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   47篇
  免费   4篇
林业   2篇
农学   8篇
  9篇
综合类   6篇
农作物   5篇
水产渔业   6篇
畜牧兽医   5篇
园艺   1篇
植物保护   9篇
  2023年   1篇
  2022年   7篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   3篇
  2016年   3篇
  2015年   2篇
  2014年   2篇
  2013年   3篇
  2012年   6篇
  2011年   1篇
  2010年   3篇
  2009年   1篇
  2008年   2篇
  2007年   1篇
  2006年   1篇
  2005年   3篇
  2003年   3篇
  2002年   1篇
  1999年   1篇
排序方式: 共有51条查询结果,搜索用时 31 毫秒
31.
In the present study, the growth and survival of early life stages (ELS) of Chitala chitala were studied in nylon hapa for 28 days, followed by rearing in fibreglass reinforcement plastic (FRP) tanks for a period of 30 days. Ten‐day‐old ELS of C. chitala reared in hapa were fed with three different diets namely Indian Major Carp (IMC) spawn (<8 mm), live tubifex and fresh fish eggs. In the second phase, 28‐day‐old ELS were stocked in 200‐lit FRP tank and supplied four different live diets namely live tubifex worm, chironomous larvae, zooplanktons and mosquito larvae. Fish accepted all types of diets in the experimental rearing period in both the systems. The experiments conducted in hapa showed a higher specific growth rate (SGR), weight gain per cent and survival rate in larvae fed with live tubifex (SGR=1.76±0.02) than fish eggs (0.77±0.31) and IMC spawn (0.46±0.12). The study carried out in FRP tanks revealed that SGR was higher in ELS fed on chironomous larvae (4.44±0.61), followed by mosquito larvae (3.29±0.40) and live tubifex (3.28±0.36), whereas minimum SGR was recorded with zooplanktons (2.84±0.66). A significant difference (P<0.05) in SGR, final mean weight and weight gain (%) was also recorded. The highest mean survival rate (100%) of ELS in an FRP tank was observed in chironomous larvae and zooplanktons, whereas with live tubifex and mosquito larvae the same survival rate (80%) was recorded. The rate of survival of the ELS reared in hapa varied from 65% to 85%. The experiments showed that ELS of C. chitala could be reared successfully in hapas and fibreglass reinforcement tanks for attaining better survivability and growth.  相似文献   
32.
Genetic Resources and Crop Evolution - Alliums are essential crops in daily diet for their flavor and medicinal value, which are highly cross pollinated crops, prone to inbreeding, or continuous...  相似文献   
33.
Abstract

Alpha-lactalbumin (α-LA) (ALA), one of the two major whey proteins, is strongly correlated with the nutritional value and the functional properties of whey and whey products. The genetic variations of ALA gene in Jakhrana Goat breed (Capra hircus) were investigated using an optimized non-radioactive polymerase chain reaction–single strand conformation polymorphism (PCR–SSCP) analysis of four amplified fragments covering all four exons of the gene. A total of eight SSCPs patterns were detected in three of these exons in a sample of 50 Jakhrana goats, indicating that this breed has high genetic variability in the ALA gene. This result opens interesting prospects for future breeding programs and conservation strategies. These ALA gene variants can be sequenced and screened in the entire population to develop single nucleotide polymorphisms for association studies with different productive and reproductive performances and marker assisted selection. In addition, our data show that PCR–SSCP is an appropriate tool for evaluating genetic variability.  相似文献   
34.
The relationships between heavy metal concentrations and physico-chemical properties of natural lake waters and also with chemical fractions of these metals in lake sediments were investigated in seven natural lakes of Kumaun region of Uttarakhand Province of India during 2003–2004 and 2004–2005. The concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in waters of different lakes ranged from 0.29–2.39, 10.3–38.3, 431–1407, 1.0–6.6, 5.3–12.1, 12.6–166.3, 0.7–2.7 and 3.9–27.1 μg l?1 and in sediments 14.3–21.5, 90.1–197.5, 5,265–6,428, 17.7–45.9, 13.4–32.0, 40.0–149.2, 11.1–14.6 and 88.9–167.4 μg g?1, respectively. The concentrations of all metals except Fe in waters were found well below the notified toxic limits. The concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were positively correlated with pH, electrical conductivity, biological oxygen demand, chemical oxygen demand and alkalinity of waters, but negatively correlated with dissolved oxygen. The concentrations of Cr, Ni, Zn, Cd and Pb in waters were positively correlated with water soluble + exchangeable fraction of these metals in lake sediments. The concentrations of Zn, Cd and Pb in waters were positively correlated with carbonate bound fraction of these metals in lake sediments. Except for Ni, Zn and Cd, the concentrations of rest of the heavy metals in waters were positively correlated with organically bound fraction of these metals in lake sediments. The concentrations of Cr, Mn, Ni, Cu and Zn in waters were positively correlated with reducible fraction of these metals in lake sediments. Except for Cd, the concentrations of rest of the metals in waters were positively correlated with residual fraction and total content of these heavy metals in lake sediments.  相似文献   
35.
Laimaphelenchus suberensis sp. nov. obtained from declining Quercus suber trees of Herdade da Gouveia de Baixo, Alentejo, Portugal, is described and illustrated based on morphological, biometrical and molecular characters. The diagnosis of Laimaphelenchus species has been commonly based on the presence or absence of a vulval flap and on the shape structure of the tail tip. The species described here has been included in the Laimaphelenchus group without vulval flap, and can be distinguished from morphologically similar species by its tail tip shape structure that has a stalk-like terminus and three diffuse tubercles with 4–6 finger-like protrusions. For the molecular analyses, the mitochondrial DNA region from the cytochrome oxidase subunit I (mtCOI), the D2-D3 expansion segments of the large subunit (LSU) and small subunit (SSU) of rRNA gene were amplified and sequenced. Sequences of L. suberensis sp. nov. clustered separately from all Laimaphelenchus spp. with available sequences in Genbank, confirming its identification as a new species. This is the second report of the genus Laimaphelenchus in Portugal, associated with Q. suber: L. heidelbergi and L. suberensis sp. nov.  相似文献   
36.
We screened soil samples collected from underneath shrubs and/or large trees at different locations in the Eastern Ghats of Andhra Pradesh for xylanase-producing microorganisms. Xylose-utilizing bacteria were numerically dominant in soils of most locations whereas xylose-and xylan-utilizing actinobacteria were minor components. Xylan-utilizing fungi constituted a major share of total microbial populations in soil samples collected at half of the sites, whereas xylan-utilizing bacteria were predominant at other sampling locations. Some of the isolates of fungi exhibited xylanase activity with a range of400–4000 U/ml, indicating great potential for their uses in paper, pulping and bioethanol industries for producing value-added products.  相似文献   
37.
An avian influenza (AI) surveillance was undertaken in Maharashtra state, India during the period 2010-2011. There are no reports of AI surveillance in emus from India. A total of 202 blood samples and 467 tracheal and cloacal swabs were collected from eight emu farms. A hemagglutination inhibition (HI) assay was performed for detection of antibodies against AI H5N1, H7N1, H9N2, and avian paramyxovirus type 1 (APMV-1) viruses. A microneutralization (MN) assay was performed to confirm the presence of neutralizing antibodies against AI H9N2 and to compare with HI assays. A total of 28.2% and 28.7% of samples were positive for antibodies against AI H9N2 by HI and MN assays, respectively, using > or = 1:40 as a cut-off titer; 15.3% samples were positive for APMV-1 by HI assay using a > or = 1:10 cut-off titer. Seropositivity of AI H9N2 was nil in the grower (<1 yr) age group and highest (78%) in the breeder (2-3 yr) age group, whereas seropositivity against APMV-1 was observed in all age groups. Performance of both HI and MN assays was similar, suggesting the utility of using the MN assay along with HI assay for surveillance studies. This is the first report of the seroprevalence of AI H9N2 and APMV-1 in emus in India.  相似文献   
38.
39.
Foliar extracts of Annona squamosa (Family: Annonaceae) were screened for antimicrobial and insecticidal activity against the common microbial infestants of pulses and the stored grain pest pulse beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). Flavonoids isolated from aqueous extracts of A squamosa showed antimicrobial activity against all the common microbial contaminants of pulses and 80% insecticidal activity against C chinensis at a concentration of 0.07 mg ml-1. Various physico-chemical tests, chromatographic and spectroscopic studies with partially purified aqueous extract indicated the presence of flavonol type flavonoids. This may provide a useful beginning for the development of botanical pesticides for post-harvest safeguard of pulses.  相似文献   
40.
In order to remain globally competitive and to ensure traceability, intensive and extensive livestock operations are adopting radio-frequency-based electronic identification (RFID) and data recording systems. Such integrated systems offer dual advantages of lowered labor costs due to automation and enhanced profits due to optimization of animal productivity, health and welfare. However, RFID-based systems might not be economically viable for small-hold livestock farmers unless there is considerable value advantage. Further, the set up and operation of a data recording system for small-hold farmers is also difficult due to size-constraints and distant farm units. We have developed an integrated system for small-hold dairy farmers to enable employing of RFID technology to ensure credibility of data recording, and avoidance of livestock insurance-related claim malpractices. The system can additionally be used to periodically collect performance records and to operate veterinary service delivery. The integrated system comprises of: (a) an RFID tag or insert; (b) an RFID reader; (c) a PDA/mini-laptop with custom software installed; (d) a USB modem internet connection; and (e) a central data server on web platform with dedicated server-level software. The unique feature of the system is that the veterinary health worker (VHW) is able to register and enter new records only when the RFID reader connected to a mini-laptop is within reading range of the associated RFID tag. This also authenticates the visit by the VHW. Other data management operations such as browsing, sorting, data analysis and report generation can be carried out when the VHW is away from the RFID field. We have deployed and validated the system in a cluster of 5000 dairy animals spread over more than 10 villages with an average of two to three animals per farmer in Thanjavur district, Tamil Nadu, India. The system is user-friendly and easy to operate in that the animals’ insurance registration and issuance of policy documents can be done in a single farm visit. The system can also be used for collecting periodic animal records and sending SMS ‘alerts’ to the farmers. Initial economic analysis suggests that the investment cost would be recovered even if fraudulent claims in around 0.5% of the insured animals can be prevented. The sustenance cost can be recovered from the improvised health and production management service delivery to the farmers. It is however emphasized that the system can only be implemented in organized dairy operations wherein the milk processing company can establish functional collaboration with veterinary service providers, insurance company micro-finance companies and this consortium can bear the cost of RFID in exchange for long term multilateral benefits to all the stakeholders.  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