全文获取类型
收费全文 | 2070篇 |
免费 | 17篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 67篇 |
废物处理 | 89篇 |
环保管理 | 256篇 |
综合类 | 424篇 |
基础理论 | 445篇 |
环境理论 | 2篇 |
污染及防治 | 562篇 |
评价与监测 | 144篇 |
社会与环境 | 109篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 22篇 |
2022年 | 32篇 |
2021年 | 37篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 60篇 |
2017年 | 43篇 |
2016年 | 57篇 |
2015年 | 57篇 |
2014年 | 63篇 |
2013年 | 88篇 |
2012年 | 88篇 |
2011年 | 125篇 |
2010年 | 93篇 |
2009年 | 125篇 |
2008年 | 108篇 |
2007年 | 116篇 |
2006年 | 78篇 |
2005年 | 74篇 |
2004年 | 90篇 |
2003年 | 64篇 |
2002年 | 79篇 |
2001年 | 56篇 |
2000年 | 38篇 |
1999年 | 23篇 |
1998年 | 29篇 |
1997年 | 27篇 |
1996年 | 27篇 |
1995年 | 31篇 |
1994年 | 23篇 |
1993年 | 13篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 21篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 7篇 |
1979年 | 10篇 |
1973年 | 7篇 |
1970年 | 7篇 |
1968年 | 6篇 |
1965年 | 8篇 |
1962年 | 11篇 |
1961年 | 8篇 |
1954年 | 6篇 |
排序方式: 共有2105条查询结果,搜索用时 140 毫秒
241.
The transition in Dutch water management 总被引:2,自引:1,他引:1
Over the past decades, the Dutch people have been confronted with severe water-related problems, which are the result of an unsustainable water system, arising from human interventions in the physical infrastructure of the water system and the water management style. The claims of housing, industry, infrastructure and agriculture have resulted in increasing pressure on the water system. The continuous subsidence of soil and climate change has put pressure on the land. Hence, the nature and magnitude of water-related problems have changed. Longitudinal research of relevant national policy documents reveals that the water management regime has changed its water management style over the past 30 years from a technocratic scientific style towards an integral and participatory style. We have investigated if the historical development in Dutch Water management can be characterized as a transition. Based on longitudinal research through an integrated systems analysis, document research and expert interviews, we have reconstructed the historical narrative by using the transition concepts of multi-level and multi-phase. This research indicates that the shift in Dutch Water management can be characterized as a transition. This transition is currently in the take-off stage and near the acceleration stage. This is a crucial stage as long as the considerable gap between the strategic macro-vision and the practical implementation at the micro-level remains. As long as these levels are not compatible (modulation), the transition will not be completed successfully. Transition management as multi-level governance model should therefore be adopted to facilitate the modulation. 相似文献
242.
243.
244.
245.
246.
247.
Christopher J. Yahnke Warren E. Johnson Eli Geffen Deborah Smith Fritz Hertel Michael S. Roy Cristian F. Bonacic Todd K. Fuller Blaire Van Valkenburgh Robert K. Wayne 《Conservation biology》1996,10(2):366-375
The temperate rain forest of Chiloé Island, Chile, is inhabited by an endemic fox ( Dusicyon fulvipes ) first described by Charles Darwin and now designated Darwin's fox. Despite morphological differences, Darwin's fox has been considered only an insular subspecies of the mainland chilla fox ( D. griseus ). This follows the assumption that the island population, with an estimated population of less than 500, has been separated from the mainland chilla fox for only about 15,000 years and may have received occasional immigrants from the mainland. Consequently, this island population has not been protected as endangered or bred in captivity. Recently, a population of Darwin's fox was discovered on the Chilean mainland 600 km north of Chiloé Island. This population exists in sympatry with chilla and possibly culpeo ( D. culpaeus ) foxes, which suggests that Darwin's fox may be reproductively isolated. To clarify the phylogenetic position of Darwin's fox, we analyzed 344 bp of mitochondrial DNA control-region sequence of the three species of Chilean foxes. Darwin's foxes from the island and mainland populations compose a monophyletic group distinct from the two other Chilean fox species. This indicates that Darwin's fox was probably an early inhabitant of central Chile, and that its present distribution on the mainland may be a relict of a once much wider distribution. Our results highlight the ability of molecular genetic techniques to uncover historical relationships masked by recent events, such as local extinctions. The "rediscovery" of Darwin's fox as a distinct species implies that greater significance should be given to the protection of this species and its unique habitat and to documenting the extent of its mainland distribution. 相似文献
248.
249.
250.
A. J. P. Smolders L. P. M. Lamers E. C. H. E. T. Lucassen G. Van Der Velde J. G. M. Roelofs 《Chemistry and Ecology》2006,22(2):93-111
In the 1980s and 1990s, it became increasingly clear that changes in external nutrient loads alone could not entirely explain the severe eutrophication of surface waters in the Netherlands. Nowadays, 'internal eutrophication' has become a widely accepted term in Dutch water management practice to describe the eutrophication of an ecosystem without additional external input of nutrients (N, P, K). This review surveys the principal mechanisms involved in this process. It also discusses possible remedies to combat internal eutrophication. 相似文献