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SAHRAN L. HIGGINS DAVID J. HOSKEN NINA WEDELL 《Biological journal of the Linnean Society. Linnean Society of London》2009,98(2):400-405
Male genitalia evolve through sexual selection and, in insects, tend to show negative static allometry, low phenotypic variation, and are usually relatively small. Much less is known about the genetic variation and heritability of male genitalia. Additionally, in instances where the intromittent organ is greatly elongated, it is unclear whether typical patterns of genital scaling and variation also apply. In the present study, we investigated the allometry, variation, and heritability of male genital length in the seedbug, Lygaeus equestris , a species with a greatly elongated intromittent organ (i.e. almost as long as male body size). We found that genital length was negatively allometric, in spite of its great length, and was no more variable than nongenital traits. Additionally, genital length was significantly heritable and had considerable evolvability. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 400–405. 相似文献
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NINA AHN MICHAEL BOM FRØST LISE WOLF FRANDSEN GARMT DIJKSTERHUIS MAGNI MARTENS 《Journal of sensory studies》2002,17(6):571-581
The objective of this study was to investigate the effect beverages have on subsequently perceived basic tastes. Two types of milk, Cola and water were used to rinse the mouth prior to conducting a Time Intensity study with basic taste solutions. From this some effects of the prior beverage onto the TI parameters was found. Especially Cola showed an effect on the intensity of the subsequently tasted sweet taste, and whole milk showed a stronger effect than skim milk. The effects showed both in size and timing of the basic taste intensities. 相似文献
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EVGENIA KARASEVA NINA LAMASH YURIJ KHOTIMCHENKO 《Invertebrate reproduction & development.》2013,57(1-3):153-158
Summary The effect of 1-methyladenine (1-MeA) on adenylate cyclase (AC) basal activity and on preliminary stimulated AC activity was investigated in oocyte membrane preparations of the starfish Aphelasterias japonica. 1-MeA inhibited the membrane-bound AC activity both after its addition to intact oocytes and in cell-free experiments. GTP did not affect AC activity but it intensified the inhibitory effect of 1-MeA on AC activity. Sodium fluoride (F″) stimulated the oocyte AC (8 fold), while 1-MeA significantly reduced F″-stimulated activity. Manganese (MnCl2, 5mM) stimulated AC (150 fold), but 1-MeA did not reduce Mn2+-stimulated activity. However, Mn2+-stimulated AC activity was inhibited by 1-MeA in the presence of MgCl2. Forskolin stimulated AC activity (7 fold) and 1-MeA had no effect on AC. Thus, the inhibitory effect of 1-MeA on stimulated AC activity is displayed only after stimulation of the regulatory AC subunit. We suggest that 1-MeA inhibits the oocyte AC acting via inhibitory regulatory Gi protein of AC. 相似文献
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SIBYLLE STEINBEISS HOLGER BEßLER CHRISTOF ENGELS VICKY M. TEMPERTON NINA BUCHMANN CHRISTIANE ROSCHER YVONNE KREUTZIGER JUSSI BAADE MAIKE HABEKOST GERD GLEIXNER 《Global Change Biology》2008,14(12):2937-2949
Increasing atmospheric CO2 concentration and related climate change have stimulated much interest in the potential of soils to sequester carbon. In ‘The Jena Experiment’, a managed grassland experiment on a former agricultural field, we investigated the link between plant diversity and soil carbon storage. The biodiversity gradient ranged from one to 60 species belonging to four functional groups. Stratified soil samples were taken to 30 cm depth from 86 plots in 2002, 2004 and 2006, and organic carbon contents were determined. Soil organic carbon stocks in 0–30 cm decreased from 7.3 kg C m?2 in 2002 to 6.9 kg C m?2 in 2004, but had recovered to 7.8 kg C m?2 by 2006. During the first 2 years, carbon storage was limited to the top 5 cm of soil while below 10 cm depth, carbon was lost probably as short‐term effect of the land use change. After 4 years, carbon stocks significantly increased within the top 20 cm. More importantly, carbon storage significantly increased with sown species richness (log‐transformed) in all depth segments and even carbon losses were significantly smaller with higher species richness. Although increasing species diversity increased root biomass production, statistical analyses revealed that species diversity per se was more important than biomass production for changes in soil carbon. Below 20 cm depth, the presence of one functional group, tall herbs, significantly reduced carbon losses in the beginning of the experiment. Our analysis indicates that plant species richness and certain plant functional traits accelerate the build‐up of new carbon pools within 4 years. Additionally, higher plant diversity mitigated soil carbon losses in deeper horizons. This suggests that higher biodiversity might lead to higher soil carbon sequestration in the long‐term and therefore the conservation of biodiversity might play a role in greenhouse gas mitigation. 相似文献
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NINA ROTHE ANDREW J. GOODAY TOMAS CEDHAGEN JOSÉ FAHRNI J. ALAN HUGHES ANTON PAGE RICHARD B. PEARCE JAN PAWLOWSKI 《Zoological Journal of the Linnean Society》2009,157(3):451-469
We describe three new species of the genus Gromia from bathyal and abyssal depths in the Weddell Sea. The new species are characterized by a combination of morphological and molecular criteria. All three species possess a distinct oral capsule and a layer of ‘honeycomb membranes’, which form the inner part of the organic test wall. Both these features are typical of gromiids. Their identification as gromiids is confirmed by analyses of partial small subunit ribosomal DNA (SSU rDNA) gene sequences. Gromia marmorea sp. nov. is a rounded species with a prominent oral capsule and a characteristically mottled appearance. In Gromia melinus sp. nov. , the test surface exhibits a polygonal pattern of ridges, with a layer of clay particles coating the surface between the ridges. Gromia winnetoui sp. nov. represents an elongate morphotype in which the organic test is enclosed within an agglutinated case, a feature previously unknown in gromiids. Phylogenetic analysis using the maximum‐likelihood method revealed that all three species form distinct clades, reflecting the morphological differences among Weddell Sea species, as well as between deep‐water Southern Ocean Gromia and previously described gromiids. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 451–469. 相似文献
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ESTHER M. PONNURAJ NINA SANAPAREDDY ANTHONY R. HAYWARD 《The Journal of eukaryotic microbiology》2003,50(S1):560-562
ABSTRACT: Transgenic and knockout mice usefully model the mechanisms that result in the clearance of Cryptosporidium parvum from the gut. CD4+ cells, cells expressing MHC class II, and CD154/CD40 interactions are essential. Unexpectedly, AND RAG-/- and DO11.10 RAG-/- mice with single specificities of T cells successfully clear Cryptosporidium infection. Clearance is accompanied by activation of CD4+ cells in the MLN. The ability of T cells bearing receptors for apparently irrelevant and non-cross reactive antigens to activate and to clear infection is surprising. The requirement for class II MHC expression for Cryptosporidium clearance raises the alternative possibilities that (a) class II MHC is required to present a peptide that is loaded as a consequence of infection or (b) that the cytokine environment engendered by a Cryptosporidium infection allows affinity for self MHC to activate nahe T cells. In order to test the hypothesis that peptide loading is necessary, we used ApEα-/-Ii-/- mice that express a hybrid IA-IE MHC molecule. They also carry a transgene that makes an Ea peptide while disruption of their invariant chain blocks the loading of a foreign peptide on to their MHC class II molecules. After oral gavage, the course of infection was followed by ELISA. CD4+ cells in the MLN of these mice were activated to express CD69 and the infection was cleared. We conclude that the loading of a Cryptosporidium or other infection-dependent peptide onto the MHC class II molecules of APCs is not necessary for clearance of Cryptosporidium. Instead the TcR affinity for self-MHC must suffice for T cell activation in the cytokine environment resulting from infection 相似文献
19.
NINA YASUDA SATOSHI NAGAI MASAMI HAMAGUCHI KEN OKAJI† KARIN GÉRARD‡ KAZUO NADAOKA§ 《Molecular ecology》2009,18(8):1574-1590
Population outbreaks of the coral-eating starfish, Acanthaster planci , are hypothesized to spread to many localities in the Indo-Pacific Ocean through dispersal of planktonic larvae. To elucidate the gene flow of A. planci across the Indo-Pacific in relation to ocean currents and to test the larval dispersal hypothesis, the genetic structure among 23 samples over the Indo-Pacific was analysed using seven highly polymorphic microsatellite loci. The F -statistics and genetic admixture analysis detected genetically distinct groups in accordance with ocean current systems, that is, the Southeast African group (Kenya and Mayotte), the Northwestern Pacific group (the Philippines and Japan), Palau, the North Central Pacific group (Majuro and Pohnpei), the Great Barrier Reef, Fiji, and French Polynesia, with a large genetic break between the Indian and Pacific Oceans. A pattern of significant isolation by distance was observed among all samples ( P = 0.001, r = 0.88, n = 253, Mantel test), indicating restricted gene flow among the samples in accordance with geographical distances. The data also indicated strong gene flow within the Southeast African, Northwestern Pacific, and Great Barrier Reef groups. These results suggest that the western boundary currents have strong influence on gene flow of this species and may trigger secondary outbreaks. 相似文献
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ATTILA HETTYEY FRANZISKA RÖLLI NINA THÜRLIMANN ANNE‐CATHERINE ZÜRCHER JOSH VAN BUSKIRK 《Biological journal of the Linnean Society. Linnean Society of London》2012,106(4):820-827
The ability of prey to detect predators directly affects their probability of survival. Chemical cues are known to be important for predator detection in aquatic environments, but the role of other potential cues is controversial. We tested for changes in behaviour of Rana temporaria tadpoles in response to chemical, visual, acoustic, and hydraulic cues originating from dragonfly larvae (Aeshna cyanea) and fish (Gasterosteus aculeatus). The greatest reduction in tadpole activity occurred when all cues were available, but activity was also significantly reduced by visual cues only. We did not find evidence for tadpoles lowering their activity in response to acoustic and hydraulic cues. There was no spatial avoidance of predators in our small experimental containers. The results show that anuran larvae indeed use vision for predator detection, while acoustic and hydraulic cues may be less important. Future studies of predator‐induced responses of tadpoles should not only concentrate on chemical cues but also consider visual stimuli. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??. 相似文献