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71.
Loos Jacqueline Krauss Jochen Lyons Ashley Föst Stephanie Ohlendorf Constanze Racky Severin Röder Marina Hudel Lennart Herfert Volker Tscharntke Teja 《Biodiversity and Conservation》2021,30(8-9):2415-2432
Biodiversity and Conservation - Across Europe, calcareous grasslands become increasingly fragmented and their quality deteriorates through abandonment and land use intensification, both affecting... 相似文献
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Marina Cools Erik De Clercq John C. Drach 《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):423-424
Abstract A paired adenosine kinase-positive/adenosine kinase-negative cell system is proposed to distinguish those adenosine analogues that need to be phosphorylated to exert their biological effects from those that are mainly targeted at S-adenosyl-L-homocysteine hydrolase. 相似文献
76.
Marina P. Arbetman Ivan Meeus Carolina L. Morales Marcelo A. Aizen Guy Smagghe 《Biological invasions》2013,15(3):489-494
The worldwide trade in bumblebees can lead to the spread of diseases, which in turn has been claimed as a factor in bumblebee decline. Populations of the introduced Bombus terrestris, which invaded NW Patagonia, Argentina, in 2006, harbor the highly pathogenic protozoan Apicystis bombi. We asked whether A. bombi had been co-introduced with B. terrestris, and if so, whether spillover occurred to the two resident bumblebee species in the region: the introduced European Bombus ruderatus and the native Bombus dahlbomii. We searched for A. bombi by means of PCR in samples of B. ruderatus and B. dahlbomii collected before and after the invasion of B. terrestris and in samples of the latter. We found no A. bombi in samples of B. ruderatus and B. dahlbomii collected before B. terrestris invasion, whereas post invasion, A. bombi was present in all 3 species. The identity of the parasite was established by sequencing the 18S region, which was identical for the three bumblebee species and also matched the European sequence, confirming it to be A. bombi. This is the first report of A. bombi in B. ruderatus and B. dahlbomii. Moreover, our results suggest that Patagonia had been free of A. bombi until this parasite was co-introduced with B. terrestris, and spilled over in situ to these two previously resident species. Finally, our findings provide indirect circumstantial evidence of a potential link between the population collapse and geographic retraction of B. dahlbomii and the introduction of this novel parasite. 相似文献
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Little is known about positive interactions among members of herbaceous plant communities initiating secondary succession (i.e., ruderal communities). Here, we explored the possibility that Euphorbia schickendantzii (Euphorbia), a latex-containing herb, facilitates other ruderals by protecting them from herbivores in recently plowed and overgrazed sites in central Argentina. To test this hypothesis, we compared plant number, height, reproductive output, and herbivore damage for four species when associated with Euphorbia versus in adjacent open zones without Euphorbia. Additionally, we classified species in the community according to their palatability, and compared community composition, richness, and diversity between Euphorbia and open zones. Dominant (66 % relative abundance) and highly palatable species exhibited increased plant number, size, and fecundity, and decreased herbivory when associated with Euphorbia relative to non-Euphorbia zones. In contrast, a physically and chemically well-defended species showed greater number of individuals in the open and no differences in herbivory between sampling zones. In detrended correspondence analysis, ordination scores of most palatable species were closer to Euphorbia, while those of most unpalatable species were closer to the open. Community composition differed between areas, with six species (25 % of the community) occurring exclusively with Euphorbia and three other species occurring only in open zones. Additionally, richness and diversity were greater in communities associated with Euphorbia than in those associated with non-Euphorbia zones. These results support our hypothesis, highlight the importance of facilitation in altering community-level responses, and indicate that positive interactions can play a more significant role in organizing terrestrial ruderal communities than previously recognized. 相似文献
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Marina A Shevchenko Elena L Bolkhovitina Ekaterina A Servuli Alexander M Sapozhnikov 《Respiratory research》2013,14(1):78
Background
Aspergillus fumigatus conidia can exacerbate asthma symptoms. Phagocytosis of conidia is a principal component of the host antifungal defense. We investigated whether allergic airway inflammation (AAI) affects the ability of phagocytic cells in the airways to internalize the resting fungal spores.Methods
Using BALB/c mice with experimentally induced AAI, we tested the ability of neutrophils, macrophages, and dendritic cells to internalize A. fumigatus conidia at various anatomical locations. We used light microscopy and differential cell and conidium counts to determine the ingestion potential of neutrophils and macrophages present in bronchoalveolar lavage (BAL). To identify phagocyte-conidia interactions in conducting airways, conidia labeled with tetramethylrhodamine-(5-(and-6))-isothiocyanate were administered to the oropharyngeal cavity of mice. Confocal microscopy was used to quantify the ingestion potential of Ly-6G+ neutrophils and MHC II+ antigen-presenting cells located in the intraepithelial and subepithelial areas of conducting airways.Results
Allergen challenge induced transient neutrophil recruitment to the airways. Application of A. fumigatus conidia at the acute phase of AAI provoked recurrent neutrophil infiltration, and consequently increased the number and the ingestion potential of the airway neutrophils. In the absence of recurrent allergen or conidia provocation, both the ingestion potential and the number of BAL neutrophils decreased. As a result, conidia were primarily internalized by alveolar macrophages in both AAI and control mice at 24 hours post-inhalation. Transient influx of neutrophils to conducting airways shortly after conidial application was observed in mice with AAI. In addition, the ingestion potential of conducting airway neutrophils in mice with induced asthma exceeded that of control mice. Although the number of neutrophils subsequently decreased, the ingestion capacity remained elevated in AAI mice, even at 24 hours post-conidia application.Conclusions
Aspiration of allergen to sensitized mice enhanced the ingestion potential of conducting airway neutrophils. Such activation primes neutrophils so that they are sufficient to control dissemination of non-germinating A. fumigatus conidia. At the same time, it can be a reason for the development of sensitivity to fungi and subsequent asthma exacerbation. 相似文献80.
Marina Corrêa Côrtes María Uriarte 《Biological reviews of the Cambridge Philosophical Society》2013,88(2):255-272
General principles about the consequences of seed dispersal by animals for the structure and dynamics of plant populations and communities remain elusive. This is in part because seed deposition patterns emerge from interactions between frugivore behaviour and the distribution of food resources, both of which can vary over space and time. Here we advocate a frugivore‐centred, process‐based, synthetic approach to seed dispersal research that integrates seed dispersal ecology and animal movement across multiple spatio‐temporal scales. To guide this synthesis, we survey existing literature using paradigms from seed dispersal and animal movement. Specifically, studies are discussed with respect to five criteria: selection of focal organisms (animal or plant); measurement of animal movement; characterization of seed shadow; animal, plant and environmental factors included in the study; and scales of the study. Most studies focused on either frugivores or plants and characterized seed shadows directly by combining gut retention time with animal movement data or indirectly by conducting maternity analysis of seeds. Although organismal traits and environmental factors were often measured, they were seldom used to characterize seed shadows. Multi‐scale analyses were rare, with seed shadows mostly characterized at fine spatial scales, over single fruiting seasons, and for individual dispersers. Novel animal‐ and seed‐tracking technologies, remote environmental monitoring tools, and advances in analytical methods can enable effective implementation of a hierarchical mechanistic approach to the study of seed dispersal. This kind of mechanistic approach will provide novel insights regarding the complex interplay between the factors that modulate animal behaviour and subsequently influence seed dispersal patterns across spatial and temporal scales. 相似文献