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   89篇
  免费   4篇
林业   1篇
农学   2篇
  19篇
综合类   8篇
农作物   2篇
水产渔业   10篇
畜牧兽医   43篇
园艺   3篇
植物保护   5篇
  2024年   1篇
  2023年   2篇
  2022年   2篇
  2021年   7篇
  2020年   6篇
  2019年   6篇
  2018年   4篇
  2017年   5篇
  2016年   2篇
  2015年   1篇
  2014年   3篇
  2013年   6篇
  2012年   11篇
  2011年   8篇
  2010年   5篇
  2009年   1篇
  2008年   4篇
  2007年   7篇
  2006年   4篇
  2005年   2篇
  2003年   1篇
  2001年   1篇
  2000年   1篇
  1995年   1篇
  1993年   1篇
  1990年   1篇
排序方式: 共有93条查询结果,搜索用时 218 毫秒
11.
Erythromycin is an antimicrobial agent recommended for the control and treatment of diseases caused by gram-positive bacteria. Few studies, however, have determined the metabolic and pharmacokinetic aspects of this antimicrobial agent in fish. The aim of the present study, therefore, was to determine the accumulation and depletion time of erythromycin after administration of medicated feed containing 52 mg kg(-1) body weight day(-1) for 8 days in rainbow trout (Oncorhynchus mykiss). Results were analyzed following the European Agency for Evaluation of Medicinal Products guidelines. We measured a withdrawal time of 187°C-day (°C-day=water temperature×days), lower than the value (500°C-day) recommended by Council Directive 2004/28/EC for veterinary medicinal products. Our results provide data to establish therapeutic regimens for the use of erythromycin in aquaculture.  相似文献   
12.
We studied the safety and efficacy of an inactivated vaccine (Ichtiovac-Lg) against Lactococcus garvieae in rainbow trout (Oncorhynchus mykiss). In an initial dose-response experiment to test safety, we injected 50 rainbow trout weighing 30-40 g with a double dose of vaccine (0.2 ml) intraperitoneally. We observed these fish three times a day until day 50 post-vaccination when they were killed to evaluate visceral reactions, adhesions and intraperitoneal absorption. Survival was 100% in both the treatment and control groups and no significant differences were found in percentage of severe adhesions and pigmentation of peritonea and viscera. In a second trial, we injected 50 rainbow trout weighing 30-40 g with 0.1 ml of vaccine and a control group was injected with 0.1 ml of PBS intraperitoneally. On day 29 post-vaccination, both groups were challenged by intraperitoneal injection with 0.1 ml of a virulent heterologous strain of L. garvieae at 3 x 10(6) cfu ml(-1) and fish were observed for a further 21 days. At the end of the experiment, the survivals of the vaccinated fish and control group were 94 and 4%, respectively.  相似文献   
13.
A 4-year-old neutered male St. Bernard-mastiff crossbred dog showed clinical signs of lethargy and anorexia after being administered phenobarbital for the treatment of idiosyncratic seizures. A complete blood (cell) count revealed pancytopenia. Auto-agglutination and Coombs tests were negative suggesting that an immunemediated cause was unlikely; therefore, an idiosyncratic reaction to phenobarbital was suspected. Supportive care and control of seizures with zonisamide was initiated and clinical signs improved. Blood values were monitored closely and returned to normal after 3 wk.  相似文献   
14.
15.
土壤添加沼渣对温室气体排放及小麦生长的影响   总被引:1,自引:1,他引:0  
Digestate, the product obtained after anaerobic digestion of organic waste for biogas production, is rich in plant nutrients and might be used to fertilize crops. Wheat(Triticum spp. L.) was fertilized with digestate, urea, or left unfertilized and cultivated in the greenhouse for 120 d. Emissions of greenhouse gasses(carbon dioxide(CO_2), methane(CH_4), and nitrous oxide(N_2O)) were monitored and plant growth characteristics were determined at harvest. The digestate was characterized for heavy metals, pathogens, and C and N mineralization potential in an aerobic incubation experiment. No Salmonella spp., Shigella spp., or viable eggs of helminths were detected in the digested pig slurry, but the number of faecal coliforms was as high as 3.6 × 10~4colony-forming units(CFU) g-~(1)dry digestate. The concentrations of heavy metals did not surpass the upper limits established by US Environmental Protection Agency(EPA). After 28 d, 17% of the organic C(436 g kg~(-1)dry digestate) and 8% of the organic N(6.92 g kg~(-1)dry digestate)were mineralized. Emissions of CO_2 and CH_4 were not significantly affected by fertilization in the wheat-cultivated soil, but digestate significantly increased the cumulative N_2O emission by 5 times compared to the urea-amended soil and 63 times compared to the uncultivated unfertilized soil. It could be concluded that digestate was nutrient rich and low in heavy metals and pathogens, and did not affect emissions of CH_4 and CO_2 when applied to a soil cultivated with wheat, but increased emission of N_2O.  相似文献   
16.
盐碱土中可培养中度嗜盐菌的研究   总被引:1,自引:1,他引:0  
为了调查大庆盐碱地的中度嗜盐菌资源,采集重度盐碱化的土壤样本进行嗜盐微生物的分离纯化,获得45株中度嗜盐细菌。形态学特征显示,40%菌落呈黄色,其余为乳白色;细胞为直线或弯曲的杆状,G+和G-细菌比例为19:26。进一步的生理生化特征分析筛选出8株进行16S rDNA基因序列的测定及系统发育分析。结果表明,它们分别属于Bacillus(3株),Halomonas(2株)和Alkalibacillus(3株)属的菌株。菌株15-2应为现有种Bacillus agaradhaerens,X10-1(或X10-7)可能为Bacillus属潜在的新种,15-7(或X10-2)可能为Halomonas潜在的新种,有待于进一步的验证。研究虽然仅获得了有限的中度嗜盐菌资源,但却丰富了我们对大庆盐碱土中可培养中度嗜盐菌多样性的认识,为今后合理开发和利用大庆地区的嗜盐微生物资源提供了素材和参考。  相似文献   
17.
18.
Fertilisers, especially nitrogen (N) and phosphorus (P) supplies, are frequently used in agricultural soil management to attain high crop yields. However, the intensive application of these chemical inputs can decrease the quality of agricultural soils and increase the probability of environmental pollution. In this study, the impact of P fertilisation on the diversity of the soil bacterial community was assessed. For this, a culture-independent approach targeting 16 rRNA and phoD genes was used on DNA extracted from pasture soils subjected to three different P fertilisation regimes for a long-term (42 years). As alkaline phosphomonoesterase (ALP) is necessary for mineralisation of organic P, an inverse relationship between the level of potential ALP activity and soil available P was expected. Indeed, a lower ALP activity was observed in soil subjected to higher chemical P fertiliser input. Analysis of the prevalence of three divergent families of ALP (PhoA, PhoD and PhoX) in metagenomic datasets revealed that PhoD is the most frequent ALP in soil samples and was selected as the most representative ALP possessed by the soil bacterial communities. Diversity of the phoD phosphorus mineraliser group, as well as the total bacterial community, was both increased in response to long-term P fertilisation. Specifically, phosphorus fertilisation decreased the relative abundance of certain taxa, including Acidobacteria and Pseudomonas fluorescens. In conclusion, this study shows that P fertilisation affects the microbial diversity of soil ecosystems, which might potentially modulate the soil biogeochemical cycle.  相似文献   
19.
Gastrointestinal disorders are an important cause of morbidity in box turtles (Terrapene carolina Carolina), however published information is currently lacking on the normal radiographic anatomy, transit, and emptying times of the gastrointestinal tract. A total of 15 healthy box turtles were recruited for this prospective, anatomic, reference interval study. Three‐view radiographic series (vertical beam dorsoventral, horizontal beam latero‐lateral, and horizontal beam rostrocaudal views) were acquired prior to contrast administration, and following contrast administration at 0, 20, 40, 60, and 90 min, 2, 4, 8, 12, and 24 h post administration, and every 24 h thereafter until all contrast was eliminated (15 mL/kg barium sulfate diluted to 30% weight per volume was administered via orogastric gavage). Vertical beam dorsoventral and horizontal beam latero‐lateral views were of excellent quality to identify gastrointestinal structures. The horizontal beam rostrocaudal view immediately postcontrast administration provided gastric and pyloric identification but had lesser diagnostic use at later time points due to anatomical superimposition. The gastrointestinal tract was composed of a tubular stomach, a pyloric sphincter near midline, a duodenum with a cranial flexure in the right cranial coelomic cavity, small intestines within the right coelom, a small cecal bulb, and a transverse and descending colon. Contrast media entered the large intestine by 24 h in all turtles, and a pyloro‐colic indentation was noted at the proximal descending colon. The large intestinal emptying was highly variable due to the interindividual variability of contrast sequestration within the cecal bulb. Findings from the current study serve as a reference on the gastrointestinal anatomy, transit, and emptying times in healthy eastern box turtles; and introduce a novel, horizontal beam, rostrocaudal view for gastrointestinal contrast studies in chelonians.  相似文献   
20.
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