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   234篇
  免费   11篇
  2023年   2篇
  2020年   4篇
  2019年   10篇
  2018年   10篇
  2017年   8篇
  2016年   10篇
  2015年   4篇
  2014年   10篇
  2013年   39篇
  2012年   11篇
  2011年   10篇
  2010年   13篇
  2009年   11篇
  2008年   17篇
  2007年   11篇
  2006年   7篇
  2005年   13篇
  2004年   10篇
  2003年   5篇
  2002年   5篇
  2001年   3篇
  2000年   8篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1991年   1篇
  1990年   1篇
  1988年   2篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1978年   1篇
排序方式: 共有245条查询结果,搜索用时 15 毫秒
21.
"两个飞跃"是邓小平为中国社会主义农业改革和发展设计的伟大纲领。从对"第一个飞跃"的肯定和支持,到对"第二个飞跃"的探索和展望,邓小平始终坚持历史发展的辩证法,不仅科学地规划了"两个飞跃"渐次实现的现实道路,而且为我们积极发展现代农业、扎实推进社会主义新农村建设提供了重要的方法论依据,具有重大而深远的现实意义。  相似文献   
22.
Differences in dental health of prehistoric human groups are commonly attributed to specific subsistence practices, whereby food foragers generally have a lower incidence of dental disease than agriculturalists. Dental health was assessed on a sample of 135 human skeletons from northwest Mexico that date to the Early Agricultural period (1600 BC–AD 200), which coincides with the initial introduction of domesticated cultigens into the region c. 2000 BC. High rates of dental caries (13.5%) and antemortem tooth loss (17.6%) encountered in these prehistoric forager‐farmers from the Sonoran Desert were determined to be the result of the consumption of highly cariogenic local wild resources such as cactus. These patterns mask the degree of reliance on agriculture in the area and highlight the importance of constructing local nutritional histories to better understand the diversity of human diets and their relationships to health and disease. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
23.
Cet article présente les caractéristiques et l'évolution de la propriété foncière, du marché foncier et des systèmes de production agricoles en Lombardie orientale au 19e siècle. L'auteur analyse les impacts sur l'exploitation de la terre de la substitution des propriétaires fonciers nobles par des bourgeois; des maladies du ver à soie et des vignobles, de l'arrivée des grains américains moins chers; de l'utilisation d'engrais chimiques et d'équipements modernes. Il montre que si la petite propriété représente toujours près d'un tiers du total et que la magnanerie et la viticulture diminuent, il est relevé une croissance des cultures céréalières et fourragères et des dépenses consacrées aux innovations technologiques. Il signale la rationalisation des cultures, l'amélioration des rendements et de la qualité des récoltes ainsi que des revenus non déclarés pour éviter les impôts et explique pourquoi les investisseurs préfèrent les petits aratori comportant des mûriers et des vignobles. Enfin, il donne à voir que l'organisation des exploitations reste liée au degré de risque pris par le propriétaire (la rente fixe garantie par le bail à ferme payé en argent ou une gestion directe de la propriété) et aux cultures (la présence des vignobles et de la magnanerie favorisant les sharecropping contracts).  相似文献   
24.
吕立峰  王锦辉 《攀登》2008,27(6):16-19
中国农村的现代化实践是一场以马克思主义为指导的探索活动。本文力求将马克思主义关于农民问题的相关理论和实证分析结合起来,论述了马克思等关于农民理论的立足点及其发展,分析了农业集体化道路及其挫折,通过对经典理论的重新审视,进而得出对社会主义农业现代化道路的启示.  相似文献   
25.
James Arthur Prescott was a prominent soil scientist whose career responded to an increasingly complex, recognisably Australian web of interpenetrating spatial scales, served to promote revolutionary global advances in his chosen field, and in the process negotiated the blurred boundaries between ‘pure’ and ‘applied’ research. Encounters with this instructive life suggest that, while resolutions of pivotal anxieties might turn on ineluctably personal qualities, they also reflect a dynamic interplay between international, imperial, national and state contexts. Prescott's innovative contributions to soil science, fruits of a tenaciously consolidated career, influenced resource appraisal and environmental management across a prodigious continental expanse. A sustained focus on local and regional development brought him into contact with a wide range of contemporaries, including pioneering geographers, and culminated in his election to a Fellowship of the Royal Society.  相似文献   
26.
With climate change projections indicating a likely future increase in extreme weather phenomena, it is an urgent matter to assess the effect of drought on civil conflict. However, studies of this relationship so far provide inconclusive findings. One reason for this inconsistency is that existing research has not sufficiently taken into account the local vulnerability and coping capacity that condition the effect of drought. In particular, the exposure to sustained droughts undermines alternative coping mechanisms of individuals. Moreover, reliance on rainfed agriculture for income and food provision renders individuals particularly vulnerable to droughts. Based on these observations, I suggest that areas experiencing sustained droughts or depending on rainfed agriculture are more likely to see civil conflict following drought as individuals in these regions are more likely to partake in rebellion in order to redress economic grievances or to obtain food and income. Using novel high-resolution data on civil conflict events in Sub-Saharan Africa from 1989 to 2008, this paper evaluates the relationship between sustained drought, rainfed agriculture and civil conflict violence at the subnational level. In line with the argument, areas with rainfed croplands see an increased risk of civil conflict violence following drought. There is also some support for the proposition that areas experiencing sustained droughts have a higher risk of conflict. The results are robust to a wide range of model specifications.  相似文献   
27.
Abstract

Food security has guided Russia’s food policy since 2010. The article examines the impact of food security policy on the food system. The Russian model of food security combines government intervention in the form of assistance for domestic production while simultaneously restricting market access. Food security does not appear to have a deleterious impact on the food system. We measure impact on four dimensions. Financial support for agriculture continues to increase in nominal rubles. In food production, the beef and dairy branches continue to lag, but increased grain production has made Russia a global leader in grain exports. Average per capita food consumption improved, although the poor consume much less, and the decline of the ruble affects the way Russians shop. The largest impact of food security has been on food trade. Food security policy has brought food to the forefront as an instrument of foreign policy. Food trade is politicized, witnessed by the food embargo against the West and food import bans against Turkey and Ukraine.  相似文献   
28.
王有邦 《人文地理》1996,11(Z2):12-15
本文在分析山东农业发展的优劣势、现状、基本特点及存在问题的基础上,探讨了其农业发展的总体战略与应采取的基本措施。  相似文献   
29.
The Romanian dairy-farming sector is marked by subsistence and semi-subsistence farms. Through consolidation in the retail and dairy sector, the price pressure has moved toward producers of raw milk. Through new European, national and private standards and global actors tapping into the Romanian market this development is reinforced. At the same time, the smallholders, formerly accepted to be acting on an informal level, cannot access their main distribution channels anymore. Additionally, through several legal constraints being developed since Romania’s accession to the European Union, the smallholders are neither able to issue invoices, nor to access certain subsidy programmes as they are not considered juridical persons. This article focuses on the consequences of this disembedding of farmers. The peasants are pushed toward informal activities or value chain positions, in which they do not have any bargaining power with the globally sourcing intermediaries they are supplying. The contemporary approaches of global value chains and global production networks build the theoretical framework for the study. Here it is argued that informal markets must be included into these approaches more concisely.  相似文献   
30.
中国发展观光农业的资源分析及对策   总被引:39,自引:1,他引:38  
观光农业是一种新兴的农业与旅游业交叉的高效产业。随着城市经济的发展,观光农业将成为城郊休闲旅游的主要形式。本文分析和讨论了我国发展观光农业的意义、资源优势、存在问题及对策。  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