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51.
52.
JEAN‐CHRISTOPHE LENOIR ALEXANDRA SCHREMPF ALAIN LENOIR JÜRGEN HEINZE JEAN‐LUC MERCIER 《Molecular ecology resources》2005,5(3):565-566
We describe primer sequences for five microsatellite markers in Cardiocondyla elegans, an ant species with ergatoid males. Polymorphism of these loci was investigated using 236 individuals from 22 colonies from four locations. The microsatellites are dinucleotide repeats with four to 16 alleles, and the observed heterozygosity ranges from 0.244 to 0.720. We characterized these markers for the study of the population as well as the social structure of colonies. 相似文献
53.
Abstract: The family Acrochordiceratidae Arthaber, 1911 ranges in age from latest Spathian to the middle/late Anisian boundary, and it represents a major component of ammonoid faunas during that time. The middle Anisian genus Acrochordiceras Hyatt, 1877 is the most widespread taxon of the family and occurs abundantly worldwide within the low paleolatitude belt. However, there is a profusion of species names available for Acrochordiceras. This excessive diversity at the species level essentially results from the fact that sufficiently large samples were not available, thus leading to a typological approach to its taxonomy. Based on new extensive collections obtained from the Anisian (Middle Triassic) Fossil Hill Member (Star Peak Group, north‐west Nevada) for which a high resolution biostratigraphic frame is available, the taxonomy and biostratigraphy of the genus Acrochordiceras Hyatt, 1877 is herein revised with respect to its intra‐specific variation. Morphological and biometric studies (c. 550 bedrock‐controlled specimens were measured) show that only one species occurs in each stratigraphic level. Continuous ranges of intra‐specific variation of studied specimens enable us to synonymize Haydenites Diener, 1907, Silesiacrochordiceras Diener, 1916 and Epacrochordiceras Spath, 1934 with Acrochordiceras Hyatt, 1877. Three stratigraphically successive species are herein recognized in the low paleolatitude middle Anisian faunas from Nevada: A. hatschekii (Diener, 1907), A. hyatti Meek, 1877 and A. carolinae Mojsisovics, 1882. Moreover, an assessment of intra‐specific variation of the adult size range does not support recognition of a dimorphic pair (Acrochordiceras and Epacrochordiceras) as previously suggested by other workers (Epacrochordiceras is the compressed and weakly ornamented end‐member variant of Acrochordiceras). The successive middle Anisian species of Acrochordiceras form an anagenetic lineage characterized by increasing involution, adult size and intra‐specific variation. This taxonomic revision based on new bedrock‐controlled collections is thus an important prerequisite before studying the evolution of the group. 相似文献
54.
ALESSANDRA SELBACH‐SCHNADELBACH SUZANA SMITH CAVALLI JEAN‐FRANÇOIS MANEN GERALDO CENI COELHO TATIANA TEIXEIRA DE SOUZA‐CHIES 《Botanical journal of the Linnean Society. Linnean Society of London》2009,159(1):182-193
The aim of the present work was to clarify the origin and phylogenetic position of the species belonging to the genus Ilex (Aquifoliaceae), especially the South American species. Phylogenetic relationships of the genus Ilex were investigated using the plastid psbA‐trnH intergenic spacer and parsimony and Bayesian analyses. The psbA‐trnH intergenic spacer was shown to evolve slowly within Ilex, but a major gap present in this region was useful in the phylogenetic study of the genus. To obtain more potentially parsimonious characters, atpB‐rbcL intergenic spacer data were combined with those for psbA‐trnH. Many gaps present in the psbA‐trnH region were useful in the phylogenetic study of the genus Ilex. The topology of the trees showed that, in general, the clades are strongly related to geographical areas, a fact especially evident in certain different Asian lineages. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 182–193. 相似文献
55.
The control of incompatibility in distylous Pulmonaria affinis Jordan (Boraginaceae) 总被引:1,自引:0,他引:1
A.J. RICHARDS JEAN MITCHELL 《Botanical journal of the Linnean Society. Linnean Society of London》1990,104(4):369-380
In P. affinis, pin pollen is shorter on average than thrum pollen. Pins have more coronal hooks on stigmatic papillae than thrums, but gaps between papillae are relatively smaller for thrums. Pin stigmas receive more pollen than thrum stigmas. Thrum stigmas receive more (dissortive) pin pollen, but pin stigmas are assortively pollinated. Pollen only germinates when trapped below papilla coronas. On thrum stigmas, most trapped pollen is pin. Pollen germination is better on thrum stigmas than pin stigmas, and thrum stigmas show a close relationship between numbers of legitimate pollen grains, numbers of germinating grains, and numbers of pollen tubes in the style. There is no inhibition of illegitimate pollen germination. Illegitimate pollen tubes are inhibited in the style. Incompatibility operates by a combination of dissortive pollination, dissortive pollen trapping, and stylar pollen tube inhibition. All heteromorphic features differing between pins and thrums are implicated in the inhibition of within-morph fertilization in thrums. 相似文献
56.
JEAN‐LUC CACAS 《Plant, cell & environment》2010,33(9):1453-1473
Eukaryotic cells have to constantly cope with environmental cues and integrate developmental signals. Cell survival or death is the only possible outcome. In the field of animal biology, tremendous efforts have been put into the understanding of mechanisms underlying cell fate decision. Distinct organelles have been proven to sense a broad range of stimuli and, if necessary, engage cell death signalling pathway(s). Over the years, forward and reverse genetic screens have uncovered numerous regulators of programmed cell death (PCD) in plants. However, to date, molecular networks are far from being deciphered and, apart from the autophagic compartment, no organelles have been assigned a clear role in the regulation of cellular suicide. The endomembrane system (ES) seems, nevertheless, to harbour a significant number of cell death mediators. In this review, the involvement of this system in the control of plant PCD is discussed in‐depth, as well as compared and contrasted with what is known in animal and yeast systems. 相似文献
57.
SEM Characterization of an Extracellular Matrix Around Somatic Proembryos in Roots of Cichorium 总被引:1,自引:0,他引:1
DUBOIS THERESE; DUBOIS JEAN; GUEDIRA MOUNA; DIOP ALIOUNE; VASSEUR JACQUES 《Annals of botany》1992,70(2):119-124
Roots of in vitro plantlets of a hybrid Cichorium intybus L.x C. endivia L. placed for 10 d in an agitated liquid inductionmedium in darkness at 35 °C give somatic embryos of varioussizes which disrupt the epidermis. Proembryos can be observedinside the root; they show a fibrillar network linking the surfacecells. The network is observed in agitated and static liquidmedium; it is not well developed on solid medium. It is notremoved by lipid solvents and pectinase but disappears partlywith protease. Ether-methanol (1:1 v/v) for 45 min and Tris-HC1buffer for 3 h at 30 °C destroy it. As in animal cells suchexternal proteic networks are constituents of an extracellularmatrix linked to the cytoskeleton, we tested microtubule destabilizationby colchicine and cold treatments which removed the network;this effect was reversed by DMSO and high temperature. Cichorium, extracellular matrix, extracellular proteins, somatic embryogenesis 相似文献
58.
Of the eleven cultivated species of Umbelliferae heavily attacked in the field by Cavariella aegopodii Scop., chervil (Anthriscus cerefolium) attracted so many alates that it was killed before a population of alienicolae developed. Carrot was next in order of alate preference and coriander (Coriandrum sativum) and caraway (Carum carvi) were last. Despite its lack of attraction, caraway proved more lastingly suitable as a host and eventually supported the largest population of alienicolae. Of the wild umbellifers tested, wild carrot, Daucus carota ssp. carota, was the species most preferred by the incoming alates and hemlock (Conium maculatum) the least. On hemlock, also, there was little colonization. Although a sequence of wild umbellifers supported C. aegopodii through most of the year, few were suitable winter hosts; the apterae hibernated largely on carrot crops. In spring, cow parsley (Anthriscus sylvestris) was one of the hosts first colonized by immigrant C. aegopodii and carried winged alienicolae before the end of June. The main development of winged alienicolae on Anthriscus and other wild Umbelliferae, however, was in July. The possible role of the wild umbelliferous hosts of C. aegopodii in the spread of motley dwarf virus to carrots is discussed. 相似文献
59.
Abstract: The rudist bivalve genus Gorjanovicia Pol?ak, 1967 from Istria, Croatia, is currently known from the Coniacian/Maastrichtian of the peri‐Adriatic and Balkan regions and includes 23 nominal species, defined mainly on shell ornamentation and radial bands. However, a re‐appraisal of ‘Radiolites’endrissi Boehm, 1927 shows the type species of the genus Gorjanovicia, G. costata Pol?ak, 1967, to be a junior synonym of Boehm’s species, which thus takes priority as the type species of Gorjanovicia. Our revision of the 24 species thus described from the literature is based on analysis of a set of 21 characters that include the dimensions, shape and ornamentation of the right valve. Sixteen variables are defined from combinations of these 21 characters and subjected to multiple correspondence analysis (MCA) and Hill and Smith analysis (HSA), with cluster analysis, which has allowed us to distinguish three taxonomic groups, each defined by a key species: Gorjanovicia endrissi (Boehm), G. ugarensis Sli?kovi? and G. kvarneri Pol?ak. Cluster analysis identifies three groups of associated variables and suggests that a limited number of characters may be used to recognize the foregoing three taxonomic entities. MCA performed on four variables (the shapes of the anterior radial band, posterior radial band and interband and the width of the anterior band relative to the posterior band) reveals the same three taxonomic groups as in the MCA based on 16 variables. We conclude that the four variables in question may thus be used as specific diagnostic characters and that the genus Gorjanovicia is thereby represented by just three species, Gorjanovicia endrissi, G. ugarensis and G. kvarneri, instead of the 24 described in the literature. Specific assemblages from the peri‐Adriatic, pre‐Apulian and Western Pontides regions are nearly identical, a pattern that suggests free faunal exchanges within the distributional area of the genus Gorjanovicia. The palaeobiogeographical distribution of species corresponds with a relatively narrow palaeolatitudinal range in the subtropical portion of the eastern Mediterranean Tethys. 相似文献
60.
CHRISTIAN GAILLARD PIERRE HANTZPERGUE JEAN VANNIER ANNE-LAURENCE MARGERARD JEAN-MICHEL MAZIN 《Palaeontology》2005,48(5):947-962
Abstract: Well-preserved arthropod trackways are described from the laminated limestones of the Crayssac Lagerstätte (south-west France, Lower Tithonian). They occur in sediments deposited in the temporary coastal mudflats of intertidal to supratidal zones. The trackways are referred to Pterichnus isopodicus isp. nov., and are interpreted as the locomotion traces of isopods. Different trackway morphotypes are recognized and clearly resulted from variations in the original consistency of the sediment. Sinuous trackways may correspond to vagrant activity on wet mud whereas numerous straight ones indicate a more rapid crawling on a soft-to-firm substratum (e.g. tidal flat during emersion). The preferred orientation of trackways indicates that isopods were crawling in a direction perpendicular to shoreline as a result of possible taxis induced by sediment wetness and/or by a migratory behaviour controlled by tidal rhythm. Unusually long emergence of the sediments may have favoured the preservation of dense networks of trackways. An isopod identity is supported by the general morphology of the tracks and the association of trackways with isopod body fossils. Archaeoniscus , which occurs abundantly in Late Jurassic deposits of England and France, was probably the trace-maker. 相似文献