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   7274篇
  免费   283篇
  2020年   98篇
  2019年   141篇
  2018年   163篇
  2017年   186篇
  2016年   231篇
  2015年   159篇
  2014年   154篇
  2013年   2098篇
  2012年   209篇
  2011年   222篇
  2010年   248篇
  2009年   220篇
  2008年   197篇
  2007年   198篇
  2006年   192篇
  2005年   103篇
  2004年   92篇
  2003年   91篇
  2002年   98篇
  2001年   110篇
  2000年   78篇
  1999年   95篇
  1998年   63篇
  1997年   56篇
  1996年   70篇
  1995年   73篇
  1994年   72篇
  1993年   80篇
  1992年   71篇
  1991年   59篇
  1990年   52篇
  1989年   66篇
  1988年   56篇
  1987年   65篇
  1986年   64篇
  1985年   76篇
  1984年   65篇
  1983年   94篇
  1982年   70篇
  1981年   72篇
  1980年   68篇
  1979年   67篇
  1978年   71篇
  1977年   63篇
  1976年   72篇
  1975年   66篇
  1974年   53篇
  1973年   54篇
  1972年   55篇
  1970年   44篇
排序方式: 共有7557条查询结果,搜索用时 15 毫秒
991.
Abstract:  We contribute to the diversification of environmental justice (EJ) by using it to frame ecotourism-related solid waste management problems. Ecotourism is a service industry portrayed as benevolent (providing benefits), and benign (reducing negative impacts). We propose four characteristics shared by ecotourism-based communities in the Global South and communities struggling with more conventional EJ conflicts. We apply these characteristics to the solid waste crisis in Tortuguero, Costa Rica, a renowned ecotourism destination. First, we show that, despite their general absences from the EJ literature, service industries such as tourism and hospitality can create environmental injustices that disproportionately impact certain types of communities. Second, we highlight the roles of location and socio-economic marginality in siting ecotourism development, in complicating related environmental impact management, and in limiting local abilities to respond to environmental management shortcomings. Third, we provide an example of opportunities to introduce EJ concepts and theory into the study of tourism.  相似文献   
992.
This article focuses on two disparate figures in the French colonial period in Africa, the ex-poet Arthur Rimbaud and the ex-soldier Charles de Foucauld. Between 1883 and 1884, each lived in Africa in self-imposed exile of a sort, and undertook rigorous exploration of the region to which he had relocated himself. Both composed reports on their regions of the ‘dark continent,’ and both reports were submitted to, and recognized by, the Société de Géographie back in Paris. The two geographical texts – Rimbaud's Rapport sur l'Ogadine and de Foucauld's Reconnaissance au Maroc – are watersheds of life-writing, as much as they are representations of colonial Africa observed by Frenchmen. Through comparing the two desert narratives, and considering the two authors' African lives, I argue that the process of writing about the desert actually evokes the essential character of each writer's voice, a voice to which he only found access in the desert. Finally, these voices in turn provide valuable information about the relationship between France and Africa, colonial force and colony, and about the various forms of resistance to each of those roles.  相似文献   
993.
If countries compete for capital in the shape of foreign direct investment (FDI), from the point of view of multinational enterprises (MNEs), there is a market for the social order on offer in different nation states. MNEs seek out particular models of social order for their FDI projects. In the middle is a diverse set of organisations who mediate between supply and demand in a world market for social order. East and Southeast Asia represent interesting and complicated cases in point. Different national models of social order are also overlain and punctured by the hybrid models apparent in cross-border zones of economic integration and joint venture industrial park enclaves. This paper examines the engagement between states, MNEs and intermediaries in this variegated FDI policy landscape.  相似文献   
994.
995.
996.
997.
998.
This paper investigates evidence for subsistence and settlement activities in the Levantine Middle Epipalaeolithic through the application of stable isotope analysis to human and non-human remains from the site of 'Uyun al-Hammam, northern Jordan. In general, bone from the site suffers a high degree of diagenesis and collagen could not be extracted for analysis here. Carbon and oxygen isotopic values from human tooth enamel samples were variable, but within expected values for the Middle Epipalaeolithic, whereas animal carbon and oxygen isotopic values varied widely, most likely due to hydrological and climatological factors. Carbon and isotopic values for the human samples indicated a predominantly C3 plant dietary input, while animal samples appeared to have varying amounts of C4 inputs into their diet. This is the first isotopic analysis conducted on material from the Middle Epipalaeolithic of the southern Levant and, as such, even results constrained by temporal and climatological variants within the region contribute to the overall knowledge of settlement and subsistence strategies during this cultural period.  相似文献   
999.
A landscape-scale conception of the circa 1688–1715 CE Seneca occupation at the White Springs Site (NYSM 1952; RMSC Plp-018), located in Geneva, NY, is important for understanding their built environment during a period of residential upheaval. This paper reports on approximately five hectares of high-resolution, multi-instrument archaeogeophysical surveys. These surveys allowed engagement with layered, temporal contexts and the gathering of otherwise inaccessible information. In combination with excavation, surface survey, and historic research, archaeogeophysical techniques provided expanded access to the site, a settlement size estimate of 1.42–2.75 ha, and tentative evidence for a palisade at the White Springs Site. The interplay between archaeogeophysics and other techniques was critical to this undertaking.  相似文献   
1000.
Results of analyses of the photoperiod response gene (PPD-H1) and simple sequence repeats (SSRs) in modern landraces of cultivated barley were used as evidence for the mechanism of agricultural spread in Neolithic Europe. In particular, we explored the usefulness of considering adaptive genes as indicators of past selective pressures acting on crops, during their spread through Europe. In some areas, such as the Alpine region, Britain and Scandinavia, we have evidence to suggest that the adaptation of crops to certain climatic conditions may have contributed to the timing of agricultural spread. At the northern fringes of Europe, and in higher altitude locations in central Europe, the introduction of more suitably adapted cereals may have facilitated successful agriculture to trigger agricultural expansion. This research opens up the possibility of investigating other genetic adaptations to climate, which would permit a fuller evaluation of the relative contributions of climate/crop and forager/farmer interactions in the process of agricultural spread.  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