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排序方式: 共有197条查询结果,搜索用时 125 毫秒
191.
Dayana Ribeiro Flávia de Souza Rocha Kátia Morais Costa Leite Siomar de Castro Soares Artur Silva Ricardo Wagner Dias Portela Roberto Meyer Anderson Miyoshi Sérgio Costa Oliveira Vasco Azevedo Fernanda Alves Dorella 《Veterinary research》2014,45(1):28
Caseous lymphadenitis (CLA) is a chronic disease that affects sheep and goats worldwide, and its etiological agent is Corynebacterium pseudotuberculosis. Despite the economic losses caused by CLA, there is little information about the molecular mechanisms of bacterial pathogenesis, and current immune prophylaxis against infection has been unable to reduce the incidence of CLA in goats. Recently, 21 different mutant strains of C. pseudotuberculosis were identified by random mutagenesis. In this study, these previously generated mutants were used in mice vaccination trials to develop new immunogens against CLA. Based on this analysis, , an iron-acquisition-deficient mutant strain, was selected. After challenge with a virulent strain, 80% of the animals that were immunized with the CZ171053 strain survived. Furthermore, this vaccination elicited both humoral and cellular responses. Intracellular survival of the bacterium was determined using murine J774 cells; in this assay, the CZ171053 had reduced intracellular viability. Because iron acquisition in intracellular bacteria is considered one of their most important virulence factors during infection, these results demonstrate the immunogenic potential of this mutant against CLA. CZ171053相似文献
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194.
The RAR1 interactor SGT1, an essential component of R gene-triggered disease resistance 总被引:1,自引:0,他引:1
Azevedo C Sadanandom A Kitagawa K Freialdenhoven A Shirasu K Schulze-Lefert P 《Science (New York, N.Y.)》2002,295(5562):2073-2076
Plant disease resistance (R) genes trigger innate immune responses upon pathogen attack. RAR1 is an early convergence point in a signaling pathway engaged by multiple R genes. Here, we show that RAR1 interacts with plant orthologs of the yeast protein SGT1, an essential regulator in the cell cycle. Silencing the barley gene Sgt1 reveals its role in R gene-triggered, Rar1-dependent disease resistance. SGT1 associates with SKP1 and CUL1, subunits of the SCF (Skp1-Cullin-F-box) ubiquitin ligase complex. Furthermore, the RAR1-SGT1 complex also interacts with two COP9 signalosome components. The interactions among RAR1, SGT1, SCF, and signalosome subunits indicate a link between disease resistance and ubiquitination. 相似文献
195.
Carvalho Ddo C Brigagão MR dos Santos MH de Paula FB Giusti-Paiva A Azevedo L 《Plant foods for human nutrition (Dordrecht, Netherlands)》2011,66(2):114-121
Differentiation between organic and conventional coffee has increased due to the growing demand and high consumption of healthy
foods that contain compounds with antioxidant potential, which have been associated with the reduction of chronic diseases.
We used organic and conventional coffee in powder 4% (w/w) and infusions 5%, 10% and 20% (w/v) incorporated in a commercial
diet to test in vivo. The levels of chlorogenic acid, caffeine and trigonelline were determined by high performance liquid chromatography. The
body weight, weight gain, food consumption, aberrant foci crypt, mucin depleted foci, stress biomarkers protein carbonyl and
malondialdehyde, biochemical parameters and behavior of the rats were compared between the experimental and control groups
within a framework of colon carcinogenesis. The organic coffee showed higher levels of chlorogenic acid, caffeine and trigonelline
than conventional, however, this difference did not significantly affect behavior. The infusions had an antioxidant effect,
reducing the levels of malondialdehyde; however, the biochemical parameters of the serum were not altered, and there was neither
induction nor prevention of preneoplasic lesions. 相似文献
196.
Lucas Silva Azevedo Incio Abreu Pestana Marcelo Gomes Almeida Wanderley Rodrigues Bastos Cristina Maria Magalhes Souza 《Ecology of Freshwater Fish》2022,31(1):72-80
Floodplain lakes are ecosystems characterised by annual flood and dry cycles. Fish ecology is influenced by the flood pulse due to the large influx of allochthonous food resources and diversification of habitats during the flood cycle, while during the dry cycle, fishes tend to be confined in reduced habitat. The aim of this study was to evaluate the seasonal variation in trophic niche width and overlap of four species—Mylossoma duriventre, Prochilodus nigricans, Cichla.pleiozona and Serrasalmus rhombeus—in an Amazonian floodplain lake. Stable isotope analyses were used to estimate trophic niche width and overlap during the flood and dry seasons. We hypothesised broader niche width for all species during the flood cycle and a higher degree of overlap between the two piscivorous fishes during the dry cycle. Isotopic niche width was 72% broader for P. nigricans, 61% for S. rhombeus and 54% for C. pleiozona during the dry cycle, which did not support our hypothesis. Core niche width overlaps were not observed between piscivorous species in either flood or dry cycle. The results indicate that seasonal variation in isotopic niche width is specific to feeding habit. Understanding how fish trophic ecology responds to changes in the hydrological regime during the seasons is crucial for sustainable fishery management in a region where many people rely heavily on fish for nutritional and economic purposes. 相似文献
197.
Francisco Gerson Araújo Mrcia Cristina Costa de Azevedo Gustavo Henrique Soares Guedes Wagner Uehara 《Ecology of Freshwater Fish》2022,31(1):45-59
Increases in temperatures over the last century, more intensively after the eighties, were recorded in several databases for the south-eastern Brazil. These increases are likely to change fish communities in aquatic systems by decreasing abundances, biomass and sizes of some species more sensitive to climate change. Reservoirs may be particularly susceptible to the effects of climate change, as they isolate previously connected areas limiting fish dispersal and migration, as well as increasing water temperature and thermal stratification. We assessed temporal changes in the abundance and biomass of the ichthyofauna in an isolate reservoir (inflowing waters from small tributaries in a highland region) aiming to associate changes with climate effects over three decades (1990, 2000, 2010). Two abundant native species, a loricariid Loricariichthys castaneus (Castelnau, 1855) and a cichlid Geophagus brasiliensis (Quoy & Gaimard, 1824), were selected to assess eventual response to climate changes in their geographical distribution in the Southeast Atlantic Hydrographic Region, considering different carbon emission scenarios using ecological niche models. A decrease in the densities and biomass of the ichthyofauna and of the two selected species were observed in both summer and winter over the three decades, coinciding with increases in temperatures. These decreases were correlated with increases in positive anomalies of temperature, which may be an indicator of climatic changes, although with low explanation of the data variation. The mean size of L. castaneus decreased between the nineties and 2010, whereas no significant trend was found for the size of G. brasiliensis. Our predictions of new area for future adequacy indicated a loss in the distribution area for both species (mainly for G. brasiliensis), considering the most pessimistic scenario for 2050 and 2070, possibly due to climatic changes. Both hydroelectric dams and global warming pose threats to freshwater fish diversity, and both will interact. Changes observed in the fish assemblage over the last decades were essential for an assessment of the consequences of global warming in this type of reservoir combining larger scale studies with future projections. 相似文献