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   281篇
  免费   20篇
  国内免费   19篇
林业   20篇
农学   33篇
基础科学   1篇
  13篇
综合类   100篇
农作物   15篇
畜牧兽医   37篇
园艺   12篇
植物保护   89篇
  2023年   8篇
  2022年   5篇
  2021年   11篇
  2020年   11篇
  2019年   11篇
  2018年   7篇
  2017年   7篇
  2016年   5篇
  2015年   7篇
  2014年   13篇
  2013年   15篇
  2012年   11篇
  2011年   12篇
  2010年   15篇
  2009年   8篇
  2008年   8篇
  2007年   11篇
  2006年   9篇
  2005年   10篇
  2004年   8篇
  2003年   5篇
  2002年   6篇
  2001年   10篇
  2000年   10篇
  1999年   4篇
  1998年   8篇
  1997年   9篇
  1996年   12篇
  1995年   6篇
  1994年   9篇
  1993年   8篇
  1992年   2篇
  1991年   6篇
  1990年   6篇
  1989年   2篇
  1988年   10篇
  1987年   3篇
  1986年   2篇
  1985年   3篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
排序方式: 共有320条查询结果,搜索用时 0 毫秒
51.
【目的】筛选对甜菜田叶螨有较好防治效果的化学药剂及配比。【方法】采用随机区组的试验方法,试验设7个药剂处理和1个清水对照,通过田间药效试验,采用田间喷雾的药效方法,于药后1、3和7 d定点取样调查各处理小区的叶螨数量,评价供试药剂处理对叶螨的防除效果及对甜菜的安全性。【结果】药后7 d,22%阿维·螺螨酯悬浮剂4 000倍液处理、25%三唑锡可湿性粉剂10 000倍液处理、10%阿维菌素可分散粒剂1 500倍液处理、73%炔螨特乳油2 000倍液处理、240 g/L螺螨酯悬浮剂4 000倍液处理对甜菜叶螨的防效分别达93.35%、93.51%、93.38%、91.80%和89.87%。【结论】筛选出5种对甜菜叶螨具有较好防治效果的杀螨剂,药后7 d防治效果均达89.87%以上,对甜菜安全,可在甜菜叶螨防治中合理轮换使用。  相似文献   
52.
The predatory mite, Phytoseius plumifer (Canestrini & Fanzago), is one of the most abundant natural enemies and efficient predator of phytophagous mites in Iran. The miticides hexythiazox (Nisorun, EC 10%), fenpyroximate (Ortus, SC 5%), and abamectin (Vertimec, EC 1.8%) were tested in the laboratory for their side effects on P. plumifer. The miticides were applied at the highest field recommended concentration (N) to detached leaves using a Potter Tower to deposit 2 mg spray solution per cm2. Percent predator mortality was evaluated from the protonymph up to the adult stage including the first five days of the oviposition period. Analysis of data showed that the total effect values of hexythiazox were below the lower threshold, and thus it could be considered to be a harmless miticide to P. plumifer. In contrast, the total effects of fenpyroximate and abamectin were found harmful to the predatory mite at the highest field recommended concentrations.  相似文献   
53.
蒲螨是食用菌栽培中最为重要的害螨。自1983年以来,我们对上海地区的蘑菇、香菇、平菇、草菇等食用菌及稻草、粪肥、棉籽等栽培材料上的蒲螨种类进行了调查研究。经鉴定共计有4科7属16种,其中包括一新记录。文中列有属种名录和分种检索表。本研究结果表明:兰氏布伦螨[Brennandania lambi(Krcz(?)l,1964)]是上海地区蘑菇生产的主要害螨,蘑菇严重减产乃至毫无收成的情况80~90%是由它造成的,而菌种带螨是其大面积发生的主要原因。矩形拟矮螨[Pseudo pygmephorus quadratus(Ewing,1917)]在蘑菇房中颇为常见。费氏穗螨[Siteroptus flechtmanni(Wicht,1970)〕在各种食用菌上常见,但并未见其造成严重的产量损失。  相似文献   
54.
This is the third survey of control practices for ectoparasites on sheep farms in Northern Ireland, providing data comparative to those recorded in previous surveys in 1981 and 1988. Data relating to all aspects of ectoparasite control were collected from 210 farms representing 4% of the total sheep population. Quantitative data have been adjusted to provide accurate estimates of total pesticide usage. Since the previous survey in 1988, the number of sheep farms in Northern Ireland has increased by 10% to 11 692 with a consequent 39% increase in sheep population to 2.9 million. Despite this level of expansion, the total quantity of organophosphorus compounds used for ectoparasite control has remained approximately constant at 7–8 tonnes. The report considers that compulsory sheep‐dipping, prescribed since 1970 and revoked in 1993, impacted significantly on subsequent ectoparasite control practices and consequent pesticide usage. During 1997, approximately 20% of sheep farmers relied on alternative methods to control ectoparasites, including injectable formulations of avermectins and pour‐on formulations of insect growth regulators and pyrethroids. Dipping formulations containing pyrethroid compounds, which accounted for <1% of treatments in 1988, increased to 9% in 1997. Previously, regulatory sheep‐dipping periods were specified during the autumn months, which tended to increase dipping frequency. The majority of farmers dipping sheep during the summer strictly for blowfly maggot (Diptera: Calliphoridae) control were required to perform additional compulsory sheep‐dipping during the autumn. Withdrawal of compulsory sheep‐dipping has allowed farmers to synchronise dipping practices to control the major ectoparasites of sheep at a single dipping occasion. An estimated 7.5 × 106 litres of surplus dipwash required disposal and there were approximately equal numbers of farmers disposing dipwash immediately after sheep‐dipping or on occasions up to and including subsequent dipping. The decline in the number of farmers who allowed dipwash to run‐off into soakaways or surrounding soil observed in 1988 continued in 1997. The majority of farmers used tractor‐operated pumps to dispose of dipwash into slurry tanks for subsequent disposal onto permanent pasture. © Crown copyright 2000. Reproduced with the permission of Her Majesty's Stationery Office. Published for SCI by John Wiley & Sons, Ltd.  相似文献   
55.
尼氏钝绥螨(Amblyseius nicholsi Ehare&Lee)能捕食硃砂叶螨(Tetranychuscinnabarinus Boisduval)各螨态,对卵的捕食量显著地高于其他螨态,其雌成螨对硃砂叶螨若螨的功能反应为HollingⅡ反应,在草莓大棚内释放尼氏钝绥螨能较好地防治硃砂螨叶  相似文献   
56.
57.
The two-spotted spider mite Tetranychus urticae Koch is one of the most important pests of a wide range of crops worldwide. Its control is still largely based on the use of acaricides. However, due to its short life-cycle, high fecundity and arrhenotokous reproduction, it is able to develop resistance to these compounds very rapidly. Preliminary studies for milbemectin resistance in T. urticae showed that, under laboratory conditions, such resistance was unstable in the absence of a selection pressure. The aim of this study was to evaluate the possible fitness costs associated with milbemectin resistance in T. urticae. Comparison of biological traits between resistant and susceptible strains indicated the occurrence of fitness costs associated with milbemectin resistance. The resistant strain showed a longer juvenile development period for females, lower fecundity and a higher proportion of males among the progeny. The figures for net reproductive rate (R 0), intrinsic rate of natural increase (r m) and finite rate of increase (λ) were higher in the susceptible strain. The instability of milbemectin resistance can be exploited in resistance management programmes.  相似文献   
58.
蜂蟹螨(Varroa destructor)对福化利抗药性及其防治的研究   总被引:1,自引:0,他引:1  
建立培养皿药膜法进行蜂蟹螨福化利(Fluvalinate)抗药浓度检测方法。分别以福化利浓度为0、12.5、25、50、100mg/L进行台湾5处蜂场蜂蟹螨抗福化利剂量调查,经回归分析,计算LC50之浓度介于23.75~79.25mg/L之间,比意大利抗性螨385~857mg/L仍低很多,显示抗药性尚未大幅增加。以隔落螨法防治蜂蟹螨平均每日可捕捉44.7~49.1只。比较隔落螨法、割雄蜂蛹加隔落螨法、蚁酸加隔落螨法、福化利防治法的效果,当蜂蟹螨密度不高时,可采用隔落螨法或加割雄蜂蛹方式进行防治,蜂蟹螨密度高时,可先以福化利、蚁酸进行1~2次防治,再配合隔落螨法,将可达到长期防治效果。  相似文献   
59.
Background:Hematophagous mites affect numerous bird species, causing severe injuries to the budgerigars. Some species can cause dermatitis in humans.Aims:The purpose was to morphologically identify the mites related to budgerigars (Melopsittacus undulatus) and their nests in Yucatan, Mexico.Methods:In May 2022, a private budgerigar hatchery was visited and mites were collected from the bodies of the birds and their nests. The morphological traits of the mites were confirmed by scanning electron microscopy.Results:Four of 30 birds showed severe clinical signs of mite infestation. The Budgerigars revealed lesions in the cere, nostrils, eyelids, beak, and paws. The bird’s skin showed signs of dryness and beige coloring. The birds with severe damage also presented anorexia and had deformed paws and beaks. The parasitosis was caused by the “burrowing mites,” Knemidocoptes pilae. The burrowing mites and the Grallacheles bakeri were recovered and identified from paw scabs. To eliminate mites, a topical application of Ivermectin was administered to the necks of the birds. The dose was a single, which has a residuality of 21 days. Two drops (0.115 mg/ml) of ivermectin were applied to each bird. A gradual reduction in crusted lesions due to mite mortality was noted. The “tropical fowl mite” Ornithonyssus bursa was identified in the nests, which represents the first record in Mexico.Conclusions:Three species of mites were discovered in a single budgerigar hatchery. This emphasizes the importance of deworming birds and keeping a clean environment in their cages to reduce the potential for parasitic mite infestation.  相似文献   
60.
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