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   259篇
  免费   15篇
  2023年   1篇
  2021年   2篇
  2020年   4篇
  2019年   19篇
  2018年   16篇
  2017年   10篇
  2016年   13篇
  2015年   8篇
  2014年   17篇
  2013年   44篇
  2012年   12篇
  2011年   12篇
  2010年   12篇
  2009年   3篇
  2008年   4篇
  2007年   4篇
  2006年   6篇
  2005年   5篇
  2004年   9篇
  2003年   4篇
  2002年   8篇
  2001年   7篇
  2000年   3篇
  1999年   5篇
  1998年   7篇
  1997年   4篇
  1996年   3篇
  1995年   3篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1981年   2篇
  1980年   4篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有274条查询结果,搜索用时 15 毫秒
21.
The Himalayas are among the world's youngest mountain ranges. In addition to the geologic processes of mountain building and erosion, they are also highly vulnerable to human influenced change, occurring at local, national, regional, and international scales. A photo-elicitation methodology is employed to show how residents perceive those changes from historical perspectives, as well as their current conditions and impacts on their daily lives. Nepal's Khumbu region has undergone major social and environmental transformations since the 1960s when international trekking first began to influence the area's economy. The current perceptions of Khumbu residents of these changes are assessed through photo-elicitation interviews. Their responses are placed in the historical context of: (1) institutional and political changes, most of which have been driven by national government policies; (2) social and economic changes, for which the tourism economy has been central; and (3) environmental changes, reflecting the impacts of resource management and climate change. The mostly positive perceptions of Khumbu residents toward how their region has changed reflects general improvements in the physical and cultural landscapes of the Khumbu over time, as well as its continuing geographic isolation, which has helped to slow the rate of globalization, while also keeping the region a dynamic and popular tourist destination.  相似文献   
22.
Julie Cupples  Kevin Glynn 《对极》2014,46(2):359-381
Hurricanes Katrina and Felix made landfall in 2005 and 2007 on the Gulf Coast of the US and the Atlantic Coast of Nicaragua respectively. Despite many economic, political and cultural differences between these two sites, they share a number of interesting similarities. Their inhabitants are subject to similar modes of racialized Othering and internal colonialism, and both places have vital links with the transnational cultural consciousness that Gilroy referred to as the Black Atlantic. Katrina and Felix also occurred at a time when centralized forms of media are increasingly perceived to be in crisis. This crisis is creating new spaces for the development of alternative ways of knowing, watching and making media. This paper draws on recent literature on decolonization by Mignolo, Escobar, Quijano and others to explore the prospects for decolonizing energies within the new media environment and a context of devastation wrought by neoliberalism and disaster. This research examines disasters in/and the new media environment, and suggests that activists should understand the distinctions between mainstream (or corporate) and alternative media, between top‐down and grassroots media, and between “old” and “new” media, in relational and non‐categorical rather than absolute terms. These media realms should be engaged from an awareness of how they interact with and impact upon one another. This research also suggests that disasters must be understood as ongoing and open‐ended events embedded within historical, social, cultural, economic and political processes and systems. Media, policymaking and emergency management practices that are informed by an awareness of this complex embedding, and which are therefore able to take a long‐term view of the unfolding of disasters, will be best equipped to engage effectively, and in democratically responsive ways, with disasters and in particular with the needs of those populations most vulnerable to their impacts.  相似文献   
23.
The Nasca culture of the south coast of Peru developed during the first millennium ad and is known internationally for its elaborately decorated polychrome pots. Despite decades of iconographic analysis, little is known about the more technological aspects of Nasca pigment production and application. We present results from a pilot study on iron isotopes as a potential line of inquiry into the differences between red and black pigments in Nasca pigments. As well, we conduct a small firing experiment to examine potential changes in isotope composition. Our analyses show three significant results. First, firing does not change the isotopic ratios of Fe in pigments. Second, red and black pigments show differences in their iron isotope composition, which relate to differences in the minerals used to make the different colors. Third, naturally available hematite samples show greater isotopic variation than pigment samples, suggesting that people selected a limited range of iron oxides to produce pigments.  相似文献   
24.
One of the defining objectives in location science is to maximize dispersion. Facilities can be dispersed for a wide variety of purposes, including attempts to optimize competitive market advantage, disperse negative impacts, and optimize security. With one exception, all of the extant dispersion models consider only one type of facility, and ignore problems where multiple types of facilities must be located. We provide examples where multiple-type dispersion is appropriate and based on this develop a general class of facility location problems that optimize multiple-type dispersion. This family of models expands on the previously formulated definitions of dispersion for single types of facilities, by allowing the interactions among different types of facilities to determine the extent to which they will be spatially dispersed. We provide a set of integer-linear programming formulations for the principal models of this class and suggest a methodology for intelligent constraint elimination. We also present results of solving a range of multiple-type dispersion problems optimally and demonstrate that only the smallest versions of such problems can be solved in a reasonable amount of computer time using general-purpose optimization software. We conclude that the family of multiple-type dispersion models provides a more comprehensive, flexible, and realistic framework for locating facilities where weighted distances should be maximized, when compared with the special case of locating only a single type of facility.  相似文献   
25.
26.
This article seeks, first, to respond to some of the more pertinent points raised in the 'new regionalism' debate, like how 'regions' are constituted and how the 'regional scale' relates to other scales in what I call the 'multi-level polity' in the European Union. Second, it explores the potential of regional innovation strategies in the context of less favoured regions and argues that they have an important role to play in regional renewal even though their impact to date has been modest. Finally, it suggests that the most limiting aspect of the 'new regionalism' debate is that virtually all contributions tend to confine themselves to an inordinately narrow metric of development and, wittingly or not, this tends to conflate what is instrumentally significant with what is intrinsically significant, a conflation of means and ends  相似文献   
27.
This article considers suburban development in Australia through the lens of its second largest city, Melbourne. Contemporary urban policies have focussed on the low densities within Australia's capitals and tried to achieve sustainability through urban consolidation policies. The article argues that these policies are often based on a distorted understanding of the relationship between housing markets and labour markets in Australia's large metropolises. The analysis of suburban development in Melbourne shows that suburban development involves complex links between changes in housing and job location and that urban sustainability policy needs to include actions designed to change the distribution of employment as well as the location and density of housing. The article shows that the vast spread of the Melbourne population masks closely linked regional labour and housing markets.  相似文献   
28.
29.
Palynology, radiocarbon dating, and open-section stratigraphies from archaeological trenches are used to examine the impact of human activity around the time of Norse landnám on vegetation and landscape associated with a small farm (Ø34) in the Qorlortoq valley, Eastern Settlement, Greenland (61° N 45° W). Peat deposits from a mire abutting the Norse ruins revealed a discontinuous palaeoenvironmental record containing a possible hiatus from ca. AD 410–1020. Palaeovegetational data were recovered either side of this period. Pollen assemblages suggest that open Salix scrub dominated the landscape during the pre-settlement phase. The later phases of landnám resulted in the creation of hay fields and heavily-grazed grassy heath. Site abandonment is reflected by a re-expansion of Salix. This occurs shortly before the onset of deposition of a Sphagnum peat, dated to cal AD 1420–1630 (2σ) and reflecting an increase in mire surface wetness, probably in response to a deteriorating climate. Radiocarbon dates were obtained on peat and plant macrofossils sampled from either side of the proposed hiatus at two different but closely-spaced (<20 m) locations across the mire. These produced significantly different dates for the cessation of peat formation in the pre-landnám period (cal BC 2130–1770 and cal AD 240–410 respectively), but near-synchronous dates for the recommencement of peat growth (cal AD 890–1150 for peat and a probably more reliable interval of cal AD 1020–1190 based on plant macrofossils). It is suggested that this hiatus may represent the first direct evidence for peat cutting in Norse Greenland.  相似文献   
30.
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