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   84篇
  免费   4篇
林业   3篇
  29篇
综合类   12篇
农作物   24篇
水产渔业   2篇
畜牧兽医   8篇
园艺   5篇
植物保护   5篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2016年   3篇
  2015年   2篇
  2014年   1篇
  2013年   3篇
  2012年   4篇
  2011年   4篇
  2010年   5篇
  2009年   2篇
  2008年   13篇
  2007年   8篇
  2006年   5篇
  2005年   2篇
  2004年   5篇
  2003年   1篇
  2002年   3篇
  2000年   1篇
  1994年   2篇
  1993年   5篇
  1992年   1篇
  1991年   2篇
  1988年   4篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1979年   1篇
  1961年   1篇
  1925年   1篇
排序方式: 共有88条查询结果,搜索用时 15 毫秒
1.
The original article to which this Correction refers was published in Pest Management Science 58 (7): 649–662 (2002).Copyright © 2004 Society of Chemical Industry  相似文献   
2.
3.
The factors responsible for widespread declines of grassland birds in the United States are not well understood. This study, conducted in the short-grass prairie of eastern Wyoming, was designed to investigate the relationship between variation in habitat amount, landscape heterogeneity, prey resources, and spatial variation in grassland bird species richness. We estimated bird richness over a 5-year period (1994–1998) from 29 Breeding Bird Survey locations. Estimated bird richness was modeled as a function of landscape structure surrounding survey routes using satellite-based imagery (1996) and grasshopper density and richness, a potentially important prey of grassland birds. Model specification progressed from simple to complex explanations for spatial variation in bird richness. An information-theoretic approach was used to rank and select candidate models. Our best model included measurements of habitat amount, habitat arrangement, landscape matrix, and prey diversity. Grassland bird richness was positively associated with grassland habitat; was negatively associated with habitat dispersion; positively associated with edge habitats; negatively associated with landscape matrix attributes that may restrict movement of grassland bird; and positively related to grasshopper richness. Collectively, 62% of the spatial variation in grassland bird richness was accounted for by the model (adj-R2 = 0.514). These results suggest that the distribution of grassland bird species is influenced by a complex mixture of factors that include habitat area affects, landscape pattern and composition, and the availability of prey.  相似文献   
4.
From 1983 to 1985, a network of agroforestry research trials was established at six localities throughout Victoria. This paper describes experimental designs and establishment procedures used at the trial sites. The overall aim of the research program is to provide definitive information on the costs and benefits of a wide range of agroforestry combinations. Accordingly, trials were established at the following locations to test a total of 93 tree species grown in combination with specific types of agriculture:
  1. Carngham (near Ballarat) — sheep grazing andPinus radiata D. Don (radiata pine);
  2. Hamilton (several sites) — sheep grazing and mixed tree species;
  3. Kyabram — irrigated pastures andEucalyptus grandis W. Hill ex Maiden (flooded gum);
  4. Rutherglen — cereal cropping and shelterbelts;
  5. Myrtleford — irrigatedMentha spp. (mint) and two clones ofPopulus spp. (poplar); and
  6. Neerim South (near Warragul) — cattle grazing and mixed tree species.
Conventional and systematic experimental designs have been used in setting up these trials, which in total constitute the most comprehensive agroforestry research in Australia. This paper describes these trials in detail, and stresses the importance of their continued expert management, so that the full benefits of the work can be realised for rural Victoria.  相似文献   
5.
Bread is consumed all over the world. However, so far, production of large volume bread is only possible with wheat. Alternatives, such as oats, are less suitable but this is partly due to the lack of knowledge about their functionality for other purposes than porridge, which is their most common use. Existing standard tests for the dough making characteristics of wheat flour are not suitable for oat flour, hampering research to optimize oats for bread-making purposes. We therefore set out to develop a test to evaluate oat in relation to mixing and dough making properties using wheat as a model. It was possible to reproduce the profile of various qualities of wheat flour using mixtures of oat flour and gluten in different proportions. Our standard test was based on a dough system composed of 87.2% oat flour and 12.8% gluten and it presented similar properties to a wheat flour with regard to resistance to extension. This dough system was sensitive and reliable (coefficient of variation lower than 10%) for detecting differences among oat cultivars, and it can be used to screen oat varieties and individual oat components in relation to relevant properties for bread-making purposes.  相似文献   
6.
After disappointing results from all efficacy trials conducted to date, the field of microbicides research now faces substantial challenges. Poor coordination among interested parties and the choice of nonvalidated scientific targets for phase III studies have hampered progress and created mistrust about the use of microbicides as a method to prevent HIV-1 sexual transmission. Although new promising strategies are available, there will need to be serious reappraisals of how decisions are made to advance the next generations of candidates into clinical trials, and the use of appropriate animal models in this process will be critical.  相似文献   
7.
8.
9.
Regulation in vitro of metallothionein gene binding factors   总被引:19,自引:0,他引:19  
  相似文献   
10.
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