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   10692篇
  免费   27篇
  国内免费   25篇
安全科学   131篇
废物处理   573篇
环保管理   1172篇
综合类   1332篇
基础理论   3284篇
环境理论   1篇
污染及防治   1959篇
评价与监测   804篇
社会与环境   1461篇
灾害及防治   27篇
  2023年   42篇
  2022年   75篇
  2021年   59篇
  2020年   29篇
  2019年   42篇
  2018年   636篇
  2017年   616篇
  2016年   558篇
  2015年   123篇
  2014年   152篇
  2013年   416篇
  2012年   374篇
  2011年   978篇
  2010年   616篇
  2009年   677篇
  2008年   851篇
  2007年   1080篇
  2006年   240篇
  2005年   274篇
  2004年   217篇
  2003年   310篇
  2002年   307篇
  2001年   269篇
  2000年   172篇
  1999年   105篇
  1998年   64篇
  1997年   58篇
  1996年   53篇
  1995年   60篇
  1994年   64篇
  1993年   59篇
  1992年   58篇
  1991年   61篇
  1990年   66篇
  1989年   52篇
  1988年   56篇
  1987年   54篇
  1986年   55篇
  1985年   41篇
  1984年   58篇
  1983年   50篇
  1982年   48篇
  1980年   30篇
  1979年   32篇
  1978年   29篇
  1977年   28篇
  1976年   28篇
  1974年   31篇
  1973年   30篇
  1972年   27篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
891.

Introduction  

Ciliated protozoa play important roles in aquatic ecosystems especially regarding their functions in micro-food web and have many advantages in environmental assessment compared with most other eukaryotic organisms. The aims of this study were focused on analyzing the application of an indicator based on taxonomic relatedness of ciliated protozoan assemblages for marine environmental assessment.  相似文献   
892.

Introduction  

In this study, we explore the identity of a range of polyfluorinated surfactants (PFS) used for food contact materials, primarily to impart oil and water repellency on paper and board. PFS are of interest, as they can be precursors of poly- and perfluorinated alkyl substances (PFAS), of which several are persistent and are found worldwide in human blood and in the environment.  相似文献   
893.

Background, aim and scope  

Water quality impairment by heavy metal contamination is on the rise worldwide. Phytoremediation technology has been increasingly applied to remediate wastewater and stormwater polluted by heavy metals.  相似文献   
894.
香港区域发展的策略性环境影响评价(简称环评)从20世纪80年代起步,已形成包括行政规定和法例规定的制度框架,其策略性环评的实践范围也逐步从规划、计划向政策、策略扩展.从评价过程、评价方法、公众参与时段安排、决策出发点等方面分析了2个香港区域发展的策略性环评案例.结果表明,为使策略性环评取得预想的成果并有助于可持续发展,...  相似文献   
895.
This paper analyses environmental and socio-economic barriers for plantation activities on local and regional level and investigates the potential for carbon finance to stimulate the increased rates of forest plantation on wasteland, i.e., degraded lands, in southern India. Building on multidisciplinary field work and results from the model GCOMAP, the aim is to (1) identify and characterize the barriers to plantation activities in four agro-ecological zones in the state of Karnataka and (2) investigate what would be required to overcome these barriers and enhance the plantation rate and productivity. The results show that a rehabilitation of the wasteland based on plantation activities is not only possible but also anticipated by the local population and would lead to positive environmental and socio-economic effects at a local level. However, in many cases, the establishment of plantation activities is hindered by a lack of financial resources, low land productivity and water scarcity. Based on the model used and the results from the field work, it can be concluded that certified emission reductions such as carbon credits or other compensatory systems may help to overcome the financial barrier; however, the price needs to be significantly increased if these measures are to have any large-scale impact.  相似文献   
896.
We present climate change projections and apply indices of weather extremes for the Mediterranean island Cyprus using data from regional climate model (RCM) simulations driven by the IPCC A1B scenario within the ENSEMBLES project. Daily time-series of temperature and precipitation were used from six RCMs for a reference period 1976–2000 and for 2026–2050 (‘future‘) for representative locations, applying a performance selection among neighboring model grid-boxes. The annual average temperatures of the model ensemble have a ±1.5°C bias from the observations (negative for maximum and positive for minimum temperature), and the models underestimate annual precipitation totals by 4–17%. The climatological annual cycles for the observations fall within the 1σ range of the 6-model average, highlighting the strength of using multi-model output. We obtain reasonable agreement between models and observations for the temperature-related indices of extremes for the recent past, while the comparison is less good for the precipitation-related extremes. For the future, the RCM ensemble shows significant warming of 1°C in winter to 2°C in the summer for both maximum and minimum temperatures. Rainfall is projected to decrease by 2–8%, although this is not statistically significant. Our results indicate the shift of the mean climate to a warmer state, with a relatively strong increase in the warm extremes. The precipitation frequency is projected to decrease at the inland Nicosia and at the coastal Limassol, while the mountainous Saittas could experience more frequent 5–15 mm/day rainfall. In future, very hot days are expected to increase by more than 2 weeks/year and tropical nights by 1 month/year. The annual number of consecutive dry days shows a statistically significant increase (of 9 days) in Limassol. These projected changes of the Cyprus climate may adversely affect ecosystems and the economy of the island and emphasize the need for adaptation strategies.  相似文献   
897.
Climate adaptation is a complex task surrounded by uncertainty. To support climate adaptation policies, a new scenario approach is pursued to explore possible discontinuous future developments of societal perspectives on climate adaptation issues. The scenario approach was tested for a case study on Dutch river management. In a series of scenario development workshops, a select group of stakeholders explored the perspectives on the management of the River Meuse in the past, present, and future. The process was supported by an analytical perspectives mapping tool to illustrate and analyze the development of perspectives over time. The process and analytical tools contributed to insight into the drivers of perspective change for the case study at hand. Moreover, the stakeholders highlighted the potential of the approach for water management policy for creating awareness about the plurality of perspectives and the dynamics of perspective change, monitoring perspectives and perspective change as part of a flexible policy approach, and anticipating on the occurrence of shock events. Further work is required to better represent the social dynamics of perspectives change, to better empirically ground the perspective change model, and to apply integrated water models in the scenario development process to assess water–society interactions.  相似文献   
898.
Using the focusing event framework, a comprehensive analysis of private households’ and businesses’ preparedness was undertaken in the aftermath of the 2002 and 2006 flood events on the Elbe River in Germany. In August 2002, preparedness of households (n = 235) and businesses (n = 103) was low: 30% of the households and 54% of the businesses took no precautionary measures before the flood event. Many undertaken emergency measures were ineffective, since only 26% of all households knew how to react when the flood warning came, and only 9% of businesses had an emergency plan in place. Due to this extreme flood, double-loop learning occurred in many households and businesses, so that many did implement precautionary measures. The distribution of adopted precautionary measures for households fits well to Preisendörfer’s low-cost hypothesis, but does not apply for businesses. Only 10% of the households (n = 112), but still 29% of the businesses (n = 41) were unprepared before the flood in 2006. Significant improvement in flood preparedness activities is still necessary. Particularly for businesses, regulatory programs and programs encouraging proactive behaviour should be implemented. The focusing event framework proofed to be a useful tool for a differentiated analysis of the responses to and learning due to a disaster also in the commercial and private sector.  相似文献   
899.
Rapid land-use change arising from incentives for afforestation has created tensions in rural communities previously dominated by agricultural enterprises. This paper reports on an innovative experiment with social learning that incorporated participatory modelling to resolve community concerns in a case study of plantation forestry in the Upper Clarence catchment of north-eastern NSW Australia. The development of a diagnostic framework helped identify socioeconomic and environmental issues within the community for investigation by a self-selected participatory advisory committee (PAC) representing a diversity of views. Implementation of a social learning exercise offered empathetic and intellectual engagement among PAC members that maintained interest, built confidence, and improved problem-solving capacity while fostering group ownership over decision making. A shared understanding of dynamic landscape problems helped empower participants to collaboratively develop solutions for improved management and operational practices, and cooperate to explore further options for plantation industry development under existing policy guidelines which are presented in this paper. As a result of frank discussions between diverse stakeholders in a mutually respectful learning environment that combined local, scientific and expert knowledge, concerns dissipated and participants developed a more favourable view of plantation forestry activity.  相似文献   
900.
Climate changes in the Mediterranean region, related to a significant increase in temperature and changes in precipitation patterns, can potentially affect local economies. Agriculture and tourism are undoubtedly the most important economic sources for Greece and these may be more strongly affected by changing future climate conditions. Climate change and their various negative impacts on human life are also detected in their environment; hence this study deals with implications, caused by changing climate, in urban and forest areas. Potential changes for the mid-twenty-first century (2021–2050) are analysed using a high-resolution regional climate model. This paper presents relevant climatic indices, indicative for potential implications which may jeopardise vital economic/environmental sectors of the country. The results provide insights into particular regions of the Greek territory that may undergo substantial impacts due to climate change. It is concluded that the duration of dry days is expected to increase in most of the studied agricultural regions. Winter precipitation generally decreases, whereas an increase in autumn precipitation is projected in most areas. Changing climate conditions associated with increased minimum temperatures (approximately 1.3°C) and decreased winter precipitation by 15% on average suggest that the risk for forest fires is intensified in the future. In urban areas, unpleasantly high temperatures during day and night will increase the feeling of discomfort in the citizens, while flash floods events are expected to occur more frequently. Another impact of climate change in urban regions is the increasing energy demand for cooling in summer. Finally, it was found that continental tourist areas of the Greek mainland will more often face heatwave episodes. In coastal regions, increased temperatures especially at night in combination with high levels of relative humidity can lead to conditions that are nothing less than uncomfortable for foreigners and the local population. In general, projected changes associated with temperature have a higher degree of confidence than those associated with precipitation.  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