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   191篇
  免费   2篇
  国内免费   5篇
安全科学   11篇
废物处理   8篇
环保管理   20篇
综合类   33篇
基础理论   63篇
污染及防治   49篇
评价与监测   6篇
社会与环境   7篇
灾害及防治   1篇
  2023年   1篇
  2022年   2篇
  2020年   1篇
  2019年   3篇
  2018年   6篇
  2017年   6篇
  2016年   9篇
  2015年   9篇
  2014年   6篇
  2013年   11篇
  2012年   12篇
  2011年   12篇
  2010年   12篇
  2009年   15篇
  2008年   12篇
  2007年   9篇
  2006年   9篇
  2005年   11篇
  2004年   5篇
  2003年   6篇
  2002年   6篇
  2001年   2篇
  2000年   5篇
  1999年   8篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1993年   3篇
  1992年   2篇
  1991年   1篇
  1988年   2篇
  1987年   1篇
  1984年   1篇
  1967年   1篇
  1965年   1篇
排序方式: 共有198条查询结果,搜索用时 15 毫秒
51.
In an acid mining lake (pH 2.6) enclosure experiments wereperformed with the addition of different concentrations oforganic carbon, nitrogen and phosphorus. SSCP-communityfingerprints, based on 16S rRNA gene amplicons, were performed tomonitor changes in the structure of the total bacterialcommunity and the sulfate reducing bacteria (SRB) in themesocosms. Total bacterial cell counts, as assessed byepifluorescence microscopy, were increased in the mesocosmsamended with organic carbon. The addition of carbon alsoincreased the number of abundant bacterial taxa substantiallyalong depth. Sulfate reducing bacteria (SRB) could be detected inall enclosures and all parts of the water column. These SRBbelonged to genus Desulfobacter as indicated bycoroborating molecular data.  相似文献   
52.
Via a historical reconstruction, this paper primarily demonstrates how the societal debate on genetically modified organisms (GMOs) gradually extended in terms of actors involved and concerns reflected. It is argued that the implementation of recombinant DNA technology out of the laboratory and into civil society entailed a “complex of concerns.” In this complex, distinctions between environmental, agricultural, socio-economic, and ethical issues proved to be blurred. This fueled the confusion between the wider debate on genetic modification and the risk assessment of transgenic crops in the European Union. In this paper, the lasting skeptical and/or ambivalent attitude of Europeans towards agro-food biotechnology is interpreted as signaling an ongoing social request – and even a quest – for an evaluation of biotechnology with Sense and Sensibility. In this (re)quest, a broader-than-scientific dimension is sought for that allows addressing the GMO debate in a more “sensible” way, whilst making “sense” of the different stances taken in it. Here, the restyling of the European regulatory frame on transgenic agro-food products and of science communication models are discussed and taken to be indicative of the (re)quest to move from a merely scientific evaluation and risk-based policy towards a socially more robust evaluation that takes the “non-scientific” concerns at stake in the GMO debate seriously.  相似文献   
53.
Summary Position preferences of well-fed and food-deprived juvenile roach were investigated in schools of 2 and 4 fish in the laboratory. Food-deprived fish appeared significantly more often in the front position than their well-fed conspecifics. For fish at the same hunger level, individuals at the front of the school had the highest feeding rate. These results represent the first evidence for a relationship between the nutritional state of individual fish and their positions in a school and suggest a functional advantage of the preference. Offprint requests to: J. Krause at the present address  相似文献   
54.
55.
56.
Dormant propagule banks are important reservoirs of biological and genetic diversity of local communities and populations and provide buffering mechanisms against extinction. Although dormant stages of various plant and animal species are known to remain viable for decades and even centuries, little is known about the effective influence of recolonization from such old sources on the genetic continuity of intermittent populations under natural conditions. Using recent and old dormant eggs recovered from a dated lake sediment core in Kenya, we traced the genetic composition of a local population of the planktonic crustacean Daphnia barbata through a sequence of extinction and recolonization events. This was combined with a phylogeographic and population-genetic survey of regional populations. Four successive populations, fully separated in time, inhabited Lake Naivasha from ca. 1330 to 1570 AD, from ca. 1610 to 1720 AD, from ca. 1840 to 1940 AD, and from 1995 to the present (2001 AD). Our results strongly indicate genetic continuity between the 1840-1940 and 1995-2001 populations, which are separated in time by at least 50 years, and close genetic relatedness of them both to the 1330-1580 population. A software tool (Colonize) was developed to find the most likely source population of the refounded 1995-2001 population and to test the number of colonists involved in the recolonization event. The results confirmed that the 1995-2001 population most probably developed out of a limited number of surviving local dormant eggs from the previous population, rather than out of individuals from regional (central and southern Kenya) or more distant (Ethiopia, Zimbabwe) populations that may have immigrated to Lake Naivasha through passive dispersal. These results emphasize the importance of prolonged dormancy for the natural long-term dynamics of crustacean zooplankton in fluctuating environments and suggest an important role of old local dormant egg banks in aquatic habitat restoration.  相似文献   
57.
58.
59.
60.
Research on international climate finance got a new impetus from the United Nations Framework Convention on Climate Change Cancun Accords in 2010 which pledge to mobilize US dollars (USD) 100 billion in international climate financing annually by 2020. The Accords’ specification that adaptation must be addressed with the same priority as mitigation is not reflected in current patterns of international climate finance where we face a strong bias towards mitigation finance. A recent study by Buchner et al. (2011) ascertains a split between mitigation and adaptation finance of 95:5. In this paper, we investigate potential reasons for this bias. In our framework, we distinguish different decision layers and actors involved in international climate finance in order to categorize the causes responsible for the low priority of adaptation in international finance. The identification of obstacles for international adaptation funding is a first crucial step in the search for ways to overcome respective barriers. We find several different causes of the mitigation bias and these might offer starting points for policies aiming at raising adaptation finance and curing this bias. Furthermore, we describe interrelations between these causes which effective policies have to take into account.  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