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   641篇
  免费   10篇
  国内免费   1篇
安全科学   18篇
废物处理   15篇
环保管理   209篇
综合类   54篇
基础理论   156篇
污染及防治   151篇
评价与监测   23篇
社会与环境   22篇
灾害及防治   4篇
  2023年   3篇
  2021年   7篇
  2020年   6篇
  2019年   9篇
  2018年   6篇
  2017年   8篇
  2016年   25篇
  2015年   14篇
  2014年   24篇
  2013年   61篇
  2012年   29篇
  2011年   26篇
  2010年   15篇
  2009年   24篇
  2008年   22篇
  2007年   26篇
  2006年   17篇
  2005年   19篇
  2004年   28篇
  2003年   26篇
  2002年   18篇
  2001年   19篇
  2000年   12篇
  1999年   7篇
  1998年   16篇
  1997年   5篇
  1996年   8篇
  1994年   16篇
  1993年   11篇
  1992年   5篇
  1991年   8篇
  1990年   12篇
  1989年   7篇
  1988年   8篇
  1987年   6篇
  1986年   11篇
  1985年   7篇
  1984年   6篇
  1983年   10篇
  1982年   8篇
  1981年   8篇
  1980年   10篇
  1979年   5篇
  1978年   6篇
  1977年   5篇
  1976年   4篇
  1975年   2篇
  1973年   3篇
  1972年   2篇
  1967年   2篇
排序方式: 共有652条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Regional municipal water plans typically do not recognize complex coupling patterns or that increased withdrawals in one location can result in changes in water availability in others. We investigated the interaction between urban growth and water availability in the Baltimore metropolitan region where urban growth has occurred beyond the reaches of municipal water systems into areas that rely on wells in low‐productivity Piedmont aquifers. We used the urban growth model SLEUTH and the hydrologic model ParFlow.CLM to evaluate this interaction with urban growth scenarios in 2007 and 2030. We found decreasing groundwater availability outside of the municipal water service area. Within the municipal service area we found zones of increasing storage resulting from increased urban growth, where reduced vegetation cover dominated the effect of urbanization on the hydrologic cycle. We also found areas of decreasing storage, where expanding impervious surfaces played a larger role. Although the magnitude of urban growth and change in water availability for the simulation period were generally small, there was considerable spatial heterogeneity of changes in subsurface storage. This suggests that there are locally concentrated areas of groundwater sensitivity to urban growth where water shortages could occur or where drying up of headwater streams would be more likely. The simulation approach presented here could be used to identify early warning indicators of future risk.  相似文献   
6.
This work applies optimization and an Eulerian inversion approach presented by Bagtzoglou and Baun in 2005 in order to reconstruct contaminant plume time histories and to identify the likely source of atmospheric contamination using data from a real test site for the first time. Present-day distribution of an atmospheric contaminant plume as well as data points reflecting the plume history allow the reconstruction and provide the plume velocity, distribution, and probable source. The method was tested to a hypothetical case and with data from the Forest Atmosphere Transfer and Storage (FACTS) experiment in the Duke experimental forest site. In the scenarios presented herein, as well as in numerous cases tested for verification purposes, the model conserved mass, successfully located the peak of the plume, and managed to capture the motion of the plume well but underestimated the contaminant peak.  相似文献   
7.
Environmental Management - Parks and protected area managers use zoning to decrease interpersonal conflict between recreationists. Zoning, or segregation, of recreation—often by non-motorized...  相似文献   
8.
Polychlorinated biphenyls (PCBs) have been monitored in perch (Perca fluviatilis), pike (Esox lucius), and Arctic char (Salvelinus alpinus) in reference lakes since the late 1960s. Temporal trends and spatial patterns are currently monitored in nine and 32 lakes, respectively. Overall, PCB concentrations are decreasing. However, this is not consistent for all congeners across all lakes and species. Perch has comparatively low PCB concentrations relative to suggested target levels, but individual congener concentrations in some lakes are concerningly high. No temporal trend is seen for CB-118 and CB-153 in perch, but significant decreasing trends exist for Arctic char and pike, for which monitoring started earlier than for perch. The lower/higher chlorinated congener ratio decreased over time in most lakes, indicating fewer new emissions. CB-118 and CB-153 concentrations in perch show spatial gradients across Sweden, with higher concentrations found near urban/industrial areas.  相似文献   
9.
Environmental restoration projects are commonly touted for their ecological positives, but such projects can also provide significant socioeconomic and cultural benefits to local communities. We assessed the social dimensions of a large-scale coral reef restoration project in Maunalua Bay, O‘ahu, where >1.32 million kg of invasive marine macroalgae was removed from 11 hectares (90,000 m2; 23 acres) of impacted coral reef in an urbanized setting. We interviewed 131 community stakeholders and analyzed both quantitative and qualitative data to assess human uses of the environment, assess perceptions of environmental health, and characterize social dimensions (+/?) associated with the invasive algae removal effort. Results indicate substantial direct economic benefits, including the creation of more than 60+ jobs, benefiting more than 250 individuals and 81 households. The project helped develop a skilled workforce in a local business dedicated to environmental restoration and increased the capacity of community organizations to address other threats to reefs and watersheds. Other major benefits include revitalization of Native Hawaiian cultural practices and traditions and the successful use of harvested invasive algae as compost by local farmers. Our results show the project heightened community awareness and a broader sense of stewardship in the area, creating enabling conditions for collective community action. Our findings show that restoration projects that explicitly incorporate efforts to build community awareness, involvement, and a shared responsibility for a site may ultimately create the long-term capacity for sustainable stewardship programs. We conclude by discussing lessons learned for engaging productively with communities in environmental restoration and stewardship, which remains a central focus in conservation worldwide.  相似文献   
10.
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