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   1280篇
  免费   130篇
  国内免费   112篇
林业   16篇
农学   51篇
基础科学   83篇
  195篇
综合类   529篇
农作物   16篇
水产渔业   5篇
畜牧兽医   596篇
园艺   6篇
植物保护   25篇
  2024年   9篇
  2023年   39篇
  2022年   72篇
  2021年   124篇
  2020年   94篇
  2019年   105篇
  2018年   45篇
  2017年   69篇
  2016年   69篇
  2015年   28篇
  2014年   96篇
  2013年   95篇
  2012年   81篇
  2011年   81篇
  2010年   56篇
  2009年   62篇
  2008年   46篇
  2007年   82篇
  2006年   49篇
  2005年   35篇
  2004年   34篇
  2003年   25篇
  2002年   18篇
  2001年   21篇
  2000年   20篇
  1999年   8篇
  1998年   10篇
  1997年   4篇
  1996年   5篇
  1995年   5篇
  1994年   3篇
  1993年   6篇
  1992年   4篇
  1991年   9篇
  1990年   2篇
  1989年   4篇
  1988年   2篇
  1987年   3篇
  1985年   1篇
  1956年   1篇
排序方式: 共有1522条查询结果,搜索用时 18 毫秒
991.
畜禽粪便不但严重污染环境,对人体健康也会产生诸多的影响,畜禽粪便的治理及综合利用一直以来备受人们的关注,我国较重视畜禽粪便资源化、无害化处理技术的研发,尤其鼓励有机肥技术的应用开发。研究以西丰县康洁生物有机肥有限公司为例,介绍生物有机肥技术应用的工艺。结果表明:该技术可获得较好的环境效益、社会效益和经济效益,可减少504tCOD及54t氨氮排放,对畜禽粪便的治理及利用具有积极的促进作用。  相似文献   
992.
大豆蛋白是从大豆类产品中提取出来的一种植物性蛋白质,其氨基酸组成与牛奶蛋白质相近。大豆蛋白中除蛋氨酸含量较低外,其余必需氨基酸的含量均比较丰富,其营养价值与动物蛋白质相同。  相似文献   
993.
利用高温堆肥原理研制生产出的病死禽畜残体堆肥生化处理设备,具有撕碎、搅拌、加热、保温、接种发酵、废气净化处理等功能,可以对病死禽畜残体进行搅拌、加热杀菌、通风加氧进行发酵处理,最后制成有机肥料。  相似文献   
994.
家畜行为智能监测系统的研究进展   总被引:1,自引:0,他引:1  
家畜行为是家畜心里、生理健康状况的外在表现。家畜行为监测、分析有利于建立行为模型并发觉异常行为,减少经济损失。目前国内主要依赖于养殖人员人工观察方式监测家畜行为,主观性强且精度低。随着现代信息技术的不断发展,智能化行为监测方法也在快速发展和不断更新。论文阐述了基于电子测量仪器的运动识别、基于视频的动作状态识别和基于声音的情绪表达识别方法的研究现状,进一步展望了家畜行为智能监测系统的后续研究方向,以期建立家畜行为数据采集数据库和行为分析专家系统,挖掘家畜行为的深层含义。  相似文献   
995.
This study was designed to evaluate the epidemiology of severe gastroenteritis in children living in Québec rural areas with intensive livestock activities. From September 2005 through June 2007, 165 cases of gastroenteritis in children aged from 6 months to 5 years, hospitalized or notified to the public health department were enrolled, and 326 eligible controls participated. The parents of cases and controls were asked questions about different gastroenteritis risk factors. The quality of the drinking water used by the participants was investigated for microbial indicators as well as for four zoonotic bacterial pathogens (Campylobacter spp, Escherichia coli, Salmonella spp and Yersinia spp) and two enteric parasites (Cryptosporidium spp and Giardia spp). From 134 stool specimen analysed, viruses were detected in 82 cases (61%), while 28 (21%) were found with at least one of the bacteria investigated, and five cases were infected by parasites. Campylobacteriosis was the main bacterial infection (n = 15), followed by Salmonella sp (n = 7) and E. coli O157:H7 (n = 5) among cases with bacterial gastroenteritis. No significant difference was found between cases and controls regarding the quality of water consumed; the frequency of faecal contamination of private wells was also similar between cases and controls. Considering the total cases (including those with a virus), no link was found between severe gastroenteritis and either being in contact with animals or living in a municipality with the highest animal density (4th quartile). However, when considering only cases with a bacterial or parasite infection (n = 32), there was a weak association with pig density that was not statistically significant after adjusting for potential confounders. Contact with domestic, zoo or farm animals were the only environmental factor associated with the disease.  相似文献   
996.
Biosecurity risks are a major threat to the profitability of the industry as well as impacting human and animal health. Livestock producers play a crucial role in biosecurity as the first to notice changes in the health or productivity of their stock and are generally responsible for implementing protective measures. However, uptake of biosecurity measures by producers is variable. We critically appraised the current literature regarding biosecurity practices in Australian livestock industries and highlight aspects that are well understood as well as those where further research or information is needed. Findings from 12 cross-sectional studies suggest that Australian producers' knowledge of biosecurity methods and importance might have a positive influence on their willingness to implement or incorporate biosecurity practices. There is moderate evidence supportive of biosecurity being well understood by livestock producers across Australia. Barriers to producers using biosecurity practices included lack of information or communication from agricultural, veterinary or government organisations. It was found that larger stock numbers were positively correlated with biosecurity implementation and that producers used veterinarians, government and industry agencies as resources for trusted information.  相似文献   
997.
Ivermectin (IVM) is one of the most widely used antiparasitic drugs worldwide and has become the drug of choice for anthelmintic and tick treatment in beef cattle production. It is known that pharmacokinetic parameters are fundamental to the rational use of a drug and food safety and these parameters are influenced by different factors. The aim of this study was to evaluate the pharmacokinetic profile of IVM in Bos indicus, Bos taurus, and crossbreed cattle (B. indicus × B. taurus) kept under same field conditions and the possible impacts of sex and IVM formulation (1% and 3.15%). It was observed that IVM concentration was significantly affected by breed. The plasma concentrations of IVM, AUC, Cmax, and t1/2β were significantly higher in B. indicus compared to B. taurus. Crossbreed animals showed an intermediate profile between European and Indian cattle. No alteration in pharmacokinetics parameters was detected when comparing different gender. Concerning the pharmacokinetic data of IVM formulation, it was verified that Tmax, AUC, and t1/2β were higher in 3.15% IVM animals than those from 1% IVM formulation. The results clearly indicated that the IVM plasma concentrations in B. indicus were higher than that in B. taurus.  相似文献   
998.
CircRNAs are a new member of endogenous RNAs, which characterized by a closed-loop structure without terminated 5′ caps and 3′ tails via covalent bonding, which are evolutionarily conserved among different species and often exhibit tissue or developmental stage-specific expression. So far, thousands of circRNAs have been discovered in eukaryotic cells. CircRNAs are more stable due to its resistance to exonuclease implying important biological functions in all kingdoms of life. They could function as miRNA sponges, interfere with splicing and bind to protein to regulate the expression of host genes and so on. In addition, emerging evidence suggests that circRNAs are closely related to a series of physiological processes in livestock and poultry. In this review, we summarized the biogenesis mechanism, major biological function and detection methods and focused on research advance of circRNAs in livestock and poultry, aiming at providing certain reference value and novel techniques for the development of new molecular genetic markers and breeding of livestock and poultry. Meanwhile, we hope this review could show significant prospect for other researches.  相似文献   
999.
本文通过对临泽县草畜产业发展现状、存在问题进行阐述,提出了几点建议,对今后草畜产业的发展具有一定的指导意义。  相似文献   
1000.
寻找抗生素替代品是养殖业面临的一大课题。片球菌(Pediococcus)是饲料添加目录中允许的益生菌之一,它是一种革兰氏阳性乳酸菌。大量研究表明,片球菌在食品、医疗和养殖行业中有着巨大的应用价值,它们在宿主肠道黏膜细胞表面具有的良好的定植能力,减少了其他细菌的黏附。同时,片球菌能够产生包括片球菌素、有机酸和过氧化氢在内的许多抗菌物质,因而在抑制病原菌生长、改善肠道微生物群落结构、刺激宿主免疫、促进养殖动物生产健康并提升动物生长性能等方面表现出良好的益生性能,但是相比较其他益生菌而言其关注程度不高。作者总结了片球菌产生抑菌物质的种类及其抑菌机制,介绍了片球菌的黏附和免疫调控作用方式,以及片球菌在猪和鸡等畜禽养殖动物生产上的应用,旨在为其在动物生产中的合理应用提供理论参考。片球菌具有广谱、稳定的抑菌效果,丰富的益生性能,它们有利于畜禽动物健康生长,预防病原菌感染,减少疾病发生,因此值得加大推广和应用的力度。  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