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   170篇
  免费   7篇
  国内免费   5篇
安全科学   30篇
废物处理   2篇
环保管理   67篇
综合类   44篇
基础理论   25篇
污染及防治   2篇
评价与监测   4篇
社会与环境   5篇
灾害及防治   3篇
  2023年   2篇
  2022年   3篇
  2021年   3篇
  2020年   3篇
  2019年   2篇
  2018年   2篇
  2017年   2篇
  2016年   9篇
  2015年   3篇
  2014年   3篇
  2013年   10篇
  2012年   13篇
  2011年   15篇
  2010年   9篇
  2009年   14篇
  2008年   8篇
  2007年   7篇
  2006年   11篇
  2005年   12篇
  2004年   4篇
  2003年   7篇
  2002年   5篇
  2001年   1篇
  2000年   4篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1990年   2篇
  1989年   2篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1980年   2篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1973年   2篇
  1971年   1篇
排序方式: 共有182条查询结果,搜索用时 31 毫秒
81.
This paper investigates farmers' willingness to participate in Best Management Practices (BMPs) through a proposed Water quality trading (WQT) program in Kentucky. This analysis includes two parts: the first part is to investigate the factors influencing farmers' current usage of BMPs; the second part is to estimate farmers' willingness to implement BMPs given different levels of compensation given in a survey. The results show that farmers who participate in the conservation programs are more likely to use BMPs, but these farmers may not accept the offer to implement additional BMPs. Farmers' experiences about BMPs are more likely to persuade them to adopt additional BMPs than the level of compensation. The results find that using riparian buffers, fencing off animals and building up waste storage facilities are responsive to the levels of compensation offered.  相似文献   
82.
We study whether a government-sponsored voluntary pollution reduction program (VPR) promotes or deters the development of new environmental technologies that yield future emission reduction benefits. Using a panel of 127 U.S. manufacturing industries defined by 3-digit SIC classifications over the 1989–2004 period, we estimate impacts of industry-level participation in the 33/50 program, a VPR initiated by government regulators in 1991, on industry-level rates of environmental patenting. We find that higher rates of 33/50 program participation are associated with significant reductions in the number of successful environmental patent applications five to nine years after the program ended.  相似文献   
83.
Predicting species distributions from samples collected along roadsides   总被引:1,自引:0,他引:1  
Predictive models of species distributions are typically developed with data collected along roads. Roadside sampling may provide a biased (nonrandom) sample; however, it is currently unknown whether roadside sampling limits the accuracy of predictions generated by species distribution models. We tested whether roadside sampling affects the accuracy of predictions generated by species distribution models by using a prospective sampling strategy designed specifically to address this issue. We built models from roadside data and validated model predictions at paired locations on unpaved roads and 200 m away from roads (off road), spatially and temporally independent from the data used for model building. We predicted species distributions of 15 bird species on the basis of point-count data from a landbird monitoring program in Montana and Idaho (U.S.A.). We used hierarchical occupancy models to account for imperfect detection. We expected predictions of species distributions derived from roadside-sampling data would be less accurate when validated with data from off-road sampling than when it was validated with data from roadside sampling and that model accuracy would be differentially affected by whether species were generalists, associated with edges, or associated with interior forest. Model performance measures (kappa, area under the curve of a receiver operating characteristic plot, and true skill statistic) did not differ between model predictions of roadside and off-road distributions of species. Furthermore, performance measures did not differ among edge, generalist, and interior species, despite a difference in vegetation structure along roadsides and off road and that 2 of the 15 species were more likely to occur along roadsides. If the range of environmental gradients is surveyed in roadside-sampling efforts, our results suggest that surveys along unpaved roads can be a valuable, unbiased source of information for species distribution models.  相似文献   
84.
本文通过谷物装卸设备存在危险的实例,强调了储粮仓内农工存在淹埋及窒息风险,重点介绍了美国职业安全和健康署(OSHA)提出的标准和相关法规,以及粮仓农工的安全风险识别与防护经验,以对我国粮仓农工的安全与防护提供帮助。  相似文献   
85.
校园考古遗址在西安高校中星罗棋布,但多数遗址面临保护与利用失衡、整体规划缺失等问题。基于校园考古遗址的"活态保护"理念,分析了遗址现状与高校的联动关系,构建了"校园遗址保护+场景复原、人文景观、研学旅行、校企共建"保护更新模式,并通过城郊型为代表的战国(秦)大墓遗址,立足于遗址背景与校园环境,提出了"形制—内核—共享"的活态营造思路,积极探寻具有可操作性的校园遗址保护规划策略。  相似文献   
86.
This article examines the likely impacts of the United States' new federalism on natural hazard land use management in Colorado. Flood and avalanche hazard programs are the focus of the study Both short- and long-term effects of changes in funding are discussed, and the conclusions summarize probable positive and negative program impacts for the state. These results may help researchers and state authorities mitigate similar effects in their states prior to the enactment of new federalism.  相似文献   
87.
高校宿舍火灾评估体系构建   总被引:1,自引:0,他引:1  
李昂  邸超  左一鸥 《灾害学》2004,19(Z1):77-82
本文基于灾害系统理论,并结合高校校园人口密度大等实际问题,从火灾孕灾环境、火灾承灾体、火灾致灾因子、火灾灾情四个方面构建出基于高校宿舍的火灾评估体系.最终补充了灾害系统理论,为高校防火工作提供了新的方法,也为其他相关工作拓展了思路.  相似文献   
88.
Reintroduction of animals to the wild to establish free-ranging viable populations is a valuable conservation tool, but ecological skills alone are not enough to ensure a successful reintroduction; also needed to do the work are effectively designed and managed programs. This article suggests general guidelines for organizing and managing reintroduction programs, reviews some basic organizational issues, and considers ways to develop high-performance teams The need to integrate reintroduction programs into their larger interorganizational context is discussed. The reintroduction program's structure must be appropriate for its function and should be properly staffed, led, and buffered from its political environment It should process information well, learn rapidly from its own mistakes, and be creative A high-performance team devotes most of its energies to solving external rather than internal problems  相似文献   
89.
The protection of wetlands and riparian areas has emerged as an important environmental planning issue. In the United States, several federal and state laws have been enacted to protect wetlands and riparian areas. Specifically, the federal Clean Water Act includes protection requirements in Sections 301 and 303 for state water quality standards, Section 401 for state certification of federal actions (projects, permits, and licenses), and Section 404 for dredge and fill permits. The Section 401 water quality state certification element has been called the “sleeping giant” of wetlands protection because it empowers state officials to veto or condition federally permitted or licensed activities that do not comply with state water quality standards. State officials have used this power infrequently. The purpose of this research was to analyze the effectiveness of state wetland and riparian programs. Contacts were established with officials in each state and in the national and regional offices of key federal agencies. Based on interviews and on a review of federal and state laws, state program effectiveness was analyzed. From this analysis, several problems and opportunities facing state wetland protection efforts are presented.  相似文献   
90.
当代大学生就业难的道德困境   总被引:1,自引:0,他引:1  
在当前社会主义市场经济环境下,如何引导好大学毕业生树立正确的就业观,如何平衡功利主义与责任意识、享乐思想与奉献精神之间的关系,如何在企业需求与学校人才培养模式之间形成良性互动,是当前大学教育工作面临的重要课题。充分调动政府、社会、企业、学校各自资源的力量,是解决当代大学生就业困境的重要出路。  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