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   36篇
  免费   1篇
林业   4篇
农学   1篇
  8篇
综合类   1篇
农作物   4篇
水产渔业   4篇
畜牧兽医   10篇
植物保护   5篇
  2020年   1篇
  2019年   4篇
  2018年   4篇
  2017年   5篇
  2016年   1篇
  2015年   2篇
  2014年   1篇
  2013年   3篇
  2012年   6篇
  2010年   1篇
  2009年   1篇
  2007年   2篇
  2000年   2篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1977年   1篇
排序方式: 共有37条查询结果,搜索用时 15 毫秒
21.
This work describes a novel method for preparing electro-conductive rotor yarns by in situ oxidative chemical polymerization of pyrrole. The effects of different process parameters on electrical resistivity of the yarn were studied by using Box-Behnken response surface design. The concentration of monomer, polymerization time and polymerization temperature were found to influence the electrical resistivity of the yarn. It was observed that electrical resistivity of the yarn increased linearly with increase of measuring length of it. Whereas the effects of yarn twist and tensile strain found to had negative correlation with electrical resistivity of electro-conductive rotor yarns. Microscopic image analysis showed that there was uniform distribution of PPy polymer on the surface of cotton fibres and FTIR analysis depicted possible chemical interaction between polypyrrole and cellulose.  相似文献   
22.
India is the largest producer and exporter of turmeric (Curcuma longa), and different cultivars of this crop are traditionally characterized using agronomic traits, such as rhizome weight, yield potential, color and aroma of rhizome, curcumin content, and stability of curcumin content, which are influenced by environmental factors. The purpose of the present study was to probe whether karyomorphological and molecular marker attributes of turmeric cultivars could be correlated to validate their distinctiveness. Detailed karyomorphological analyses revealed uniform somatic chromosome number (2n = 63), with symmetric karyotype in all the studied cultivars. Chromosomes varied from 0.67 to 2.03 µm in length, with up to 72% bearing primary constrictions in the nearly median region (i-value ranging from 27.17 to 50). Asymmetry indices also indicated overall karyotypic symmetry among cultivars. On the contrary, random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) marker analyses revealed significant variability in the genetic constitution among them; Jaccard’s similarity coefficient value ranged from 0.569 to 0.969. Unweighted pair group method with arithmetic average (UPGMA) dendrogram and principal coordinate analysis based on the Jaccard’s coefficient produced four distinct clusters, which showed no geographical bias. Thus, it was concluded that although significant genetic variability that exists among the turmeric cultivars can be utilized for examining their authenticity, practicality of the use of karyomorphological characters for identification is significantly limited by the gross karyotypic similarity. Cryptic genetic changes accumulate in the genome of these plants because of their interaction with the environment. However, these remain confined within each cultivar in the absence of large-scale hybridizations and predominant vegetative propagation. This probably leads to variability in agronomic characters and may even help in developing novel characters in different cultivars. However, detection of any such change in the chromosomal structure would require fluorescent hybridization techniques.  相似文献   
23.
Antibacterial activity of Litsea glutinosa bark   总被引:1,自引:0,他引:1  
The methanol extract of the bark of Litsea glutinosa showed antibacterial activity, comparable to chloramphenicol, against all 16 tested microorganisms.  相似文献   
24.
Nanoparticles (NPs) are emerging as a new type of contaminant in water and wastewater. The fate of titanium dioxide nanoparticles (TiO2NPs) in a granular activated carbon (GAC) adsorber and their impact on the removal of trichloroethylene (TCE) was investigated. Key parameters governing the TiO2NP?CGAC interaction such as specific surface area (SSA), zeta potential, and the TiO2NP particle size distribution (PSD) were determined. The impact of TiO2NPs on TCE adsorption on GAC was tested by conducting TCE adsorption isotherm, kinetic, and column breakthrough studies in the presence and absence of TiO2NPs. SSA and pore size distribution of the virgin and spent GAC were obtained. The fate and transport of the TiO2NPs in the GAC fixed bed and their impact on TCE adsorption were found to be a function of their zeta potential, concentration, PSD, and the nature of their aggregation. The TiO2NPs under investigation are not stable in water and rapidly form larger aggregates. Due to the fast adsorption kinetics of TCE, the isotherm and kinetic studies found no effect from TiO2NPs. However, TiO2NPs attached to GAC and led to a reduction in the amount of TCE adsorbed during the breakthrough experiments suggesting a preloading pore blockage phenomenon. The analysis of the used GAC confirmed the pore blockage and SSA reduction.  相似文献   
25.
A field experiment was conducted to investigate the role of boron and zinc on growth, yield and quality of onion. There were eight treatment combinations consisted of four levels of boron (0, 0.1, 0.2 and 0.5%) and 4 levels of zinc (0, 0.1, 0.2 and 0.5%) were applied as foliar spraying. application of 0.5% boron significantly increased the growth (plant height, 63.93cm and number of leaves per plant, 7.25), yield (30.74 t ha?1) and quality (total soluble solids, 13.45 0B and pyruvic acid 5.94 µmol g?1) of onion. Among various levels of zinc 0.5% exhibited the best growth (plant height, 67.25cm and number of leaf per plant, 7.75), yield (33.34 t ha?1) and quality (total soluble solids, 14.57 0B and pyruvic acid, 5.86 µmol g?1) attributes of onion. These results suggest that the foliar application of boron and zinc significantly influenced the growth, yield and quality of onion.  相似文献   
26.
Bluetongue is an economically important viral disease of small ruminants. The present/current diagnostic kits and methods to diagnose BTV are laborious, time consuming and expensive. In the present study, we have attempted to develop a novel approach to detect BTV antibodies in sera that in future can be harnessed for developing a pen side diagnostic test. Briefly, we identified the immunodominant regions of the VP7 protein of BTV and synthesized them in the multiple antigenic peptide (MAP) format with cysteine at C-terminal of the lysine mosaic, which elicited highly ordered conformation as well as ELISA reactivity. Finally, we coated the MAP peptides on the gold nanoparticles that can be used to detect BTV specific antibodies in the sera using a spot test.  相似文献   
27.
Twelve isolates of Echinococcus granulosus, collected from domestic animals, including cattle, buffalo and sheep were analysed for DNA nucleotide sequence variation within mitochondrial cytochrome c oxidase I (coxI), NADH dehydrogenase subunit I (nadI) and internal transcribed spacer gene I (ITS1). After analysis of sequence information this was found that the fragment size of ITS1 of buffalo isolate was more in comparison to cattle and sheep isolates. Based on the nadI genotype this was found that Indian cattle, buffalo and sheep isolates could be grouped into E. granulosus sensu stricto. Based on coxI genotype two sheep isolates and one buffalo isolate were homologous to G2 genotype. Rests of the isolates were microvariants of G2 genotype. Presence of G2 genotype in buffalo is the first report of this genotype from this host.  相似文献   
28.
Thirty-one shiga toxin-producing (STEC) and 6 enteropathogenic Escherichia coli (EPEC) were isolated from 87 raw yak milk and 63 'churpi' samples. Of 18 stx(1) positive isolates (48.6%), 14 carried stx(1c) (77.7%). Subtyping of 28 stx(2) positive isolates (75.7%) revealed the presence of stx(2c) (9, 32.1%), stx(2d) (3, 10.7%), stx(2e) (1, 3.57%) and stx(2f) (3, 10.7%) variants. Furthermore, intimin (eaeA), enterohaemolysin (ehxA), autoagglutinating adhesin (saa), iha (adherence conferring protein), efa1 (EHEC factor for adherence), bundle forming pilli (bfpA) and toxB (type III secreted protein encoded on LEE Island, similar to toxin B of Clostridium difficile) genes were detected in 14, 16, 12, 4, 3, 2 and 2 isolates, respectively. Univariate and multivariate analysis depicted that both stx(1) and stx(2) or their variants were more likely to occur in isolates from Arunachal Pradesh (p<0.04) rather than Sikkim. Dendogram constructed on the basis of RAPD and ERIC PCR profile distributed the STEC and EPEC isolates in separate clusters irrespective of their sources and serotypes. The STEC and EPEC isolates exhibited resistance against erythromycin, amikacin, azithromycin, amoxicillin, ampicillin+cloxacillin, cephalothin, furazolidone, gentamicin, kanamycin, streptomycin and tetracycline. This is the first ever report on occurrence and characterization of STEC and EPEC isolated from yak milk and milk products.  相似文献   
29.
Sarkar et al. (this issue) proposed a laboratory measurement method for obtaining the hydraulic conductivity of soil at near‐saturated moisture conditions, bridging the gap between measurements that can be obtained with the evaporation method in the medium dry region, and measurements of the saturated conductivity by traditional methods. The method is based on a tension infiltration on a limited part of the surface of a soil sample and drainage of the sample at the same tension, leading to a divergent flow field. Despite equal tensions at top and bottom of the sample (“unit gradient”), the water flux in the sample is smaller than the corresponding value of the soil hydraulic conductivity at the applied tension. From numerical analysis of the flow problem, they concluded that unsaturated conductivity can be obtained with an accuracy of 10% for all texture classes of the USDA soil texture triangle. In this paper, we test the methodology for three different soil types using an appropriate apparatus. The results match well with independent saturated conductivity measurements on the wet side, and with unsaturated conductivity measurements in the medium moisture range that were obtained with the evaporation method.  相似文献   
30.
Bioassays were conducted with technical grade and commercial formulation of cypermethrin using freshwater fish Oreochromis niloticus as the test fish. The technical grade cypermethrin contained 92% active ingredient (a.i.) and the commercial formulation was an emulsified concentrate (EC) containing 10% a.i. (10% EC). Based on the actual concentration in water (2 h), the commercial formulation was found to be more acutely toxic to O. niloticus (96-h LC50 = 4.85 μg/L) than the technical grade cypermethrin (96-h LC50 = 9.74 μg/L). Exposure to sub-lethal concentrations (1.25, 2.5 μg/L) of commercial cypermethrin for 96 h produced stress on the fish, which was evident from the reduction of hepatic glycogen, reduction in the activities of alkaline phosphatase, acetylcholinesterase and catalase in liver and elevation of plasma glucose level and activities of hepatic acid phosphatase, aspartate aminotransferase and alanine aminotransferase. Exposure to these concentrations of cypermethrin for 14–28 days produced anaemia in fish. Long-term exposure (90 days) of the fish to these concentrations reduced the growth and deposition of protein and lipid in the body of fish as compared to control. It is concluded from this study that even minute concentration (1.25 μg/L) of cypermethrin (10% EC) in water can produce stress on fish. Long term exposure to such concentration of cypermethrin may also affect growth of the fish.  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