全文获取类型
收费全文 | 562篇 |
免费 | 26篇 |
国内免费 | 32篇 |
专业分类
测绘学 | 55篇 |
大气科学 | 88篇 |
地球物理 | 19篇 |
地质学 | 226篇 |
海洋学 | 104篇 |
天文学 | 2篇 |
综合类 | 16篇 |
自然地理 | 110篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 18篇 |
2020年 | 19篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 32篇 |
2016年 | 22篇 |
2015年 | 22篇 |
2014年 | 52篇 |
2013年 | 35篇 |
2012年 | 35篇 |
2011年 | 36篇 |
2010年 | 42篇 |
2009年 | 25篇 |
2008年 | 34篇 |
2007年 | 33篇 |
2006年 | 26篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 17篇 |
2002年 | 11篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有620条查询结果,搜索用时 562 毫秒
91.
过去2000年中国气候变化研究 总被引:8,自引:1,他引:7
总结了中国科学院地理科学与资源研究所在过去2000年中国气候变化研究方面的主要进展,并对未来研究动向进行了展望。在过去10余年中,中科院地理资源所的历史气候变化研究在已有基础上,面向国际本领域研究的前缘科学问题,开展了大量研究工作,在代用资料的收集、整理与数据库建设,温度与降水变化重建以及气候变化的时空特征分析等方面取得了许多新成果。未来不但需要进一步利用历史文献、树轮等气候变化重建手段,加强高分辨率的气候变化重建工作,加密气候变化代用资料的空间覆盖度,并结合历史气候模拟等手段,深入开展气候变化动力学机制研究;而且还需要进一步利用地理资源所在本领域已积累的研究优势,开展历史时期的气候变化与人类相互作用等方面的研究。 相似文献
92.
Urban regeneration has intermittently been identified within Commonwealth policy circles as central to the functioning of Australian cities since the 1940s. This paper adds to existing knowledge by exploring the role of the Commonwealth Department of Urban and Regional Development (DURD) in the 1970s in facilitating a series of urban regeneration projects in Sydney. Drawing upon ministerial correspondence and minutes recently out of confidential embargo, the genesis of a holistic urban regeneration agenda is explored. The paper traces the approaches to Commonwealth intervention at a time marked by disillusionment with the comprehensive redevelopment paradigm. It explores the relationships and tensions apparent between and within different levels of government in establishing a Commonwealth presence, focusing on three inner city neighbourhoods: Waterloo, Glebe and Woolloomooloo. The significance of the interventions is considered to lie primarily in the pioneering of an all-of-government approach to urban governance. 相似文献
93.
结合地质实体概念厘清数据类型及其特征对地层信息系统的发展有重要意义。地层信息系统数据可以归类为属性数据、几何数据、关系数据、元数据4类,地层信息中的地质实体可分为基础地质实体和地质实体要素,进一步把地质实体要素分为关联要素和非关联要素。文中分析了矿体、风化分界面、断层、褶皱、不整合面、滑坡体的几何属性。区分观测者位置、数据采集点和数据本身空间属性,数据获取方法可分为地表调查、钻入调查、岩层透视调查、岩层非透视调查,并分析了原始数据与地质实体的对应关系。 相似文献
94.
ABSTRACT A geometric algorithm for Tilted-Camera Perspective (TCP) projection is proposed in this paper based on the principle of perspective projection. According to that, the difference between TCP projection and External Perspective (EXP) projecton is analyzed. It is put forward prerequisites making these two projections were compatible, and some examples are given. 相似文献
95.
同安水洋矿区1∶5万水系沉积物测量和1∶1万土壤测量,共圈出W、Mo、Ag等元素综合异常多处,其中异常值较高、规模较大异常主要有Ag 1个、Mo 5个和W异常2个,各异常相互套叠,根据主要综合异常,地表已发现多条钼矿体和钼矿(化)体,显示矿区良好的找矿前景。 相似文献
96.
福建南靖南坑钼多金属矿异常特征及找矿远景分析 总被引:2,自引:0,他引:2
南靖南坑土壤地球化学圈出5个Mo多金属综合异常,异常呈北东向分布在燕山早期中酸性侵入岩与文宾山组碎屑岩接触带及断裂带附近,异常元素组合以Cu、Mo为主,伴有Pb、Zn、W等,浓集中心明显,局部证实为矿致异常,其中甲3-1异常经详查,Mo多金属矿达中型规模,综合分析该区成矿地质背景、地球化学特征和已发现矿(化)点,认为南坑一带具有良好的钼矿找矿远景。 相似文献
97.
98.
The objective of this paper is to develop independent and systematic criteria for assessing CCS policy in terms of its level of policy integration. We believe that we should assess CCS policy in terms of the distance to an ideal integrated CCS policy in order to keep track of its trajectory toward sustainable development. After reviewing the existing literature of environmental policy integration, an assessment framework for integrated CCS policy is developed based on Arild Underdal's notion of ‘integrated policy’ then, its usefulness is demonstrated by applying it to CCS policies in Japan and Norway. In the final part, we summarize the findings of the cases and conclude with some observations regarding explanatory factors of the difference in terms of the achieved level of policy integration between Japan and Norway's CCS policies, and some policy implications derived from the analysis based on the framework. 相似文献
99.
O'Leary BC Smart JC Neale FC Hawkins JP Newman S Milman AC Roberts CM 《Marine pollution bulletin》2011,62(12):2642-2648
We analysed the extent to which European politicians have adhered to scientific recommendations on annual total allowable catches (TACs) from 1987 to 2011, covering most of the period of the Common Fisheries Policy (CFP). For the 11 stocks examined, TACs were set higher than scientific recommendations in 68% of decisions. Politically-adjusted TACs averaged 33% above scientifically recommended levels. There was no evidence that the 2002 reform of the CFP improved decision-making, as was claimed at the time. We modelled the effects of such politically-driven decision-making on stock sustainability. Our results suggest that political adjustment of scientific recommendations dramatically increases the probability of a stock collapsing within 40 years.In 2012 European fisheries policy will undergo a once-a-decade reform. Ten years ago radical reforms were promised but the changes failed to improve sustainability. It is likely that the 2012 reform will be similarly ineffective unless decision-making is changed so that catch allocations are based on science rather than politics. 相似文献
100.