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   120篇
  免费   12篇
  国内免费   1篇
林业   2篇
农学   5篇
  31篇
综合类   8篇
农作物   6篇
水产渔业   11篇
畜牧兽医   39篇
园艺   1篇
植物保护   30篇
  2023年   2篇
  2021年   1篇
  2020年   6篇
  2019年   4篇
  2018年   4篇
  2017年   8篇
  2016年   4篇
  2015年   4篇
  2014年   5篇
  2013年   12篇
  2012年   5篇
  2011年   9篇
  2010年   4篇
  2009年   6篇
  2008年   8篇
  2007年   13篇
  2006年   5篇
  2005年   6篇
  2004年   4篇
  2003年   8篇
  2002年   6篇
  2001年   1篇
  2000年   2篇
  1998年   1篇
  1995年   1篇
  1988年   1篇
  1985年   1篇
  1953年   2篇
排序方式: 共有133条查询结果,搜索用时 15 毫秒
91.
Septoria tritici blotch caused by the fungus Zymoseptoria tritici (formerly Mycosphaerella graminicola) is one of the most yield-reducing diseases worldwide. Effective disease management involves the use of resistant cultivars and application of fungicides. In this study, the population structure and genetic diversity of 183 Z. tritici isolates from Denmark, Sweden, Finland and the Baltic countries were analysed by molecular markers. In population structure analysis, isolates from Denmark and Sweden were grouped together, whereas isolates from the Baltics and Finland were grouped together. Analysis of genetic diversity and ?-values confirmed the division of Nordic and Baltic regions. Danish isolates sampled from different regions and different varieties were not genetically different. However, significant genetic differences were detected between isolates sampled from different years in Denmark and for isolates sampled from specific cultivars in different years. Additionally, the frequency of several known point mutations in the gene cyp51, conferring decreased sensitivity to DMI fungicides, was investigated. Several of the examined mutations were detected at a lower frequency in Baltic isolates compared to Danish and Swedish isolates. Analysis of the Danish population revealed a significant increase in specific mutations over the years. Lastly, some mutations were significantly more frequent in isolates derived from certain varieties. By using different resistance sources in breeding programmes and application of a wide range of fungicides, a sustainable and efficient disease management can be obtained.  相似文献   
92.
Journal of Plant Diseases and Protection - Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria tritici (formerly known as Mycosphaerella graminicola), is a devastating...  相似文献   
93.
Litchi (Litchi chinensis Sonn.) ‘Mauritius’ is a popular export cultivar due to its attractive red color and excellent fruit quality. Three orchards were selected based on planting distance and routine pruning practices followed by each growing season. Orchards A and B are essentially similar regarding these production practices, whereas orchard C had overlapping canopies due to lack of routine pruning practices after each growing season and short planting distance. Canonical variate analysis was used as a statistical tool to compare fruit quality attributes from different orchards (A, B, and C) in terms of physical, chemical and sensory parameters and correlating to leaf nutrient status. The correlations and plot of loadings of the variates indicated that skin color (visual), color values (chroma and hue angle, h°), fruit weight, firmness, and consumer acceptability were the main factors that discriminated orchard C from the other two orchards. The soluble solids concentrations, titratable acidity and fruit taste were the quality attributes discriminating orchard A from orchard B. The relationship between the leaf nutrients and fruit quality attributes showed positive relationships between leaf potassium (K) and anthocyanin content and titratable acidity (TA); leaf phosphorus (P) and pericarp h°, leaf nitrogen (N) and fruit weight; leaf calcium (Ca) and fruit firmness.  相似文献   
94.
There is a need for simple and inexpensive diagnostic and screening tests for the detection of Cryptosporidium parvum infection in calves. A sucrose wet mount test and a lateral immunochromatography test were evaluated for epidemiological sensitivity and specificity, cost per test, simplicity, test time and ease of batching. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the Cryptosporidium oocyst wall protein (COWP) gene locus, with gel electrophoresis, was used as a gold standard. Cohen's kappa statistic of agreement (kappa) between the Ontario Veterinary College (OVC) sucrose wet mount test and COWP PCR-RFLP was 0.82, and the sensitivity and specificity of the OVC sucrose wet mount test were 88.6% and 93.8%, respectively. The sensitivity and specificity of the lateral immunochromatography test were 78.3% and 93.3%, respectively, and agreement between this test and PCR-RFLP was good (kappa=0.73). There was substantial agreement between the OVC sucrose wet mount test and the lateral immunochromatography test (kappa=0.84). Both tests were inexpensive and easy to use; however, the lateral immunochromatography test was faster and simpler to perform than the sucrose wet mount test, and was generally more user-friendly. These tests provide practitioners and researchers with cheap, quick and accurate methods of detecting C. parvum infection in young calves.  相似文献   
95.
Concepts for the clinical use of stem cells in equine medicine   总被引:1,自引:1,他引:0  
Stem cells from various tissues hold great promise for their therapeutic use in horses, but so far efficacy or proof-of-principle has not been established. The basic characteristics and properties of various equine stem cells remain largely unknown, despite their increasingly widespread experimental and empirical commercial use. A better understanding of equine stem cell biology and concepts is needed in order to develop and evaluate rational clinical applications in the horse. Controlled, well-designed studies of the basic biologic characteristics and properties of these cells are needed to move this new equine research field forward. Stem cell research in the horse has exciting equine specific and comparative perspectives that will most likely benefit the health of horses and, potentially, humans.  相似文献   
96.
Humans have one mannan-binding lectin (MBL) in circulation but rodents, pigs, rabbits and rhesus monkeys have two, MBL-A and MBL-C. Plasma forms of these proteins have similar mannan-binding activity in vitro, but might differ in their ability to bind other microbial targets. In these studies, we compared carbohydrate-dependent binding of mouse plasma MBL-A and MBL-C to mannan-sepharose beads and to intact bacteria isolated as pathogens from mice. After incubation of mouse plasma with intact bacteria, MBL-A and MBL-C were eluted with N-acetylglucosamine (GlcNAc) and identified in nonreducing SDS-PAGE using Western blot analysis and MBL-A or MBL-C specific monoclonal antibodies. GlcNAc eluates of plasma incubated with mannan-sepharose beads, Klebsiella oxytoca and Staphylococcus aureus contained similar bands (mainly approximately 50kDa) that were immunoreactive with MBL-C antibody. Furthermore, a smaller form of MBL-C (approximately 45kDa) was detected bound to Pseudomonas aeruginosa. By comparison, immunoreactive MBL-A (a ladder of approximately 175kDa and larger bands) was identified in these GlcNAc eluates from mannan-sepharose beads, S. aureus and K. oxytoca but not P. aeruginosa. These studies demonstrate that mouse MBL-A and MBL-C in plasma are not equivalent in their ability to recognize bacteria that are pathogens for mice.  相似文献   
97.
Tropical Animal Health and Production - A population structure study was performed in South African ovine populations using the OvineSNP50 beadchip. Blood samples were obtained from 295 sheep of...  相似文献   
98.
• Crop diversification is a dynamic pathway towards sustainable agrifood systems.• Technological and institutional barriers restrict uptake of crop diversification.• More coordination and cooperation among agrifood system stakeholders is required.• The European Crop Diversification Cluster calls for multiactor networks.European cropping systems are often characterized by short rotations or even monocropping, leading to environmental issues such as soil degradation, water eutrophication, and air pollution including greenhouse gas emissions, that contribute to climate change and biodiversity loss. The use of diversification practices (i.e., intercropping, multiple cropping including cover cropping and rotation extension), may help enhance agrobiodiversity and deliver ecosystem services while developing new value chains. Despite its benefits, crop diversification is hindered by various technical, organizational, and institutional barriers along value chains (input industries, farms, trading and processing industries, retailers, and consumers) and within sociotechnical systems (policy, research, education, regulation and advisory). Six EU-funded research projects have joined forces to boost crop diversification by creating the European Crop Diversification Cluster (CDC). This Cluster aggregates research, innovation, commercial and citizen-focused partnerships to identify and remove barriers across the agrifood system and thus enables the uptake of diversification measures by all European value-chain stakeholders. The CDC will produce a typology of barriers, develop tools to accompany actors in their transition, harmonize the use of multicriteria assessment indicators, prepare policy recommendations and pave the way for a long-term network on crop diversification.  相似文献   
99.
The aim of this study was to evaluate the addition of artificial substrates in biofloc technology systems that are used for the intensive production of Litopenaeus vannamei. The experiment lasted 35 days. Tanks each with a useful volume of 800 L were filled with water containing bioflocs (25 % of the total volume) and filtered seawater. Three treatments with three replicates each were compared: (1) Ctrl (control), i.e., without the addition of artificial substrate, (2) 200 and (3) 400, with added artificial substrate equivalent to 200 and 400 % of the lateral area of the tanks, respectively. The shrimp with initial weight of 0.40 ± 0.15 g were stocked at a density of 300 shrimp/m2. Feed (Guabi/38 Active, Brazil) was supplied two times per day. The water quality parameters were suitable for the production of L. vannamei. The settleable solids (SS) were higher in the Ctrl treatment (82.1 ± 19 mL L?1) and differed statistically from the 200 and 400 treatments that presented average SS values below 10 mL L?1. The reuse of water with bioflocs accelerated nitrification in the tanks, and no significant differences were shown between tanks. The presence of biofilm did not interfere with ammonium or nitrite levels, but it did serve as a food source that optimized shrimp performance, as shown by higher final weights. More studies are needed to evaluate the circulation and mixing intensity effects of the substrates on water throughout the production cycle.  相似文献   
100.
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