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   80篇
  免费   3篇
林业   9篇
农学   2篇
基础科学   1篇
  14篇
农作物   7篇
水产渔业   19篇
畜牧兽医   6篇
园艺   13篇
植物保护   12篇
  2023年   2篇
  2022年   3篇
  2021年   1篇
  2020年   2篇
  2019年   2篇
  2018年   14篇
  2017年   6篇
  2016年   5篇
  2015年   3篇
  2014年   2篇
  2013年   3篇
  2012年   8篇
  2011年   8篇
  2010年   6篇
  2009年   4篇
  2008年   5篇
  2007年   4篇
  2003年   1篇
  1990年   1篇
  1986年   1篇
  1984年   2篇
排序方式: 共有83条查询结果,搜索用时 31 毫秒
1.
Landscape Ecology - Several case studies investigated the role of ecosystem services in participatory planning processes. However, no systematic study exists that cuts across a large number of...  相似文献   
2.
Journal of Plant Diseases and Protection - Citrus (Citrus spp. L.), which has high nutritional and economic value, is one of the most commonly grown fruits in Turkey. In spring 2020, large aerial...  相似文献   
3.
ABSTRACT:   The effects of the different catching methods (gillnet, longline, harpoon) on sensory, chemical (pH, total volatile base nitrogen, K -value) and microbiological (total viable count [TVC]) changes in pike perch Sander lucioperca stored in ice were investigated. The same soaking time was used for both gillnet and longline fishing. The catching method had considerable influence on the freshness quality of pike perch. The acceptable shelf life was 15 days for pike perch caught by gillnet, and 22 days for longline and harpoon. The initial concentrations of inosine monophosphate (2.4 μmol/g) in pike perch caught by gillnet were significantly lower ( P  < 0.05) than longline (4.1 μmol/g), and especially by harpoon (16.7 μmol/g). However, the initial K -values for fish caught by harpoon were significantly ( P  < 0.05) lower (24.36%) than fish caught by longline and gillnet (57.69%, 64.41%, respectively). The average K , Ki, G and H -values at rejection day in terms of sensory assessment were approximately 90, 98, 156 and 40%, respectively, for all catching methods during ice storage. However, TVC reached 7.0 log cfu/g after approximately 11 days of storage for fish caught by gillnet, 19 days for fish caught by longline and 8 days for fish caught by harpoon. The result of this study suggests that the best catching method for preserving the freshness of pike perch is longline, based on the data obtained from the sensory and microbiological analysis.  相似文献   
4.
The Tatura system for the preparation of seed-beds for irrigated annual row-crops is described, where the soil is tilled when wet and friable and so requires few passes with implements to become suitable for crops, and where seeds are sown into wet soil. In soil prepared by the Tatura system, the percentage of aggregates < 0.5 mm diameter (as measured by dry-sieving) in the seed-bed was about half that found in commercially prepared seed-beds which were tilled up to 50 times when dry. With the Tatura system, the wetter the soil (up to 22% water content) when tilled, or the more passes (up to 4) of the implement at a water content of 22%, the less dust (< 0.5 mm diameter) and/or fewer clods (> 20 mm diameter) were formed.

The macro-structure of the surface layer of soil tilled at different water contents by the Tatura system was also quantified statistically by the method of wax-impregnation. The macro-structures were compared at the 10 mm, 20 mm, 40 mm, 60 mm and 80 mm depths in beds of soil prepared for irrigated annual row-crops by a system which has been described previously. Within each treatment (21.7%; 19.0%; 11.6% water content at 0–100 mm depth at tillage), the linear porosity and mean pore-size each tended to decrease with depth to 40 mm, with no further change or slight decrease to 80 mm depth. In all treatments, the mean aggregate-size tended to increase with depth from 10 mm depth to 80 mm depth. The sizes of pores and aggregates varied across each bed and possibly depended on the position of tines within the bed at each pass at tillage. Water content at tillage led to small differences in structure of the beds of soil. Soil tilled at a water content slightly above the Casagrande Plastic Limit generally had slightly larger pores and aggregates than soil tilled at lower water contents.  相似文献   

5.
6.
Xanthomonas axonopodis pv. manihotis (Xam) is the causal agent of cassava bacterial blight (CBB) disease. CBB is a major constraint to cassava cultivation in Ghana. In this study, a survey was conducted in eight regions of Ghana to assess the presence of CBB disease. Out of the eight regions visited, CBB, though at different prevalence, was observed in five regions. Cassava plants samples showing suspected bacterial blight symptoms were collected for analysis by Polymerase Chain Reaction (PCR). The results of the analysis showed that Ashanti region had the highest prevalence in percentage of CBB, which recorded (70%), followed by Volta region (60%); Brong Ahafo region (40%); Eastern region (40%) and Greater Accra region (20%). Morphological examination of the putative pathogen was carried out on Cefazolin trehalose agar (CTA) and Nutrient agar (NA) media. The isolates were subjected to conventional PCR using Xanthomonas genus specific primer, RST2/RST3, Xam specific Variable Number Tandem Repeat (VNTRs) loci, XaG1_67F/R and X-gumD primers, which produced 840, 446 and 402 bp, respectively. The isolates also tested positive with SYBR Green fluorescent dye, using Real-time PCR. The resulting PCR products were sequenced and analyzed using a BLASTn program, which revealed homology between 93 and 100% with several other Xam strains retrieved from GenBank nucleotide database. The pathogenicity test of the isolates on the susceptible Esam cassava variety produced symptoms typical of Xam and the pathogen was consistently re-isolated from the inoculated cassava plants and thereby satisfying the Koch’s postulates.  相似文献   
7.
8.
The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a major pest of pepper. In this study, we collected data on the development, survival, fecundity, and proportion of apterous and alate forms of green peach aphid reared on five commercial pepper cultivars (Amiral, Erciyes, Mert, Mertcan, and Naz) at 25?±?1°C, 60?±?5% RH, and a photoperiod of 16:8 (L:D) h. We analyzed the life history raw data by using the age-stage, two-sex life table. The shortest development time (6.66 days) and highest fecundity (62.68 individuals) occurred on the Erciyes cultivar. The highest intrinsic rate of increase (r?=?0.332 d?1), finite rate of increase (λ?=?1.394 d?1), net reproductive rate (R0?=?62.7 offspring) and shortest mean generation time (T?=?12.45 d) also occurred on the Erciyes cultivar; while the lower fitness occurred on the Amiral, Mertcan and Naz cultivars. Our results compared differences in the population growth rate of M. persicae on different pepper cultivars. This information will be useful to individuals working in pest management programs particularly those involving M. persicae.  相似文献   
9.
Polypropylene (PP) fabrics were activated by an atmospheric pressure, dielectric barrier discharge to optimize the effects of some discharge parameters on the dyeability of PP fabrics. Air and argon plasmas were used to modify the surfaces of the fabrics, and the effects on dyeability were investigated when the treated fabrics were dyed by leuco and pigment forms of vat dyestuffs. Surface properties of plasma-treated samples were characterized by Fourier transform infrared spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Vat-dyed samples showed a significant increase in color strength when PP fabrics were pretreated with atmospheric pressure plasmas of either argon or air.  相似文献   
10.
The potential risk of pesticides to cause harm to humans and other organisms even at trace levels calls for sensitive and accurate analytical techniques for their simultaneous qualitative and quantitative determinations. In this study, a sensitive binary dispersive liquid-liquid microextraction (B-DLLME) strategy was developed for the simultaneous determination of phorate and oxyfluorfen by gas chromatography mass spectrometry after extraction/preconcentration from aqueous solution. An experimental design was used to optimize parameters of the B-DLLME method to obtain maximum outcome. Under the optimum conditions of B-DLLME, the limit of detection (LOD) for phorate and oxyfluorfen were found to be 0.41 μg L?1 and 0.54 μg L?1, respectively. The detection limits correlate to about 37 and 73 folds enhancement in detection powers when compared to direct GC-MS determination of phorate and oxyfluorfen, respectively. In order to find out the applicability of developed method to real samples, recovery tests were performed for 20 μg L?1 of phorate and oxyfluorfen spiked in well water samples. Percent recovery values were found to be 94.5% for phorate and 101.9% for oxyfluorfen.  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