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   688篇
  免费   49篇
  国内免费   23篇
测绘学   20篇
大气科学   52篇
地球物理   34篇
地质学   157篇
海洋学   86篇
综合类   52篇
自然地理   359篇
  2024年   3篇
  2023年   6篇
  2022年   27篇
  2021年   33篇
  2020年   25篇
  2019年   24篇
  2018年   25篇
  2017年   54篇
  2016年   39篇
  2015年   40篇
  2014年   51篇
  2013年   25篇
  2012年   26篇
  2011年   25篇
  2010年   19篇
  2009年   22篇
  2008年   26篇
  2007年   24篇
  2006年   30篇
  2005年   13篇
  2004年   13篇
  2003年   21篇
  2002年   19篇
  2001年   20篇
  2000年   20篇
  1999年   16篇
  1998年   22篇
  1997年   21篇
  1996年   10篇
  1995年   14篇
  1994年   7篇
  1993年   6篇
  1992年   5篇
  1991年   8篇
  1990年   3篇
  1989年   8篇
  1987年   4篇
  1986年   2篇
  1985年   1篇
  1982年   2篇
  1980年   1篇
排序方式: 共有760条查询结果,搜索用时 15 毫秒
611.
黄宁生 《热带地理》1999,19(1):29-34
根据1991~1996年各市耕地面积的减少程度,广东省可分出轻微减少、中等减少、较严重减少和严重减少4类地区,它们在空间分布上具有半环带状结构的特点。环珠江口两岸的核心地区是耕地面积减少程度较严重和严重的地区,较偏远的粤东、粤西和粤北地区是耕地面积减少程度较轻微的地区。经济发展速度和水平是导致这一空间分布现象出现的主要原因。人口增长因素对耕地减少的影响作用不甚明显。  相似文献   
612.
长江经济带乡村功能区域差异及类型划分   总被引:2,自引:0,他引:2  
深度挖掘乡村功能价值是实现乡村全面振兴的重要途径,论文通过构建乡村功能综合评价指标体系,运用GIS和泰尔指数,揭示了2016年长江经济带130个市(区)乡村“生产-生活-生态”功能地区差异特征和差异来源,并进行功能分区。研究结果显示:① 长江经济带乡村功能具有显著的空间分异特征,农业生产功能强的区域集中在中游和下游平原地区;人居生活功能强的区域集中在下游省会及核心发展城市周边;生态保育功能强的区域在上游和中游山地丘陵地区。② 乡村功能总体区域差异来源于上、中、下游地区内部差异,农业生产功能在上游内部区域差异显著,人居生活功能和生态保育功能在下游内部区域差异显著,中游地区乡村功能整体区域差异较小。③ 基于研究结果将研究区划分农业生产区、人居生活区、生态保育区、人居生活-农业生产复合区、人居生活-生态保育复合区、生态保育-农业生产复合区、农业生产-人居生活-生态保育综合发展区和农业生产-人居生活-生态保育综合协调区8种功能类型区,可为完善长江经济带乡村功能的空间布局提供科学依据。  相似文献   
613.
The most prominent ‘victim’ of the global financial crisis in 2007/2008 has been Greece, which is, even now, in the middle of an economic and social storm that is threatening its economic and social cohesion and its membership of the Eurozone. Using the social well-being conceptual framework as a benchmark and exploiting the literature of composite indicators, the paper aims to assess and measure the regional impact of the crisis in a systematic and comprehensive way. Differing from most of previous studies, both at national and international levels, this study is based on the assumption that the effects of the crisis go far beyond economics and create a social crisis strongly associated with significant human and social costs that might transform Greece’s regional status and threaten its regional well-being, probably in a very unequal way. The main finding of the analysis is that although all regions were severely affected by the dynamics and intensity of the crisis, some regions were more affected than others, leading to ‘winners’ and ‘losers’. From a policy point of view, the results of this study have serious implications for crisis management, recovery policy actions and a country’s social cohesion, especially in Greece where austerity policy measures not only imposed considerable cutbacks in regional development policies but also ignored the spatial dimension of the crisis.  相似文献   
614.
湖南区域经济布局初探   总被引:1,自引:0,他引:1  
陈湘满 《热带地理》1996,16(2):160-166
本文在分析湖南经济布局的现状基础上,根据“据点开发,轴线开发,网络开发三阶段”理论,提出了湖南区域经济布局的战略构想,确立了发展极,产业带和经济发展圈,文章认为,对各产业带和经济发展圈的开发应实施非均衡协调发展战略,近期应选择湘东产业带,环洞庭湖经济发展圈和长株潭经济发展圈为重点开发地域。  相似文献   
615.
碳酸岩(carbonatite)一词自首次被提出至今已有一百多年的历史, 它是一种神秘而颇具争议的岩石类型。碳酸岩富含碳酸盐矿物, 通常与基性、超基性或碱性硅酸盐岩伴生形成碳酸岩-硅酸盐岩杂岩体, 具有独特的化学成分和矿物学特征并具有承载重要经济矿床的能力。在过去的几十年里, 碳酸岩的研究在岩石成因及岩浆起源、地球化学与地质年代学、高温高压实验、与碳酸岩相关的经济矿产、碳酸岩型稀土矿床中稀土元素的富集分异及成矿机理等领域取得了巨大进步。本文从碳酸岩的定义与分类、成岩背景与时空分布、岩石学特征及矿物组成、岩浆起源及演化过程以及与碳酸岩相关的矿产资源等方面对碳酸岩的研究进展进行了综述与评论, 提出从成因角度探索碳酸岩分类方案的必要性, 总结和梳理了我国目前发现的碳酸岩的产地和分布特征, 并认为碳酸岩岩浆与硅酸盐岩浆演化具有差异性, 应重视对碳酸岩岩浆演化过程中熔体-流体过渡阶段的研究。最后从文献计量学角度利用大数据和可视化手段对来自Scopus数据库的近十年以"carbonatite"为检索词的近千篇文献进行了可视化分析, 总结归纳了碳酸岩现阶段的研究热点, 并对未来碳酸岩的研究趋势进行了展望。  相似文献   
616.
There is currently an expansion of local energy initiatives, underpinned by the desire to reduce energy-related carbon emissions and in recognition of the importance of the local arena to achieving such change. Much of the research on these initiatives has been framed by a conventional economic approach, identifying barriers, drivers and incentives to explain their emergence (or not). Here a new economic sociological approach is taken which sees markets as socio-materially constructed and points to the importance of tracing exchange flows and determining modalities of valuation for such exchanges. Artefacts or market devices are seen to play a particular role in connecting actors and technologies within coordinating institutional arrangements and offer the potential for making innovative projects conventional. These aspects are explored in four international case-studies from Wales, Sweden, Germany and USA, mapping relations, identifying exchange flows, pinpointing how artefacts coordinate and showing the multiple modalities of valuation involved in each case. Conclusions concerning the importance of negotiation against a market backdrop and rendering exchange flows more certain are drawn.  相似文献   
617.
The realisation that the world’s oceans play an important role in climate regulation and many territory activities, notably food production, coupled with economic changes and the rapid advancement in ocean technology have seen a shift in the perception of the importance of marine resources. This increased focus on marine resources means that governments and policy-makers require accessible and reliable information regarding the role of the marine sector. This information may then be used to formulate new environmental and economic policy measures. The aim of this paper is to define, describe and quantify the value of the marine sector in Ireland. This paper outlines a methodology that provides a robust analysis of the Irish marine sector for 2007. It was found that in 2007 the Irish marine sector contributed €1.44 billion in GVA to the wider Irish economy and employed over 17,000 individuals in full time equivalents.  相似文献   
618.
Fisheries management around the world has experimented with regulations to promote privatization, in order to reach such multifaceted goals as ending overfishing and reducing economic inefficiencies. This review surveys a wide range of empirical experiences in different contexts around the world to help provide a fuller picture of potential and sometimes disparate consequences from privatization in general and new ways of organizing around fishing that can follow in the wake of such measures. Looking at the many different participants in the fishing industry—from crew, small-boat owners, to households and communities—as well as the diverse sociocultural contexts in which fishing takes place, enables a better understanding of who and what is impacted, how they are impacted, why and with what further consequences, such that communities come to be seen less oppositional to economy, but rather constituted by multiple scalar processes and by economic relations comprising different motivations and behaviors.  相似文献   
619.
The arid southeast region has been one of the areas with the oldest settlement in the Iberian Peninsula. Despite limitations imposed by lack of water and low soil fertility, a great number of dwellers have settled in this land for three thousand years thanks to its easy access to the commercial paths of the Mediterranean. The area is currently under great territorial and socioeconomic transformation activated by intensive agriculture through greenhouses and irrigation. The history of this territory offers a series of successful and downward cycles determined, from an ecological and economic point of view, by its integration in different stages of the globalization process. Most recently, in the 19th century an intensive deforestation process took place caused by the mining and iron industry. The deep economic and social crisis which followed the declining of this development model brought also about an ecological crisis. In the second half of the 20th century, negative environmental effects have continued and extended to the next generations with problems such as territorial saturation and aquifer depletion that characterize the new intensive agriculture under plastic. The current debate about the sustainability of this developmental model in such vulnerable environment can take advantage of some ecological lessons from the past.  相似文献   
620.
广西百色市县域经济区划研究   总被引:1,自引:1,他引:0  
戴德艺  曾令锋  黎忠 《热带地理》2007,27(3):254-258
通过对广西百色市各县级行政区经济发展情况的调查实证研究,选取16个典型同时具地方代表性的区划指标,建立县域经济区划指标体系;运用SPSS13.0软件提取4个主成分并计算其得分,在此基础上进行系统聚类分析,对百色市进行经济区划分,划分出3类县域经济区,进而得出百色市县域经济区划方案,以此为依据,确定百色市3类县域经济区分类发展目标。  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