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排序方式: 共有321条查询结果,搜索用时 15 毫秒
81.
中国自然保护区生态旅游开发研究刍议   总被引:24,自引:0,他引:24  
刘继生  孔强  陈娟 《人文地理》1997,12(4):20-24
本文从生态旅游的角度的出发,阐述了自然保护区生态旅游开发的意义,分析了自然保护区生态旅游资源的特点和开发限制因素,初步探讨了我国自然保护区生态旅游开发原则。  相似文献   
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We apply GIS techniques to analyze a carefully selected database of 93 Early Neolithic sites in the Iberian Peninsula. This allows us to study the spatial dynamics of the Neolithic transition in Iberia. We study how the Neolithic was introduced into the peninsula in order to test the hypothesis that the Neolithic was introduced almost simultaneously from two sources: one at the northeast (via the Mediterranean coast) and another one at the south (possibly from Northern Africa). We also analyze how the expansion of the Neolithic transition took place within the Iberian Peninsula and measure local rates of spread in order to identify regions with fast and slow rates (such as the slowdown at the Cantabrian coast). In addition, we attempt to reproduce the main results obtained from the GIS analysis by applying reaction–dispersal models to the expansion of the Neolithic transition in the Iberian Peninsula. We conclude that a model with two sources is a reasonable assumption that agrees better with the archaeological data available at present than a model with a single source.  相似文献   
84.
This article describes the conditions for the development of four industrial clusters and the mechanisms of their integration in the regional economy. The case studies are the aerospace and apparel clusters in Montreal, and the agri‐food and marine science and technology clusters in the Lower St. Lawrence region. Clusters are defined as arrangements of businesses, government actors, public authorities, and local intermediary organizations in a local area. However, the study shows that clusters are based on actors and processes operating at different scales, from the local to the global. It also shows the importance of the sectoral leadership acknowledged by the different stakeholders.  相似文献   
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第二轮修志如何落实《关于第二轮地方志书编纂的若干意见》和《地方志书质量规定》等文件提出的地方志工作质量和志书质量标准体系,成为史志工作者的紧要任务。山东省结合《山东省志》的编纂,就质量管理体系建设进行了探索和思考:一是树立全面质量管理理念,以质量第一为原则,指导全方位工作;二是建立健全质量管理组织机构体系,确保组织到位;三是制定全面的制度规范体系,提供制度保障;四是构建严格的质量监控体系,强化质量监督;五是加强队伍建设等,营造良好的质量保障机制;六是不断积累和总结,形成持续改进的质量管理机制。  相似文献   
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As deportations from the United States rose to unprecedented levels, a nationwide immigration enforcement program Secure Communities helped identify deportable noncitizens under arrest in county jails. Examining county‐level variation in deportation activity between 2008 and 2013, this paper contributes to immigration policy research by examining how county officials in some locations facilitated exceptionally restrictive deportation outcomes while others exercised the discretion to turn noncitizens over for deportation sparingly. Consistent with a hypothesized “tiered influence” relationship, but contrary to a “racial threat” hypothesis, Hispanic concentration predicts the highest levels of exercised discretion where Hispanic concentration is neither too small nor too large. Noncitizens under arrest seem to have benefited from above‐average Hispanic concentrations, except in counties where Hispanics exceed about 40 percent of the population.  相似文献   
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Journal of Maritime Archaeology - This study analyses nautical harbour activities and their spatial distribution using a high-resolution method of wind-wave hindcasting, in order to identify the...  相似文献   
89.
上古史是中国近代历史学的重要研究对象,有关上古神话的研究更引起了广泛关注。吕思勉利用文献考据、社会从低级到高级的发展规律及“统属思维”塑造的“同质人类群体”的概念,对上古神话进行清理和重构,形成了区别于传统的新解释,并尝试以此取代传统思想中有关上古神话的“旧常识”。这种新旧知识迭代背后隐藏着吕思勉以“统属性思维”取代“关联性思维”的研究理路,是近代新史学打造学科话语体系的尝试,也彰显出历史学家普遍面对的“当下主义”的困境,以及这种困境对于历史知识迭代的意义。  相似文献   
90.
The term “millets” is used to identify several genera of grasses (Poaceae), most of which belong to the subfamily Panicoideae. Millets are one of the major food sources in arid and semi-arid areas of the world and they have been important crops in the prehistory of Africa and Eurasia. In this paper, we discuss phytoliths and starch grains from two of the less studied major millets (Pennisetum glaucum and Sorghum bicolor) as well as from some small millet species that are not normally considered of much importance (so-called forgotten millets: Digitaria ciliaris, Echinochloa colona, Echinochloa frumentacea, Brachiaria ramosa, Setaria pumila and Setaria verticillata). The preliminary results of this study on phytolith morphology, both at single and joined (silica skeletons) morphotypes, and starch grains show great potentials for the identification of different genus or species on the basis of microremains.  相似文献   
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