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   150篇
  免费   6篇
林业   33篇
基础科学   1篇
  28篇
综合类   14篇
农作物   1篇
水产渔业   16篇
畜牧兽医   57篇
园艺   3篇
植物保护   3篇
  2021年   2篇
  2020年   7篇
  2019年   8篇
  2018年   7篇
  2017年   3篇
  2016年   5篇
  2014年   1篇
  2013年   11篇
  2012年   10篇
  2011年   8篇
  2010年   8篇
  2009年   14篇
  2008年   11篇
  2007年   12篇
  2006年   8篇
  2005年   8篇
  2004年   9篇
  2003年   5篇
  2002年   4篇
  2001年   1篇
  2000年   2篇
  1998年   3篇
  1997年   2篇
  1995年   1篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1982年   1篇
  1977年   1篇
排序方式: 共有156条查询结果,搜索用时 78 毫秒
41.
A 27-kg German Shorthaired Pointer was referred for evaluation due to the complaint of left pelvic limb lameness and signs of pain in the left stifle joint. Radiographs revealed signs of a healed supracondylar femoral fracture that had been previously repaired at another hospital with an intramedullary pin and two cross pins. In addition, there were signs of severe osteoarthritis (OA). The OA had been managed medically with administration of carprofen and nutraceuticals for nine months without any improvement. Left total knee replacement (TKR) surgery was performed to alleviate signs of pain. The patient was assessed preoperatively and at six months, one year, and two years after surgery using radiology, force platform analysis of gait, thigh circumference measures, goniometry, and lameness evaluation. Following surgery, the dog resumed normal activity without any signs of pain and a good quality of life at 3.5 months. Force plate analysis found that peak vertical force on the TKR limb was 85.7% of the normal contralateral limb after two years. Total knee replacement was a successful treatment to manage knee OA associated with a healed distal femoral fracture and internal fixation in this dog.  相似文献   
42.
在内蒙古阿尔山的田间诱捕试验中,落叶松八齿小蠹引诱剂1共诱集到16头落叶松八齿小蠹和1319头天敌红胸郭公虫,而落叶松八齿小蠹引诱剂2诱集到24104头落叶松八齿小蠹和776头红胸郭公虫。室内的触角电位试验结果表明:落叶松八齿小蠹对引诱剂2的触角反应(雌虫2.139mV±0.678mV,雄虫2.169mV±0.473mV)大于引诱剂1(雌虫0.440mV±0.232mV,雄虫0.297mV±0.142mV),对引诱剂1的反应值和对照差不多;而红胸郭公虫对引诱剂1的触角反应(雌虫4.618mV±1.106mV,雄虫4.534mV±1.087mV)明显大于引诱剂2(雌虫2.209mV±0.680mV,雄虫1.953mV±0.601mV),对引诱剂2也有一定的反应值。触角电位试验与田间诱捕试验结果相符合。GC-MS分析结果表明:引诱剂1的主要成分为3.06%的cis-geraniol,1.98%的Ipsenol,80.36%的(S)-cis-verbenol和1.03%的1-verbenone;结合卖方公司提供的数据,引诱剂1的主要成分为4.78%的2-methyl-3-buten-2-ol,63.71%的Ipsenol(纯度为96.9%),1.46%的Cedrene和22.42%的Isocaryophillene。结合以上数据分析得出:不同成分引诱剂对落叶松八齿小蠹及天敌红胸郭公虫引诱能力显著不同,Ipsenol对诱集落叶松八齿小蠹起重要作用,而(S)-cis-verbenol则对诱集天敌红胸郭公虫起重要作用。  相似文献   
43.
A 6-month-old female alpaca was presented for stranguria. Based on the history, physical examination findings, and radiographic studies, the alpaca was diagnosed with bladder outlet obstruction, secondary to pelvic displacement of the bladder, a condition previously unreported in camelids. Cystopexy was performed and the alpaca recovered unremarkably.  相似文献   
44.
Cycling of extracellular DNA in the soil environment   总被引:1,自引:0,他引:1  
Upon entering the soil environment, extracellular DNA is subjected to dynamic biological, physical, and chemical factors that determine its fate. This review concerns the fate of both recombinant and non-recombinant sources of DNA. A schematic of DNA cycling coupled with genetic transformation is presented to understand its behavior in soil. Extracellular DNA may persist through cation bridging onto soil minerals and humic substances, be enzymatically degraded and restricted by DNases of microbial origin, and/or enter the microbial DNA cycle through natural transformation of competent bacteria. Lateral gene transfer may disseminate DNA through the microbial community. An understanding of DNA cycling is fundamental to elucidating the fate of extracellular DNA in the soil environment.  相似文献   
45.
46.
Norway spruce saw meal was extracted with pressurized hot water at 120–240°C using a flow-through system. Only small amounts of hemicelluloses were extracted at 120–160°C, but dissolution was significantly enhanced when higher extraction temperatures were applied. All hemicelluloses but only 15% of lignin were removed from wood at 220°C, and even less lignin was extracted at lower temperatures. Partial degradation of cellulose seemed to take place only at 240°C. Of the total amount of extracted hemicelluloses, 4–22% was hydrolyzed to monosaccharides. Although the average molar masses of extracted hemicelluloses decreased with increasing extraction temperature, even at 240°C the extracted carbohydrates occurred, on average, as polysaccharides. Polysaccharides with an average molar mass of 31 kDa were obtained at 170°C. The molecular-mass characteristics and yield of carbohydrates depend on the extraction temperature, which should be chosen based on the end use of the isolated hemicelluloses.  相似文献   
47.
The study develops a bio-economic crop management model that internalizes the environmental cost of nitrate pollution, accounts for stochastic weather, and includes an option for split fertilization. The integrated model is designed to indicate whether a producer can benefit from applying fertilizer several times during the growing season, in response to crop needs, rather than a single time, at sowing. The model is parameterized for the cultivation of spring malting barley (Hordeum vulgare L.) in Southern Finland. The costs of negative externalities from nitrogen leaching are internalized in the landowner’s decision problem through a pollution tax. The results indicate that without a pollution tax a single application of fertilizer gauged to meet the needs of the entire season is optimal. With a tax, the benefits of split application - applying varying amounts of fertilizer at selected stages of the growing season - increase significantly. In comparison to a single application of fertilizer at sowing, split fertilization improves yields, increases the total amount of fertilizer used, and reduces nitrogen leaching.  相似文献   
48.
Rapeseed, raspberry, and pine bark are promising bioactive sources of plant phenolics selected from among ca. 100 previously screened plant materials for in vitro preclinical evaluation of health related effects. Phenolic extracts and isolated fractions of the selected materials were investigated for antioxidant, antimicrobial, antiinflammatory, and antimutagenic properties as well as for cell permeability. It was shown that rapeseed and pine bark phenolics and raspberry anthocyanins were good or excellent antioxidants toward oxidation of phosphatidylcholine membrane (liposomes), rapeseed oil (crude) phenolics were effective radical scavengers (DPPH test), and both raspberry and pine bark phenolics inhibited LDL oxidation. Rapeseed oil phenolics, principally vinylsyringol, raspberry anthocyanins, and pinoresinol and matairesinol, the principal components of pine bark phenolic isolate, were effective against formation of the proinflammatory mediator, prostaglandin E(2). Raspberry ellagitannins inhibited the growth of Proteus mirabilis and Klebsiella oxytoca. Pine bark and rapeseed had minor effects on the permeability of model drugs in Caco-2 experiments. None of the tested extracts were mutagenic nor toxic to Caco-2 cells or macrophages. Thus, phenolic isolates from rapeseed, raspberry, and pine bark and are safe and bioactive for possible food applications including functional foods intended for health benefit.  相似文献   
49.
50.
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