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   65篇
  免费   2篇
林业   1篇
农学   7篇
基础科学   1篇
  23篇
综合类   12篇
农作物   5篇
畜牧兽医   15篇
园艺   2篇
植物保护   1篇
  2023年   3篇
  2022年   2篇
  2020年   7篇
  2019年   3篇
  2018年   6篇
  2017年   11篇
  2016年   4篇
  2015年   2篇
  2014年   1篇
  2013年   2篇
  2012年   4篇
  2011年   9篇
  2010年   5篇
  2009年   4篇
  2008年   2篇
  2007年   2篇
排序方式: 共有67条查询结果,搜索用时 8 毫秒
61.
62.
Hybrid maize farmers have to face diverse kinds of climate, biological, price and financial risks. Farmers' risk perceptions and risk attitudes are essential elements influencing farm operations and management decisions. However, this important issue has been overlooked in the contemporary studies and therefore there is a dearth of literature on this important issue. The present research is therefore, an attempt to fill this gap. This study aims to quantify hybrid maize farmers' perceptions of disastrous risks, their attitudes towards risk and to explore the impacts of various farm and farm household factors on farmers' risk attitudes and risk perceptions. The present study is conducted in four hybrid maize growing districts of Punjab Province, Pakistan, using cross-sectional data of 400 hybrid maize farmers. Risk matrix and equally likely certainty equivalent (ELCE) method are used to rank farmers' perceptions of four catastrophic risk sources including climate, biological, price and financial risks and to investigate farmers' risk aversion attitudes, respectively. Furthermore, probit regression is used to analyze the determinants affecting farmers' risk attitudes and risk perceptions. The results of the study showed that majority of farmers are risk averse in nature and perceive price, biological and climate to be potential sources of risks to their farm enterprise. In addition, analysis divulges that distance from farm to main market, off-farm income, location dummies for Sahiwal and Okara, age, maize farming experience, access to extension agent, significantly (either negatively or positively) influence farmers' risk attitudes and risk perceptions. The study delivers valuable insights for farmers, agricultural insurance sector, extension services researchers and agricultural policy makers about the local understanding of risks to hybrid maize crop in developing countries, like Pakistan, and have implications for research on farmers' adaptation to exposed risks.  相似文献   
63.
Phosphorous (P) and zinc (Zn) are plant nutrients that interact with each other in soil–plant systems. Such interactions may cause deficiency of one of the nutrients interacting with each other if interactions are antagonistic. In the present trial, a field experiment was conducted to investigate the interactive effect of Zn (0 and 16 kg ha?1) and P (0 and 60 kg ha?1) on growth, yield and grain Zn concentration of two maize (Zea mays L.) genotypes, i.e., Neelam (local) and DK‐6142 (hybrid). Growth and yield of both maize genotypes were increased by the application of Zn and P treatments compared with control, but Zn+P was more effective than their sole application. When compared to control, combined application of Zn+P increased grain Zn and P concentrations by 52% and 32%, respectively, averaged for the two genotypes. Single application of P decreased grain Zn concentration by 10% over control. Application of P and Zn particularly in combination decreased the grain [phytate] : [Zn] ratio and increased the estimated human Zn bioavailability in grains based on a trivariate model of Zn absorption in both maize genotypes. Conclusively, combined Zn+P application appeared more suitable for enhancing grain yield and agronomic Zn biofortification in maize grains. However, Zn fertilization aiming at increasing grain yield and grain Zn concentration should consider the genotypic variations and P rate.  相似文献   
64.
The present study explained the effect of pretreatments on the biosorption of Cr (III) and Cr (VI) by Cassia fistula biomass from aqueous solutions. For this purpose Cassia fistula biomass was pretreated physically by heating, autoclaving, boiling and chemically with sodium hydroxide, formaldehyde, gluteraldehyde, acetic acid, hydrogen peroxide, commercial laundry detergent, orthophosphoric, sulphuric acid, nitric acid, and hydrochloric acid. The adsorption capacity of biomass for Cr (III) and Cr (VI) was found to be significantly improved by the treatments of gluteraldehyde (95.41 and 96.21 mg/g) and benzene (85.71 and 90.81 mg/g) respectively. The adsorption capacity was found to depend on pH, initial metal concentration, dose, size, kinetics, and temperature. Maximum adsorption of both the Cr (III) and Cr (VI) was observed at pH 5 and 2. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The kinetic studies showed that the sorption rates could be described better by a second order expression than by a more commonly applied Lagergren equation.  相似文献   
65.
The main aim of the current study was to explore molecular insights for potentially new dual cholinesterase inhibitor(s) from Asparagus adscendens via molecular docking. This medicinal plant is traditionally used as a nerve tonic and remedy for memory impairments. Conypododiol was isolated from the chloroform fraction of methanolic extract of A. adscendens, based on bioactivity guided isolation. Conypododiol exhibited significant inhibition of both acetylcholinesterase and butyrylcholinesterase, having the IC50 values 2.17 ± 0.1 μM and 11.21 ± 0.1 μM, respectively. IC50 values of the standard compound Galanthamine for both the enzymes were 0.537 ± 0.018 μM and 8.6 ± 0.27 μM, respectively. Based on MTT cytotoxicity assay, Conypododiol was found safe against LCMK-2 monkey kidney epithelial cells and mice hepatocytes. Molecular docking studies revealed the hydrogen bonding interactions of Conypododiol with His440 and Ser200 at esteratic site (ES), and also with Tyr334 at peripheral anionic site (PAS) of the aromatic gorge of acetylcholinesterase. Simultaneous contacts of Conypododiol with PAS and ES shows its significance as a bivalent ligand. This preliminary study highlighted the potential of Conypododiol to be further developed and modified as new lead compound identified by its folk use.  相似文献   
66.

Purpose  

To evaluate a 3% solution of household detergent viz., Surf Excel (Surf field mastitis test, SFMT) vis-à-vis California mastitis test (CMT), Whiteside test (WST), somatic cell counts (SCC; cut off limit = 5 × 105 cells per millilitre) and bacteriological cultures for the detection of subclinical mastitis in quarter foremilk samples (n = 800) of dairy cows and buffaloes.  相似文献   
67.
Soil organic carbon(SOC) and nitrogen(N) mineralization are important biogeochemical processes associated with soil fertility. These processes are influenced by physically, chemically, and biologically stabilized SOC fractions, the mechanisms of which are not well known. The present study was conducted to evaluate the combined effect of manure and mineral fertilizers on the contents of SOC fractions to promote the mineralization of SOC and N.Treatments included: i) no fertilizer control(CK); ii)...  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