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31.
食品安全控制中条码质量追溯标签的设计与应用   总被引:8,自引:1,他引:7  
(1中国科学院生态环境研究中心,北京 100085;2国家农业信息化工程技术研究中心,北京 100089)  相似文献   
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Amphibians are among the most endangered animals on Earth, and climatic shifts are among the hypothesized factors in their decline. We used spatial patterns of recent amphibian declines in Italy to test hypotheses pertaining to three potential, nonexclusive factors: climate change, habitat alteration, and high levels of incident solar radiation. This study was based on patterns of presence in a geographic grid for 19 species. Grid-squares in which presence had previously been documented, but was not re-confirmed after a specific threshold year, were considered to represent declines. Using a GIS-based approach, we calculated, for each cell, the mean values - or shift in mean values - of different parameters, used as proxies for the three factors. The measures of these parameters were entered as predictors in specific autocovariate models fitted on grid-square status. Our results suggest that while multiple factors have contributed to declines, climate change has been a major cause of population disappearances. We identified a common pattern of disappearances in areas that have been especially affected by climatic shifts. Our findings also strongly suggest that habitat alteration, due mainly to urban land use, has contributed to the decline of several species and that solar irradiation, though probably not a direct cause of mortality, may have been important in association with other stressors. By identifying the most threatened species, geographical hot spots of decline, and the primary causes of decline, our work provides a basis for improving management and setting conservation priorities.  相似文献   
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Context

Current shifts in biodiversity are driven by multiple processes of environmental and landscape change. Particularly, land use/land cover (LU/LC) dynamics are among the major drivers of biodiversity loss worldwide.

Objectives

In this study we aim to explore the applicability of a new modelling framework to predict top predators’ responses to LU/LC changes.

Methods

The framework integrates remote-sensing based predictors, statistical inference, stochastic-dynamic simulations and spatial projections in a common and interactive approach. From an ecological modelling perspective, the main innovation of our approach lies on the integration of (1) biomass of birds of prey as an upper trophic indicator of the community characteristics that emerge from the habitat quality across multiple scales of organization and (2) fine-scale biophysical attributes to add a new level of understanding about the role of local LU/LC drivers influencing those emergent biodiversity patterns.

Results

Based on species data from published atlases this approach allowed transposing species biomass to finer resolutions, overcoming the lack of detailed information for the study area. Our demonstrative case study revealed a disruptive effect of ongoing LU/LC changes in the spatio-temporal distribution of top predators’ biomass, suggesting the possibility of an emergent disturbance pattern in habitat suitability and community stability. Comparative analysis between simulations and independent field data revealed a promising model performance.

Conclusions

Our modelling approach highlights the importance of integrating local LU/LC functional dynamics to predict key trophic’ responses, considered as pertinent ecological indicators for biodiversity management under realistic' future changing regional scenarios.
  相似文献   
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Emerging research suggests that the nitric oxide system may play a role in persistent breeding‐induced endometritis (PBIE) in the mare. Differences in uterine nitric oxide (NO) levels between mares susceptible or resistant to PBIE and a dose‐dependent inhibitory effect of NO on uterine contractility have been demonstrated. The objectives of this study were to investigate the difference in total nitric oxide synthase (NOS) activity of the endometrium between susceptible and resistant mares and the effect of a specific inducible nitric oxide synthase (iNOS) inhibitor on the endometrial NOS activity in vitro. Six susceptible and six resistant mares were selected based on preset criteria and the results of an intrauterine challenge with killed spermatozoa during oestrus. Endometrial biopsy samples were collected 24 hr post‐challenge and cultured at 37°C for 24 hr in L‐arginine supplemented minimum essential medium with or without a specific iNOS inhibitor (1,400 W dihydrochloride, 1 mM). The medium and the cultured endometrial tissue were collected after 24 hr of culture and assayed for NO and total protein, respectively. Total NO content of the medium, normalized to endometrial tissue wet weight or total protein, was used as a measure of endometrial NOS activity. Non‐parametric tests were applied for statistical analysis. Susceptible mares had significantly greater endometrial NOS activity than resistant mares. The iNOS inhibitor treatment significantly reduced NOS activity in endometrial samples derived from susceptible and resistant mares. These findings provide a basis for in vivo testing of specific iNOS inhibitors as preventative or therapeutic options for PBIE in mares.  相似文献   
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The present study aims to reveal the antibacterial potential of the wild mushrooms of Nepal. Despite the recognition of the medicinal potential of the natural resources in this country, a systematic study on the bioactivities of the wild mushrooms is still lacking. Therefore, in an attempt to fill this gap, ethanol extracts of 90 Nepalese wild mushroom samples were tested for antibacterial activity against Staphylococcus aureus and Propionibacterium acnes. Staphylococcus aureus was comparatively more susceptible with Inonotus clemensiae exhibiting the least minimum bactericidal concentration (MBC) of 100 μg/mL. The major compound in I. clemensiae was identified to be hispidin using high resolution liquid chromatography–electron spray ionization mass spectrometry (LC–ESI-MS) and nuclear magnetic resonance (NMR) analyses. Furthermore, the minimum inhibitory concentration (MIC) and MBC values of hispidin were determined to be 25 and 100 µg/mL for S. aureus and P. acnes, respectively. These findings show that the Nepalese wild mushrooms have the potential to be a novel addition to the functional ingredients industry due to their strong antibacterial potential.  相似文献   
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Z Lin  TS Hahm  WW Lee  WM Tang  RB White 《Science (New York, N.Y.)》1998,281(5384):1835-1837
Three-dimensional gyrokinetic simulations of microturbulence in magnetically confined toroidal plasmas with massively parallel computers showed that, with linear flow damping, an asymptotic residual flow develops in agreement with analytic calculations. Nonlinear global simulations of instabilities driven by temperature gradients in the ion component of the plasma support the view that turbulence-driven fluctuating zonal flows can substantially reduce turbulent transport. Finally, the outstanding differences in the flow dynamics observed in global and local simulations are found to be due to profile variations.  相似文献   
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