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   69篇
  免费   4篇
林业   5篇
农学   10篇
  9篇
综合类   2篇
农作物   5篇
水产渔业   11篇
畜牧兽医   16篇
植物保护   15篇
  2023年   1篇
  2022年   4篇
  2021年   2篇
  2020年   3篇
  2019年   3篇
  2018年   1篇
  2017年   4篇
  2016年   2篇
  2015年   4篇
  2014年   2篇
  2013年   9篇
  2012年   6篇
  2011年   6篇
  2010年   5篇
  2009年   2篇
  2008年   4篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2003年   3篇
  2002年   1篇
  2000年   1篇
  1996年   1篇
  1990年   2篇
  1987年   1篇
  1985年   1篇
  1983年   1篇
  1974年   1篇
排序方式: 共有73条查询结果,搜索用时 15 毫秒
1.
The anionic nature and high cation exchange capacity (CEC) of clinoptilolite zeolite can be exploited to reduce ammonia (NH3) loss from urea and to improve soil chemical properties to increase nutrient utilization efficiency in lowland rice cultivation. A closed-dynamic airflow system was used to determine NH3 loss from treatments (20, 40, and 60 g clinoptilolite zeolite pot?1). Seed germination study was conducted to evaluate the effects of clinoptilolite zeolite on rice seed germination. A pot study was conducted to determine the effects of clinoptilolite zeolite on rice plant growth variables, nutrient uptake, nutrient recovery, and soil chemical properties. Standard procedures were used to determine NH3 loss, rice plant height, number of leaves, number of tillers, dry matter production, nutrient uptake, nutrient recovery, and soil chemical properties. Application of clinoptilolite zeolite (15%) increased shoot elongation of seedlings and significantly reduced NH3 loss (up to 26% with 60 g zeolite pot?1), and increased number of leaves, total dry matter, nutrient uptake, nutrient recovery, soil pH, CEC, and exchangeable Na+. Amending acid soils with clinoptilolite zeolite can significantly minimize NH3 loss and improve rice plant growth variables, nutrient uptake, nutrient recovery, and soil chemical properties. These findings are being validated in our ongoing field trials.  相似文献   
2.
The effect of seed size on germination and seedling growth was assessed using cultivars of greengram and blackgram. Significant positive correlation was noticed between seed size and germination, seedling height, root length, primary leaf size and seedling weight. The possible advantages of choosing cultivars with heavier seeds for attaining better crop stand especially under rainfed situation are discussed.  相似文献   
3.
4.
The ease with which seeds are detached from panicles is one of the early domestication traits. Genotypes with sticky panicles are hard to thresh, and whenever threshed, the grain tends to remain attached to the glume which reduces market value and processability. This study was conducted to determine the genetic mechanisms underlying the threshability trait in sorghum. Four seed parents and eleven pollinators differing for threshability were intercrossed in Design II mating scheme and the resulting hybrids and the parents were grown in four environments. Threshability was estimated as the ratio of seed yield to panicle weight (TW) and proportion of seeds without sticky glumes (TG). Variation was significant among the entries, inbreds and hybrids with GCA for TG and TW varying markedly. Mean TG for inbred and hybrids of low threshable genotypes was not markedly different indicating that threshability trait is under the control of additive genes with dominant or partially dominant effects. Segregation analysis indicates that the TG trait may be under the control of few major genes with approximately one to three loci affecting the trait.  相似文献   
5.
Brassica oleracea L. includes various types of important vegetables that show extremely diverse phenotypes. To elucidate the genetic diversity and relationships among commercial cultivars derived by different companies throughout the world, we characterized the diversity and genetic structure of 91 commercial B. oleracea cultivars belonging to six varietal groups, including cabbage, broccoli, cauliflower, kohlrabi, kale and kai-lan. We used 69 polymorphic microsatellite markers showing a total of 359 alleles with an average number of 5.20 alleles per locus. Polymorphism information content (PIC) values ranged from 0.06 to 0.73, with an average of 0.40. Among the six varietal groups, kohlrabi cultivars exhibited the highest heterozygosity level, whereas kale cultivars showed the lowest. Based on genetic similarity values, an UPGMA clustering dendrogram and a two-dimensional scale diagram (PCoA) were generated to analyze genetic diversity. The cultivars were clearly separated into six different clusters with a tendency to cluster into varietal groups. Model-based structure analysis revealed six genetic groups, in which cabbage cultivars were divided into two subgroups that were differentiated by their head shape, whereas cauliflower and kai-lan cultivars clustered together into a single group. Furthermore, we identified 18 SSR markers showing 27 unique alleles specific to only one cultivar that can be used to discriminate 22 cultivars from the others. Our phylogenetic and population structure analysis presents new insights into the genetic structure and relationships among 91 B. oleracea cultivars and provides valuable information for breeding of B. oleracea species. In addition, we demonstrate the utility of SSR markers as a powerful tool for discriminating between the cultivars. The SSR markers described herein will also be helpful for Distinctness, Uniformity and Stability (DUS) test of new cultivars.  相似文献   
6.
The role played by complement and fibrinolysis in the pathogenesis of pulmonary oedema and the disseminated, subendothelial, petechial haemorrhages in cattle infected with Theileria parva was investigated. There was a marked reduction in total haemolytic complement in animals that died of this disease whereas the survivors showed only transient changes. The reduction in C3 levels in animals with severe disease, however, was equivalent to that in the survivors. Neither circulating soluble immune complexes nor free antibody against macroschizonts were detected in sera from cattle with severe infection. In addition to the complement changes, high levels of fibrinogen degradation products (FDPs) were detected in sera from the infected animals. The rate of production of FDPs and reduction in total haemolytic complement paralleled the clinical course of the disease. It is, therefore, suggested that the pulmonary oedema and disseminated petechial haemorrhages seen in East Coast fever may be the direct result of the combined effects of complement activation and consumption of fibrinogen and fibrin.  相似文献   
7.
A simple, quick and reliable method is described for the colorimetric estimation of residues of eight carbamate insecticides. The method is applicable to carbamates which on hydrolysis yield phenols with free para-positions suitable for coupling with a diazo reagent to yield coloured solutions. Optimum conditions for the development and measurement of the colour are described. Analytical data including graphs and some results from mud-bricks and cloth are presented to show the wide applicability of the method.  相似文献   
8.
Artificial breeding of mithun poses several challenges including lack of standard protocol for cryopreservation of spermatozoa. This is further complicated by harmful effects of hen's egg yolk (EY) as additive in extender. Purified low‐density lipoproteins (LDL) extracted from EY have been shown as beneficial over EY extender for long‐term semen storage in several species. This investigation explored use of LDL versus EY on semen quality and oxidative stress following freezing–thawing of spermatozoa. A total of 25 of 50 ejaculates based on biophysical parameters were selected for the experiment. After diluting with the Tris‐citrate‐glycerol (TCG) extender, each sample was split into three equal aliquots: Group I, control, EY; Group II and Group III contained 8% and 10% purified LDL, respectively. Frozen–thawed samples were evaluated for motility parameters (progressive, and in the bovine cervical mucus penetration test [BCMPT]), viability, sperm and nuclear abnormality, acrosome integrity, and enzymatic (leakage of intracellular contents) and biochemical (oxidative stress) profiles and in vitro fertility (IVF) assay. Study revealed a significant (< .05) improvement in viability, sperm and nuclear abnormality, acrosome integrity, motility (progressive and in cervical mucus), cholesterol content, and reduction in the leakage of intracellular enzymes in Group II. Moreover, intactness of acrosome and biochemical membranes was protected significantly (p < .05) in addition to significant (p < .05) improvement in binding per cent and binding index in IVF assay in extender containing 8% LDL. These results demonstrate that although cryopreservation of mithun's spermatozoa in EY was comparable with other species, addition of 8% LDL holds a clear advantage over EY or 10% LDL.  相似文献   
9.
The methanol extract of the roots of Tragia involucrata topically tested at doses of 100 and 200 mg/kg exerted significant wound healing effect in Staphylococcus aureus-induced excision wound in rats.  相似文献   
10.
Pseudomonas fluorescens strains CHA0 and Pf1 were investigated for their biocontrol efficacy against Banana bunchy top virus (BBTV) in banana (Musa spp.) alone and in combination with chitin under glasshouse and field conditions. Bioformulation of P. fluorescens strain CHA0 with chitin was effective in reducing the banana bunchy top disease (BBTD) incidence in banana under glasshouse and field conditions. In addition to disease control, the bioformulation increased the economic yield significantly compared to the untreated control. Increased accumulation of oxidative enzymes, peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), pathogenesis-related (PR) proteins, chitinase, β-1,3-glucanase and phenolics were observed in CHA0 bioformulation amended with chitin-treated plants challenged with BBTV under glasshouse conditions. Indirect ELISA indicated the reduction in viral antigen concentration in P. fluorescens strain CHA0 with chitin-treated banana plants corresponding to reduced disease ratings. The present study revealed that induction of defence enzymes by P. fluorescens with chitin amendment reduced the BBTD incidence and increased bunch yield in banana.  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