synapomorphies supporting the monophyly of the group. Several of these synapomorphies, such as the modifications associated with the mesethmoid, the jaw bones, and the ribs of the fifth vertebra, are unique to the Characidiinae, thus providing a solid basis for recognizing the group as a monophyletic unit of characiform fishes. Demonstration of characidiin monophyly provides a solid foundation for further phylogenetic analysis of characidiin interrelationships, and higher level relationships among characiform fishes. 相似文献
8.
Morphological phylogenetic analysis of Ophrys (Orchidaceae): insights from morpho‐anatomical floral traits into the interspecific relationships in an unresolved clade 下载免费PDF全文
Ana Francisco Miguel Porto Lia Ascensão 《Botanical journal of the Linnean Society. Linnean Society of London》2015,179(3):454-476
Reconstructing the phylogeny of the sexually deceptive orchid genus Ophrys is crucial to our understanding of the evolution of its complex floral morphology. Molecular phylogenetic analyses showed that section Pseudophrys forms a well supported clade with Ophrys bombyliflora, O. tenthredinifera and O. speculum, but were unable to elucidate the relationships between these four groups of taxa. Here we conduct a morphological phylogenetic analysis of this unresolved clade of Ophrys based on a data matrix of 45 macro‐ and micromorphological and anatomical floral characters, using maximum parsimony and Bayesian inference. Our cladistic analysis yielded a single most parsimonious tree and a Bayesian 50% majority‐rule consensus tree which differed in their overall topology but agreed that O. tenthredinifera and O. bombyliflora are not sister groups. The phylogenetic placement of O. tenthredinifera was ambiguous since it shares six valid synapomorphies each with the cluster of O. speculum–O. bombyliflora and with section Pseudophrys. In contrast, O. bombyliflora is most likely the sister group to O. speculum, a finding that rejects an earlier morphological phylogenetic hypothesis and favours the existing molecular trees based on nuclear ITS rather than plastid data. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 454–476. 相似文献
9.
Phylogenetic reassessment and biogeography of the Ectateus generic group (Coleoptera: Tenebrionidae: Platynotina) 下载免费PDF全文
Marcin Jan Kamiński 《Zoological Journal of the Linnean Society》2015,175(1):73-106
Owing to the reinterpretation of its morphological synapomorphies, the taxonomic composition of the Ectateus generic group had been ambiguous. The present study scrutinized all existing taxonomic concepts of the group based on a cladistic analysis of the adult morphology of all of the Afrotropical platynotoid Platynotina genera. The phylogenetic relationships were reconstructed using parsimony and Bayesian inference. The results show that all previous taxonomic concepts of the Ectateus generic group concerned paraphyletic entities. The cladistic analysis revealed the following synapomorphies for the taxon: (1) presence of basal indentations of the pronotal disc, (2) ratio of prothorax width to its maximal height > 6.0, and (3) ratio of maximal height of the prothorax to total height < 0.3. Moreover, phylogenetic studies revealed the existence of the Upembarus generic group, a sister‐taxon group to the Ectateus generic group, within the Afrotropical platynotoid Platynotina. Autapomorphic and synapomorphic character mapping show that several taxonomic and nomenclatural changes are needed to consider the particular generic‐level entities traditionally assigned to Afrotropical platynotoid Platynotina as monophyletic lineages. The following taxonomic and nomenclatural adjustments are made in this paper: P teroselinus gen. nov. is erected to accommodate a single species that was previously assigned to Zidalus: Pteroselinus insularis comb. nov. Additionally, the following synonymies are proposed: Anchophthalmops (= Platykochius syn. nov. ), Angolositus (= Aberlencus syn. nov. , = Platymedvedevia syn. nov. ), Glyptopteryx (= Microselinus syn. nov. , = Quadrideres syn. nov. , = Synquadrideres syn. nov. ). In addition, Kochogaster is lowered in rank and is treated as one of the subgenera of Anchophthalmus. Moreover, Pseudoselinus is treated as a subgenus of Upembarus. An identification key to all Afrotropical platynotoid Platynotina genera and subgenera is presented. Zoogeographical analyses revealed the following dispersal barriers for the Ectateus generic group: (1) the Sahara (northern barrier); (2) the dry ecosystems of Botswana, Namibia, and South Africa (southern barrier); and (3) the Congolian rainforests (internal distributional gap). The ancestor of the taxon probably originated in East African ecoregions that predominantly contained wattletrees (acacias) and Commiphora Jacq. Moreover, past climate changes seem to have had a great impact on the observed generic distribution. © 2015 The Linnean Society of London 相似文献
10.
MARTIN D. BRAZEAU 《Biological journal of the Linnean Society. Linnean Society of London》2011,104(3):489-498
The effects of different coding practices in morphological phylogenetic analysis are well documented. In many cases, we can determine that certain practices can be regarded as undesirable and should be avoided. Certain coding practices do not correctly translate the expected information to the cladistic algorithm. It may go unnoticed that expressions of character information in character lists, which may be entirely logical to any reader, do not necessarily reflect the mathematics employed by a phylogenetic algorithm. Despite a wealth of literature on coding procedures and documentation of these issues, problematic character coding practices are still common. A review is provided of different coding and character formulation practices, particularly relating to multistate character information that may either: (1) lead to a failure to capture grouping information implied in the character list; (2) cause problematic weighting or spuriously high certainty in particular optimizations; and (3) impose congruence artificially, by linking more than one variable character to a particular state. Each of these is reviewed and presented with a hypothetical example. Recommendations for avoiding these pitfalls are described in light of how parsimony algorithms work with character data. Character lists must be drawn up not only to present character variation logically, but also with consideration for how computer algorithms implement cladistic logic. The widespread use of problematic character coding procedures may account for some of the perceived problems with morphological data. Therefore, an exploration of the effects of these methods and standardization of methods should be a goal for the very near future. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 489–498. 相似文献