全文获取类型
收费全文 | 931篇 |
免费 | 37篇 |
国内免费 | 52篇 |
专业分类
测绘学 | 245篇 |
大气科学 | 41篇 |
地球物理 | 65篇 |
地质学 | 170篇 |
海洋学 | 66篇 |
天文学 | 13篇 |
综合类 | 75篇 |
自然地理 | 345篇 |
出版年
2024年 | 4篇 |
2023年 | 14篇 |
2022年 | 40篇 |
2021年 | 42篇 |
2020年 | 44篇 |
2019年 | 35篇 |
2018年 | 35篇 |
2017年 | 44篇 |
2016年 | 42篇 |
2015年 | 39篇 |
2014年 | 66篇 |
2013年 | 73篇 |
2012年 | 37篇 |
2011年 | 30篇 |
2010年 | 30篇 |
2009年 | 20篇 |
2008年 | 43篇 |
2007年 | 43篇 |
2006年 | 37篇 |
2005年 | 49篇 |
2004年 | 37篇 |
2003年 | 45篇 |
2002年 | 24篇 |
2001年 | 16篇 |
2000年 | 35篇 |
1999年 | 20篇 |
1998年 | 18篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有1020条查询结果,搜索用时 9 毫秒
971.
Jorge E. Rubiano 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):115-130
Biophysical conditions and in particular soil conditions are generally seen as important determinants of land use and receive much emphasis both in land use planning and in attempts to understand actual land use patterns. This paper explores the justification for this emphasis. Based on a study of farmers' decisions regarding land use type (forest, pasture, fallow or crop) and crop choice in the Colombian Andes, the paper shows that despite farmers' detailed knowledge of the diverse soil conditions in the area, other factors, such as total farm size and market and input-related concerns, are more important for farmers' actual choice of land use type and crop. 相似文献
972.
Brian Ceh 《The Professional geographer》2013,65(2):275-277
Land use information over large areas is increasingly important for many studies related to environment in general and global change in particular. Yet there is a dearth of methodological knowledge in this area, especially regarding the practical task of producing land use maps. In this article, a systematic land use mapping approach is developed, based on land cover maps that in turn are produced through remote sensing. The concept is based on the recognition of varying strengths of land cover (LC) – land use (LU) relationships, from the thematic and spatial points of view. Several categories of relationships are identified, ranging from direct (case 1) to multiple/complex (case 4), and appropriate mapping strategies are discussed for these cases. Using a mapping study in Lebanon, it is shown that the principles embodied in this approach correspond to issues and conditions in real mapping situations. Finally, the concepts are translated into a series of steps through which the method can be applied to large areas, taking into consideration the specific requirements and constraints of each case. The final land use map represents an acceptable compromise between accuracy, level of detail, and cost. 相似文献
973.
知识经济与21世纪中国人文地理学发展 总被引:3,自引:0,他引:3
文章由总结前知识经济时代人文地理学发展特点入手,分析了知识经济时代人文地理学学科发展困境;知识经济向人文地理学学科建设提出了信息化,综合化,决策化和持续化的要求;最后重点展望了知识经济时代中国人文地理学学科建设与发展趋向。 相似文献
974.
知识经济是相对于传统经济的、新型的、富有生命力的经济类型它以知识创新、转化和利用为特征,能带来巨大的经济效益,利于提高社会、生态效益,协调人与自然的关系。它既是人类知识进步和发达国家或地区生产力高度发展的结果,又为发展中国家或地区的生产组织的选择指明了方向。文章结合知识经济,内涵,讨论了发展中国家或地区在知识经济时代的生产组织选择的重点和方向问题。 相似文献
975.
This study analyzes the use of maps in Turkish newspapers in order to evaluate their potential to contribute to the enhancement of geographic knowledge in society. This study reviewed the content of three Turkish newspapers published between January 2008 and August 2012. Only 835 maps were used in the newspapers during the study period, or an average of 278 maps per newspaper. During the study period, about 15,720 news articles were published per month in the three newspapers; however, only five of these were illustrated with a map. The study reveals the potential for Turkish newspapers to increase society's geographic awareness with additional published maps. 相似文献
976.
Geographies of knowledge, practices of globalization: learning from the oil exploration and production industry 总被引:2,自引:0,他引:2
In this paper we initiate a dialogue between work on the geographies of globalization and knowledge economies, areas of inquiry that have tended to develop in isolation. We argue for a critical harnessing of these two bodies of work to (1) understand how and where different types of knowledge are acquired, produced and mobilized by firms as they seek to 'go global', (2) map the multi-scalar geographies of knowledge that enable practices of globalization and (3) examine the ways in which networks of knowledge structure emerging geographies of production. We demonstrate the potential of this move using oil exploration and production as an example. 相似文献
977.
《The Journal of geography》2012,111(3):427-433
Abstract Research presented in this paper addresses two fundamental questions: how effective have state geographic alliance summer geography institutes (ASGIs) been in changing the classroom teaching behaviors of participants, and to what extent do the institutes reflect characteristics of effective inservice training? Both questions are grounded in Shulman's concept of pedagogical content knowledge—the notion that effective teaching requires knowledge of how specific ideas and procedures in a particular content domain can best be taught. On-site evaluations and four follow-up evaluations provided data regarding the strengths and weaknesses of the institutes as well as evidence regarding the institutes' long-term effectiveness in promoting change in geography instruction. Results of the study indicate that ASGI graduates not only make substantive changes in how they teach geography, but also conduct high-quality inservices that lead to changes in the teaching practices of their colleagues. 相似文献
978.
Honghua Dai 《大气科学进展》1996,13(4):471-488
Discovery of useful forecasting rules from observational weather data is an outstanding interesting topic.The traditional methods of acquiring forecasting knowledge are manual analysis and investigation performed by human scientists.This paper presents the experimental results of an automatic machine learning system which derives forecasting rules from real observational data.We tested the system on the two large real data sets from the areas of centra! China and Victoria of Australia.The experimental results show that the forecasting rules discovered by the system are very competitive to human experts.The forecasting accuracy rates are 86.4% and 78% of the two data sets respectively 相似文献
979.
Anthropogenic hillslope terraces and swidden agriculture in Jiuzhaigou National Park, northern Sichuan, China 总被引:2,自引:0,他引:2
Amanda Henck James Taylor Yongxian Li Barbara Grub Alicia Robbins Tom Hinckley Lauren Urgenson Xinxin Hu Yaowu Yuan Xun Liao 《Quaternary Research》2010,73(2):201-207
Small, irregular terraces on hillslopes, or terracettes, are common landscape features throughout west central China. Despite their prevalence, there is limited understanding of the nature of these topographic features, the processes that form them, and the role humans played in their formation. We used an interdisciplinary approach to investigate the geology, ecology, and cultural history of terracette development within Jiuzhaigou National Park, Sichuan Province, China. Terracettes occur on south facing, 20° slopes at 2500 m elevation, which appears to coincide with places people historically preferred to build villages. Ethnographic interviews suggest that traditional swidden agricultural cycles removed tree roots, causing the loess sediments to lose cohesion, slump, and the terrace risers to retreat uphill over time. This evidence is supported by landslide debris at terracette faces. Archaeological analysis of terracette sites reveal remains of rammed spread soil structures, bones, stone tools, and ceramics dating from at least 2200 years before present within a distinct paleosol layer. Radiocarbon and optically stimulated luminescence dating of terracette sediments ranged in age from between 1500 and 2000 14C yr BP and between 16 and 0.30 ka, respectively. These multiple lines of evidence indicate a long history of human habitation within Jiuzhaigou National Park and, taken together, suggest strong links between terracette formation and human-landuse interactions. 相似文献
980.