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   68篇
  免费   7篇
林业   4篇
农学   5篇
  19篇
综合类   6篇
农作物   8篇
水产渔业   5篇
畜牧兽医   21篇
园艺   3篇
植物保护   4篇
  2022年   1篇
  2021年   1篇
  2020年   3篇
  2019年   6篇
  2018年   5篇
  2017年   9篇
  2016年   3篇
  2014年   2篇
  2013年   5篇
  2012年   7篇
  2011年   3篇
  2010年   3篇
  2009年   5篇
  2008年   4篇
  2007年   5篇
  2006年   3篇
  2005年   3篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2000年   1篇
  1999年   1篇
  1995年   1篇
排序方式: 共有75条查询结果,搜索用时 15 毫秒
71.
Stocking density is an important factor in cage aquaculture of finfish. Effects of high stocking density (35 fish cubic m?1) on a range of biochemical and immunological parameters in Asian seabass reared in open sea floating net cages were compared to fish held in relatively low density (15 fish cubic m?1). The results revealed that chronic stress due to high stocking density induced variations in most of the parameters studied as evidenced by increased cortisol and glucose levels and decreased activity of lysozyme, myeloperoxidase and complement. Production of reactive oxygen species, total leucocyte count and total serum protein were also decreased, whereas anti-protease, alkaline phosphatase and acid phosphatase activities were increased in high stocking-density group when compared to low stocking-density group. Effects of chronic stress due to high stocking density were discussed in relation to variations in these parameters.  相似文献   
72.
Withania somnifera (L.) Dunal. (Indian ginseng) is an important medicinal plant which yields pharmaceutically active compounds called withanolides. The present work deals with optimization of parameters of hairy root culture of W. somnifera for the production of biomass and withanolide A. We also investigated the effects of carbon source [sucrose, glucose, fructose, maltose, glucose + fructose (1:1), fructose + sucrose (1:1) and sucrose + glucose (1:1)], sucrose concentration (1%, 2%, 3%, 4%, 6% and 8%) and the initial medium pH (4.0, 4.5, 5.0, 5.5, 5.8, 6.0 and 6.5) on growth and production of withanolide A in hairy root cultures of W. somnifera. We found that biomass accumulation and production of withanolide A was highest when sucrose was used as the carbon source (11.92 g l−1 DW and 11.96 mg g−1 DW of withanolide A). Further 3% sucrose concentration was found to be optimal for biomass accumulation (11.92 g l−1 DW) and 4% sucrose favoured the production of withanolide A (13.28 mg g−1 DW) in the tested range of concentrations (1-8%). The biomass of hairy roots was optimal when the initial medium pH was 5.8 (12.1 g l−1 DW) and the withanolide A production was highest in the medium pH set at 6.0 (13.84 mg g−1 DW).  相似文献   
73.
Information about the nutritional status of a plant is a basic prerequisite for its adequate nutrition and is crucial to achieve high-yield productivity. Assessing the annual amount of nutrient that a tree needs to absorb in order to successfully complete a vegetative and reproductive growth is a fundamental step for developing rational fertilization in orchards. We are unaware of any report describing macro- and micronutrient dynamics in fruit at different growth stages of mango. Seven cultivars of mango (Dashehari, Langra, Mahmood Bahar, Menka, Sabri, Sundar Langra and Zardalu) were selected for the study. Different macronutrients such as nitrogen, phosphorus, potassium, calcium and magnesium (N,P, K, Ca, and Mg) and micronutrients such as iron, manganese, zinc and copper (Fe, Mn, Zn, and Cu) were analyzed at four growth stages, namelymarble stage, prestone formation stage, stone hardening stage and harvest stage. There was a significant variation in nutrient content of fruits throughout the developmental stages irrespective of cultivars. There was no definite trend of nutrient variation among cultivars but in general, most of the nutrients like N, P, K, Mg, Mn, Zn, and Cu were the highest at the marble stage, and Ca and Fe at the stone hardening stage.  相似文献   
74.
(1) The nitrogen-corrected apparent metabolisable energy (AME(N)) content of solvent-extracted rapeseed and sunflower seed (un-decorticated) meals in relation to species (chicken, guinea fowl and quail) and dietary addition of feed enzymes (0 or 0.5 g/kg diet) was evaluated by a diet replacement method in a 3 x 2 factorial design. (2) The metabolism trial was conducted at two substitution levels (200 and 400 g/kg diet) of each meal with or without supplementation of commercial enzyme preparation in 6 individuals or 6 groups of cockerels, guinea fowls and quails. (3) The experimental diets were fed for a period of 12 d followed by a 3-d collection period during which total feed consumed and droppings output were quantitatively recorded. (4) The AME(N) values of rapeseed meal for cockerels, guinea fowls and quails were 8.4, 8.7 and 8.8 MJ/kg, respectively, while the corresponding values for sunflower seed meal were 6.1, 6.1 and 6.2 MJ/kg dry matter, without enzyme supplementation. (5) The AME(N) value of rapeseed meal did not improve with enzyme supplementation. However, AME(N) values of sunflower seed meal significantly increased with enzyme supplementation, from 6.1 to 6.5 MJ/kg dry matter. (6) Since AME(N) values of rapeseed meal and sunflower seed meal were similar in chicken, guinea fowl and quail, values reported for chicken could, therefore, be used for guinea fowl and Japanese quail.  相似文献   
75.

A feeding trial of 10 weeks duration was undertaken on laying hens (n = 240) to evaluate feeding value of rice distiller’s dried grains with soluble (rDDGS) with or without enzyme supplementation (α-amylase, β-glucanase, xylanase, carboxymethylcellulase, pectinase, proteinase, α-galactosidase, β-galactosidase, lipase, and phytase), following 4 × 2 factorial design, on egg production, nutrient utilization, and cost economics of egg production. The birds were randomly assigned to eight dietary treatments with 30 birds/treatment. The birds were housed individually in layer cages and each bird was taken as an experimental unit. Eight experimental diets were prepared by incorporating four levels (0, 50, 75, and 100 g/kg) of rDDGS with and without enzyme supplementation. The results revealed a significant (P < 0.01) increase of egg mass, feed intake, egg production, and body weight gain in dietary treatments with up to 75 g rDDGS though the values were statistically similar to the hens fed 100 g rDDGS. Enzyme supplementation resulted in significant (P < 0.01) improvement of egg mass, egg production, feed conversion ratio (FCR) per dozen eggs, FCR per kilogramme egg mass, and net FCR. The significantly (P < 0.01) higher yolk index was observed at 100 g rDDGS level, while shell thickness improved significantly (P < 0.01) up to 75 g rDDGS level. No significant effect of rDDGS inclusion was observed on shape index, albumin index, and Haugh unit. Enzyme supplementation significantly improved the shell thickness and yolk colour of eggs. Nitrogen, calcium, and phosphorus retention and dry matter metabolizability did not show any significant treatment effects. There was significant (P < 0.01) reduction in feed-cost per kilogramme egg mass or per dozen eggs with the increased DDGS levels and dietary enzyme supplementation. It was concluded that rDDGS can be used up to 100 g/kg diet of laying hens along with enzyme supplementation for better productivity of layer hens.

  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