首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3348篇
  免费   12篇
  国内免费   36篇
安全科学   76篇
废物处理   155篇
环保管理   322篇
综合类   549篇
基础理论   1182篇
环境理论   2篇
污染及防治   699篇
评价与监测   217篇
社会与环境   192篇
灾害及防治   2篇
  2023年   6篇
  2022年   9篇
  2021年   22篇
  2020年   8篇
  2019年   12篇
  2018年   123篇
  2017年   132篇
  2016年   197篇
  2015年   63篇
  2014年   42篇
  2013年   47篇
  2012年   440篇
  2011年   238篇
  2010年   39篇
  2009年   40篇
  2008年   69篇
  2007年   83篇
  2006年   90篇
  2005年   416篇
  2004年   543篇
  2003年   417篇
  2002年   51篇
  2001年   50篇
  2000年   18篇
  1999年   42篇
  1998年   9篇
  1997年   11篇
  1996年   6篇
  1995年   13篇
  1994年   10篇
  1992年   6篇
  1991年   8篇
  1990年   5篇
  1989年   7篇
  1972年   4篇
  1970年   3篇
  1969年   3篇
  1968年   4篇
  1967年   4篇
  1966年   5篇
  1965年   12篇
  1964年   4篇
  1963年   5篇
  1961年   4篇
  1958年   6篇
  1957年   9篇
  1955年   4篇
  1920年   4篇
  1917年   3篇
  1916年   6篇
排序方式: 共有3396条查询结果,搜索用时 15 毫秒
31.
The larvae and pupae of the ladybird Thalassa saginata develop inside colonies of the dolichoderine ant Dolichoderus bidens. This association is the first specific and obligatory relationship recorded between ants and ladybirds. The ants provide shelter and protection to the larvae but the diet of the latter remains unclear. The integration of T. saginata larvae into the ant colonies is achieved by mimicking the cuticular patterns of the ants brood. Moreover, the larvae secrete substances from their hairs and anal gland that are likely to enhance their attractiveness.  相似文献   
32.
Carbon sequestration in the global carbon cycle is almost always attributed to organic carbon storage alone, while soil mineral carbon is generally neglected. However, due to the longer residence time of mineral carbon in soils (102–106 years), if stored in large quantities it represents a potentially more efficient sink. The aim of this study is to estimate the mineral carbon accumulation due to the tropical iroko tree (Milicia excelsa) in Ivory Coast. The iroko tree has the ability to accumulate mineral carbon as calcium carbonate (CaCO3) in ferralitic soils, where CaCO3 is not expected to precipitate. An estimate of this accumulation was made by titrating carbonate from two characteristic soil profiles in the iroko environment and by identifying calcium (Ca) sources. The system is considered as a net carbon sink because carbonate accumulation involves only atmospheric CO2 and Ca from Ca-carbonate-free sources. Around one ton of mineral carbon was found in and around an 80-year-old iroko stump, proving the existence of a mineral carbon sink related to the iroko ecosystem. Conservation of iroko trees and the many other biomineralizing plant species is crucial to the maintenance of this mineral carbon sink.  相似文献   
33.
34.
35.
36.
Erratum     
Naturwissenschaften Aktuell  相似文献   
37.
38.
A study of the relationship between natural hazards and climate change in the international context provides the background for a discussion of the expected changes. In the context of this global discussion, this paper reviews the current perspectives of those natural hazards that are likely to be influenced by climate change, using northern Canada as a regional case study. The northern implications of the United Nations Framework Convention on Climate Change are examined, including the status of climate change action by the northern territorial governments, the evolving role of indigenous people, and the responsibility for climate change impacts. The difficulties surrounding natural hazards research in remote locations, and the approaches of indigenous people to natural hazards are then presented. The paper concludes with a suggested policy approach for climate change and natural hazards in northern Canada, underscoring the need for more comprehensive adaptive strategies to complement the current tendency to focus on the mitigation of greenhouse gases produced in this region.  相似文献   
39.
40.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号