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   101篇
  免费   0篇
  国内免费   4篇
测绘学   8篇
大气科学   2篇
地球物理   15篇
地质学   24篇
海洋学   6篇
天文学   1篇
综合类   5篇
自然地理   44篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   4篇
  2018年   2篇
  2017年   4篇
  2016年   3篇
  2015年   7篇
  2014年   7篇
  2013年   13篇
  2012年   5篇
  2011年   4篇
  2010年   6篇
  2009年   6篇
  2008年   6篇
  2007年   3篇
  2006年   3篇
  2005年   1篇
  2004年   3篇
  2002年   1篇
  2000年   1篇
  1999年   4篇
  1998年   3篇
  1997年   2篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1989年   1篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
排序方式: 共有105条查询结果,搜索用时 15 毫秒
31.
因重要的生态屏障功能和生态系统的脆弱性,中国北方农牧交错区可持续发展是一个重要科学问题。以典型北方农牧交错区——宁夏盐池县为例,借鉴"可持续性晴雨表"理论和方法,采用熵值法确定指标权重,对盐池县的可持续发展进行定量评价,并对影响可持续发展的因素进行了分析。结果表明:(1) 1990—2015年盐池县区域发展成就显著,人类福利指数保持持续增长的趋势,但生态系统福利指数稳定增长则始于2005年禁牧等生态政策的生态效益显现以后。(2)改善教育等公共服务水平、优化产业结构可以进一步提高人类福利,经济发展可以直接改善人类福利,经济发展的成果也可以通过生态政策加大对生态环境的投入从而改善生态系统福利。在此基础上提出了盐池县可持续发展的建议。  相似文献   
32.
温航南  蔡永香  张根  高静文  徐庶 《地理空间信息》2019,17(4):63-65,91,I0003
近年来,互联网与经济社会各领域紧密结合,产生了许多基于互联网的新产品。在这样的社会背景下,以问卷调查和座谈会等方式为基础,深入了解当代大学生的学习和生活需求,开发出了基于Android的公益文化平台"小桔灯"APP。系统采用移动终端/服务器(M/S)的架构模式,并调用百度地图Android SDK接口引入移动GIS技术,实现了线上阅读、线下评论、发起活动、地图显示活动以及聊天等功能,适合大规模的推广使用。  相似文献   
33.
Amongst many ongoing initiatives to preserve biodiversity, the Millennium Ecosystem Assessment again shows the importance to slow down the loss of biological diversity. However, there is still a gap in the overview of global patterns of species distributions. This paper reviews how remote sensing has been used to assess terrestrial faunal diversity, with emphasis on proxies and methodologies, while exploring prospective challenges for the conservation and sustainable use of biodiversity. We grouped and discussed papers dealing with the faunal taxa mammals, birds, reptiles, amphibians, and invertebrates into five classes of surrogates of animal diversity: (1) habitat suitability, (2) photosynthetic productivity, (3) multi-temporal patterns, (4) structural properties of habitat, and (5) forage quality. It is concluded that the most promising approach for the assessment, monitoring, prediction, and conservation of faunal diversity appears to be the synergy of remote sensing products and auxiliary data with ecological biodiversity models, and a subsequent validation of the results using traditional observation techniques.  相似文献   
34.
In a recent article in this journal (Butterworth and Richardson. A review of animal welfare implications of the Canadian commercial seal hunt. Marine Policy 2013;38:457–469), the authors argued that “generally accepted principles of humane slaughter cannot be carried out effectively or consistently during the Canadian commercial seal hunt”. The present review purports to show that these authors' conclusions were incorrect because they were highly selective in their treatment of the information available and made no attempt to consider other perspectives. In addition, their reliance on anecdotal video sequences to support some of their points was seriously flawed since a vast proportion of these sequences failed to meet fundamental criteria of scientific rigor. The article by Butterworth and Richardson [5] failed to provide an unbiased presentation of the available data and therefore did not bring further clarity to the debate on the Canadian commercial seal hunt.  相似文献   
35.
气象公益服务管理问题在社会主义市场经济条件下亟待强化。人们迫切需要对公益服务管理的地位与作用、主要内容、目标与原则以及领导体制等问题进行系统化的理论认识。  相似文献   
36.
As human codings of animals are often simultaneously legal and spatial, it may be useful to bring together the animal geographies literature and scholarship on legal geography. Through a case study set in southwest Finland, we explore the emergent and fraught entanglements of wolves, humans and sheep, characterizing the attempts at the regulation of the wolf as entailing tense biopolitical calculations between the contradictory legal imperatives of biodiversity and biosecurity. Under the former, the wolf must be made to live; under the latter, it may need to die. These are worked out in and productive of two territorial configurations: the everyday spaces of encounter (real or imagined) between wolf and human, and the propertied territories of sheep farming. While human imperatives and anxieties are clearly central to these spatializations, we also seek to give the wolf its due, noting its important role in the making of legal territories. The coproduction of law and space, we conclude, offers important ethical lessons for humans in their relations to the wolf, as well as directing us to the need for more capacious thinking regarding territory.  相似文献   
37.
A burgeoning geographic literature examines the politics of faith-based organizations (FBOs) in neoliberalized social welfare landscapes. This scholarship on FBOs in the “postsecular city” argues for a “messy middle ground” that explores moments of subversion and resistance, but avoids drawing a clear dividing line between those groups that advance neoliberal agendas and those that resist them. In this paper, I use a case study approach to examine the contours of “messiness” at the Open Door Community, an FBO in Atlanta. The subjectivity of FBO participants is argued as integral to the complex set of perspectives that pre-empt any easy classification of FBO politics. Multiple, conflicting subjectivities and power disparities characterize even FBOs with emancipatory agendas.  相似文献   
38.
对珠三角地区30种风水林植物群落进行了标准地调查,调查研究结果表明:珠三角地区风水林植物群落的植物种类共698种,隶属于124个科399个属。说明该地区风水林植物群落的植物种类丰富,而且是以樟科、茶科、桃金娘科、锦葵科、大戟科的植物为主。并在30种风水林类型植物群落全面进行调查研究的基础上,利用调查研究的成果,特别是风水林植物群落的树种组成和植被类型信息,进一步分析了风水林在生态公益林建设上的参考价值,提出了生态公益林建设可以借鉴的树种选择及混交组合。  相似文献   
39.
The goal of this study was to quantify the microbial load (enterococci) contributed by the different animals that frequent a beach site. The highest enterococci concentrations were observed in dog feces with average levels of 3.9 × 107 CFU/g; the next highest enterococci levels were observed in birds averaging 3.3 × 105 CFU/g. The lowest measured levels of enterococci were observed in material collected from shrimp fecal mounds (2.0 CFU/g). A comparison of the microbial loads showed that 1 dog fecal event was equivalent to 6940 bird fecal events or 3.2 × 108 shrimp fecal mounds. Comparing animal contributions to previously published numbers for human bather shedding indicates that one adult human swimmer contributes approximately the same microbial load as one bird fecal event. Given the abundance of animals observed on the beach, this study suggests that dogs are the largest contributing animal source of enterococci to the beach site.  相似文献   
40.
通过对《中国震例》中所辑宏观异常的统计分析认为,随着震级的增大,震前出现宏观异常的概率逐步增大,震级大的地震震前宏观异常数量也相对较多。宏观异常大多数为短期和临震异常,多数发生在距震中100km的范围内。在时间上,宏观异常开始时数量较少;随着时间的推进,异常不断增多;越近临震,异常数量越多,直到发震达到高潮。在地域上则表现出始于震中、然后向外围发展、最后震中爆发式增多的特点。  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