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   37篇
  免费   3篇
林业   1篇
农学   1篇
  15篇
综合类   1篇
畜牧兽医   13篇
园艺   1篇
植物保护   8篇
  2021年   2篇
  2020年   3篇
  2018年   1篇
  2017年   2篇
  2016年   5篇
  2014年   2篇
  2013年   1篇
  2012年   1篇
  2009年   2篇
  2008年   4篇
  2007年   1篇
  2006年   4篇
  2005年   3篇
  2004年   1篇
  2002年   1篇
  2000年   2篇
  1999年   1篇
  1997年   2篇
  1988年   1篇
  1983年   1篇
排序方式: 共有40条查询结果,搜索用时 15 毫秒
11.
A collection of 30 strains of Verticillium dahliae, recovered during 2004–2006 from 12 cultivars of chrysanthemum (Chrysanthemum morifolium) in five districts of İzmir province in Turkey, was assigned to vegetative compatibility groups (VCGs) based on pairings of complementary nitrate-nonutilizing (nit) mutants induced on a chlorate-containing medium. Of these strains, nine were assigned to VCG1, seven to VCG2A, 11 toVCG2B and one to VCG4B. The remaining two strains could not be tested for vegetative compatibility because of their inability to yield nit mutants. Pathogenicity tests conducted by the root-dip method, demonstrated that wilt of chrysanthemum in Turkey is caused by V. dahliae, and most strains in VCG1 were significantly more aggressive to chrysanthemum than those in VCGs 2 and 4B. This is the first known study in the world of the VCGs of V. dahliae isolates from chrysanthemum.  相似文献   
12.
Cuticular wax on the plant epidermis inhibits or enhances prepenetration events of powdery mildew (Erysiphe necator Schwein). We examined the role of cuticular leaf and berry waxes as a resistance mechanism in four grapevine genotypes (Italia?×?Mercan-174, Gürcü, Isabella, Özer Karas?) resistant to powdery mildew after natural infection and inoculation. To understand cuticular wax properties, we determined the amount of wax and antifungal effects of thin layer chromatography (TLC) fractions from cuticular leaf and berry waxes, then assessed the chemical composition of fractions with different antifungal activities using gas chromatography/mass spectrometry (GC/MS). Susceptible genotypes Cabernet Sauvignon and Italia were used for comparison. Resistant and sensitive genotypes did not differ significantly in the total amount of wax on leaves and berries; however, 27 fatty acids, 26 alkanes, 6 terpenes, 4 indole derivatives and 4 ketones, and 3 amides, 3 phenols and 3 steroids were detected in fractions with high antifungal activity (≥75% inhibition of germination) in leaf and/or berry cuticular waxes of resistant genotypes only. These compounds may be evaluated as markers for powdery mildew resistance during genotype selection in a grapevine breeding program.  相似文献   
13.
An environmentally friendly water-based pathway to form the azide derivatives of soybean oil and fatty esters is reported. This entails first the formation of epoxides and then the azidization of the epoxides. The azidization reaction is carried out at high yields in water with only a small amount of an ionic liquid as a catalyst. The distribution of azide and alcohol functionalities on the fatty acid moiety is approximately random. This reaction has been applied to methyl oleate, methyl linoleate, soybean oil, and methyl soyate. The resulting structures have been studied by NMR.  相似文献   
14.
This, partly retrospective study, was designed to determine the seroprevalence of Schmallenberg virus (SBV), a new Orthobunyavirus first reported in Germany in late 2011, in domestic ruminants from the Middle Black Sea, West, and Southeast regions of Turkey. An indirect enzyme-linked immunosorbent assay was used to screen serum samples collected from slaughterhouse animals between 2006 and 2013. The overall seroprevalence was 335/1,362 (24.5 %) with 325/816 (39.8 %), 5/307 (1.6 %), 3/109 (2.8 %), and 2/130 (1.5 %) recorded in cattle, sheep, goats, and Anatolian water buffalo, respectively. This is the first study to demonstrate the presence of antibodies to SBV in Turkish ruminants; it indicates that cattle are more susceptible to infection than sheep, goats, or buffalo and that exposure of domestic ruminants to SBV in Turkey may have occurred up to 5 years prior to the first recorded outbreak of the disease in 2011.  相似文献   
15.
16.
Ovulation rate and litter size are important reproduction traits in sheep and are of high economic value. Reproduction traits typically have low to medium heritabilities and do not exhibit a noticeable response to phenotypic selection. Therefore, inclusion of genetic information of the genes associated with reproductive ability could efficiently enhance the selection response. The most important major genes affecting prolificacy and their genetic diversities in different sheep breeds were reviewed. Different causative mutations with major effects on reproductive traits including ovulation rate and litter size have been found in various sheep breeds around the world. A general overview of the studies on main prolificacy genes showed that some alleles may express different phenotypic effects in different breeds, and thus, further studies on epistatic effects are necessary for more understanding of genetic control of reproductivity in sheep. Regarding the polygenic control of fertility traits, application of new high‐throughput technologies to find new variants is essential for future studies. Moreover, genomewide association studies and genomic best linear unbiased predictions of breeding values are likely to be effective tools for genetic improvement of sheep reproductive performance traits.  相似文献   
17.
The effects of Isaria farinosa (Holm.) and Beauveria bassiana (Balsamo) on adult stages of sunn pests Eurygaster integriceps Puton and Eurygaster austriaca (Schrk.) were investigated at 27±1°C, 95% r.h. and 16L:8D in the laboratory. Two concentrations, 1×106 and 1×108 conidia ml-1, were used. Mortality of inoculated and non-inoculated adults was counted at 6, 9 and 12 days after treatment. Beauveria bassiana caused higher mortality of both species than I. farinosa. Neither caused significantly high mortality at 1×106 conidia ml-1. Both were more pathogenic at 1×108 conidia ml-1 and caused more than 85% mortality 12 days post treatment. Both were more pathogenic to E. austriaca.  相似文献   
18.
Soil organic carbon(SOC) has primary importance in terms of soil physics, soil fertility and even of climate change control. One hundred soil samples were taken from an intensively cultivated Cambisol to quantify SOC redistribution triggered by soil erosion under a subhumid climate, by the simultaneous application of diffuse reflectance(240–1 900 nm) and traditional physico-chemical methods.The representative sample points were collected from the solum along the slopes at the depth of 20–300 cm with a mean SOC content of 12 g kg~(-1). Hierarchical cluster analyses were performed based on the determined SOC results. The spatial pattern of the groups created were similar, and even though the classifications were not the same, diffuse reflectance had proven to be a suitable method for soil/sediment classification even within a given arable field. Both organic and inorganic carbon distributions were found to be a proper tool for estimations of past soil erosion processes. The SOC enrichment was found on two sedimentary spots with different geomorphological positions. Soil organic matter composition also differed between the two spots due to selective deposition of the delivered organic matter. The components with low-molecular-weight reached the bottom of the slope where they could leach into the profile, while the more polymerised organic matter compositions were delivered and deposited even before on a higher segment of the slope in an aggregated form. This spatial difference appeared below the uppermost tilled soil layer as well, referring the lower efficiency of conventional ploughing tillage in soil spatial homogenisation.  相似文献   
19.
In this study, the performance of oxidation with actived persulfate (PS) by graphene oxide-TiO2 nanosheet (GO-TiO2) was investigated for diclofenac (DCF) removal, an anti-inflammatory analgesic being widely used in human health care and veterinary treatment. GO-TiO2 containing oxygen functional groups is employed as an activator for the activation of PS used as the oxidizing agent. Modeling and optimization of the process were performed by central composite design (CCD) as a response surface methodology (RSM). The effects of various factors, including PS concentration, GO-TiO2 amount, initial pH of DCF solution, and reaction time on DCF oxidation, were evaluated. When the estimated values of the full quadratic model obtained with CCD were compared with the actual experimental results, a strong agreement was obtained with an R2 value of 0.9553. Besides, the model consistency was verified by analysis of variance (ANOVA) with a value of 20.17 of F value and P value of less than 0.05. After the optimization run, maximum DCF removal of 93.06% occurred with contact time of 14 min, pH of 5.54, PS concentration of 10 g/L, and 0.1 g of GO-TiO2 as optimal variable values.  相似文献   
20.
The environment must be protected against pollution caused by lubricants based on petroleum oils. The pollution problem is so severe that approximately 50% of all lubricants sold worldwide end up in the environment via volatility, spills, or total loss applications. This threat to the environment can be avoided by either preventing undesirable losses, reclaiming and recycling mineral oil lubricants, or using environmentally friendly lubricants. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates as base fluids in environment friendly lubricants. Lubricants based on vegetable oils display excellent tribological properties, high viscosity indices, and flash points. To compete with mineral-oil-based lubricants, some of their inherent disadvantages, such as poor oxidation and low-temperature stability, must be corrected. One way to address these problems is chemical modification of vegetable oils at the sites of unsaturation. After a one-step chemical modification, the chemically modified soybean oil derivatives were studied for thermo-oxidative stability using pressurized differential scanning calorimetry and a thin-film micro-oxidation test, low-temperature fluid properties using pour-point measurements, and friction-wear properties using four-ball and ball-on-disk configurations. The lubricants formulated with chemically modified soybean oil derivatives exhibit superior low-temperature flow properties, improved thermo-oxidative stability, and better friction and wear properties. The chemically modified soybean oil derivatives having diester substitution at the sites of unsaturation have potential in the formulation of industrial lubricants.  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