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   191篇
  免费   36篇
林业   4篇
农学   5篇
  6篇
综合类   7篇
农作物   3篇
水产渔业   2篇
畜牧兽医   195篇
园艺   3篇
植物保护   2篇
  2023年   6篇
  2022年   2篇
  2021年   3篇
  2020年   6篇
  2019年   4篇
  2018年   10篇
  2017年   10篇
  2016年   9篇
  2015年   6篇
  2014年   10篇
  2013年   11篇
  2012年   6篇
  2009年   7篇
  2008年   6篇
  2007年   5篇
  2006年   5篇
  2005年   4篇
  2004年   5篇
  2003年   10篇
  2002年   3篇
  2001年   9篇
  2000年   6篇
  1999年   8篇
  1998年   6篇
  1997年   3篇
  1996年   3篇
  1995年   6篇
  1994年   2篇
  1993年   5篇
  1992年   3篇
  1991年   3篇
  1990年   2篇
  1988年   2篇
  1986年   2篇
  1985年   3篇
  1981年   2篇
  1980年   2篇
  1973年   2篇
  1970年   2篇
  1969年   2篇
  1968年   2篇
  1964年   2篇
  1960年   1篇
  1958年   1篇
  1956年   1篇
  1948年   1篇
  1943年   3篇
  1940年   2篇
  1939年   1篇
  1938年   1篇
排序方式: 共有227条查询结果,搜索用时 31 毫秒
151.
A light-weight plastic faecal extractor and its use in the collection of faecal samples from sheep is described.  相似文献   
152.
Vulture populations across the Asian subcontinent have declined dramatically in the last 15 years and are now on the verge of extinction. Although the cause of the population decline was initially unknown, the decrease has recently been conclusively linked to the use of the nonsteroidal anti-inflammatory drug diclofenac in cattle that inadvertently ended up in the vulture food chain. With the vulture numbers continuing to decline by up to 48% a year, the Indian, Nepali and Pakistan governments have recently banned the manufacture and importation of veterinary diclofenac. They have also suggested meloxicam as an alternate anti-inflammatory for use in cattle. This recommendation was based on extensive acute safety studies in the African White-backed vulture ( Gyps africanus ), which evaluated worst case scenarios of maximum intake based on a once in three day feeding pattern. However, the possible cumulative pharmacokinetic and pharmacodynamic effects in vultures receiving multiple daily doses of meloxicam over time were not assessed. At present very little pharmacokinetic or pharmacodynamic information is available to add further support for the safety of meloxicam in this animal species. This article discusses the oral and intramuscular pharmacokinetics of meloxicam in Cape Griffon vultures ( Gyps coprotheres ). Therapeutic drug monitoring was also undertaken in White-backed, Egyptian ( Neophron pernopterus ) and one Lappet Faced vulture ( Torgos tracheliotos ). In all these species, meloxicam was characterized by a short half-life of elimination. The rapid metabolism of meloxicam in combination with a short duration of effect in the studied species Gyps vultures shown in this study makes it unlikely that the drug could accumulate. This confirms the safety of repeated exposure to meloxicam in vultures of this genus.  相似文献   
153.
Among other factors (eg, feed), bedding material has an important effect on stable air quality with respect to airborne particle formation. This study was designed to establish which material is suited to create an improved stable environment for horses. First, the following materials were analyzed under standardized conditions in a laboratory experiment: wheat straw, dry wood shavings, hemp shives, linen shives, wheat straw pellets, paper cuttings (unprinted newspaper). The second investigation was carried out under in situ conditions in which three of these bedding materials (wheat straw, wood shavings, and straw pellets) were analyzed under practical conditions. In both experiments, airborne particle concentrations were detected online with the gravimetrically measuring analyzer TEOM 1400a (Rupprecht & Patashnick Co., Franklin, MA). In the laboratory experiment, the TEOM was equipped successively with different inlets to measure the particle fractions PM1, PM2.5, PM10, and PM20. During the in situ experiment, only the fraction PM10 was detected. In the laboratory experiment, hemp and linen had the highest generation of airborne particles in all fractions. The lowest particle generation was detected with straw pellets. Results of the in situ investigation supported results of the laboratory experiment with respect to mean particle generation of straw pellets. With an average of 111.2 ± 149.2 μg/m3, it was significantly lower than the mean particle generation of wheat straw with 227.5 ± 280.8 μg/m3. The particle generation of wood shavings had an average of 140.9 ± 141.9 μg/m3 and also was significantly lower than the generation by wheat straw. An activity-correlated variation of particle concentrations was found. In conclusion, taking both experiments into consideration, straw pellets seemed to be suitable for horse stables, to promote an improvement in the stable climate in relation to airborne particle formation.  相似文献   
154.
155.
Diuretics, in particular furosemide, are generally recommended as a supportive treatment in the advanced stages of heartwater in ruminants. However, after what appeared to be possible adverse effects accompanying its use in field cases of heartwater, the effects of this drug on certain blood and urine parameters were investigated in normal sheep at the same dose rates. Diuresis with concomitant natriuresis was significant after furosemide administration, as was the expected plasma volume decrease. Other significant changes included metabolic alkalosis, hypokalaemia and reduced blood ionised calcium. The difference in duration of the diuretic effect and the duration of the changes in blood parameters from c. 3 h and c. 6 h respectively make it difficult to determine a time interval between successive treatments with furosemide. It appears that the probable cause of death of sheep with heartwater is a drastic reduction in blood volume and decreased cardiac output that leads to general circulatory failure. A therapeutic approach that involves further loss of plasma volume due to diuresis appears contradictory. The added effects of potentiating respiratory alkalosis and the terminal drop in blood ionised calcium seen in heartwater-affected animals indicate that the use of furosemide in supportive treatment of this disease is not warranted.  相似文献   
156.
157.
158.
159.
160.
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