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   8369篇
  免费   46篇
  国内免费   74篇
安全科学   188篇
废物处理   489篇
环保管理   764篇
综合类   1122篇
基础理论   2152篇
环境理论   8篇
污染及防治   2481篇
评价与监测   710篇
社会与环境   546篇
灾害及防治   29篇
  2023年   61篇
  2022年   172篇
  2021年   229篇
  2020年   98篇
  2019年   95篇
  2018年   316篇
  2017年   320篇
  2016年   451篇
  2015年   204篇
  2014年   315篇
  2013年   486篇
  2012年   726篇
  2011年   594篇
  2010年   319篇
  2009年   242篇
  2008年   348篇
  2007年   385篇
  2006年   297篇
  2005年   599篇
  2004年   677篇
  2003年   545篇
  2002年   194篇
  2001年   154篇
  2000年   84篇
  1999年   85篇
  1998年   31篇
  1997年   45篇
  1996年   27篇
  1995年   47篇
  1994年   29篇
  1993年   15篇
  1992年   19篇
  1991年   27篇
  1990年   18篇
  1989年   16篇
  1988年   7篇
  1987年   11篇
  1986年   9篇
  1985年   12篇
  1984年   11篇
  1983年   12篇
  1982年   6篇
  1981年   7篇
  1979年   8篇
  1967年   7篇
  1966年   9篇
  1964年   9篇
  1961年   5篇
  1958年   17篇
  1957年   8篇
排序方式: 共有8489条查询结果,搜索用时 15 毫秒
91.
Erratum     
Naturwissenschaften Aktuell  相似文献   
92.
This paper is part of a two-year study to investigate the feasibility of initiating a Clean Development Mechanism (CDM) project in an indigenous community of Eastern Panamá, Ipetí-Emberá. We use participatory mapping and matrices as well as household surveys to develop a land-use/land-cover baseline scenario and examine the role of local participation in assessing land-use change. In Ipetí, land-use change has not occurred in a linear way over the last decades, and our data unveils socio-economic factors as potential key drivers of change. The concordance that we observed between geographic information and individual and collective perceptions of land-use change substantiates the possibility of using local knowledge in the establishment of baseline data for CDM projects. Our calculations suggest that the total carbon (C) stocks in the Tierra Colectiva (TC) of Ipetí-Emberá in 2004 represents a 47% reduction from the estimated C stock at the onset of settlement in the early 1970’s. Results from the participatory assessments predict that, in 2024 and in absence of a CDM project, the C stocks will decline from 301,859 t C in 2004 to 155,730 t C, which constitutes a reduction of 52%. The scenario with CDM estimates C stocks of 305,853 t C for 2024, a value slightly superior to the 2004 value. In the TC there is ground to believe that cattle ranching is likely to become an ever more important activity as the population is young and growing and cannot easily move elsewhere. Forests tend to be cleared for cultivation while pastures are established on short fallows. Our baseline scenario underlines the potential for a CDM project to make a significant difference in the future C stocks of this landscape.  相似文献   
93.
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   
94.
95.
96.
97.
98.
99.
化学混凝-SBR法处理肉禽屠宰废水的研究   总被引:7,自引:0,他引:7  
针对肉禽屠宰废水的特点,采取了先混凝后生化的处理方法。在实验中确定了最佳混凝剂和最佳工艺条件。实验结果表明,采取此方法处理肉禽屠宰废水,其各项指标可达国家规定的排放标准。  相似文献   
100.
ABSTRACT: The objective of this article is to open a dialogue on integrating service‐learning into community based watershed management programs and to discuss opportunities and challenges that a service‐learning program presents to universities and communities. The article presents the concept and definition of service‐learning, and arguments concerning why institutions of higher education and university faculty and students should be involved with community based watershed management programs. The article describes a case study for developing a service‐learning program for watershed management at Virginia Tech and discusses lessons learned from the case study. The paper concluded that to make a service‐learning program sustainable, there should be a long term plan, regular and effective communication with the stakeholders, and some incentives for faculty and students for long term commitment to the community based watershed management programs.  相似文献   
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