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111.
The movement of organisms between subdivided populations is considered a key influence on the persistence of species in modified landscapes. In particular, the ability to recolonize ‘empty’ fragments of habitat is directly relevant to conservation management, and to understanding the link between pattern and process in metapopulations. We studied the movement and recolonization ability of the bush rat, Rattus fuscipes, in a highly fragmented agricultural landscape in south‐western Victoria, Australia. Populations were monitored in seven small (<2.5 ha) and two large (>49 ha) forest fragments before removal of all residents from four of the small fragments. Subsequent monitoring (for up to 16 months) allowed the detection of colonizing individuals, and comparisons between ‘experimental’ and ‘control’ fragments. Rattus fuscipes readily moved between fragments and successfully recolonized (i.e. both males and females arrived) two of four fragments in which extinctions were simulated. A single male moved into a third experimental fragment. In one fragment, new animals were detected 1 month after the removal of residents, indicating that recolonization can occur rapidly. Dispersers were not a random sample of the population: although both males and females, and adults and sub‐adults were recorded dispersing, adult males in reproductive condition predominated. Functional connectivity appears to be high for R. fuscipes in the study landscape. Results from this manipulative experiment provide direct empirical evidence that a capacity for movement allows recolonization of fragments of suitable habitat and is a key process responsible for species persistence in fragmented landscapes, as predicted by theory. 相似文献
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GREG W. ROUSE 《Zoologica scripta》1993,22(3):249-261
New species in the genus Fabriciola Friedrich are described. Fabriciola is defined by a single synapomorphy, the presence of non-vascularized, ventral filamentous appendages. Otherwise the genus is variable, with differences among species in chaetae, eyes, and peristomial organization. The new species, Fabriciola flammula, F. liguronis and F. parvus , reflect this heterogeneity. Fabriciola liguronis has spermathecae in the radiolar crown of females, the first record of these structures in Fabriciola , but F. flammula and F. parvus lack spermathecae. Sperm ultrastructure in all three species share apomorphies with other fabriciins, but vary in other respects. Fabriciola may be paraphyletic, but material of the type species F. spongicola (Southern, 1921) has been unobtainable so far, and detailed study of this species is required to define the genus Fabriciola adequately. 相似文献
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JOHNSTON RB 《The Journal of biological chemistry》1956,221(2):1037-1046
116.
Vulnerability of African mammals to anthropogenic climate change under conservative land transformation assumptions 总被引:4,自引:1,他引:3
WILFRIED THUILLER † OLIVIER BROENNIMANN†‡ GREG HUGHES† J. ROBERT M. ALKEMADE§ GUY. F. MIDGLEY† FABIO CORSI¶ 《Global Change Biology》2006,12(3):424-440
Recent observations show that human‐induced climate change (CC) and land transformation (LT) are threatening wildlife globally. Thus, there is a need to assess the sensitivity of wildlife on large spatial scales and evaluate whether national parks (NPs), a key conservation tools used to protect species, will meet their mandate under future CC and LT conditions. Here, we assess the sensitivity of 277 mammals at African scale to CC at 10′ resolution, using static LT assumptions in a ‘first‐cut’ estimate, in the absence of credible future LT trends. We examine the relationship between species' current distribution and macroclimatic variables using generalized additive models, and include LT indirectly as a filter. Future projections are derived using two CC scenarios (for 2050 and 2080) to estimate the spatial patterns of loss and gain in species richness that might ultimately result. We then apply the IUCN Red List criteria A3(c) of potential range loss to evaluate species sensitivity. We finally estimate the sensitivity of 141 NPs in terms of both species richness and turnover. Assuming no spread of species, 10–15% of the species are projected to fall within the critically endangered or extinct categories by 2050 and between 25% and 40% by 2080. Assuming unlimited species spread, less extreme results show proportions dropping to approximately 10–20% by 2080. Spatial patterns of richness loss and gain show contrasting latitudinal patterns with a westward range shift of species around the species‐rich equatorial zone in central Africa, and an eastward shift in southern Africa, mainly because of latitudinal aridity gradients across these ecological transition zones. Xeric shrubland NPs may face significant richness losses not compensated by species influxes. Other NPs might expect substantial losses and influxes of species. On balance, the NPs might ultimately realize a substantial shift in the mammalian species composition of a magnitude unprecedented in recent geological time. To conclude, the effects of global CC and LT on wildlife communities may be most noticeable not as a loss of species from their current ranges, but instead as a fundamental change in community composition. 相似文献
117.
MATTHEW I. PYNE KERRY M. BYRNE KIRSTIN A. HOLFELDER LINDSAY MCMANUS MICHAEL BUHNERKEMPE NATHANIAL BURCH EDDIE CHILDERS SARAH HAMILTON GREG SCHROEDER PAUL F. DOHERTY JR. 《The Journal of wildlife management》2010,74(7):1463-1471
Abstract: The iconic plains bison (Bison bison) have been reintroduced to many places in their former range, but there are few scientific data evaluating the success of these reintroductions or guiding the continued management of these populations. Relying on mark-recapture data, we used a multistate model to estimate bison survival and breeding transition probabilities while controlling for the recapture process. We tested hypotheses in these demographic parameters associated with age, sex, reproductive state, and environmental variables. We also estimated biological process variation in survival and breeding transition probabilities by factoring out sampling variation. The recapture rate of females and calves was high (0.78 ± 0.15 [SE]) and much lower for males (0.41 ± 0.23), especially older males (0.17 ± 0.15). We found that overall bison survival was high (>0.8) and that males (0.80 ± 0.13) survived at lower rates than females (0.94 ± 0.04), but as females aged survival declined (0.89 ± 0.05 for F ≥15 yr old). Lactating and non-lactating females survived at similar rates. We found that females can conceive early (approx. 1.5 yr of age) and had a high probability (approx. 0.8) of breeding in consecutive years, until age 13.5 years, when females that were non-lactating tended to stay in that state. Our results suggest senescence in reproduction and survival for females. We found little support for the effect of climatic covariates on demographic rates, perhaps because the park's current population management goals were predicated from drought-year conditions. This reintroduction has been successful, but continued culling actions will need to be employed and an adaptive management approach is warranted. Our demographic approach can be applied to other heavily managed large-ungulate systems with few or no natural predators. 相似文献
118.
A cladistic analysis of Siboglinidae Caullery, 1914 (Polychaeta, Annelida): formerly the phyla Pogonophora and Vestimentifera 总被引:7,自引:0,他引:7
GREG W. ROUSE 《Zoological Journal of the Linnean Society》2001,132(1):55-80
It has been proposed in recent years that the phyla Pogonophora and Vestimentifera are a derived clade of polychaete annelids. It has also been proposed that if this clade belongs among polychaetes, then the taxon name Pogonophora is misleading and should revert to a name first formulated for the group, Siboglinidae Caullery, 1914. This recommendation is adopted in this paper, and a cladistic study using terminals of 'generic' rank in the former Pogonophora (including Vestimentifera) is undertaken. The purpose of this is to assess which taxon names should now be used for clades within Siboglinidae, and to provide a revised taxonomy, based on phylogenetic principles. Another major aim is to assess the position of the vestimentiferan clade within Siboglinidae. The results show that Vestimentifera is the sister group to Sclerolinum, and this clade is then sister group to Frenulata, i.e. the remaining Siboglinidae. The results suggest that all taxa within Siboglinidae that are not genera or species are redundant, except for the following: Siboglinidae is defined as the first polychaete, and all its descendants, to have an gut occluded by expanded endoderm filled with chemoautotrophic bacteria, as seen in the holotype of Riftia pachyptila Jones, 1981. Monilifera can be defined based on apomorphy-based system such that it is the first siboglinid, and all its descendants, to have rings of chaetae (uncini) in the opisthosoma, as seen in the holotype of Sclerolinum magdalenae Southward, 1972. Vestimentifera can be denned as the first siboglinid and all its descendants to have a vestimentum as seen in the holotype of Riftia pachyptia. Frenulata is defined as the siboglinid, and all its descendants, to have a mid-trunk girdle, as seen in the holotype of Siboglinum weberi Caullery, 1914. The taxa of generic rank are not defined here since their monophyly was not investigated. 相似文献
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