首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15篇
  免费   0篇
林业   1篇
  1篇
综合类   2篇
水产渔业   2篇
畜牧兽医   7篇
植物保护   2篇
  2021年   1篇
  2020年   2篇
  2013年   3篇
  2012年   1篇
  2010年   1篇
  2005年   2篇
  2002年   2篇
  2001年   2篇
  1998年   1篇
排序方式: 共有15条查询结果,搜索用时 343 毫秒
1.
低死亡率和较高的饲料利用率 ,看来是鸡抗氧化状态得到改善的结果。增高日粮维生素E的含量并应用有机硒可减少肺高压 (腹水症 )引起的死亡。  相似文献   
2.
Since 2006, the members of the molecular epidemiological working group of the European "EPIZONE" network of excellence have been generating sequence data on avian influenza and avian paramyxoviruses from both European and African sources in an attempt to more fully understand the circulation and impact of these viruses. This review presents a timely update on the epidemiological situation of these viruses based on sequence data generated during the lifetime of this project in addition to data produced by other groups during the same period. Based on this information and putting it all into a European context, recommendations for continued surveillance of these important viruses within Europe are presented.  相似文献   
3.
Since summer 2010, numerous cases of Rabbit Haemorrhagic Disease (RHD) have been reported in north-western France both in rabbitries, affecting RHD-vaccinated rabbits, and in wild populations. We demonstrate that the aetiological agent was a lagovirus phylogenetically distinct from other lagoviruses and which presents a unique antigenic profile. Experimental results show that the disease differs from RHD in terms of disease duration, mortality rates, higher occurrence of subacute/chronic forms and that partial cross-protection occurs between RHDV and the new RHDV variant, designated RHDV2. These data support the hypothesis that RHDV2 is a new member of the Lagovirus genus. A molecular epidemiology study detected RHDV2 in France a few months before the first recorded cases and revealed that one year after its discovery it had spread throughout the country and had almost replaced RHDV strains. RHDV2 was detected in continental Italy in June 2011, then four months later in Sardinia.  相似文献   
4.
The biochemical composition of grape berries depends on the cultivar genome and is influenced by environmental conditions and growing practices, which vary according to origin and "terroir" (French word accounting for the factors of climate, soil, and cultural practices on grape and wine quality). The components currently measured to determine the potential quality of grapes for wine-making at harvest are sugars, acidity, pH, and total phenolics, referred to as "classic analysis". The aim of this work was to establish metabolic profiles using both conventional physicochemical analyses and 1H NMR spectrometry of the skin and pulp of mature berry extracts in order in four appellations situated in different locations in southern-western France (Bordeaux). Principal component analysis was applied to the physiochemical and 1H NMR data to investigate the variability of the grape composition and to characterize groups of samples. A significant clustering of the metabolic profile of pulps or skins in relation to their terroir was observed. Physicochemical analyses were more discriminant than 1H NMR data, but NMR spectroscopy allowed metabolic finger-printings using identified metabolites and some still nonattributed resonances.  相似文献   
5.
Human infants begin to acquire their native language in the first months of life. To determine which brain regions support language processing at this young age, we measured with functional magnetic resonance imaging the brain activity evoked by normal and reversed speech in awake and sleeping 3-month-old infants. Left-lateralized brain regions similar to those of adults, including the superior temporal and angular gyri, were already active in infants. Additional activation in right prefrontal cortex was seen only in awake infants processing normal speech. Thus, precursors of adult cortical language areas are already active in infants, well before the onset of speech production.  相似文献   
6.
Does literacy improve brain function? Does it also entail losses? Using functional magnetic resonance imaging, we measured brain responses to spoken and written language, visual faces, houses, tools, and checkers in adults of variable literacy (10 were illiterate, 22 became literate as adults, and 31 were literate in childhood). As literacy enhanced the left fusiform activation evoked by writing, it induced a small competition with faces at this location, but also broadly enhanced visual responses in fusiform and occipital cortex, extending to area V1. Literacy also enhanced phonological activation to speech in the planum temporale and afforded a top-down activation of orthography from spoken inputs. Most changes occurred even when literacy was acquired in adulthood, emphasizing that both childhood and adult education can profoundly refine cortical organization.  相似文献   
7.
ABSTRACT To investigate the biocontrol mechanisms by which the antagonistic Fusarium oxysporum strain Fo47 is active against Fusarium wilt, a Fot1 transposon-mediated insertional mutagenesis approach was adopted to generate mutants affected in their antagonistic activity. Ninety strains in which an active Fot1 copy had transposed were identified with a phenotypic assay for excision and tested for their biocontrol activity against F. oxysporum f. sp. lini on flax in greenhouse experiments. Sixteen strains were affected in their capacity to protect flax plants, either positively (more antagonistic than Fo47) or negatively (less antagonistic). The molecular characterization of these mutants confirms the excision of Fot1 and its reinsertion in most of the cases. Moreover, we demonstrate that other transposable elements such as Fot2, impala, and Hop have no transposition activity in the mutant genomes. The phenotypic characterization of these mutants shows that they are affected neither in their in vitro growth habit nor in their competitiveness in soil compared with wild-type strain Fo47. These results show that mutants are not impaired in their saprophytic phase and suggest that the altered biocontrol phenotype should likely be expressed during the interaction with the host plant.  相似文献   
8.
Fish sperm collected by stripping males is frequently contaminated by urine. In this study, carp milt mixed with urine (0.5–7.5% of volume) was studied in order to evaluate the changes of some motility parameters (percentage of motile spermatozoa, velocity and beat frequency) and the ATP content of spermatozoa. In the absence of urine contamination, spermatozoa had an ATP content in the range of 8–9 nmol/108 spermatozoa, an initial velocity of 100–160 μm s−1 and a flagellar beat frequency around 30–50 Hz, 10 s after a 1/2000 dilution in an activating medium (45 mM NaCl, 5 mM KCl, 30 mM Tris–HCl, pH 8.0, osmolality <160 mosM kg−1). In contrast, when milt was contaminated with 7.5% of urine for 1 h, the ATP content was 4–5 nmol/108 spermatozoa and most spermatozoa had low initial velocity (30–100 μm s−1) and flagellar beat frequency (10–30 Hz). It appears that the low osmolality of urine was responsible for the degradation in the quality of carp spermatozoa by an early activation in the collecting tube which induced an early reduction of the intracellular ATP store. From a practical point of view, milt contamination by urine during stripping can be avoided by first pressing the abdomen before sampling and then collecting the remaining urine by means of a catheter introduced into the urinary bladder.  相似文献   
9.
This case report comprises studies of four Goeldi's monkeys (Callimico goeldii) from the same enclosure. Globe samples from two related C goeldii (the female C goeldii and her male offspring) were available for a histopathological evaluation. Both cases presented histopathologically evident outer retinal degeneration with differences in severity. There was marked outer retinal atrophy characterized by loss of the outer and inner photoreceptor segments, and depletion of the outer retinal nuclear layer. Furthermore, we report a reduction in the thickness of the outer retinal plexiform, inner retinal nuclear layer, and inner retinal plexiform layer in these C goeldii monkeys. To the authors’ knowledge, these findings have not yet been reported in wild‐ or captive‐bred population of C goeldii.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号