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   172篇
  免费   15篇
林业   17篇
农学   27篇
基础科学   6篇
  14篇
综合类   35篇
农作物   8篇
水产渔业   37篇
畜牧兽医   35篇
园艺   3篇
植物保护   5篇
  2024年   2篇
  2023年   3篇
  2022年   1篇
  2021年   6篇
  2020年   11篇
  2019年   6篇
  2018年   6篇
  2017年   4篇
  2016年   10篇
  2015年   4篇
  2014年   12篇
  2013年   21篇
  2012年   10篇
  2011年   8篇
  2010年   15篇
  2009年   5篇
  2008年   10篇
  2007年   10篇
  2006年   8篇
  2005年   10篇
  2004年   5篇
  2002年   4篇
  2001年   3篇
  2000年   8篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1993年   1篇
排序方式: 共有187条查询结果,搜索用时 31 毫秒
181.
Abstract: The Vietnamese state's interaction with international capital has been influenced by the Communist Party's strategy to develop a ‘socialist market economy’ which aims to maintain the leading role of the state and its one party dominance while implementing economic reforms. This is at odds with alternatives proposed by neo‐liberal institutions such as the IMF and World Bank who favour a progression towards a more fully‐fledged market economy coupled with political pluralism. As a result, foreign investors and the Vietnamese government have had a turbulent relationship over the past decade stemming in large part from differing perceptions of a market economy and what foreign investment should entail. This paper depicts the principal issues that lay behind the restrictive policies toward foreign tour operators through a case study of their management and regulation in Vietnam throughout the 1990s. It is argued that foreign tour operators and Vietnamese tourism authorities perceive the role of international capital in tour operations quite differently. Over‐regulation has provided little space for foreign tour businesses to operate in a manner that has met their expectations, while government policies have been intent on ensuring that profits remain in the country. This paper also illustrates how social networks undermine top‐down government policy directives and allow foreign tour businesses to continue operating, albeit in a complex and insecure environment.  相似文献   
182.
Abstract: This paper offers an analysis of the relations between youth and the socialist state in contemporary Vietnam, which sheds light on the wider state–society relations. Amid rapid social changes brought about by economic liberalisation, the Vietnamese Communist Party and socialist state may no longer be the sole driving force that motivates young people. As they seek to be both in control of and in touch with youth, the leaders of the Party and state find themselves negotiating between maintaining their ideological integrity and accommodating the changing needs and desires of youth. An analysis of recent events demonstrates that youth are no longer merely a subject of political propaganda and mass mobilisation, but instead they have evolved to become an important social actor urging the leadership to further reform itself. As young people express a desire to embrace socioeconomic and cultural changes wrought by processes of marketisation and globalisation, the Party and state are actively reforming themselves not only to respond to young people’s desires and aspirations, but also to strengthen their political authority and leadership, and to consolidate their control and management of youth amid the new conditions of a market‐oriented society. Overall, this paper sheds light on the changes in what is considered to be the ‘strategic’ relationship between the state and youth, and the wider process of sociopolitical transformation in present‐day Vietnam.  相似文献   
183.
184.
越南与中国山水相连,气候相似。为了两国之间的食用菌技术能相互借鉴,详细介绍了越南的食用菌产业发展情况,为我国食用菌同行提供技术参考。  相似文献   
185.
Most agricultural production in central Vietnam relies on sandy soils distributed along the sea coast. Because of their low exchangeable potassium (K) and low cation exchange capacity (CEC), careful adjustment of K fertilization on these soils is needed to minimize K leaching. Quantity/intensity curves were established on 24 sandy soils from Thua Thien Hue Province from which K buffering capacity (PBC) was calculated and compared with basic soil properties. Potassium buffering capacity was found to correlate best with soil texture and only a little with humus content, although these two characteristics are responsible for CEC. A simple equation based on sand content, which is easier to determine than clay content, is proposed to calculate optimum exchangeable K level as a function of target K level in soil solution.  相似文献   
186.
越南黄麻黄脉病毒(Corchorus yellow vein Vietnam virus, CoYVV)是影响黄麻纤维品质和产量的双生病毒,其基因组含2个环状单链DNA(DNA-A和DNA-B)。鉴定黄麻双生病毒CoYVV并筛选抗病毒种质,不仅丰富对双生病毒分布和进化的认识,而且为黄麻抗性基因克隆奠定了基础。2018年福建省三明市福建农林大学洋中科教基地发现黄麻种质资源圃长果种黄麻福农5号疑似感染黄色花叶病。利用CTAB法提取该品种感病叶片DNA,通过PCR、滚环扩增及测序技术获得病毒基因组序列。通过同源序列比对和进化树构建明确该病毒与新旧世界双生病毒的关系。含有CoYVV DNA-A和CoYVV DNA-B侵染性克隆载体的农杆菌等比例混合,子叶注射法侵染具有代表性的7份长果种和7份圆果种黄麻品种(系),定期观察发病株数(病株率)并PCR检测接种黄麻的侵染率。PCR检测结果证实,福农5号病样感染了CoYVV,命名为CoYVV-FS。其DNA-A为2724 bp, DNA-B为2691 bp。进化分析表明,相较于旧世界菜豆金黄花叶病毒(begomoviruses), CoYVV-FS与新...  相似文献   
187.
There has been an increased interest in the use of vegetative barriers in acid‐infertile upland management systems in Southeast Asia. This paper analyses the experimental designs and policies in early‐1990s of using vetiver grass barriers (Vetiveria zizanioides L.) in microwatersheds with short‐rotation tree plantations in Vinh Phu Province, Vietnam. Four different mixed tree‐vetiver models on degraded Ferric‐Plinthic Acrisols are discussed. It is concluded that the institutional approach of demonstrating vetiver barriers as a model had a poor cost‐wise performance, and that the model itself did not address the underlying issues of land degradation due to uncontrolled harvest of organic matter from the forest floors. The institutional approach was tainted with price distortions and ‘disbursement‐oriented’ actions. Alternative and more flexible on‐farm approaches, using V. zizanioides or the indigenous leguminous shrub Tephrosia candida (Roxb.) DC as vegetative barriers, were found to be more cost‐effective and likely to have a higher rate of adoption among farmers. The institutional changes in land allocation policies (securing long‐term usufruct users and transfer rights of agricultural and forest land) that took place in Vietnam in the early 1990s, in combination with a reorientation of programme policies to support needs of individuals and farmers' households, are hypothesized to have contributed more to the ‘regreening’ of the hills, than any single approaches of technical barrier designs by the Swedish‐Vietnamese Forestry Co‐operation Programme (FCP) in northern Vietnam. Copyright © 2002 John Wiley & Sons, Ltd.  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