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   41篇
  免费   0篇
林业   3篇
农学   2篇
  8篇
农作物   1篇
水产渔业   1篇
畜牧兽医   17篇
植物保护   9篇
  2021年   1篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   5篇
  2012年   1篇
  2011年   3篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2006年   2篇
  2005年   4篇
  2004年   1篇
  2003年   4篇
  2002年   6篇
  1996年   1篇
排序方式: 共有41条查询结果,搜索用时 0 毫秒
21.
Field observations on egg hatch of Thaumetopoea processionea suggest that temporal asynchrony with Quercus robur budburst leads to starvation, retarded neonate development and mortality. However, T. processionea neonates are generally well adapted to variable between-tree and within-tree budburst phenology reflecting the species’ close bond to its host. They are able to withstand starvation periods of up to 3 weeks while searching extensively for suitable buds to feed on. Feeding and movements of young larvae frequently occur during daytime presumably taking advantage of higher day temperatures when night temperatures are below the species’ thermal threshold. Due to the specific adaptations, we assume precise temporal synchrony to play a minor role regarding its influences on T. processionea population dynamics. However, if hatching precedes budburst for more than 2–3 weeks, temporal asynchrony may become a significant mortality factor for the neonates particularly when other adverse events (e.g. unfavourable weather conditions) during that period are involved. Therefore, future studies should try to reveal further details of this interaction and focus on the impact of global warming on T. processionea—oak budburst synchronisation.  相似文献   
22.
Rhizoctonia solani AG-1 IA causes leaf blight on soybean and rice. Despite the fact that R. solani AG-1 IA is a major pathogen affecting soybean and rice in Brazil and elsewhere in the world, little information is available on its genetic diversity and evolution. This study was an attempt to reveal the origin, and the patterns of movement and amplification of epidemiologically significant genotypes of R. solani AG-1 IA from soybean and rice in Brazil. For inferring intraspecific evolution of R. solani AG-1 IA sampled from soybean and rice, networks of ITS-5.8S rDNA sequencing haplotypes were built using the statistical parsimony algorithm from Clement et al. (2000) Molecular Ecology 9: 1657–1660. Higher haplotype diversity (Nei M 1987, Molecular Evolutionary Genetics Columbia University Press, New york: 512p.) was observed for the Brazilian soybean sample of R. solani AG-1 IA (0.827) in comparison with the rest of the world sample (0.431). Within the south-central American clade (3-2), four haplotypes of R. solani AG-1 IA from Mato Grosso, one from Tocantins, one from Maranhão, and one from Cuba occupied the tips of the network, indicating recent origin. The putative ancestral haplotypes had probably originated either from Mato Grosso or Maranhão States. While 16 distinct haplotypes were found in a sample of 32 soybean isolates of the pathogen, the entire rice sample (n=20) was represented by a single haplotype (haplotype 5), with a worldwide distribution. The results from nested-cladistic analysis indicated restricted gene flow with isolation by distance (or restricted dispersal by distance in nonsexual species) for the south-central American clade (3-2), mainly composed by soybean haplotypes.  相似文献   
23.
Manure application to managed grassland is a common agricultural practice. There are, however, limited studies looking at the fluxes and interactions of reactive N compounds and aerosols following fertilisation with manure. In this study, state-of-the-art chemical analysers (GRAEGOR, QCLAS, PTRMS) were used to investigate concentrations, fluxes and chemical interactions of reactive nitrogen containing trace gases (NH3, HNO3, HONO) and aerosols (NO3) above a grassland fertilised with 164 kg N ha−1 of cattle slurry. Emissions of NH3 peaked at >67 μg m−2 s−1, based on a 30 min average. The estimated overall loss of total ammoniacal nitrogen (TAN) from the applied slurry through NH3 emissions in the first 5 days was 33.5%. The average trimethylamine flux in the first 31 h following the first slurry application was 40 ng m−2 s−1 and amounted to 0.38% of the NH3-N emissions. Apparent nitrate aerosol emissions were observed following the slurry application peaking at 13.0 ng m−2 s−1. This suggests formation of NH4NO3 from reaction of the emitted NH3 with atmospheric HNO3, consistent with the observation of gaseous concentration products exceeding the dissociation constants of ammonium nitrate. Fluxes of total nitrate (HNO3 + NO3) were bi-directional and positive during the mid-day period after fertilisation, suggesting that the slurry acted as a net source for these compounds. There is evidence of small HONO emission following fertilisation (up to 1 ng m−2 s−1), although the production process is currently not identified. By contrast, all compounds showed deposition to the adjacent unfertilised grassland.  相似文献   
24.
We carried out a microscopic examination of stools from a 2-month-old female puppy with bloody diarrhea, and this revealed large numbers of different spiral-shaped bacteria. To isolate these organisms, a rectal swab specimen was inoculated onto plates of Skirrow's agar and incubated at 37 degrees C for 6 days in a microaerobic atmosphere. Finally, a total of six different spiral-shaped bacteria (strains G1104, 94105, FR106, B0101, 3J102, and J2103) were isolated. Based on their morphology, biochemical traits, whole-cell protein profiles, and analysis of their 16S rDNA sequences, they were identified as Campylobacter upsaliensis, Helicobacter cinaedi, 'Flexispira rappini', two Anaerobiospirillum spp. with different morphologies, and Helicobacter sp., respectively. Analysis of 16S rRNA gene sequence data for strains 94150 (H. cinaedi) and FR106 (F. rappini) revealed that this approach has limitations when identifying isolates to the species level because of a high degree of sequence homology between these species (>99%) and considerable sequence variation among different isolates within these species. The dog was treated orally with amoxicillin for 3 days, which resolved the diarrhea. However, 1 day after the last dose the bloody diarrhea recurred but regarded to six more days amoxicillin treatment. This suggests a bacterial cause for the diarrhea. The approach to identification to microaerobic spiral-shaped bacteria in diarrheic dogs can be applied further to characterize their role in diarrhea illness.  相似文献   
25.
A spontaneously occurring subcutaneous mass in the left forelimb of a nine-year-old rabbit (Oryctolagus cuniculus) was examined histopathologically and immunohistochemically. Clinically, edema and hemorrhage were seen around the mass. No connection of the tumor mass to the appendicular skeleton was found. The tumor was arranged in a solid growth pattern and irregular bundles, and neoplastic cells were polygonal to spindle-shape. Osteoid (positive for osteocalcin) and multinucleated giant cells were diffusely or focally seen. Neoplastic cells were positive for vimentin, osterix and Ki-67, indicating the nature of osteoblasts with proliferating activity, but negative for α-smooth muscle actin, desmin or CD204. Based on these findings, a diagnosis of extraskeletal osteosarcoma was made, a very rare tumor both in laboratory and pet rabbits.  相似文献   
26.
Journal of Plant Diseases and Protection - The forest cockchafer Melolontha hippocastani is a serious forest pest whose infestation levels have been increasing in South-West Germany since the...  相似文献   
27.
The phytic acid (myo-inositol hexakisphosphate or InsP6) content of seed crops is important to their nutritional quality. Since it represents 75?±?10% of the total seed phosphorus (P), phytic acid is also important regarding the management of P in agricultural production. A low-phytate F5 line, No. T-2-250-4-20, was selected from the progeny of a cross between the low-phytate soybean line CX1834 and the Japanese commercial cultivar Tanbakuro. This line and its parents were grown in a field nursery, and the growth characteristics, phytate accumulation, and processing suitability for tofu were evaluated. At full maturity, the weight of seeds per plant of line T-2-250-4-20 was 5.2- and 1.3-fold higher than that of CX1834 and Tanbakuro, respectively. The amount of phytate-phosphorus as a percentage of the total P content in seeds was 23% in line T-2-250-4-20-34, 30% in CX1834, and 69% in Tanbakuro. No significant difference was observed among the three cultivars/lines in their seed magnesium (Mg), potassium (K), crude protein, and sugar. However, the calcium (Ca), crude fat and ash contents in seeds of line T-2-250-4-20-34 and Tanbakuro was lowered compared to that of CX1834. The breaking stress of tofu was estimated employing a rheometer with a decreasing concentration of the coagulant magnesium chloride (MgCl2), starting at 15.7?mmol?L?1. In tofu made from Tanbakuro, the concentration of MgCl2 required to achieve the maximum breaking stress was 12.6?mmol?L?1; however, it was 9.5?mmol?L?1 for tofu made from T-2-250-4-20-34 and CX1834. The tofu made from Tanbakuro was soft and broke at 6.3?mmol?L?1 MgCl2, but, in line T-2-250-4-20-34, harder tofu was made with lower MgCl2 concentrations. No difference was observed among the cultivars/lines in the SDS-PAGE patterns of protein in soymilk. These results indicate that we have developed a low-phytate soybean with adequate productivity, and confirmed that tofu made from the low-phytate T-2-250-4-20-34 soybean becomes coagulated and harder at a lower MgCl2 concentration than that from high-phytate soybean cultivars.  相似文献   
28.
Dissemination of extended-spectrum cephalosporin (ESC)-resistant Salmonella is a public health concern in the egg production industry. ESC-resistant Salmonella often acquires the bla gene via insertion sequences (ISs). Therefore, this study aimed to assess antimicrobial resistance in Salmonella from Japanese layer breeding chains and egg processing chains, and determine the genetic profiles of IS-like elements in ESC-resistant Salmonella. Antimicrobial susceptibility testing was performed on 224 isolates from 49 facilities involving layer breeder farms, hatcheries, pullet-rearing farms, and layer farms in breeding chains along with egg processing chains. ESC-resistant Salmonella strains were whole-genome sequenced. Among them, 40 (17.9%) were resistant to at least streptomycin, tetracycline, ampicillin, chloramphenicol, cefpodoxime, nalidixic acid, ciprofloxacin, and/or kanamycin despite lacking resistance to azithromycin and meropenem. Moreover, 15 were ESC-resistant Salmonella harboring blaCMY-2 (Salmonella enterica serovar Ohio, n=12; S. Braenderup, n=1; untypeable with O7:b:-, n=1) and blaCTX-M-14 (S. Cerro, n=1). IncA/C2 plasmids containing ISEcp1, IS26, and multiple antimicrobial resistance genes (including blaCMY-2) were identified in S. Ohio isolates from pullet-rearing and layer farms belonging to the same company. Chromosomal integration of partial or whole IncA/C2 plasmids was seen with two S. Ohio isolates via ISEcp1 or IS26, respectively. Antimicrobial resistance genes such as blaCMY-2 might be transmitted among the upper and the lower levels of layer breeding chains via the replicon type IncA/C2 plasmids containing ISEcp1 and IS26.  相似文献   
29.
Permeability of Na-gluconate, Na-malate and Na-acetate into fish-meat strips by soaking, and their osmotic dehydrating effects were investigated in comparison with those of sodium chloride (NaCl) and sorbitol. Carboxylic acids, anion species of carboxylates, were less permeable into soaked meats than chlorine of NaCl, and their permeability was similar to that of sorbitol. However, the permeation of sodium, cation species of the carboxylates and NaCl, was promoted with the concentration of free sodium ion dissociated in soaking solutions. The ratio of sodium to the anion species in soaked meats was varied, depending on the numbers of the sodium atom in the molecules as well as the dissociation degree of the ionic compounds in the soaking solution. Furthermore, the osmotic dehydrating effects of Na-gluconate and Na-malate were analogous with that of sorbitol, and higher than those of NaCl and Na-acetate. These results indicated that the permeation characteristics and the osmotic dehydrating effects of the carboxylates were associated with their ionization in soaking solution as well as their molecular weights.  相似文献   
30.
In this paper we present the first report of the occurrence of a binucleate Rhizoctonia spp. causing hypocotyl and root rot in kale in Brazil. Rhizoctonia spp. were isolated from kale (Brassica oleracea var. acephala) with symptoms of hypocotyl and root rot. The isolates, characterized as binucleate Rhizoctonia spp., did not show an anastomosis reaction with any of the binucleate Rhizoctonia spp. testers used. The pathogenicity of the isolates was tested under greenhouse conditions; all isolates were pathogenic and showed different symptom severities on kale. The ITS-5.8S rDNA sequences of kale isolates and 50 testers (25 binucleate Rhizoctonia spp. and 25 Rhizoctonia solani) were compared in order to characterize the genetic identity of Rhizoctonia spp. infecting kale. The kale isolates showed genetic identities ranging from 99.3 to 99.8% and were phylogenetically closely related to CAG 7 (AF354084), with identities of 98.5 and 98.7%. It is suggested that the binucleate Rhizoctonia spp. causing hypocotyl and root rot on kale Brazil comprises a new AG not yet described.  相似文献   
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