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   1225篇
  免费   59篇
  国内免费   51篇
林业   114篇
农学   89篇
基础科学   89篇
  174篇
综合类   715篇
农作物   16篇
水产渔业   40篇
畜牧兽医   61篇
园艺   12篇
植物保护   25篇
  2024年   7篇
  2023年   37篇
  2022年   36篇
  2021年   49篇
  2020年   54篇
  2019年   52篇
  2018年   17篇
  2017年   31篇
  2016年   36篇
  2015年   21篇
  2014年   53篇
  2013年   54篇
  2012年   87篇
  2011年   112篇
  2010年   90篇
  2009年   79篇
  2008年   67篇
  2007年   74篇
  2006年   71篇
  2005年   80篇
  2004年   54篇
  2003年   30篇
  2002年   32篇
  2001年   27篇
  2000年   35篇
  1999年   13篇
  1998年   11篇
  1997年   3篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1991年   3篇
  1990年   2篇
  1989年   3篇
排序方式: 共有1335条查询结果,搜索用时 15 毫秒
141.
142.
21世纪是全球经济、竞争经济和知识经济的世纪,人力资源开发的空间更为广阔,它在经济 社会发展中的意义和作用也越来越大。探索人力资源开发的规律是我国经济发展战略中的重要课题。  相似文献   
143.
龙超 《国际木业》2005,35(9):22-25
本文阐述了现代木结构建筑在中国的应用、研究现状、建筑实例,指出木结构在我国具有很大的潜在市场,并且有利于合理有效的利用我国的林木资源,生产出具有高附加值的产品,做到经济、社会、生态效益的三者相统一。  相似文献   
144.
BACKGROUND: The Systematized Nomenclature of Medicine (SNOMED) is an established standard nomenclature for the expression of human and veterinary medical concepts. Nomenclature standards ease sharing of medical information, create common points of understanding, and improve data aggregation and analysis. OBJECTIVES: The objective of this study was to determine whether SNOMED adequately represented concepts relevant to veterinary clinical pathology. METHODS: Concepts were isolated from 3 different types of clinical pathology documents: 1) a textbook (Textbook), 2) the Results sections of industry pathology reports (Findings), and Discussion sections from industry pathology reports (Discussion). Concepts were matched (mapped) by 2 reviewers to semantically-equivalent SNOMED concepts. A quality score of 3 (good match), 2 (problem match), or 1 (no match) was recorded along with the SNOMED hierarchical location of each mapped concept. Results were analyzed using Cohen's Kappa statistic to assess reviewer agreement and chi-square tests to evaluate association between document type and quality score. RESULTS: The percentage of good matches was 48.3% for the Textbook, 45.4% for Findings, and 47.5% for Discussion documents, with no significant difference among documents. Of remaining concepts, 40% were partially expressed by SNOMED and 14% did not match. Mean reviewer agreement on quality score assignments was 76.8%. CONCLUSIONS: Although SNOMED representation of veterinary clinical pathology content was limited, missing and problem concepts were confined to a relatively small area of terminology. This limitation should be addressed in revisions of SNOMED to optimize SNOMED for veterinary clinical pathology applications.  相似文献   
145.
In Uganda, control of vector-borne diseases is mainly in form of vector control, and chemotherapy. There have been reports that acaricides are being misused in the pastoralist systems in Uganda. This is because of the belief by scientists that intensive application of acaricide is uneconomical and unsustainable particularly in the indigenous cattle. The objective of this study was to investigate the strategies, rationale and effectiveness of vector-borne disease control by pastoralists. To systematically carry out these investigations, a combination of qualitative and quantitative research methods was used, in both the collection and the analysis of data. Cattle keepers were found to control tick-borne diseases (TBDs) mainly through spraying, in contrast with the control of trypanosomosis for which the main method of control was by chemotherapy. The majority of herders applied acaricides weekly and used an acaricide of lower strength than recommended by the manufacturers. They used very little acaricide wash, and spraying was preferred to dipping. Furthermore, pastoralists either treated sick animals themselves or did nothing at all, rather than using veterinary personnel. Oxytetracycline (OTC) was the drug commonly used in the treatment of TBDs. Nevertheless, although pastoralists may not have been following recommended practices in their control of ticks and tick-borne diseases, they were neither wasteful nor uneconomical and their methods appeared to be effective. Trypanosomosis was not a problem either in Sembabule or Mbarara district. Those who used trypanocides were found to use more drugs than were necessary.  相似文献   
146.
知识服务是信息时代赋予图书馆的使命。在知识经济环境下,高校图书馆的信息服务正面临着挑战和机遇。通过对高校图书馆知识服务平台体系结构的分析,从服务理念、服务内容和服务方式等方面对构建高校图书馆知识服务平台的新模式进行探索。  相似文献   
147.
服务是一个双向过程,既需要将读者信息图书馆化,也需要将图书馆服务知识读者化。其中,服务知识外化却往往被忽视,基于此,文章把它作为一个专门的问题加以研究,包括它的概念、内容、影响因素及实施。  相似文献   
148.
The computer swine disease diagnosis is an important tool for swine farming industry,but the traditional expert system cannot meet the requirement of practical application.To improve the situation,a sw...  相似文献   
149.
论述了信息资源保障体系对曹妃甸工业区知识创新的支撑作用,对曹妃甸工业区信息资源需求进行了分析,提出了曹妃甸工业区信息资源保障体系建设的途径和策略。  相似文献   
150.
现代数字图书馆在服务观念和模式上都有着根本性的变化,同时对馆员的综合素质也提出了更高的要求。图书馆员应当充分认识并加强学习各种新知识、新理念,不断提高自身素质,从而适应数字图书馆发展的需要。  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