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991.
Potential effects of climate change on plant species in the Faroe Islands   总被引:3,自引:0,他引:3  
Aim To identify the effect of climate change on selected plant species representative of the main vegetation types in the Faroe Islands. Due to a possible weakening of the North Atlantic Current, it is difficult to predict whether the climate in the Faroe Islands will be warmer or colder as a result of global warming. Therefore, two scenarios are proposed. The first scenario assumes an increase in summer and winter temperature of 2 °C, and the second a decrease in summer and winter temperature of 2 °C. Location Temperate, low alpine and alpine areas in the northern and central part of the Faroe Islands. Methods The responses of 12 different plant species in the Faroe Islands were tested against measured soil temperature, expressed as Tmin, Tmax, snow cover and growing degree days (GDD), using generalised linear modelling (GLM). Results The tolerance to changes in winter soil temperature (0.3–0.8 °C) was found to be lower than the tolerance to changing summer soil temperature (0.7–1.0 °C), and in both cases lower than the predicted climate changes. Conclusions The species most affected by a warming scenario are those that are found with a limited distribution restricted to the uppermost parts of the mountains, especially Salix herbacea, Racomitrium fasciculare, and Bistorta vivipara. For other species, the effect will mainly be a general upward migration. The most vulnerable species are those with a low tolerance, especially Calluna vulgaris, and also Empetrum nigrum, and Nardus stricta. If the climate in the Faroe Islands should become colder, the most vulnerable species are those at low altitudes. A significantly lower temperature would be expected to produce a serious reduction in the extent of Vaccinium myrtillus and Galium saxatilis. Species like Empetrum nigrum, Nardus stricta, and Calluna vulgaris may also be vulnerable. In any case, these species can be expected to migrate downwards.  相似文献   
992.
Aim Oceanic islands represent a special challenge to historical biogeographers because dispersal is typically the dominant process while most existing methods are based on vicariance. Here, we describe a new Bayesian approach to island biogeography that estimates island carrying capacities and dispersal rates based on simple Markov models of biogeographical processes. This is done in the context of simultaneous analysis of phylogenetic and distributional data across groups, accommodating phylogenetic uncertainty and making parameter estimates more robust. We test our models on an empirical data set of published phylogenies of Canary Island organisms to examine overall dispersal rates and correlation of rates with explanatory factors such as geographic proximity and area size. Location Oceanic archipelagos with special reference to the Atlantic Canary Islands. Methods The Canary Islands were divided into three island‐groups, corresponding to the main magmatism periods in the formation of the archipelago, while non‐Canarian distributions were grouped into a fourth ‘mainland‐island’. Dispersal between island groups, which were assumed constant through time, was modelled as a homogeneous, time‐reversible Markov process, analogous to the standard models of DNA evolution. The stationary state frequencies in these models reflect the relative carrying capacity of the islands, while the exchangeability (rate) parameters reflect the relative dispersal rates between islands. We examined models of increasing complexity: Jukes–Cantor (JC), Equal‐in, and General Time Reversible (GTR), with or without the assumption of stepping‐stone dispersal. The data consisted of 13 Canarian phylogenies: 954 individuals representing 393 taxonomic (morphological) entities. Each group was allowed to evolve under its own DNA model, with the island‐model shared across groups. Posterior distributions on island model parameters were estimated using Markov Chain Monte Carlo (MCMC) sampling, as implemented in MrBayes 4.0, and Bayes Factors were used to compare models. Results The Equal‐in step, the GTR, and the GTR step dispersal models showed the best fit to the data. In the Equal‐in and GTR models, the largest carrying capacity was estimated for the mainland, followed by the central islands and the western islands, with the eastern islands having the smallest carrying capacity. The relative dispersal rate was highest between the central and eastern islands, and between the central and western islands. The exchange with the mainland was rare in comparison. Main conclusions Our results confirm those of earlier studies suggesting that inter‐island dispersal within the Canary Island archipelago has been more important in explaining diversification within lineages than dispersal between the continent and the islands, despite the close proximity to North Africa. The low carrying capacity of the eastern islands, uncorrelated with their size or age, fits well with the idea of a historically depauperate biota in these islands but more sophisticated models are needed to address the possible influence of major recent extinction events. The island models explored here can easily be extended to address other problems in historical biogeography, such as dispersal among areas in continental settings or reticulate area relationships.  相似文献   
993.
The Oceania region is home to some of the world's most restrictive abortion laws, and there is evidence of Pacific Island women's reproductive oppression across several aspects of their reproductive lives, including in relation to contraceptive decision-making, birthing, and fertility. In this paper we analyse documents from court cases in the Pacific Islands regarding the illegal procurement of abortion. We undertook inductive thematic analysis of documents from eighteen illegal abortion court cases from Pacific Island countries. Using the lens of reproductive justice, we discuss the methods of abortion, the reported context of these abortions, and the ways in which these women and abortion were constructed in judges' summing up, judgements, or sentencing. Our analysis of these cases reveals layers of sexual and reproductive oppression experienced by these women that are related to colonialism, women's socioeconomic disadvantage, gendered violence, limited reproductive control, and the punitive consequences related to not performing gender appropriately.  相似文献   
994.
Summary

Non-native species form a significant, but under-recorded, component of the Falkland Islands vascular flora. With this in mind a comprehensive re vie w of the non-native flora of the Falkland Islands was undertaken for the first time since the publication of the definitive Flora in 1968. We have recorded 175 non-native taxa, from 46 families, from the Falkland Islands which are listed with accompanying notes on habitat, status and distribution. Twenty-nine of these are likely to be commonly encountered, though only Aira praecox, Cerastium fontanum, Rumex acetosella and Sagina procumbens are near ubiquitous throughout. The origins of much of the non-native flora are obscure, however most species seem to be of European descent, and a significant proportion of taxa seem to have become established after introductions for agricultural and horticultural purposes.  相似文献   
995.
A total of 180 mtDNA sequences from hair Caribbean (93), West African (73) and Canarian‐wooled (14) sheep were analysed to shed light on the origin of hair sheep. A comparison of 360 Iberian sheep sequences retrieved from GenBank was performed to assess a possible European origin of the Caribbean hair sheep. These 180 sequences gave 48 different haplotypes (16 in Caribbean sheep). All Caribbean and Canarian‐wooled sequences and 91.8% of the West African samples belonged to haplogroup B. The sheep analysed showed wide haplotypic identity. Caribbean sheep shared roughly two‐thirds of their samples with Canarian‐wooled and West African samples, respectively. Principal component analysis showed that the Caribbean and the Canarian‐wooled sheep clustered together. Additional analyses showed that hair and Iberian sheep had wide genetic identity. It was not possible to ascertain a single Canarian, African or European origin of the Caribbean hair sheep using mtDNA markers only. European, African and Caribbean hair sheep maternal genetic backgrounds likely result from related domestication events.  相似文献   
996.
Abstract

A scientific reserve of 200 ha has been created on Pitt Island, Chatham Islands for some 300 sheep from a flock of merino origin which has been feral for about 70 years. The reserve has a history of burning-off, and of grazing by cattle, sheep, and pigs. Transects have been established to follow changes in the vegetation. Although the original sheep were white, about 90% of the feral sheep have pigmented fleeces. Self-shedding of the wool is common in the population. The contribution that feral mammals can make to genetic conservation, and the problems that they pose to other conservation priorities, are discussed.  相似文献   
997.
Predators are an essential component of past and present ecosystems and trophic networks. In addition, their role as bone bio-accumulators may at least partly determine the richness of fossil sites. Prior to human arrival, terrestrial mammals were absent from the Pityusic Archipelago (Eivissa and Formentera islands, Western Mediterranean Sea), a feature that represents an ecological singularity in the Mediterranean islands. The diurnal and nocturnal predatory bird guild from the Upper Pleistocene and Holocene of the Eivissa Island is approached here through the study of Accipitridae, Falconidae and Strigidae from Es Pouàs, an extraordinarily rich fossil site that provided more than two thousand bones of birds belonging to these three families. The importance of each species as bio-accumulator and a comparison with current fauna are outlined.  相似文献   
998.
Saunders’s terns (Sternula saundersi) are a small, ground-nesting marine bird species that have a massive rearing range, including the shores and islands of Asia and Africa adjacent to the north Indian Ocean. Despite occupying a large breeding range, little is known about the breeding ecology of this species. This research explored aspects of Saunders’s terns’ breeding ecology and predation rate in 2013 on the Farasan Islands of Saudi Arabia. The outcomes confirm that the mean clutch size of a Saunders’s tern was 1.77 ± 0.08 (n = 31) eggs per clutch and the mean egg size was 31.05 × 23.15 mm. The results of this study show a remarkable relationship between clutch size and egg volume and length (p = .002, p = .004, respectively). Predation was the major reason for nest damage (62.5%). Evidence from cameras at nests showed that the predators of Saunders’s tern nests on the Farasan Islands were white-tailed mongoose (Ichneumia albicauda) and Egyptian vultures (Neophron percnopterus). This is the first study on the breeding ecology of Saunders’s terns, and it shows that predator control is essential to the existence of the species. The results of this study suggest that fencing some breeding sites may help to minimize human disturbance and decrease the risk of nest predation from mammalian predators. Further research is needed to compare the predation rates on the mainland and islands and to develop efficient strategies to conserve this ground-nesting species.  相似文献   
999.
Effective and comprehensive regional-scale marine conservation requires fine-grained data on the spatial patterns of threats and their overlap. To address this need for the Papahānaumokuākea Marine National Monument (Monument) in Hawaii, USA, spatial data on 14 recent anthropogenic threats specific to this region were gathered or created, including alien species, bottom fishing, lobster trap fishing, ship-based pollution, ship strike risks, marine debris, research diving, research equipment installation, research wildlife sacrifice, and several anthropogenic climate change threats i.e., increase in ultraviolet (UV) radiation, seawater acidification, the number of warm ocean temperature anomalies relevant to disease outbreaks and coral bleaching, and sea level rise. These data were combined with habitat maps and expert judgment on the vulnerability of different habitat types in the Monument to estimate spatial patterns of current cumulative impact at 1 ha (0.01 km2) resolution. Cumulative impact was greatest for shallow reef areas and peaked at Maro Reef, where 13 of the 14 threats overlapped in places. Ocean temperature variation associated with disease outbreaks was found to have the highest predicted impact overall, followed closely by other climate-related threats, none of which have easily tractable management solutions at the regional scale. High impact threats most tractable to regional management relate to ship traffic. Sensitivity analyses show that the results are robust to both data availability and quality. Managers can use these maps to (1) inform management and surveillance priorities based on the ranking of threats and their distributions, (2) guide permitting decisions based on cumulative impacts, and (3) choose areas to monitor for climate change effects. Furthermore, this regional analysis can serve as a case study for managers elsewhere interested in assessing and mapping region-specific cumulative human impacts. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
1000.
Eulerian time-series were completed at three sites on the south eastern shelf of the Sub-Antarctic Prince Edward Islands (PEI), from 9 to 27 April 2000, to investigate the spatial and temporal variability of mesozooplankton communities in relation to on-shelf hydrodynamics. Surface temperature and phytoplankton biomass were recorded daily at all three sites, while two Bongo net tows and vertical temperature profiles were collected daily at two sites. Contrary to predictions of on-shelf water retention at low ambient current velocities, cross-correlation analysis identified a northward advection of ∼8.23 cm s−1 over the study area. Day to day changes in both physical and biological parameters were associated with cross-shelf advection. However, sea temperature had a narrow range of 6.2–7.4°C, while average between sample Bray–Curtis similarity in zooplankton communities was high, exceeding 75%. The relatively consistent average sample biomass amounted to ∼494 tonnes dry weight of mesozooplankton per day being advected onto the south eastern sector of the PEI shelf. We hypothesise that the observed stability of both physical and biological parameters was due to the Sub-Antarctic Front, with its high volume transport and steep physical gradients, being far to the north of the islands. Spatial and temporal variability of hydrodynamics on the PEI shelf, and particularly its relationship to shifting frontal positions, is highlighted as a future research area necessary to quantify the gross delivery of allochthonous biomass to the PEI ecosystem.  相似文献   
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