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 31 毫秒
21.
Objective To determine in Australian pig herds the accuracy of French protocols for risk factor assessment of post-weaning diarrhoea and illthrift.
Procedure French protocols for the collection of data on health indicators and risk factors for post-weaning diarrhoea were conducted on 54 batches of weaner pigs from 28 Western Australian pig herds during three years.
Results Large variations in post-weaning performance were found. About one-third of the batches were growing at <200 g/day during the 3 weeks after weaning, and 54% had growth rates of <250 g/day. Weaning age and weight of at least 30 days and 7.9 kg, respectively, optimised weaner performance. Other risk factors associated with little post-weaning diarrhoea and good weaner performance were high creep feed intakes, relatively little diarrhoea as suckers, and, contrary to expectations, large temperature fluctuations.
Conclusion Overall, the 'predictability' of post-weaning problems as assessed by measurement of risk status, was good. However, the model was less accurate at predicting the performance of a single batch of pigs.  相似文献   
22.
The biodegradable properties and lubricating ability of greases depend on both the base oil and the thickener. Mineral oils are the most widely used lubricant base fluids due to their inherent lubricity and low cost, but recent environmental awareness has forced consideration of the use of biodegradable fluids such as vegetable oils and certain synthetic fluids in grease formulations. This study presents data on the thermo-oxidation behavior and tribology of biodegradable greases formulated with soybean oil and different compositions of metal soap thickener. The composition of thickener has been varied by using fatty acids with different degrees of unsaturation and fatty acids of different chain lengths. The improvement of thermo-oxidation and tribological properties as a result of changing thickener/base oil ratio and the antioxidative effect of some suitable additives have also been evaluated.  相似文献   
23.
Regression of the corpus luteum (CL) is characterized by a decay in progesterone (P4) production (functional luteolysis) and disappearance of luteal tissues (structural luteolysis). In mares, structural luteolysis is thought to be caused by apoptosis of luteal cells, but functional luteolysis is poorly understood. 20α-hydroxysteroid dehydrogenase (20α-HSD) catabolizes P4 into its biologically inactive form, 20α-hydroxyprogesterone (20α-OHP). In mares, aldo-keto reductase (AKR) 1C23, which is a member of the AKR superfamily, has 20α-HSD activity. To clarify whether AKR1C23 is associated with functional luteolysis in mares, we investigated the expression of AKR1C23 in the CL in different luteal phases. The luteal P4 concentration and levels of 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA were higher in the mid luteal phase than in the late and regressed luteal phases (P<0.05), but the level of 3β-HSD protein was higher in the late luteal phase than in the regressed luteal phase (P<0.05). The luteal 20α-OHP concentration and the level of AKR1C23 mRNA were higher in the late luteal phase than in the early and mid luteal phases (P<0.05), and the level of AKR1C23 protein was also highest in the late luteal phase. Taken together, these findings suggest that metabolism of P4 by AKR1C23 is one of the processes contributing to functional luteolysis in mares.  相似文献   
24.
Vegetable oils have significant potential as a base fluid and a substitute for mineral oil for grease formulation. This paper describes the preparation of biobased grease with high oxidative stability and a composition useful for industrial, agriculture/farming equipment, and forestry applications. The process utilizes more oxidatively stable epoxy vegetable oils as the base fluid, metal-soap thickener, and several specialty chemicals identified to address specific applications. Performance characteristics of greases used for industrial and automotive applications are largely dependent on the hardness and the oxidative stability of grease. Grease hardness was determined using standard test methods, and their oxidative stabilities were determined using pressurized differential scanning calorimetry and rotary bomb oxidation tests. Wear data were generated using standard test methods in a four-ball test geometry. Results indicate that grease developed with this method can deliver at par or better performance properties (effective lubrication, wear protection, corrosion resistance, friction reduction, heat removal, etc.) than existing mineral oil-based greases currently used in similar trades. Therefore, developed greases can be a good substitute for mineral oil-based greases in industrial, agriculture, forestry, and marine applications.  相似文献   
25.
Bio-based additives are desirable commodities due to their eco-friendly nature. These additives can demonstrate physical and chemical properties comparable to those of conventional mineral oil-based products. Sulfur incorporated triacylglycerol can function as an antiwear/antifriction additive for lubricants. The synthesis of four useful hydroxy thio-ether derivatives of vegetable oils, from commercially available epoxidized soybean oil and common organic thiols, is reported in this paper. The common thiols used herein were 1-butanethiol, 1-decanethiol, 1-octadecanethiol, and cyclohexyl mercaptan. Currently, there is no reported literature describing the synthesis of hydroxy thio-ether derivatives of vegetable oil. The reaction was monitored, and products were confirmed by NMR and FTIR spectroscopies. Experimental conditions involving various thiols, solvent, catalyst amount, time, and temperature were optimized for research quantity and laboratory scale-up. The synthetic process retains the vegetable oil structure, eliminates polyunsaturation in the molecule, and adds polar functional groups on triacylglycerol. These products can be used as agriculturally-based antiwear additives for lubricant applications.  相似文献   
26.
Journal of Plant Diseases and Protection - Samples of potato tubers from commercial seed stocks and from grower’s own seed in Turkey were received from 2011 through 2014. Six potato cultivars...  相似文献   
27.
The aim of this study was to determine the efficacy of several alternative postharvest treatments to sulfur dioxide (SO2) in maintaining quality and reducing fungal decay during cold storage of ‘Red Globe’ table grapes. Grapes were packaged in perforated polyethylene (PPE) or modified atmosphere packaging (MAP) bags (ZOEpac or Antimicrobial) with or without different grades of ethanol vapor-generating sachets (Antimold®30, Antimold®60 or Antimold®80) or a SO2-generating pad, and the grapes were kept at 0 °C and 90-95% relative humidity for 4 months. Packaging of grapes with a SO2 pad in PPE or ZOEpac bags provided better control of fungal decay and stem browning than PPE or ZOEpac bags alone, PPE or ZOEpac bags with Antimold sachets or Antimicrobial bags alone. The PPE bag containing the Antimold®80 sachet was as effective as the SO2 treatments in reducing the incidence of fungal decay in naturally infected and artificially inoculated grapes for 1 month. Ethanol vapor released by the Antimold sachets enhanced berry color, but caused stem browning depending on ethanol vapor concentrations in the headspace of the bags. The ZOEpac-210 bags alone resulted in significantly lower weight loss and incidence of stem browning, compared to other treatments; however, they did not reduce fungal decay or develop an appreciable level of modified atmosphere.  相似文献   
28.
A total of 101Verticillium dahliae isolates were recovered from cotton plants at 57 sites in the Aegean region of Turkey between 2003 and 2004. Isolates were tested for vegetative compatibility by observing heterokaryon formation among complementary nitrate-nonutilizing (nit) mutants. Forty-six isolates were assigned to VCG 1, 12 to VCG 2A, 33 to VCG 2B and four to VCG 4B. The remaining six isolates could not be tested for vegetative compatibility because of their inability to yieldnit mutants. All isolates recovered were tested for pathogenicity on cotton cultivars Acala SJ-1 and Deltapine 15-21 by the stem-injection method. The isolates of VCG 2 and 4B, irrespective of their origin, induced weak to severe symptoms on cotton and were similar to the previously described cotton non-defoliating pathotype. In contrast, all cotton isolates of VCG1 caused severe foliar symptoms, stunting, defoliation and often death. This is the first report on VCG 1 ofV. dahliae in Turkey. http://www.phytoparasitica.org posting May 4, 2007.  相似文献   
29.
生姜是塔山镇主要经济作物 ,采用姜蒜套种栽培形式 ,提高了土地利用率 ,增加了经济效益 ,具有广泛的发展前景。1 大蒜栽培管理1 .1 整地施肥选择水源条件好、排灌方便的平肥地。 3月下旬至 4月初结合整地施腐熟优质农肥 70 0 0~750 0kg/667m2 。1 .2 作垅整地施肥后作垅 ,行距 55cm。1 .3 播种4月 5日至 1 0日播种 ,株距 7~ 8cm ,双行栽培 ,小行距 1 5cm左右 ,保苗 350 0 0~ 40 0 0 0株 /667m2 。1 .4 防虫大蒜主要虫害是地蛆 ,用地蛆净 1 0 0 0倍液或用 80 %敌百虫 80 0倍液进行灌根。1 .5 追肥4叶期结合灌水追施尿素 5…  相似文献   
30.
在真核生物基因组转录过程中,除了一些蛋白质编码RNA以外,还有一些不同类型的非编码RNA(non-coding RNA,ncRNA)也参与了复杂生命活动过程的调节。近年来,全转录组测序技术的出现和生物信息学的快速发展极大地促进了人们对ncRNA的研究,ncRNA在生物领域的多个方面具有重要作用,如在人类肿瘤、非肿瘤等方面的疾病治疗,在动物胚胎发育、肌肉生长、脂肪沉积、免疫应答及皮肤毛囊调控等领域都有了很大的进展。作者主要综述了全转录组测序技术、ncRNA分类、主要作用机制和ncRNA在畜禽中的应用,为探究ncRNA在动物中的调控机制提供理论依据。  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