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   250篇
  免费   6篇
  国内免费   2篇
测绘学   2篇
大气科学   14篇
地球物理   3篇
地质学   28篇
海洋学   9篇
综合类   5篇
自然地理   197篇
  2023年   1篇
  2022年   11篇
  2021年   9篇
  2020年   9篇
  2019年   17篇
  2018年   7篇
  2017年   19篇
  2016年   8篇
  2015年   10篇
  2014年   15篇
  2013年   18篇
  2012年   18篇
  2011年   13篇
  2010年   3篇
  2009年   5篇
  2008年   13篇
  2007年   9篇
  2006年   8篇
  2005年   11篇
  2004年   9篇
  2003年   12篇
  2002年   7篇
  2001年   8篇
  2000年   4篇
  1999年   6篇
  1998年   3篇
  1997年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1985年   1篇
排序方式: 共有258条查询结果,搜索用时 234 毫秒
61.
铌主要应用于钢铁的生产,含铌钢材广泛应用于航空航天、海洋工程、汽车与交通、能源化工及工程机械等高端制造领域。中国是当前世界第一大铌资源消费国,供需矛盾极为突出,严重依赖国外资源。为保障中国铌资源供应安全与钢铁产业结构调整提供依据,本文基于恒等式原理构建了钢铁工业铌资源需求预测模型,参考发达国家钢铁工业铌资源消费经验,对中国钢铁工业铌需求进行了定量预测。研究结果表明:(1)中国铌工业和钢铁工业现代化程度明显落后于发达国家;(2)典型发达国家含铌钢产量占粗钢产量比例从最低值增长至最高值呈现出一定的规律性;(3)到2030年,中国钢铁工业铌资源需求将持续增长,2025年钢铁工业铌资源需求为3.3~5.2万t、2030年为4.0~7.1万t,中国铌资源供应安全面临严峻挑战。为此,本文建议持续扩大中国铌资源海外权益产量、提高国内储量、加强铌资源提取和二次资源回收技术研发来保障国内外铌资源稳定的供应,同时推进国内铌相关产业建设。  相似文献   
62.
地球外部扰动重力严密改化模型及分析检验   总被引:1,自引:0,他引:1  
直接积分模型是计算地球外部扰动重力的主要数学工具,将全球积分模型改化为局域积分模型是实现地球外部重力场赋值的前提条件.相比表层积分模型和向上延拓积分模型,Stokes积分模型要求的输入信息种类最少,故在减轻数据保障压力方面具有比较明显的优势.在实施Stokes积分模型工程化应用过程中,我们发现扰动重力径向分量积分模型从...  相似文献   
63.
Many migrants and their descendants make journeys to their homelands, and these visits form an important part of their ethnic identities, kinship relations and transnational connections. While such journeys have attracted increased attention recently, there has been relatively little exploration of the experiences that migrants’ children have when visiting their parents’ homeland, especially in an exile context when there has been little contact with the homeland for an extended period. This paper examines why the children and grandchildren of Estonian migrants to Australia journey to Estonia, and the experiences they have there. Motivations for visiting are complex and varied, and typically interweaved with parents’ stories, ethnic identities, kinship and curiosity. While visiting was a positive but emotional experience for some, it involved awkward encounters for others. This paper explores how these journeys led to respondents reconceptualising their senses of identity, belonging and home, and how many came to align their identities to both Estonia and Australia simultaneously.  相似文献   
64.
Alternative Places of Detention (APODs) are a new way of detaining asylum seekers in Australia. The establishment of APODs creates a new formal structure of belonging in Australia which challenges everyday practices of belonging and senses of belonging at the local and national scale. This paper examines practices of belonging which emerged following the establishment of the Inverbrackie APOD in Woodside, South Australia. Using a critical discourse analysis approach, informed by the insights of theories of performativity, this research explores the competing stories of two broadly defined groups (opponents and supporters of Inverbrackie) engaged in a dialogue about asylum seekers, refugees, immigration detention and belonging. While opposition to the APOD was vocal and frequent in the lead-up to the establishment of the detention centre, once the Inverbrackie APOD became operational opponents’ voices began to fade. On the other hand, supporters continued to say things—and more importantly continued to do things—to nurture belonging for asylum seekers in Inverbrackie, Woodside, and Australia.  相似文献   
65.
《The Journal of geography》2012,111(4-5):194-197
Abstract

Geographers, along with anthropologists and sociologists, have been debating the homeland concept as it applies in North America for decades. In recent years, the political ideology of the war on terror has added another dimension to this discussion. If the attention given to the concept by introductory textbooks is any indication, homelands are rarely discussed in our geography classrooms despite their critical relationship to our understanding of world and regional culture. This article calls for increasing our attention to homelands in the classroom as the concept serves as a readily available discussion topic with fruitful conclusions and student comprehension.  相似文献   
66.
Consumption practices involving disposal can provide important insights into how ‘being’ is accumulated. Analysis of 36 semi‐structured interviews with 13 individuals aged 59–70 in the Manawatu, Kapiti, Rangitikei and Horowhenua regions of the North Island in New Zealand illustrates how practices of gifting, ridding and passing on goods as legacy contribute to the production of familial and individual subjectivities. The research revealed that practices of disposal are performative, with both the absent presence of the objects placed away and the practices by which this occurs having agentic effects. The places that objects were assumed to occupy in the real and imagined lives of others and the moving of things away contributed to older adults' identities as caring parents, productive citizens and individuals of significance. Disposal practices consequently enabled participants to stabilise and order parent and child relations and one's relative position in the life course.  相似文献   
67.
身份认同是文化和社会研究中一个重要的概念,是指个人在特定的社会文化语境中逐步确定自己在这一社会文化秩序中的个体角色,从而形成完整的自我认知与自我定义。而地方认同则是对某个地方作为社会角色自我感知的一部分的认知,通过地方的意义来形成对个人或社会群体文化与身份的认同。以地方与身份认同作为主要的研究维度,将广州独特的“艺术村...  相似文献   
68.
Home movies provided valuable insights into childhood experiences during much of the twentieth century. Contrasting footage of children in rural and urban setting in Northern England between c.1937 and 1970, viewed through the cinematic gaze of two male amateur film-makers underpins this discussion of childhood geographies in the past. Issues explored in the paper include the social construction of childhood, power relations and visual representation of children, and the role of home movie-making in shaping memories and constituting ideas and ideologies about family and children.  相似文献   
69.
ABSTRACT. In pursuit of its foreign‐policy goals, the administration of President George W. Bush has attempted a dramatic reshaping of the vision of the Middle East in the American mind. References to the “new” or “greater” Middle East now include countries far outside traditional concepts of the region, including those in West Africa, Southeast Asia, and Central Asia. The administration argues that this region is defined not by cultural (Arab) or religious (Islam) characteristics but by a lack of democracy; hence a grand strategy is needed to execute reform. This article examines current U.S. efforts to achieve reform in the region, the components of the ideological construction of the New Middle East, the perceived role of Iraq, Turkey's potential role as a “model” for the region, and responses from the region to current U.S.‐led reform efforts.  相似文献   
70.
We are concerned here with the notion of space as a primary condition for building social relations. From this stand, we have created two analytical matrixes that can help us characterize two modes: that of ‘being-there-in-space’ and that of ‘being-of-the-space’; the nomospace and the genospace. While the nomospace is characterized by ‘cold’ connotations, which are ideally defined as a result of a logical option, the genospace is mainly characterized by emotional or ‘warm’ connotations, which originate from a feeling of shared nature and common destiny. We believe that these matrixes could help us to identify the meanings of some behaviours and, therefore, make us more capable of interpreting many dynamics that occur in modern societies. The importance of geography is justified by the existing relationship between these behaviours and their proper spatial form. This revised version was published online in July 2006 with corrections to the Cover Date.  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