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   111篇
  免费   10篇
  国内免费   3篇
林业   2篇
农学   9篇
  6篇
综合类   35篇
农作物   4篇
水产渔业   6篇
畜牧兽医   17篇
园艺   2篇
植物保护   43篇
  2024年   1篇
  2023年   3篇
  2022年   6篇
  2021年   6篇
  2020年   5篇
  2019年   3篇
  2018年   4篇
  2017年   1篇
  2016年   1篇
  2015年   5篇
  2014年   3篇
  2013年   8篇
  2012年   1篇
  2011年   10篇
  2010年   7篇
  2009年   4篇
  2008年   7篇
  2007年   10篇
  2006年   4篇
  2005年   8篇
  2004年   5篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1998年   5篇
  1996年   3篇
  1993年   1篇
  1991年   2篇
  1990年   2篇
  1986年   1篇
  1955年   1篇
排序方式: 共有124条查询结果,搜索用时 15 毫秒
1.
姜立纲 《华北农学报》1990,5(1):117-123
蜂乐1号烟剂是一种最近研制成功的新型杀蜂螨药剂,其有效成分为溴螨酯.经室内外试验结果,对蜂螨有较强杀伤力,对蜜蜂十分安全.烟剂中的溴螨醋对雅氏大蜂螨的LC_(50)为0.26克/米~3,LC_(95)为2.92克/米~3 对蜜蜂则分别为71.45克/米~3和218.70克/米~3,二者分别相差274.8倍和74.9倍.一平箱蜂群一次用含0.45克有效成分的药,对蜂体上大蜂螨的防除效果平均93%以上.对蜂群每隔5天施药一次,经3次施药后蜂群状况正常.在施药3次后对所取蜜样进行检测,其中溴螨酯的残留量远远低于联合国粮农组织所规定的参考限量.该烟剂适于在蜂箱外施药,比目前国内一般的开箱施药方法提高工效15倍以上,更适用于许多过去不便用药的场合.  相似文献   
2.
We describe the spatial epidemiology of Varroa destructor infestation among honey bee apiaries in the greater Auckland area of the North Island of New Zealand. The study population was comprised of 641 apiaries located within the boundaries of the study area on 11 April 2000. Cases were those members of the study population declared Varroa-infested on the basis of testing conducted between April and June 2000. The odds of Varroa was highest in apiaries in the area surrounding transport and storage facilities in the vicinity of Auckland International Airport. A mixed-effects geostatistical model, accounting for spatial extra-binomial variation in Varroa prevalence, showed a 17% reduction in the odds of an apiary being Varroa infested for each kilometre increase in the squared distance from the likely site of incursion (95% Bayesian credible interval 7–28%). The pattern of spatially autocorrelated risk that remained after controlling for the effect of distance from the likely incursion site identified areas thought to be ‘secondary’ foci of Varroa infestation initiated by beekeeper-assisted movement of infested bees. Targeted investigations within these identified areas indicated that the maximum rate of local spread of Varroa was in the order of 12 km/year (interquartile range 10–15 km/year).  相似文献   
3.
香精油抗蜂螨作用的研究进展   总被引:2,自引:0,他引:2  
香精油及其组分具有显著的抗螨效果。萜类化合物(主要是单萜)是香精油的主要成分。占总量的90%左右。研究者通过筛选试验测定了多种香精油及其一些组分的抗螨能力。大部分表现出良好的抗螨效果。但只有少部分在蜂群试验中表现出强抗螨能力。因此,有必要对此作进一步的研究。以达到最优化目标。同时联合其它防治手段,建立一套全面的害虫防治策略,实现蜂螨的最终控制。  相似文献   
4.
5.
6.
甘薯茎线虫与镰孢菌对甘薯的复合侵染   总被引:1,自引:0,他引:1  
从甘薯茎线虫病的薯块中分离到茄病镰孢(Fusarium solani)和尖孢镰孢(F.oxysporum)2种真菌.通过苗期和薯块接种证实,尖孢镰孢与腐烂茎线虫(Ditylenchus destructor)能共同侵染甘薯引起复合侵染病害.  相似文献   
7.
以甘薯茎线虫为材料,对取样、固定、干燥等制样方法进行比较研究.结果表明,以活线虫为研究试样,采用戊二醛 -锇酸双固定及临界点干燥法(或叔丁醇干燥法 )制样效果好,能获得良好的微形态结构,侧线数目清晰,虫体不皱缩,不变形.  相似文献   
8.
Twenty-four honeybee (Apis mellifera) colonies were used to monitor the efficacy of a solution of 2.9% oxalic acid (OA) and 31.9% sugar against the mite Varroa destructor. Mite mortality was established prior to and after OA treatments, which were conducted in August and September. The treatments resulted in 37% mite mortality as opposed to 1.11% in the controls. OA treatment conducted in September on previously untreated colonies resulted in 25% mite mortality. OA treatments in October and November resulted in approximately 97% mite mortality. These results suggest that OA is effective during the broodless period and less effective when applied to colonies with capped broods. The possible use of OA against the Varroa mite in honeybee colonies as an alternative to routine chemical treatments is discussed.  相似文献   
9.
用改进的Ellman方法测定了河北省昌黎、涿州、卢龙和抚宁四个不同地理种群甘薯茎线虫Ditylenchus destructor的乙酰胆碱酯酶(AChE)的生化特性及其对抑制剂涕灭威和毒扁豆碱的敏感性差异。结果表明:甘薯茎线虫AChE至少存在两种类型,一种类型对毒扁豆碱的IC50值小于10^-6mol/L,另一种类型大于10^-4mol/L。当抑制剂毒扁豆碱浓度为10^-6~10^10mol/L、涕灭威浓度为10^-5~10^10mol/L时,甘薯茎线虫昌黎种群AChE的敏感性抑制率明显高于涿州、抚宁、卢龙三地的甘薯茎线虫种群AChE的抑制率。各地种群AChE对抑制剂敏感性差异是由于甘薯茎线虫AChE的多态性和各分子型综合性改变的结果。  相似文献   
10.
Cherax albidus (A) and Cherax destructor (D) male juveniles (mean weight 0.95 ± 0.03 g) were reared for 20 weeks on isoenergetic diets containing 150 g kg?1 protein (A 15, D15) or 300 g kg?1 protein (A30, D30). Mean weight, percentage weight gain, and specific growth rate (%) were substantially higher for both species on the 300 g kg?1 protein diet. Mean percentage weight gain ranged from 2.39% day?1 (D15) to 17.59% day?1 (A30). A maximum weight of 33.81 g was attained by C. albidus on the higher protein diet. The most effective utilization of food was observed in C. albidus when fed the higher protein diet (food conversion ratio, 0.79; protein efficiency ratio, 4.21; apparent net protein utilization, 44.64%). Carcass composition was influenced by feed type. The higher protein diet resulted in an increase in carcass protein and ash and a decrease in carcass lipid and energy relative to the low-protein diet (150 g kg?1 protein diet –C. albidus: 37.15% protein, 15.00% lipid, 25.20% ash, 15.55kJ g?1 energy; C. destructor: 38.10% protein, 15.43% lipid, 25.70% ash, 15.65kJ g?1 energy; 300 g kg?1 protein diet –C. albidus: 46.10% protein, 8.71% lipid, 27.36% ash, 14.94kJ g?1 energy; C. destructor: 42.99% protein, 8.56% lipid, 26.44% ash, 14.71kJ g?1 energy). Carcass moisture and calcium were not affected by feed type. The time spent in the intermoult phase of growth was highly dependent on the premoult weight and varied according to diet and to species. A comparison of animals of similar weight (< 8 g) revealed that elevated dietary protein caused a reduction in the intermoult period by 11 days in C. albidus and 7 days in C. destructor. The moult increment, however, was independent of animal weight, and the highest percentage weight increment occurred for C. albidus fed the 300 g kg?1 protein diet (per cent weight increase; A15, 33.1%; A30, 61.3%; D15, 31.2%; D30, 56.5%). Dietary induced morphological changes were also recorded. Animals of a standard carapace length had significantly larger abdomens (both species) and larger claws (C. albidus) when fed the higher protein diet.  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