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   233篇
  免费   17篇
  国内免费   1篇
林业   13篇
农学   5篇
  48篇
综合类   44篇
农作物   8篇
水产渔业   39篇
畜牧兽医   73篇
园艺   7篇
植物保护   14篇
  2024年   1篇
  2023年   3篇
  2022年   10篇
  2021年   5篇
  2020年   19篇
  2019年   13篇
  2018年   9篇
  2017年   8篇
  2016年   10篇
  2015年   8篇
  2014年   10篇
  2013年   15篇
  2012年   22篇
  2011年   27篇
  2010年   11篇
  2009年   9篇
  2008年   17篇
  2007年   10篇
  2006年   4篇
  2005年   9篇
  2004年   7篇
  2003年   8篇
  2002年   4篇
  1999年   1篇
  1994年   1篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1984年   2篇
  1976年   1篇
  1975年   1篇
  1966年   1篇
排序方式: 共有251条查询结果,搜索用时 171 毫秒
71.
Landscape Ecology - The Sunda clouded leopard is vulnerable to forest loss and fragmentation. Conservation of this species requires spatially explicit evaluations of the effects of landscape...  相似文献   
72.
The fastidious, anaerobic spirochaete Brachyspira is capable of causing enteric disease in avian, porcine and human hosts, amongst others, with a potential for zoonotic transmission. Avian intestinal spirochaetosis (AIS), the resulting disease from colonisation of the caeca and colon of poultry by Brachyspira leads to production losses, with an estimated annual cost of circa £18 million to the commercial layer industry in the United Kingdom. Of seven known and several proposed species of Brachyspira, three are currently considered pathogenic to poultry; B. alvinipulli, B. intermedia and B. pilosicoli. Currently, AIS is primarily prevented by strict biosecurity controls and is treated using antimicrobials, including tiamulin. Other treatment strategies have been explored, including vaccination and probiotics, but such developments have been hindered by a limited understanding of the pathobiology of Brachyspira. A lack of knowledge of the metabolic capabilities and little genomic information for Brachyspira has resulted in a limited understanding of the pathobiology. In addition to an emergence of antibiotic resistance amongst Brachyspira, bans on the prophylactic use of antimicrobials in livestock are driving an urgent requirement for alternative treatment strategies for Brachyspira-related diseases, such as AIS. Advances in the molecular biology and genomics of Brachyspira heralds the potential for the development of tools for genetic manipulation to gain an improved understanding of the pathogenesis of Brachyspira.  相似文献   
73.
74.
At a recent workshop, experts discussed the benefits, risks, and research priorities associated with using genetically manipulated insects in the control of vector-borne diseases.  相似文献   
75.
76.
Lee LP  Szema R 《Science (New York, N.Y.)》2005,310(5751):1148-1150
Observing systems in nature has inspired humans to create technological tools that allow us to better understand and imitate biology. Biomimetics, in particular, owes much of its current development to advances in materials science and creative optical system designs. New investigational tools, such as those for microscopic imaging and chemical analyses, have added to our understanding of biological optics. Biologically inspired optical science has become the emerging topic among researchers and scientists. This is in part due to the availability of polymers with customizable optical properties and the ability to rapidly fabricate complex designs using soft lithography and three-dimensional microscale processing techniques.  相似文献   
77.
Prefoldins (PFDs) are members of a recently identified, small-molecular weight protein family able to assemble into molecular chaperone complexes. Here we describe an unusually large member of this family, termed URI, that forms complexes with other small-molecular weight PFDs and with RPB5, a shared subunit of all three RNA polymerases. Functional analysis of the yeast and human orthologs of URI revealed that both are targets of nutrient signaling and participate in gene expression controlled by the TOR kinase. Thus, URI is a component of a signaling pathway that coordinates nutrient availability with gene expression.  相似文献   
78.
To extend the analytical capabilities of the pyrolysis-gas chromatograph-mass spectrometry system that has been successfully utilized in the past as an integrated reaction, separation, and identification system to study label incorporation patterns in Maillard reaction products, a novel methodology was developed to analyze the composition of nonvolatile residues of the initial reaction products. This was achieved through a postpyrolytic in-situ derivatization technique using trimethylsilyldiethylamine. Application of this technique to the investigation of the nonvolatile products formed during pyrolysis of glucose alone and in the presence of glycine has indicated the formation of several redox-active hydroxylated benzene derivatives such as 1,2,3-trihydroxybenzene (pyrogallol), 1,4-dihydroxybenzene (hydroquinone), 1,2-dihydroxybenzene (catechol), and 2,5-dihydroxypyrazine. Labeling studies have indicated that the intact glucose carbon backbone was involved in the construction of the benzene ring of the hydroxylated benzene derivatives and that dimerization of glycine alone can lead to the formation of 2,5-dihydroxypyrazine.  相似文献   
79.
80.
Sleep  Bethany  Mason  Sean  Janik  Les  Mosley  Luke 《Precision Agriculture》2022,23(1):194-218
Precision Agriculture - Soil acidification is a major and growing concern in many cropping regions globally. Whilst spatial variability in acidification is a common consideration in the management...  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