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   166篇
  免费   24篇
林业   3篇
农学   6篇
  4篇
综合类   16篇
农作物   5篇
水产渔业   12篇
畜牧兽医   142篇
植物保护   2篇
  2020年   3篇
  2019年   7篇
  2018年   9篇
  2017年   9篇
  2016年   4篇
  2015年   7篇
  2014年   11篇
  2013年   23篇
  2012年   3篇
  2011年   7篇
  2010年   18篇
  2009年   10篇
  2008年   4篇
  2007年   3篇
  2006年   4篇
  2005年   2篇
  2004年   2篇
  2003年   6篇
  2002年   3篇
  2001年   5篇
  1999年   2篇
  1998年   13篇
  1997年   11篇
  1996年   9篇
  1995年   2篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1979年   1篇
排序方式: 共有190条查询结果,搜索用时 15 毫秒
111.
112.
The study was conducted to evaluate the thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road. A total of 44 Chamarita breed adult ewes were randomly allotted to one of two groups, one control group (untransported) and transported group (journey of 4 h), and blood stress indicators were measured 1 day before transport and at four time points post‐transport (0, 4 and 24 h). Thermophysiological profiles of ewes were measured by temperature buttons (iButton Thermochron®) and placed in intravaginal sponges. Direct observations, with a combination of scan and behaviour sampling, were carried out to collect information on individual behaviour and the time it took the ewes to drink water, eat and rest after returning to their pen respectively. Transported ewes lost approximately 1 kg live weight compared to controls and had higher body temperatures until 12 h post‐transport. Cortisol, glucose, non‐esterified fatty acid (NEFA) concentrations as well as the neutrophil–lymphocyte ratio (N/L) and other physiological indicators were higher immediately after unloading in transported ewes but mostly returned to normal after 4 h, with complete recovery after 24 h. Behavioural analysis post‐transport demonstrated that transported ewes chose to eat before drinking and spent less time resting than controls in the first 3 h after unloading. The study demonstrates that transportation even under short‐journey conditions induced behavioural, physiological and thermophysiological responses indicative of the induction of significant stress, leading to live weight shrinkage that may jeopardize farmer's incomes. Finally, results of this study validated the use of iButton Thermochron® data loggers for monitoring the stress response during transport.  相似文献   
113.
114.
Verminous bronchopneumonia caused by infection with Otostrongylus circumlitus and Parafilaroides gymnurus is an important cause of death during the rehabilitation of harbour seals (Phoca vitulina). During the winter of 2000/01, 35 juvenile harbour seals with severe clinical signs of verminous bronchopneumonia were treated with either 0.2 mg/kg ivermectin orally or 0.2 mg/kg moxidectin subcutaneously, and monitored for 30 days. The efficacy of the anthelmintics was determined by the pattern of larval excretion (Baermannisation) and the progress of the clinical signs. Both anthelmintics had reduced larval excretion by at least 99 per cent after 10 days, but the seals' rapid breathing rate and and dyspnoea returned to normal more quickly in the animals treated with moxidectin. The pharmacokinetics of the anthelmintics were determined by solid-phase extraction, and high-performance liquid chromatography with fluorescence detection. Moxidectin had a mean (sd) residence time of 9.04 (2.12) days compared with 4.83 (1.14) days for ivermectin.  相似文献   
115.
VCARS, the Veterinary Computerized Anesthetic Record System, has been developed to capture pre-, peri- and post-anesthetic data using Tablet PCs, 802.11b wireless networks, and a web-based database. Patient demographics, anticipated procedures and anesthetist, service information and hematologic and chemistry values are imported from the Veterinary Medical Teaching Hospital patient information system. Using a wireless Tablet PC, pre-anesthetic examination findings are recorded and an anesthetic plan including anesthetic drugs and anesthetic and monitoring equipment is developed. During induction and maintenance of anesthesia, physiologic variables, drug, fluid, anesthetic gas and oxygen administration, laboratory values, patient location, and important events can be charted with the simplicity of a paper anesthetic record. This information can be manipulated for display in a variety of ways depending on the specific needs of the case. Tools for calculating optimal fluid rates and drug dosages are incorporated into the design. The anesthetic records from multiple cases can be viewed simultaneously using a centrally-located monitor. Detailed audit trails ensure data integrity. A high-end search engine will allow rapid and complete retrieval of patient and anesthetic information. Macromedia flash is used to allow temporary disconnection from the wireless network without losing the ability to view, add, or edit data. The initial stages of software development are nearing completion, a wireless network is in place and hardware is being purchased. A pilot study will be conducted using manual entry of physiologic data prior to integration of automatically captured patient physiological variables. It is anticipated that this system will drastically improve the accuracy of data collection and retrieval and will provide important information about anesthetic management allowing improvement in overall patient care.  相似文献   
116.
117.
温度对荔枝开花的影响   总被引:9,自引:0,他引:9  
低温能促进荔枝(LitchichinestsSonn.)开花,但是成功诱导开花的临界温度和所需低温量并不清楚。研究了最高温/最低温:15°/5°,20°/5°,20°/10°,20°/15°,25°/10°,25°/15°,25°/20°和30°/20℃8个温度处理对KwaiMayPink荔枝和Casino荔枝营养生长和开花的影响。在第2个试验中,WaiChee荔枝在转移到无诱导条件的30°/20℃温度前,分别给予0,2,4,6,8,10和31周的15℃低温诱导。在第3个试验中.WaiChee荔枝生长温度为15℃时,每24小时内给予高于20℃的温度处理时间分别为0,1,2和8h(15℃以上分别为0,2,4和15h)。在第1个试验中,KwaiMayPink的营养生长温度为25°/20℃和30°/20℃,温度为25°/10℃和25°/15℃时,既有营养生长,又有花穗发育,较低的温度更利于开花。Casino荔枝除了在25°/10℃和25°/15℃的温度条件下既无营养生长,也无花穗发育外,其余处理的反映和KwaiMayPink荔枝类似。对2个荔枝品种而言,在20°/15℃和更低的温度时,几乎所有枝条都开了花。‘WaiChee’荔枝成花诱导条件为在转移到高温条件下之前,保持15℃的低温4周,最长6周。低温时间的长短还影响花穗的类型,15℃的低温诱导10周后,‘WaiChee’荔枝几乎无有叶花穗。保持15℃的低温  相似文献   
118.
Community respiration (R) rates are scaled as the two-thirds power of the gross primary production (P) rates of aquatic ecosystems, indicating that the role of aquatic biota as carbon dioxide sources or sinks depends on its productivity. Unproductive aquatic ecosystems support a disproportionately higher respiration rate than that of productive aquatic ecosystems, tend to be heterotrophic (R > P), and act as carbon dioxide sources. The average P required for aquatic ecosystems to become autotrophic (P > R) is over an order of magnitude greater for marshes than for the open sea. Although four-fifths of the upper ocean is expected to be net heterotrophic, this carbon demand can be balanced by the excess production over the remaining one-fifth of the ocean.  相似文献   
119.
Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.  相似文献   
120.
The Sierra Madre fault, along the southern flank of the San Gabriel Mountains in the Los Angeles region, has failed in magnitude 7.2 to 7.6 events at least twice in the past 15,000 years. Restoration of slip on the fault indicated a minimum of about 4.0 meters of slip from the most recent earthquake and suggests a total cumulative slip of about 10.5 meters for the past two prehistoric earthquakes. Large surface displacements and strong ground motions resulting from greater than magnitude 7 earthquakes within the Los Angeles region are not yet considered in most seismic hazard and risk assessments.  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