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   36篇
  免费   3篇
  2篇
综合类   4篇
水产渔业   1篇
畜牧兽医   30篇
植物保护   2篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2018年   1篇
  2016年   2篇
  2015年   2篇
  2013年   3篇
  2012年   4篇
  2011年   2篇
  2010年   3篇
  2009年   4篇
  2007年   5篇
  2006年   3篇
  2003年   1篇
  2002年   1篇
  1995年   1篇
  1989年   1篇
  1988年   1篇
  1981年   1篇
  1952年   1篇
排序方式: 共有39条查询结果,搜索用时 15 毫秒
1.
A major objective of environmental impact assessment (EIA) is prediction. Two major goals in science are: (1) explanation of observed phenomena, and (2) prediction. The EIA process makes use of the methods of academic science to provide the explanatory framework for the required data gathering which is needed for the scientifically valid prediction of effects. Follow-up monitoring after a development proceeds is required to test the predictions for their accuracy, important in both scientific and decision-making aspects of EIA. This testing is needed not only for future EIAs in the area, but also for ongoing project management. In boreal forest management, where EIA prediction is ecosystem-oriented rather than site-specific only, the EIA process needs to be tied to long-term, ecosystem-based forest management plans. This must be done via ongoing tests of predictions, and then by feeding the test-derived information back into a dynamic decisionmaking process. In Saskatchewan this unique and holistic application of the EIA process to long-term forest ecosystem management has been initiated by applying EIA to the twenty-year management plan required by the holder of any forest management agreement (FMA). This is an example of harnessing scientific predictive and testing capacity of the EIA process to set the stage for ecologically sustainable, integrated forest resource management. This also is an example of local action to address a global problem by ensuring the continued integrity of ecological processes in a portion of Canada's boreal forest.  相似文献   
2.
Our review has emphasized that AI tools are programming languages inspired by some problem-solving paradigm. We want to underscore their status as programming languages; even if an AI tool seems to fit a problem perfectly, its proficient use still requires the training and practice associated with any programming language. The programming manuals for PC-Plus, Smalltalk/ V, and Nexpert Object are all tutorial in nature, and the corresponding software packages come with sample applications. We find the manuals to be uniformly good introductions that try to anticipate the problems of a user who is new to the technology. All three vendors offer free technical support by telephone to licensed users. AI tools are sometimes oversold as a way to make programming easy or to avoid it altogether. The truth is that AI tools demand programming-but programming that allows you to concentrate on the essentials of the problem. If we had to implement a diagnostic system, we would look first to a product such as PC-Plus rather than BASIC or C, because PC-Plus is designed specifically for such a problem, whereas these conventional languages are not. If we had to implement a system that required graphical interfaces and could benefit from inheritance, we would look first to an object-oriented system such as Smalltalk/V that provides built-in mechanisms for both. If we had to implement an expert system that called for some mix of AI and conventional techniques, we would look first to a product such as Nexpert Object that integrates various problem-solving technologies. Finally, we might use FORTRAN if we were concerned primarily with programming a well-defined numerical algorithm. AI tools are a valuable complement to traditional languages.  相似文献   
3.
In 2003, an outbreak of West Nile virus (WNV) occurred in Saskatchewan, Canada from July to September. One-hundred thirty-three horse cases and 947 human cases were recorded and data were analyzed retrospectively for evidence of clustering to determine if clinical infection in the horse population could be used to estimate human risk of infection with WNV. Kulldorff's scan statistic was used to identify spatial-temporal clusters in both the human and horse cases. In most areas, human clusters were not preceded by horse clusters. In one area, a significant cluster of horse cases preceded human cases by 1 week; however, 1 week does not provide sufficient time for human-health authorities to act and provide advance warning for the public.  相似文献   
4.
In 2006, an outbreak of anthrax in Saskatchewan affected several species but most of the losses occurred in cattle. Potential risk factors contributing to this outbreak were investigated through questionnaires involving 117 case farms and 259 control farms geographically representative of the Saskatchewan beef herd. The occurrence of flooding [odds ratio (OR) = 3.4; 95% confidence interval (CI): 1.8 to 6.4], wetter pastures (Good: OR = 3.5; 95% CI: 1.4 to 8.5; Wet: OR = 7.2; 95% CI: 2.9 to 18.1), shorter pasture grass length (OR = 3.0; 95% CI: 1.4 to 6.4), and higher density of the animals on pasture (OR = 3.0; 95% CI: 1.6 to 5.7) were more likely to have been reported for case herds than for control herds. Case farms were more likely than control farms to have vaccinated more than 1 week after the first reported case in the rural municipality (OR = 6.3; 95% CI: 2.6 to 15.3). Timing of vaccination in case herds was also significantly associated with the occurrence of subsequent deaths on these farms (P = 0.001).  相似文献   
5.
The objective of this study was to develop a model using equine data from geographically limited surveillance locations to predict risk categories for West Nile virus (WNV) infection in horses in all geographic locations across the province of Saskatchewan. The province was divided geographically into low-, medium-, or high-risk categories for WNV, based on available serology information from 923 horses obtained through 4 studies of WNV infection in horse populations in Saskatchewan. Discriminant analysis was used to build models using the observed risk of WNV in horses and geographic division-specific environmental data as well as to predict the risk category for all areas, including those beyond the surveillance zones. High-risk areas were indicated by relatively lower rainfall, higher temperatures, and a lower percentage of area covered in trees, water, and wetland. These conditions were most often identified in the southwest corner of the province. Environmental conditions can be used to identify those areas that are at highest risk for WNV. Public health managers could use prediction maps, which are based on animal or human information and developed from annual early season meteorological information, to guide ongoing decisions about when and where to focus intervention strategies for WNV.  相似文献   
6.
7.
In December 2011, the Malignant Catarrhal Fever (MCF) Task Force in Saskatchewan recommended that research be conducted on the relationship between the proximity of bison and sheep under typical commercial production settings and bison deaths due to MCF. The objective of this study was to evaluate all causes of death in bison herds and compare the incidence of MCF in herds at varying distances of exposure from sheep operations. Necropsies were completed on 76 of 133 bison reported to have died during the 18-month study period. A total of 7 MCF deaths was reported from 2 large herds within 1.0 km of sheep operations. Although there was a greater risk of MCF deaths in bison herds within 1.0 km of sheep operations than in herds more than 1.0 km away, the overall incidence of MCF deaths within the study period was very low. Most deaths were attributed to non-infectious causes, including copper deficiency.  相似文献   
8.
The goal of this study was to establish a short list of zoonotic pathogens involving the domestic dog that can be prioritized for a companion animal surveillance program specific to the Prairie Provinces of Canada. A list of pathogens documented in dogs was created through a comprehensive review of infectious disease textbooks for the following taxonomical categories: bacteria, ectoparasites, fungi, helminths, protozoa, rickettsia, and viruses. This created an initial list of 594 pathogens that was then pared down through an extensive review of the literature using the following criteria: i) the pathogen is zoonotic/sapronotic/anthroponotic; ii) the dog is involved in transmission to humans, maintenance, or detection of the pathogen; and iii) there is a level of risk for occurrence of the pathogen in Canada. This process yielded a final list of 84 pathogens and 3 supplementary lists of canine zoonotic/sapronotic/anthroponotic pathogens that may become relevant to future surveillance programs.  相似文献   
9.
The aim of the study was to elucidate the distribution and possible transmission routes of Toxocara spp. infection in Estonia. Out of 454 faecal and sand samples collected from park lawns and sandpits in the town of Tartu, 19 were Toxocara positive (4.2%). Out of the 45 sandpit samples 17.8% were Toxocara positive. Cat faeces was found in 21 sandpit samples. Parasitological necropsies were performed on 41 euthanised stray dogs and 27 cats in the Tallinn Dog Home. Additionally, 13 wild free-roaming brown rats (Rattus norvegicus) were captured from the Tallinn Dog Home territory, necropsied and studied for the presence of Toxocara larvae. Toxocara canis adults were found in 14.6% of the dogs and Toxocara cati (syn. mystax) adults in the small intestines of 48.2% of the cats examined. Larval infection was detected in the kidney and liver in 5 dogs (12.2%). Our study demonstrated only low-level larval Toxocara infections in adult dogs. Toxocara larvae were not found in cats and brown rats. According to the results of this study, cats more often carry Toxocara infection than dogs. Under our conditions, stray and free-roaming cats are the main contaminators of the environment with Toxocara eggs. Children playing in sandpits are the main risk group for larval toxocarosis.  相似文献   
10.
This study evaluated the effects of an anesthetic protocol using intravenous ketamine and midazolam, and intramuscular buprenorphine on hematologic variables in cats. Twelve healthy adult cats had blood collected for a complete blood count before and after the induction of anesthesia. There were significant decreases in red blood cell counts, hemoglobin concentrations and hematocrits after the induction of anesthesia. On average, red blood cell counts and hematocrits decreased by 25%, and hemoglobin concentrations decreased by 24%. Based on hematocrit, 3/12 samples (25%) taken while the cats were anesthetized would have been interpreted as belonging to anemic patients while none of the cats would have been considered anemic before anesthesia. This study suggests that a complete blood count performed on blood taken under anesthesia with this anesthetic protocol should be interpreted cautiously in order to not make a false diagnosis of anemia.  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