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   119篇
  免费   10篇
  国内免费   10篇
测绘学   7篇
大气科学   3篇
地球物理   18篇
地质学   29篇
海洋学   3篇
综合类   6篇
自然地理   73篇
  2022年   1篇
  2021年   3篇
  2020年   2篇
  2019年   5篇
  2018年   3篇
  2017年   7篇
  2016年   8篇
  2015年   8篇
  2014年   13篇
  2013年   15篇
  2012年   11篇
  2011年   4篇
  2010年   1篇
  2009年   7篇
  2008年   3篇
  2007年   8篇
  2006年   4篇
  2005年   4篇
  2004年   8篇
  2003年   5篇
  2002年   1篇
  2001年   1篇
  2000年   4篇
  1998年   4篇
  1997年   1篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1988年   1篇
  1987年   2篇
  1985年   1篇
  1982年   1篇
排序方式: 共有139条查询结果,搜索用时 15 毫秒
71.
Between 1975 and 1979, approximately two million people were killed in the Cambodian genocide. To date, considerable research has examined the legacies of this period of Cambodia's history, as well as the geographies of memorialization associated with genocidal violence. In this paper we both critique and expand current understandings. We do so, first, through a destabilization of the periodization of Cambodia's violent past and, second, through a re‐theorization of violence itself. Specifically, we resituate the Cambodian genocide as part of a more systemic effort of post‐conflict reconstruction. We argue that from the perspective of the Khmer Rouge, those policies and practices imposed post‐1975 were forwarded in the context of state‐building following five years of civil war (1970–1975). Consequently, a view of genocide as post‐conflict reconstruction calls into question standard understandings of the genocide and especially the post‐1979 memorialization of genocide. To accomplish our goals, we introduce a dialectical understanding of both potential and realized violence, and potential and realized memorialized landscapes.  相似文献   
72.
陈文光 《地质论评》2007,53(B08):171-174
花岗岩是湖南省最为发育的一类岩浆岩,由于花岗岩岩性及构造条件的不同,造就了独特的地质地貌景观。本文以南岳衡山、宜章莽山、城步南山、宁远九嶷山、浏阳大围山风景旅游地为例,简述了湖南省几例主要花岗岩风景地貌特色及其旅游开发价值。  相似文献   
73.
74.
Transient landscape disequilibrium is a common response to climatic fluctuations between glacial and interglacial conditions. Such landscapes are best suited to the investigation of catchment-wide response to changes in incision. The geomorphology of the Trub and Grosse Fontanne, adjacent stream systems in the Napf region of the Swiss Molasse, was analyzed using a 2-m LIDAR DEM. The two catchments were impacted by the Last Glacial Maximum, LGM, even though the glaciers never overrode this region. They did, however, cause base levels to drop by as much as 80 m. Despite their similar tectonic, lithologic and climatic settings, these two basins show very different responses to the changing boundary conditions. Stream profiles in the Trub tend to be smooth, while in the Fontanne, numerous knickzones are visible. Similarly, cut-and-fill terraces are abundant in the Trub watershed, but absent in the Fontanne, where deep valleys have been incised. The Trub appears to be a coupled hillslope–channel system because the morphometrics throughout the basin are uniform. The morphology of hillslopes upstream of the knickzones in the Fontanne is identical to that of the Trub basin, but different downstream of the knickzones, suggesting that the lower reaches of the Fontanne have been decoupled from the hillslopes. However, the rapid incision of the Fontanne is having little effect on the adjacent upper hillslopes.We tested this interpretation using cosmogenic 10Be-derived basin-averaged denudation rates and terrace dating. The coupled nature of the Trub basin is supported by the similarity of denudation rates, 350 ± 50 mm ky− 1, at a variety of spatial scales. Upstream of the knickzones, rates in the Fontanne, 380 ± 50 mm ky− 1, match those of the Trub. Downstream of the knickzones, denudation rates increase to 540 ± 100 mm ky− 1. The elevated rates in the downstream areas of the Fontanne are due to rapid incision causing a decoupling of the hillslope from the channel. Basin response time and the magnitude of base level drop exert the principal control over the difference in geomorphic response between the two basins. The timing of the filling of the Trub valley, 17 ± 2 ka, and the initial incision of the Fontanne, 16 ± 3 ka, were calculated, verifying that these are responses to late glacial perturbations. Unique lithologic controls allow for one of the fastest regolith production rates yet to be reported,  380 mm ky− 1.  相似文献   
75.
The densities of pits made by goannasVaranus gouldiiwere estimated in the three distinct zones of banded mulga landscapes (erosion slope, interception zone, and mulga grove) in paddocks of a grazing study in north-western New South Wales, Australia. In light and moderately grazed paddocks, soil pits were significantly more abundant in the interception zones (M=119.057 m−2) than in the groves and erosion slopes (M=16.057 m−2). In the overgrazed paddock there were no differences in densities of pits in any of the zones. In the groves and erosion slopes approximately 70-80% of the pits contained litter, seeds, and fruits. However, on the erosion slopes less than 20% of the pits contained litter and seeds. The data support the hypothesis that soil disturbance byVaranuslizards produces a positive feedback mechanism for the viability of the interception zone and the functioning of banded vegetation landscapes.  相似文献   
76.
While research into the formation of memorial landscapes in the American South has focused on those resulting from racial conflicts, a new landscape memorializing labor conflict and class consciousness is also emerging in the region's textile‐producing Piedmont. This memorialization poses significant challenges to dominant regional discourses of economic development and class mutuality in a region in which labor organizing and radical politics remain anathema. This paper examines this emerging landscape for what it can tell us about class relations in the region and the process by which memorial landscapes are formed.  相似文献   
77.
78.
Because of the role that peripheral forest landscapes played in postwar nation-building, the Lao military has long played a significant, even if often hard-to-see, role in the administration of the country’s protected areas. This role is becoming increasingly apparent as transnational market-based forest governance efforts begin to threaten military administration of protected areas. As a consequence, the multi-dimensional nature of security – both defensive in the classic military sense, but also increasingly economic and complex – is coming to light through uses of what we describe as the security exception: the invocation of national security, in this case by military actors, to manage the reach and efficacy of emerging forest governance efforts. Projects to reduce climate-related emissions from deforestation and forest degradation (REDD+) have been especially prone to trigger the security exception due to their focus on forest measurement and change over time, and are examined here in two cases from protected areas in western and southern Laos. We suggest that even as conflicts over forest management may be interpreted through the lens of foreign domination and the loss of domestic sovereignty – indeed the security exception feeds on such interpretations – these conflicts are better understood as struggles within the Lao state and society over the how to manage and use forest resources in a context of economic uncertainty and persistent underdevelopment. In such a context, the role of conservation NGOs and Western donors as gatekeepers to ongoing transnational governance efforts is nonetheless highly significant.  相似文献   
79.
Rob Inkpen  Peter Collier  Mark Riley 《Area》2007,39(4):536-543
This paper considers whether the deployment of a topographical metaphor may add value to the recent discussion of networked relations. The paper discusses how viewing relations as part of a relational landscape may add a third dimension to the discussion by allowing an appreciation of the strength, or entrenchment, of relations, and how these entrenchments impact on the development of new relations and the resistance to watershed events. The heuristic device is explored through the case of air survey in the 1920s and 1930s. This illustrative case demonstrates how relations are held together, resisted and reformed to different degrees depending on the varying topography of the relational landscape.  相似文献   
80.
Proglacial stream development was studied in coastal British Columbia and Washington, focusing on reaches exposed by post‐Little Ice Age (LIA) glacier retreat, to address three principal questions: (i) Does the legacy of LIA glaciation influence the evolution of channel morphology? (ii) How long does it take for riparian forest to establish following glacier retreat? (iii) Can newly exposed proglacial streams provide suitable fish habitat? Channel morphologies were identified by field surveys of 69 reaches in 10 catchments. Riparian forest development and potential fish habitat were characterized in those reaches and an additional 22 catchments using GIS analysis. The landscape template imposed by the Quaternary glaciation appears to override most of the modern effects of the LIA in controlling channel‐reach morphology. Binary logistic regression analysis identified elevation and time since deglaciation as primary controls on the presence of riparian forest. At higher elevations, establishment of morphologically functional riparian forest could take several centuries, prolonged by channel instability associated with post‐LIA sediment inputs. Of the recently deglaciated streams included in this analysis, the majority (86%) of the total length was of suitable gradient for fish and could be accessed either by downstream populations or from adjacent lakes. Predicted maximum weekly average stream temperature (MWAT) indicated that the post‐LIA study streams were thermally suitable for cold‐water fish. A future scenario of glacier loss would cause a 14% decline in accessible cold‐water thermal habitat in post‐LIA streams. Decreased summer flows due to glacier retreat could further limit usable habitat by reducing stream depths and wetted perimeters. Copyright © 2013 John Wiley & Sons, Ltd.  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