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   103篇
  免费   3篇
  2023年   1篇
  2020年   1篇
  2019年   3篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   13篇
  2012年   5篇
  2011年   6篇
  2010年   7篇
  2009年   10篇
  2008年   5篇
  2007年   6篇
  2006年   5篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1997年   3篇
  1996年   4篇
  1995年   3篇
  1993年   3篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1985年   1篇
  1982年   2篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
排序方式: 共有106条查询结果,搜索用时 265 毫秒
71.
72.
Pollen and macrofossils from an organic deposit probably 44 ka BP in age record subalpine heath with abundant local Athrotaxis cupressoides. This was succeeded by subalpine heath that included Casuarina, Phyllocladus and Eucalyptus. The pollen/vegetation assemblages are comparable with present subalpine vegetation located between 850–1050 m, though the site is at 550 m and potentially below the limit of temperate rainforest (620 m). It is inferred that the vegetation altered from upper to lower subalpine heath and that the climate became warmer and wetter. The mean temperature is estimated to have been at least 3.2°C to 1.7°C colder than today. The trend of vegetation and climate change compares closely with Late Glacial changes but does not compare with changes recorded from sites of Middle Last Glacial age in the West Coast Ranges. A radiocarbon date of 34 ka BP and a trend towards warming suggests that the deposit may represent the onset of an interstadial during the Early Last Glacial Stage.  相似文献   
73.
74.
75.
76.
When official representatives of more than 170 countries adopted the principle of the ‘responsibility to protect’ (R2P) at the September 2005 World Summit, Darfur was quickly identified as the test case for this new doctrine. The general verdict is that the international community has failed the test due to lack of political will. This article argues that the failure is real but that it is more fundamentally located within the doctrine of R2P itself. Fulfilling the aspiration of R2P demands an international protection capability that does not exist now and cannot be realistically expected. The critical weakness in R2P is that the ‘responsibility to react’ has been framed as coercive protection, which attempts to be a middle way between classic peacekeeping and outright military intervention that can be undertaken without the consent of the host government. Thus far, theoretical and practical attempts to create this intermediate space for coercive protection have failed to resolve basic strategic and operational issues. In addition, the very act of raising the prospect of external military intervention for human protection purposes changes and distorts the political process and can in fact make a resolution more difficult. Following an introductory section that provides background to the war in Darfur and international engagement, this article examines the debates over the R2P that swirled around the Darfur crisis and operational concepts developed for the African Union Mission in Sudan (AMIS) and its hybrid successor, the UN–African Union Mission in Darfur (UNAMID), especially during the Abuja peace negotiations. Three operational concepts are examined: ceasefire, disarmament and civilian protection. Unfortunately, the international policy priority o bringing UN troops to Darfur had an adverse impact on the Darfur peace talks without grappling with the central question of what international forces would do to resolve the crisis. Advocacy for the R2P set an unrealistic ideal which became the enemy of achievable goals.  相似文献   
77.
Several parts of Binh Phuóc Province, southern Vietnam, suffer from degraded soils and vegetation as a result of both natural erosion of weak mud rocks and sandstones and intensive human activity, especially through land clearing for agriculture on unstable slopes, deforestation, and abandonment of poor farmland. The underlying cause of this land degradation has been the farming habits of migrants of varying ethnic groups who have settled in the area since 1980. The indigenous farming knowledge of these people and the role of that knowledge in soil erosion were examined by a series of household surveys. They enabled farming practices to be related to ground cover established from a 2002 Landsat 7 ETM (Enhanced Thematic Mapper), and erosion data from a series of erosion bridge measurements. A GIS (Geographical Information System) approach was piloted as a means of identifying areas vulnerable to erosion. This could then be combined with the understanding of farming practices to reveal the relative roles of farmer behaviour, crop cover, and slope and soil characteristics in the erosion process. Land use, local people's knowledge and economic realities are the main factors, as well as natural conditions, that drive this land degradation.  相似文献   
78.
79.
In Sri Lanka, gender and national identities intersect to shape people's mobility and security in the context of conflict. This article aims to illustrate the gendered processes of identity construction in the context of competing militarised nationalisms. We contend that a feminist approach is crucial, and that gender analysis alone is insufficient. Gender cannot be considered analytically independent from nationalism or ethno‐national identities because competing Tamil and Sinhala nationalist discourses produce particular gender identities and relations. Fraught and cross‐cutting relations of gender, nation, class and location shape people's movement, safety and potential for displacement. In the conflict‐ridden areas of Sri Lanka's North and East during 1999–2000, we set out to examine relations of gender and nation within the context of conflict. Our specific aim in this article is to analyse the ways in which certain identities are performed, on one hand, and subverted through premeditated performances of national identity on the other hand. We examine these processes at three sites—shrines, roads and people's bodies. Each is a strategic site of security/insecurity, depending on one's gender and ethno‐national identity, as well as geographical location.  相似文献   
80.
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