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   1217篇
  免费   106篇
  国内免费   159篇
安全科学   167篇
废物处理   7篇
环保管理   259篇
综合类   512篇
基础理论   251篇
污染及防治   41篇
评价与监测   59篇
社会与环境   143篇
灾害及防治   43篇
  2024年   4篇
  2023年   15篇
  2022年   41篇
  2021年   70篇
  2020年   51篇
  2019年   54篇
  2018年   30篇
  2017年   45篇
  2016年   57篇
  2015年   43篇
  2014年   71篇
  2013年   88篇
  2012年   85篇
  2011年   94篇
  2010年   96篇
  2009年   91篇
  2008年   76篇
  2007年   95篇
  2006年   70篇
  2005年   53篇
  2004年   42篇
  2003年   41篇
  2002年   25篇
  2001年   17篇
  2000年   23篇
  1999年   9篇
  1998年   17篇
  1997年   12篇
  1996年   13篇
  1995年   7篇
  1994年   14篇
  1993年   7篇
  1992年   6篇
  1991年   2篇
  1990年   1篇
  1989年   4篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1984年   2篇
  1978年   2篇
  1977年   2篇
  1974年   1篇
  1973年   1篇
  1971年   1篇
排序方式: 共有1482条查询结果,搜索用时 93 毫秒
991.
以湖南省长株潭地区24个环境空气质量监测国控点数据为基础,对2013年6月~8月持续高温干旱天气条件下,长株潭地区城市PM2.5浓度的日、月变化规律,以及点位差异性分布等进行分析。结果表明,进入夏季持续高温干旱天气后,PM2.5质量浓度较冬季显著下降。受人为活动影响,位于商业区的监测站点的PM2.5较其他站点高;不同城市PM2.5的日变化规律基本一致,呈双峰型;夏季PM2.5上午出现最高值的时间比冬季提前1 h左右,商业区站点的PM2.5最高值出现的时间较其他类型站点早1~2 h。非工作日PM2.5的峰值出现在夜间和凌晨,而工作日则出现在上午9~11点。  相似文献   
992.
Surface water and air volatile organic compound (VOC) data from 10 U.S. Geological Survey monitoring sites were used to evaluate the potential for direct transport of VOCs from the atmosphere to urban streams. Analytical results of 87 VOC compounds were screened by evaluating the occurrence and detection levels in both water and air, and equilibrium concentrations in water (Cws) based on the measured air concentrations. Four compounds (acetone, methyl tertiary butyl ether, toluene, and m‐ & p‐xylene) were detected in more than 20% of water samples, in more than 10% of air samples, and more than 10% of detections in air were greater than long‐term method detection levels (LTMDL) in water. Benzene was detected in more than 20% of water samples and in more than 10% of air samples. Two percent of benzene detections in air were greater than one‐half the LTMDL in water. Six compounds (chloroform, p‐isopropyltoluene, methylene chloride, perchloroethene, 1,1,1‐trichloroethane, and trichloroethene) were detected in more than 20% of water samples and in more than 10% of air samples. Five VOCs, toluene, m‐ & p‐xylene, methyl tert‐butyl ether (MTBE), acetone, and benzene were identified as having sufficiently high concentrations in the atmosphere to be a source to urban streams. MTBE, acetone, and benzene exhibited behavior that was consistent with equilibrium concentrations in the atmosphere.  相似文献   
993.
重点生态功能区关乎地区乃至国家的生态安全,属于限制开发区。该类功能区为提供生态产品投入大量的环境建设成本,又因限制开发导致发展权受限,需要对其进行生态补偿。作为当前生态补偿的主要方式,重点生态功能区转移支付制度在资金分配、资金使用、监督考核和激励机制方面存在不足,因此提出确定生态环境保护为转移支付的主要目标、健全资金用途监管和绩效评估制度、补充适用横向生态补偿制度等措施予以完善。  相似文献   
994.
Abstract

As the main organic pollutant in municipal living waste, kitchen waste causes secondary pollution in the course of its being gathered and transported to the landfill by mixing with other refuse and by decomposition. This makes pollution prevention more difficult and raises the cost of landfill engineering. However, the amount of solid waste to be treated can be decreased and such pollution burden lessened by disposing of the solid waste in local municipal areas. The program in Beijing also shows that this works well with our situation in China and can accelerate marketization and public participation.  相似文献   
995.
Abstract

On the basis of applying quantitative and qualitative approaches as well as GIS technology, this paper established an index system to make a comprehensive evaluation on socioeconomic development of minority areas in China. The result showed that socio-economic development in minority area presents a series of characteristics that the north is high and the south is low, center-margin pattern is obvious and the areas with middle and lower development indices are distributed centrally and continuously. However, the causes of the socioeconomic characteristics mainly include natural conditions, economic development basic, population cultural quality, regional combination and development conditions of mineral and energy resources, informal institutional factors and distribution of major traffic lines.  相似文献   
996.
Abstract: Relationships between nutrient concentrations and fish nutrient tolerance were assessed relative to established nutrient criteria. Fish community, nitrate plus nitrite (nitrate), and total phosphorus (TP) data were collected during summer low‐flow periods in 2003 and 2004 at stream sites along a nutrient‐enrichment gradient in an agricultural basin in Indiana and Ohio and an urban basin in the Atlanta, Georgia, area. Tolerance indicator values for nitrate and TP were assigned for each species and averaged separately for fish communities at each site (TIVo). Models were used to predict fish species expected to occur at a site under minimally disturbed conditions and average tolerance indicator values were determined for nitrate and TP separately for expected communities (TIVe). In both areas, tolerance scores (TIVo/TIVe) for nitrate increased significantly with increased nitrate concentrations whereas no significant relationships were detected between TP tolerance scores and TP concentrations. A 0% increase in the tolerance score (TIVo/TIVe = 1) for nitrate corresponded to a nitrate concentration of 0.19 mg/l (compared with a USEPA summer nitrate criterion of 0.17 mg/l) in the urban area and 0.31 mg/l (compared with a USEPA summer nitrate criterion of 0.86 mg/l) in the agricultural area. Fish nutrient tolerance values offer the ability to evaluate nutrient enrichment based on a quantitative approach that can provide insights into biologically relevant nutrient criteria.  相似文献   
997.
Abstract: Runoff from parking lots during summer storms injects surges of hot water into receiving water bodies. We present temperature data collected near urban storm sewer outfalls in Blacksburg, Virginia, using arrays of sensors in a stream and a stormwater pond. Surges occurred roughly a dozen times per month, ranging up to 8.1°C with average duration 2 h in the stream and up to 11.2°C with average duration 7 h in the pond. Surges were larger in the pond due to a larger contributing watershed, no dilution by upstream water, and cool background temperatures near the outfall. Surges began abruptly, warming at rates averaging 0.2°C/min for periods of 5‐20 min. Surges dissipated as they propagated into the water bodies, travelling further in the stream (>19 m) than the pond (~10 m) consistent with greater advection in the stream. Surges were largest and most frequent in the afternoon but occurred at all times of day and night. Stream surges exhibited two phases: an early high‐temperature low‐volume input from the storm sewer and a later low‐temperature high‐volume input from upstream. Surges at the pond did not exhibit two phases, consistent with inputs only from storm sewers. Surges are likely common in urban areas, and may cumulatively have consequences for aquatic organisms, biogeochemical process rates, and even human health. Such effects may be compounded by urban heat islands and climate change, so prevention or mitigation should be considered.  相似文献   
998.
This article aims at comparing power resources that opponents to environmental policy apply in shaping and constructing discourses that contest the implementation of marine and terrestrial area protection. Document analyses and qualitative interviews have been undertaken with key actors and documents in two case areas to show how actors, knowledge, and financial and organisational capacities are introduced in the planning processes in order to contest the dominating environmental discourse established by environmental authorities. The results demonstrate how opponents to the terrestrial case were rather fragmented, consisting of a wide range of local and regional actors with various interests and agendas, and without substantial financial and organisational strength. Here, the environmental administration managed to create a partnership with local authorities that eventually proclaimed the national park as a win–win situation for local society. As a contrast, the opponents to the marine case had strong organisational, financial and even scientific capacities that were effectively unified with local authorities in the Skjerstad fjord. Here, the win–win situation was not accepted by the local parties. Together, these resources seemed to explain some of the variance in institutional responses in environmental administration, and finally different outcomes of the two cases.  相似文献   
999.
Despite over two decades of efforts towards involving indigenous and traditional peoples in protected area management, there are few successful examples. Several international principles and guidelines on indigenous peoples' involvement in protected areas exist. However, because of the lack of evaluation of whether or not these principles and guidelines have been put into practice, there is hardly any information that indicates the actual involvement of indigenous peoples in protected areas. This paper attempts to compare efforts in partnership between indigenous peoples and protected area authority in three Asian countries: Nepal, Thailand, and China. It shows that the involvement of indigenous peoples is more successful where park planning is participatory and where political and socioeconomic reforms are underway. Indigenous peoples are in conflict with park authorities where park management is centralized and nonparticipatory. Unless concrete efforts are made to address livelihood issues of indigenous peoples living in and around protected areas, park management aimed to protect wildlife will rarely succeed. Participatory park management that involves indigenous peoples and that addresses livelihood issues of indigenous communities will ultimately succeed in its efforts toward wildlife conservation.  相似文献   
1000.
The United States and Finland have passed laws to classify and manage Arctic wilderness areas, but their national policies are based on different nature ideologies. Finns tend to perceive wilderness as a human-centered idea, while Americans are inclined to see the same land from a nature-based point of view. Rural residents in the Arctic, and especially indigenous peoples, use motorized vehicles for hunting and gathering in wilderness areas. Attempts of southern-based environmental groups to restrict motor use by imposing a nature-based ideology on rural residents in northern Alaska will result in high levels of political conflict. Alaska land managers need to respect the minority rights of rural residents and a study of wilderness policies in Finnish Lapland is instructive toward this end.  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