全文获取类型
收费全文 | 37774篇 |
免费 | 6395篇 |
国内免费 | 11799篇 |
专业分类
测绘学 | 972篇 |
大气科学 | 1120篇 |
地球物理 | 2966篇 |
地质学 | 36291篇 |
海洋学 | 2686篇 |
天文学 | 5233篇 |
综合类 | 2604篇 |
自然地理 | 4096篇 |
出版年
2024年 | 189篇 |
2023年 | 557篇 |
2022年 | 1219篇 |
2021年 | 1514篇 |
2020年 | 1397篇 |
2019年 | 1736篇 |
2018年 | 1344篇 |
2017年 | 1563篇 |
2016年 | 1715篇 |
2015年 | 1768篇 |
2014年 | 2441篇 |
2013年 | 2199篇 |
2012年 | 2604篇 |
2011年 | 2709篇 |
2010年 | 2552篇 |
2009年 | 2741篇 |
2008年 | 2593篇 |
2007年 | 2689篇 |
2006年 | 2605篇 |
2005年 | 2292篇 |
2004年 | 2219篇 |
2003年 | 1946篇 |
2002年 | 1681篇 |
2001年 | 1682篇 |
2000年 | 1564篇 |
1999年 | 1482篇 |
1998年 | 1273篇 |
1997年 | 1056篇 |
1996年 | 947篇 |
1995年 | 779篇 |
1994年 | 622篇 |
1993年 | 558篇 |
1992年 | 427篇 |
1991年 | 340篇 |
1990年 | 253篇 |
1989年 | 200篇 |
1988年 | 144篇 |
1987年 | 88篇 |
1986年 | 66篇 |
1985年 | 49篇 |
1984年 | 30篇 |
1983年 | 24篇 |
1982年 | 24篇 |
1981年 | 10篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 17篇 |
1973年 | 6篇 |
1954年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
Karen Brown 《Area》2003,35(4):343-356
Focusing on the contested issue of trees and forests, this paper looks at various ways in which historians have explored environmental change and human agency in Africa. It looks in particular at the colonial period and positions the case of the Cape Colony (South Africa) in a broader historiographical context. Colonial silviculture involved both the appropriation of the natural forests and the creation of exotic plantations. These policies generated a mixture of reactions from African communities and had varying effects on the environment. Colonial science and the projects it gave rise to have since been critiqued, contributing to the promotion of community-based forestry schemes that try to incorporate indigenous knowledge and ideas about land use. 相似文献
912.
STEVEN HENDERSON 《The Australian geographer》2003,34(1):3-17
Land use conflict involving farm externalities represents an increasing policy concern in Australia as agricultural activities intensify and as the nation's metropolitan areas continue to expand outwards. A review of the rural-urban fringe literature reveals a noticeable absence of research exploring the intensity of conflict experienced by farmers. Similarly, inadequate attention has been given to the policies adopted by government to manage conflict. This article contrasts the regulatory system that has been implemented to manage conflict involving poultry farming on the metropolitan fringe of two Australian state capitals: Perth, Western Australia and Sydney, New South Wales. Spatial variation in the nature of government intervention is uncovered. In the discussion that follows reasons are identified to help explain such variation including state ideology, metropolitan growth, industry activism, geographical constraints and farm characteristics. It is concluded that where agricultural industries experience internal political divisions and a geographically dispersed membership it becomes more difficult to influence government policy. 相似文献
913.
I. H. Burnley 《The Australian geographer》2003,34(3):267-280
This paper considers the likely future population in Australia to 2050 and is cast within the context of environmental limitations, to which Griffith Taylor alerted the nation in the 1920s and 1930s, and for which he was vilified in several quarters. While acknowledging the relative accuracy of his long-range forecasts, the arguments here depart from environmental determinism, although varying sets of environmental ethics and values are considered in relation to Australia's global responsibilities and international commitments. It is argued that an increase in population to 26 million by 2050 will not place severe stresses on the physical environment, provided environmental and resource management strategies are put firmly in place, and if consumption and resource use practices are significantly modified. An ideological linkage exists between a resurgent Australian nationalism and a number of environmental perspectives, but one which rejects growth and biological diversity among humans while embracing environmentalism. This inward-looking nationalism–environmentalism is seen as harmful both to Australia's moral integrity as a nation, and in local and world citizenship. 相似文献
914.
通过对建宁黄埠地区金矿地质特征、矿化特点、成矿地质规律的研究,认为该区成矿年龄为91Ma,提出了北西西向碎裂带为主要的含矿构造,并指出该区具有较好的找金远景。 相似文献
915.
从江县翁浪金矿床容矿岩石与围岩蚀变及其找矿标志 总被引:1,自引:7,他引:1
文章简单介绍了构造蚀变岩型金矿翁浪金矿床的容矿岩石和围岩蚀变特征,指出该类矿床的找矿标志,对进一步寻找此类矿床有一定的意义。 相似文献
916.
用PowerPoint制作地质专业演示文档技术概述 总被引:1,自引:0,他引:1
地质专业演示文档通常是用PowerPoint制作和放映的。本文分析了地质专业演示文档的特点、要求,以及地质人员普遍关心或存在的问题,有针对性地叙述了用Power-Point制作地质专业演示文档的技术要点,可供有一定制作基础者参考。 相似文献
917.
天然气水合物研究现状与展望 总被引:4,自引:0,他引:4
自20世纪90年代以来,世界各国对潜力巨大的新型能源———天然气水合物的研究做了大量的投入,已经取得了重大进展。本文在阐述国外天然气水合物的研究现状的同时,重点介绍了我国在天然气水合物勘探开发和实验模拟方面取得的一些进展,并展望其在能源、环境和其它研究领域的发展前景。 相似文献
918.
以大平山铜矿、天台山黄铁矿矿为例,阐述了该区的矿区、矿床地质及火山机构特征,并从成矿时间、空间及成因三个方面论述了矿床成矿与古火山机构的关系。 相似文献
919.
920.