全文获取类型
收费全文 | 75篇 |
免费 | 2篇 |
专业分类
林业 | 17篇 |
农学 | 9篇 |
13篇 | |
综合类 | 5篇 |
农作物 | 6篇 |
水产渔业 | 3篇 |
畜牧兽医 | 12篇 |
园艺 | 4篇 |
植物保护 | 8篇 |
出版年
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 1篇 |
2009年 | 8篇 |
2008年 | 1篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 2篇 |
1995年 | 1篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有77条查询结果,搜索用时 0 毫秒
51.
52.
The heteropteran bug, Helopeltis theivora is a polyphagous pest attacking the foliage crop tea and several other crops grown in the old world tropics. Application of synthetic insecticides, especially organophosphate was so far an effective and economic means of conventional management of the pest. Severe selection (bottlenecking) of H. theivora population by exposure to LC80 dose of an organophosphate insecticide, monocrotophos resulted in 105 fold increase in tolerance level in the third generation. The total activity of general esterases (GE) and cytochrome P450 mono-oxygenases (CYP450) analogously increased in insecticide-selected F2 generation by 16.4 and 9.5 fold, respectively. Such enhanced enzyme activity could be related to the higher tolerance levels of the selected bug. Electropherogram of GE and CYP450 of the insecticide-selected generations indicated a change in isozyme profile with their elevated expressions. Induced isozymes in insecticide selected generations were only partially inhibited, when blocked by the insecticide. These findings imply that different groups (zones) of isozymes of the detoxifying enzymes are involved in imparting higher tolerance in insecticide-selected generations. Isozyme profiles of defence enzymes can be used as indices for identifying tolerance level in the field population of H. theivora, enabling tea planters to carry out rapid monitoring of the tolerance status of the pest populations, thereby providing a ready clue to choose an effective insecticide for pest management. 相似文献
53.
Som Dev Sharma Pramod Kumar Harender Raj Satish Kumar Bhardwaj 《Scientia Horticulturae》2009,123(1):267-123
Soil samples were collected from rhizosphere of litchi-growing areas of North-Western Himalayan Region (NWHR) of India, for finding qualitative and quantitative differences in arbuscular mycorrhizal (AM) fungi and Azotobacter chroococcum. These samples were taken from plants being grown in different cultivation types namely, weed control with weedicides or tillage; orchard floor either clear or with cover crops; intercropping with cereals and legumes. Qualitative and quantitative differences were noticed with different cultivation types and a marked reduction in the AM fungi was observed in orchards where chemicals were used for weed control and intensive farming system was used on the orchard floor. AM fungi were generally abundant in the soils with range pH 5.5–6.6. Among different AM fungi retrieved from the soils, Glomus spp. was most dominant. Fifteen AM fungal species were isolated, identified and characterized and along with their ability to colonize the roots. In the soil samples, a marked variation in viable bacterial count of A. chroococcum was also noticed due to varied physico-chemical characteristics of the orchard soils. The changes in AM fungal species composition can be attributed to changes in soil chemical properties resulting from cultural practices such as ploughing, application of chemical fertilizers and weedicides. An experiment was also conducted to study the comparative efficacy of four dominant and frequently occurring indigenous AM species namely, Glomus fasciculatum (Thaxter sensu Gerdemann), G. magnicaulis (Hall), G. mosseae (Nicol. & Gerd.), Gigaspora heterogamma (Nicol. & Gerd.) and two A. chroococcum strains viz., AZ1 and AZ2 singly and in dual combination to evaluate their effect in air-layers system. Dual inoculation of G. fasciculatum and AZ1 increased total root length of air-layered shoots by 81.39% over uninoculated control. These studies indicated that indigenously isolated AM fungal species and A. chroococcum strains can be used for air-layering for better adaptation under specific agro-climatic and ecological zone conditions. 相似文献
54.
犊牛早期断奶开食料的研究 总被引:7,自引:1,他引:7
选30头中国荷斯坦初生犊牛,分为6组,每组5头,分别饲喂6种开食料,用150kg鲜奶于42d断奶。通过不同开食料对犊牛生长发育影响的分析结果表明,在上述培育方式下,犊玷开食料中的蛋白质水平应高于21.0%(DM),若以大豆饼(粕)为主体蛋白南饲料,蛋白质水平达到22.38%,并补加0.14%的蛋氨酸,不需使用鱼粉,开食料亦有很好的效果,开食料中添加5%的糖蜜会使开食料采食量提高15.6%。 相似文献
55.
56.
Md. Masud Karim Asfakun Siddika Nazmoon Naher Tonu Delwar M. Hossain Md. Bahadur Meah Takahiro Kawanabe Ryo Fujimoto Keiichi Okazaki 《Breeding Science》2014,63(5):495-502
Brassica napus is a leading oilseed crop throughout many parts of the world. It is well adapted to long day photoperiods, however, it does not adapt well to short day subtropical regions. Short duration B. napus plants were resynthesized through ovary culture from interspecific crosses in which B. rapa cultivars were reciprocally crossed with B. oleracea. From five different combinations, 17 hybrid plants were obtained in both directions. By self-pollinating the F1 hybrids or introgressing them with cultivated B. napus, resynthesized (RS) F3 and semi-resynthesized (SRS) F2 generations were produced, respectively. In field trial in Bangladesh, the RS B. napus plants demonstrated variation in days to first flowering ranging from 29 to 73 days; some of which were similar to cultivated short duration B. napus, but not cultivated short duration B. rapa. The RS and SRS B. napus lines produced 2–4.6 and 1.6–3.7 times higher yields, respectively, as compared to cultivated short duration B. napus. Our developed RS lines may be useful for rapeseed breeding not only for subtropical regions, but also for areas such as Canada and Europe where spring rapeseed production can suffer from late spring frosts. Yield and earliness in RS lines are discussed. 相似文献
57.
58.
Francesca Bampa Lilian O'Sullivan Kirsten Madena Taru Sandn Heide Spiegel Christian Bugge Henriksen Bhim Bahadur Ghaley Arwyn Jones Jan Staes Sylvain Sturel Aneta Trajanov Rachel E. Creamer Marko Debeljak 《Soil Use and Management》2019,35(1):6-20
Soil and its ecosystem functions play a societal role in securing sustainable food production while safeguarding natural resources. A functional land management framework has been proposed to optimize the agro‐environmental outputs from the land and specifically the supply and demand of soil functions such as (a) primary productivity, (b) carbon sequestration, (c) water purification and regulation, (d) biodiversity and (e) nutrient cycling, for which soil knowledge is essential. From the outset, the LANDMARK multi‐actor research project integrates harvested knowledge from local, national and European stakeholders to develop such guidelines, creating a sense of ownership, trust and reciprocity of the outcomes. About 470 stakeholders from five European countries participated in 32 structured workshops covering multiple land uses in six climatic zones. The harmonized results include stakeholders’ priorities and concerns, perceptions on soil quality and functions, implementation of tools, management techniques, indicators and monitoring, activities and policies, knowledge gaps and ideas. Multi‐criteria decision analysis was used for data analysis. Two qualitative models were developed using Decision EXpert methodology to evaluate “knowledge” and “needs”. Soil quality perceptions differed across workshops, depending on the stakeholder level and regionally established terminologies. Stakeholders had good inherent knowledge about soil functioning, but several gaps were identified. In terms of critical requirements, stakeholders defined high technical, activity and policy needs in (a) financial incentives, (b) credible information on improving more sustainable management practices, (c) locally relevant advice, (d) farmers’ discussion groups, (e) training programmes, (f) funding for applied research and monitoring, and (g) strengthening soil science in education. 相似文献
59.
Hari Bahadur Khatri-Chhetri Govinda Prasad Timsina Hira Kaji Manandhar Maurice Moens 《Journal of pest science》2011,84(4):457-469
Holotrichia longipennis Blanch. (Coleoptera: Scarabaeidae) is a serious pest of commercial crops in Siduwa, Dhankuta, Nepal. Seven indigenous isolates
of entomopathogenic nematodes (Steinernema lamjungense LMT5, S. lamjungense SS4, S. everestense DKP4, S. abbasi CS1, S. sp. KL1, Heterorhabditis indica CK2 and H. indica CK6) were used in a series of bioassays against the insect. All isolates showed an increased dispersal in response to H. longipennis. Nematodes were more attracted towards third instar larvae than to second instars. Differences in penetration and multiplication
in the insect were observed amongst the seven isolates. Steinernema lamjungense LMT5, S. everestense DKP4 and S. abbasi CS1 caused greater mortality than other isolates to different developmental stages. Pupae and second instar larvae were more
susceptible than third instar larvae. Significant differences were observed in LT50 values of the isolates against different stages of H. longipennis. Three isolates (S. lamjungense LMT5, S. everestense DKP4 and S. abbasi CS1) along with a commonly used insecticide (chlorpyrifos) were tested against this insect in pot and field experiments.
In pot experiments using maize and cabbage as a host crop, S. lamjungense LMT5 and S. everestense DKP4 performed better than S. abbasi CS1 and yielded a mortality comparable with chlorpyrifos. Similar results were observed in field experiments 3 weeks after
nematode application. These experiments overall suggest S. lamjungense LMT5 to be a promising biocontrol agent against H. longipennis followed by S. everestense DKP4 and S. abbasi CS1. 相似文献
60.