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   173篇
  免费   17篇
  国内免费   5篇
测绘学   12篇
大气科学   11篇
地球物理   6篇
地质学   24篇
海洋学   8篇
综合类   16篇
自然地理   118篇
  2023年   5篇
  2022年   10篇
  2021年   17篇
  2020年   11篇
  2019年   9篇
  2018年   14篇
  2017年   11篇
  2016年   15篇
  2015年   11篇
  2014年   10篇
  2013年   10篇
  2012年   15篇
  2011年   4篇
  2010年   5篇
  2009年   6篇
  2008年   5篇
  2007年   6篇
  2006年   9篇
  2005年   4篇
  2003年   5篇
  2002年   2篇
  2001年   2篇
  2000年   5篇
  1999年   2篇
  1995年   1篇
  1988年   1篇
排序方式: 共有195条查询结果,搜索用时 15 毫秒
91.
This paper examines the status of traditional agriculture in two areas of Azilal province in the Atlas Mountains, seeking to identify what is needed to counter any breakdown in livelihood strategies and improve the quality of life enjoyed by the farmers. Irrigated terrace agriculture is an important part of livelihood strategies in the areas studied and has the potential to be more productive and sustainable. In some areas it is reported to be endangered by socioeconomic changes and highland land degradation caused by excessive shifting cultivation, sheep and goat grazing, and charcoal production. Field visits made during summer 1998 to establish the condition of irrigated terrace and runoff agriculture and the factors affecting it showed that in at least one of the villages supportive social capital has ensured that challenges are being met and beneficial innovations are being made. Considerable variation in success was evident from community to community, with some farmers maintaining adequate lifestyles and innovating, while in other communities prospects are less promising. The effects of structural adjustment have clearly been felt and may also have triggered some of the highland degradation and difficulties, which clearly threaten some irrigated terrace agriculture and other livelihood practices.  相似文献   
92.
新冠肺炎(COVID-19)疫情给农户生计发展带来了重大风险,而生计资本是抵御疫情冲击、阻断返贫危机的关键。论文以重点疫区湖北省及周边地区为研究区域,基于可持续生计分析框架,从生计资本“结构—存量”多维视角出发,采用内生转换回归模型分析疫区465户农户生计资本对疫情风险的抵御作用。研究发现:① 重点疫区农户生计资本总量不高,疫情可能诱发生计脆弱性但不是唯一要素,基层公共卫生建设也极为重要;② 生计资本对疫情风险有显著抵御效应,人力资本维度作用更为凸显,物质资本占比过高反而会削弱疫情应对能力;③ 农户生计资本结构与存量分布不均,家庭劳动力、健康投入、财富积累、居住环境、社会阅历等是核心要素;④ 疫后生计恢复主要依赖于人力与金融资本的积累,而帮扶关键在于应急和兜底保障,要根据区域农户生计特征拟定差异化的疫情常态防控举措。  相似文献   
93.
基于可持续生计框架,采用统计分析和深度访谈法,将研究区293户农户按生计活动类型划为牧户(牛户、羊户、牛羊户和马户)、种植户和非农户,并按农户生计资产总值进一步划为高、中、低3个等级类型,进而分析了不同类型和不同等级农户的生计资产与生计活动及方式的依存关系。研究发现:各类农户的生计资产均值差距明显,牧户最高,为0.37,种植户为0.25,非农户为0.21;牧户的劳动力、草场、牲畜、现金、贷款等资产均值最高,种植户的农机和耕地资产均值最高,非农户的社会资产均值最高。目前,半农半牧区的农户仍然以旱作种植业和草地畜牧业为主要生计,但农牧业生产均面临较大的资源环境压力;非农户只占15.3%,且面临非农就业机会不足、个人技能缺失、语言障碍和务农时间与用工季节的冲突。最后,提出了提高农户收入和改善农户生计的对策建议。  相似文献   
94.
Human–wildlife conflict is one of the major challenges in conservation biology. Here, we investigated the human–wildlife conflicts and their impacts in and around Chebera-Churchura National Park, Ethiopia. We conducted semistructured interview for 300 people and five focus group discussions from November 2010 to January 2011. In addition, scats of 60 spotted hyenas were collected and analyzed. Totally, 12 carnivores, 6 herbivores, and 2 primate species posing a significant problem were identified. Intensive human–wildlife conflict was observed in Churchura, Sere, and Chebera villages which were very close to the park. The carnivore’s attacks during 2007–2011 had caused about 30.49% of livestock losses. The overall economic loss by wildlife attacks was estimated to be US$ 75,234 (US$ 83/household/year). Scat analysis confirmed a substantial contribution (59%) of livestock to spotted hyena’s diet. Thus, combined strategies like improving livestock husbandries and strengthen the capacity of managers are imperative to mitigate the problems.  相似文献   
95.
生计安全研究的可视化分析   总被引:2,自引:2,他引:0  
苏飞  应蓉蓉  黄建毅  李博  朱赛颖  莫潇杭 《地理科学》2018,38(12):2058-2065
以Web of science 核心库中1991~2016年间收录主题为“livelihood security”的文献为基础,应用CiteSpace软件,采取突现词分析、关键词共现分析、文献共被引分析等方法对生计安全研究进行可视化分析。研究发现,干旱、健康、妇女、艾滋病、粮食安全、难民等是生计安全研究的前沿领域;生计安全研究热点主要包括生计结果类、生态环境类、生计策略类和重点地区类;生计安全研究的知识基础主要包括粮食安全、海洋资源、气候变化适应性等研究领域;从研究内容来看,中国生计安全研究主要包括自然资源与粮食安全、自然灾害与生计安全、快速城镇化与生计安全、气候变化与生计安全等4个方面。  相似文献   
96.
杨小泊 《城市地质》2008,3(1):45-47
完善和加强地质环境监测单位设备管理,提高设备使用效益,保障设备的安全和完整,防止国有资产流失,对促进地质环境监测的健康发展具有重要意义。本文分析了目前地质环境监测单位设备的特点、设备管理中存在的问题,进而提出了相应的对策建议。  相似文献   
97.
Traditional farming practices conform to sustainable rural livelihoods, while agricultural modernisation tends to undermine these practices through various perturbations. A case study in Tengchong County (western Yunnan, China) shows that transformation of traditional alder (Alnus nepalensis) and dry rice (upland rice) rotational farming to introduced Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations leads to localised water scarcity and soil fertility decline. While farmers are aware of ecological sustainability of traditional farming, they prefer Chinese fir forestry because it is less labour-intensive, has a high market value, and releases time for profitable off-farm work. Farmers adapt to economic liberalization by planting high value crops and trees. However, alternatives to make local agricultural production more profitable through competitive business strategies, cooperative approaches, innovations in integrating high value crops and ‘downstream’ processing for sustainable rural livelihoods have been overlooked largely due to poor information availability and lack of organisational framework.  相似文献   
98.
为适应建立市场经济体制的要求 ,广西地勘单位必须进行资产重组。要结合国家的产业政策 ,着力培育支柱产业和优势企业 ,把推进领导班子建设放在重要位置 ,在机构改革的关键时期实现平稳过渡  相似文献   
99.
With rapid urbanization and the socio-economic transformation,cultivated land protection has gradually become a major concern in China. The economic compensation plays a crucial role in promoting cultivated land protection and improving the utilization ratio of cultivated land. Farmer household's satisfaction has a great influence on the effectiveness of compensation. Therefore,households' willingness to select the economic compensation pattern for cultivated land protection has been considered and re-examined. By employing Participatory Rural Appraisal method (PRA),3 villages and 392 households were investigated and sampled in mesa and hilly areas of Chongqing. Then a quantitative analysis framework of household livelihood hexagon has been developed to quantify the livelihood assets of different farmer households. Finally,the Gray Relation Model and Probit Regression Model have been employed to explore the coupling relationship between the household livelihood assets and their compensation pattern options. The results show that there are both qualitative and spatial heterogeneity in household livelihood assets. We found that the inequality of livelihood assets is evident for five household types. There is a spatial trend that the higher the elevation,the less livelihood assets are. In addition,their options of economic compensation pattern vary from Chengdu Pattern to Foshan Pattern due to their difference in livelihood assets and difference in location. In detail,there is a coupling relationship between household livelihood assets and their compensation pattern;negative correlation is observed between natural assets value and household pattern options,while the other livelihood assets have positive impacts on compensation pattern in varying degrees,which from the top are psychological assets,human assets,physical assets,financial assets,and social assets respectively. A conceptual compensation pattern system has been designed to meet the demands for farmer households mainly according to their shortage in livelihood assets. In addition,compensation method,compensation standard,the basis of compensation and the source of compensation funds have been proposed accordingly.  相似文献   
100.
生态补偿项目对农户生计的影响关系到项目可持续性及社会公平性,近年来已成为生态补偿领域的研究热点。本文通过调查退牧还草工程前后甘南黄河水源补给区农户生计资本及生计方式的变化,分析了生态补偿项目对农户生计的影响,提出应建立多样化、差别化的补偿方式,提高项目区农户的生计能力,确保生计安全。研究发现:①生态补偿后农户生计总资本显著增加,除自然资本下降外,其余各类生计资本均增加,但纯牧区、半农半牧区、农区农户的生计资本变幅不同;②生态补偿后农户生计方式发生显著变化,从事非农活动的农户比例增加,生计多样化指数增加,其中农区农户的非农化程度及生计多样化指数的增幅均高于纯牧区与半农半牧区。  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