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71.
72.
FERNANDO GÓMEZ PURIFICACIÓN LÓPEZ-GARCÍA DAVID MOREIRA 《The Journal of eukaryotic microbiology》2009,56(5):440-445
ABSTRACT. Members of the family Warnowiaceae are unarmored phagotrophic dinoflagellates that possess an ocelloid. The genus Erythropsidinium (= Erythropsis ) has also developed a unique dynamic appendage, the piston, which is able to independently retract and extend for at least 2 min after the cell lyses. We provide the first small subunit ribosomal RNA gene sequences of warnowiid dinoflagellates, those of the type Erythropsidinium agile and one species of Warnowia . Phylogenetic analyses show that warnowiid dinoflagellates branch within the Gymnodinium sensu stricto group, forming a cluster separated from the Polykrikos clade and with autotrophic Pheopolykrikos beauchampii as closest relative. This reinforces their classification as unarmored dinoflagellates based on the shape of the apical groove, despite the strong ecological and ultrastructural diversity of the Gymnodinium s.s. group. Other structures, such as the ocelloid and piston, have no systematic value above the genus level. 相似文献
73.
JANELLE STEVENSON FERNANDO SIRINGAN JAN FINN DOMINGO MADULID HENK HEIJNIS 《Global Change Biology》2010,16(6):1672-1688
The last 7000 years of environmental history for Paoay Lake and its surrounding landscape is examined through the analysis of pollen, diatoms, charcoal, mineral magnetics and AMS dating. Basal sediments contain shells of Cerithiidae and the saline‐tolerant diatom Diploneis indicating that this was an estuarine environment before becoming a freshwater lake after 6000 bp . Pollen analysis shows that submontane forests, characterized by Pinus pollen, underwent a major disturbance around 5000 years ago, recovering to previous levels by 1000 years ago. Charcoal as an indicator of fire is abundant throughout record, although the highest levels occur in the earlier part of the record, between 6500 and 5000 years ago. An aspect of the project was to examine whether there is evidence of land clearance and agricultural development in the region during the late Holocene. While a clear signal of human impact in the record remains equivocal, there appears to be a correspondence between submontane forest decline and mid‐Holocene ocean data that depict warmer and possibly drier conditions for the region. The study highlights the vulnerability of these montane forests to forecasts of a warmer and drier climate in the near future. 相似文献
74.
GRAHAM J. EDGAR STUART A. BANKS MARGARITA BRANDT RODRIGO H. BUSTAMANTE ANGEL CHIRIBOGA SYLVIA A. EARLE LAUREN E. GARSKE PETER W. GLYNN JACK S. GROVE SCOTT HENDERSON CLEVE P. HICKMAN KATHY A. MILLER FERNANDO RIVERA GERALD M. WELLINGTON 《Global Change Biology》2010,16(10):2876-2890
Comparisons between historical and recent ecological datasets indicate that shallow reef habitats across the central Galapagos Archipelago underwent major transformation at the time of the severe 1982/1983 El Niño warming event. Heavily grazed reefs with crustose coralline algae (‘urchin barrens’) replaced former macroalgal and coral habitats, resulting in large local and regional declines in biodiversity. Following recent threat assessment workshops, a total of five mammals, six birds, five reptiles, six fishes, one echinoderm, seven corals, six brown algae and nine red algae reported from coastal environments in Galapagos are now recognized as globally threatened. The 2008 International Union for the Conservation of Nature (IUCN) Red List includes 43 of these species, while two additional species (Galapagos damsel Azurina eupalama and 24‐rayed sunstar Heliaster solaris) not seen for > 25 years also fulfil IUCN threatened species criteria. Two endemic species (Galapagos stringweed Bifurcaria galapagensis and the damselfish A. eupalama) are now regarded as probably extinct, while an additional six macroalgal species (Dictyota galapagensis, Spatoglossum schmittii, Desmarestia tropica, Phycodrina elegans, Gracilaria skottsbergii and Galaxaura barbata) and the seastar H. solaris are possibly extinct. The removal of large lobster and fish predators by artisanal fishing probably magnified impacts of the 1982/1983 El Niño through a cascade of indirect effects involving population expansion of grazing sea urchins. Marine protected areas with adequate enforcement are predicted to ameliorate but not eliminate ecosystem impacts caused by increasing thermal anomalies associated with El Niño and global climate change. 相似文献
75.
FERRUCCIO MALTAGLIATI GRAZIANO DI GIUSEPPE MICHELE BARBIERI ALBERTO CASTELLI FERNANDO DINI 《Biological journal of the Linnean Society. Linnean Society of London》2010,100(4):910-923
Phylogeographical analysis of Paracentrotus lividus was carried out by means of sequencing the mitochondrial cytochrome b gene (1143 bp) of 260 individuals collected at 22 Mediterranean and four Atlantic localities. Against a background of high haplotype diversity and shallow genetic structuring, we observed significant genetic divergence between the Adriatic Sea and the rest of the Mediterranean, as well as between the Mediterranean and the Atlantic sample groups. Furthermore, on the largest spatial scale, isolation by distance was detected. Three main haplogroups were identified by network and Bayesian assignment analyses. The relative proportions of haplogroups were different in the four regions considered, with the exception of Western and Eastern Mediterranean that showed a similar pattern. This result together with the outcome of Snn statistics, analysis of molecular variance and network analyses allowed to identify three weakly differentiated populations corresponding to the Atlantic, Western + Eastern Mediterranean, and Adriatic seas. Analyses of mismatch distribution and neutrality tests were consistent with the presence of genetic structuring and past demographic expansion(s). From a fisheries perspective, the results obtained in the present study are consistent with genetic sustainability of current exploitation; local depleted stocks are recurrently replenished by recruits that may have originated from nonharvested areas. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 910–923. 相似文献
76.
77.
M. ROMINA SCHIAFFINO FERNANDO UNREIN JOSEP M. GASOL RAMON MASSANA VANESSA BALAGUÉ IRINA IZAGUIRRE 《Freshwater Biology》2011,56(10):1973-1991
1. We analysed the latitudinal variation of bacterioplankton in 45 freshwater environments (lakes, shallow lakes and ponds) across a transect of more than 2100 km stretching from Argentinean Patagonia (45°S) to Maritime Antarctica (63°S), to determine the factors that mainly determine bacterioplankton community structure. 2. Bacterioplankton community composition (BCC) was assessed by a fingerprinting method (denaturing gradient gel electrophoresis) followed by band sequencing, whereas the abundances of total bacteria and picocyanobacteria were estimated by epifluorescence microscopy. 3. Bacterioplankton community composition was controlled by a combination of spatial (latitude and longitude) and environmental [e.g. phosphate, light diffuse attenuation coefficient (Kd) and dissolved organic carbon] factors. Total bacterioplankton abundance declined with latitude. A multiple regression analysis showed that phosphate, Kd and latitude had significant effects on total bacterioplankton abundance. 4. Of 76 operational taxonomic units identified in the studied lakes, 45 were shared between Patagonian and Antarctic water bodies, 28 were present only in Patagonian lakes and three were restricted to the Antarctic lakes. Significant differences were found in BCC between Patagonia and Antarctica. Among the sequences, 54% were similar (>97% sequence similarity) to others reported from cold habitats elsewhere on the planet (glaciers, high mountain lakes, Arctic). 5. Our results provide new evidence that supports the hypotheses of biogeographic patterns of bacterial assemblages and suggest that both spatial and environmental factors control bacterioplankton community structure. 相似文献
78.
ANITA AISENBERG FERNANDO G. COSTA MACARENA GONZÁLEZ 《Biological journal of the Linnean Society. Linnean Society of London》2011,103(1):68-75
Sexual cannibalism usually involves females attacking and consuming males before, during or after copulation. Sex role reversed systems may provide insight into the debate about whether it arises as mistaken identity, a spillover in female aggressiveness, foraging decisions, and/or extreme mate choice. In such systems, males may be selective and voracious to compensate for their higher reproductive costs, and thus males may be the sexually cannibalistic sex. Allocosa brasiliensis shows a reversal in sex roles and male‐biased sexual size dimorphism (the opposite of the common pattern in spiders). The present study aimed to test whether males cannibalize or mate according to female reproductive status or body characteristics. Each of 20 adult males was consecutively exposed to one virgin and one mated female, alternating the order of exposure. Males preferred to mate with virgin females in good body condition and heavier‐mated females. Males attacked 15% of virgins and 40% of mated females and cannibalized 10% and 25% of the total trials, respectively. The astonishing male cannibalistic behaviour best agrees with extreme mate choice hypotheses because attacks were more frequent on mated females of low body condition. This is the first report of male sexual cannibalism in a sex role reversed system. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 68–75. 相似文献
79.
FERNANDO LENCASTRE SICURO 《Biological journal of the Linnean Society. Linnean Society of London》2011,103(1):176-190
The skulls of 33 extant cat species were characterized through three‐dimensional geometric morphometrics using 20 landmarks. A principal component analysis (PCA) was performed with Procrustes fitted coordinates, and the PC‐scores were phylogenetically corrected by independent contrasts method. Three PCs allowed for the definition of five cat skull patterns. PC1: ‘snouted/massive‐headed cats’ (genus Panthera) opposing the ‘round‐headed small cats’ (genus Oncifelis, Prionailurus rubiginosus, Prionailurus bengalensis, among other small cats); PC2: ‘tapering‐headed cats’ (Neofelis nebulosa, Herpailurus yagouaroundi, Prionailurus planiceps) opposing the ‘stout‐headed cats’ (Acinonyx jubatus, Uncia uncia, Otocolobus manul, Felis margarita, and Felis nigripes); and PC3: ‘low profiled‐headed cats’ (mostly, Pr. planiceps). A sixth pattern, the ‘generalized skull’, observed in the Caracal lineage, genus Lynx, Leopardus pardalis, and Catopuma temminckii, indicates a morphological convergence among midsized‐cats. The morphological trends ‘snouted/massive’ and ‘round’ clearly denote a co‐evolution between size and shape. The other skull patterns evolved unrelatedly to the size (i.e. their allometric variations are not a size function). Nevertheless, each species comprises an amalgam of these patterns, so the influence of the size permeates, in some extent, the skull morphology along all cat lineages. The felid ecomorphological fit to hypercarnivory is obvious; however, different skull shapes in same‐sized species with similar habits, indicate that the variation in the skull morphology may result from phenotypic fluctuations, whose adaptive value (if indeed there is any) is still obscure. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 176–190. 相似文献
80.
FERNANDO AUGUSTO OLIVEIRA SILVEIRA DANIEL NEGREIROS LUZIA MÁRCIA ARAÚJO GERALDO WILSON FERNANDES 《Plant Species Biology》2012,27(2):170-173
We tested the regeneration niche hypothesis by comparing the germination ecology of two sympatric Diplusodon species differing in their geographic range and microhabitat. Diplusodon orbicularis is an endemic shrub achieving high densities on sandy soils, whereas Diplusodon hirsutus has a wider geographic range and establishes on rocky outcrops. Seeds were set to germinate under constant temperatures of 15, 20, 25, 30 and 35°C under 12 h light/12 h dark conditions. Light induced germination in both species, but germination under darkness was also observed. Optimum conditions for germination were 25°C/light for both species. The lack of differences in soil temperatures between rocky outcrops and sandy soils provides evidence of no temperature‐dependent microhabitat selection. Unexpectedly, germinability of the more widespread species was lower than that of the endemic congener. Higher germinability of D. orbicularis may account for higher densities when compared with D. hirsutus. Our results provide limited support for the role of germination in contributing to ecological breadth and geographic range. 相似文献