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   130篇
  免费   1篇
安全科学   11篇
废物处理   2篇
环保管理   22篇
综合类   12篇
基础理论   30篇
污染及防治   31篇
评价与监测   10篇
社会与环境   6篇
灾害及防治   7篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2017年   3篇
  2016年   5篇
  2014年   2篇
  2013年   11篇
  2012年   3篇
  2011年   4篇
  2010年   2篇
  2009年   7篇
  2008年   3篇
  2007年   2篇
  2005年   6篇
  2004年   6篇
  2003年   4篇
  2002年   4篇
  2001年   2篇
  2000年   2篇
  1999年   2篇
  1998年   3篇
  1997年   3篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1991年   4篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1985年   3篇
  1984年   5篇
  1983年   2篇
  1982年   2篇
  1981年   5篇
  1980年   3篇
  1979年   2篇
  1978年   4篇
  1977年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有131条查询结果,搜索用时 31 毫秒
41.
42.
Nine hectares (23 acres) of a degraded section of Patuxent Research Refuge in Laurel, Maryland, USA, were converted to wetland habitat by the Baltimore Gas and Electric Company in 1994. The wetlands were created as mitigation for 5.7 ha (14 acres) of wetlands that were impacted as part of the construction of an 8.5-km (5.3-mile) 500-kV overhead transmission line on the refuge. The area consists of a created forested wetland of 5.5 ha (13.5 acres), a seasonally inundated green-tree reservoir of 7.6 ha (6.5 acres), and an impounded pond wetland of 1.2 ha (3 acres). Construction included the planting of 6131 trees, 4276 shrubs, and 15,102 emergent plants. Part of the site has been studied intensively since completion and survival of trees and shrubs after two years was 88%. Measurements of these transplants have shown growth greater than on other created sites in Maryland. Grasses and other herbaceous vegetation were dominant plants in the meter-square plots in the first two years of sampling of the created forested wetland. Wildlife surveys for birds, mammals, amphibians, and reptiles have revealed diverse communities. Although these communities represent species consistent with open habitat, more typical forest species should colonize the area as it undergoes succession into a more mature forested wetland. The creation, management, and research of this mitigation site represents an excellent example of a partnership between a private electric power company and a federal wildlife refuge. This partnership has increased local biodiversity and improved regional water quality of the Patuxent River and the Chesapeake Bay.  相似文献   
43.
44.
ABSTRACT: Traditional focus on reducing one environmental externality may cause another externality to increase. This article examines the environmental and economic costs of abating soil loss and (or) nitrate leaching through alternative optimal production systems in the nonirrigated farming systems of Northeastern Oregon. Models estimating soil loss and nitrate‐nitrogen leaching rates associated with current production processes, are linked to a Multi‐Objective Programming (MOP) model. The results show that site specific conditions influence the level of abatement expenditures and optimal production strategies to reduce soil loss and leaching rates. Moreover, while existing production strategies are effective in reducing soil loss at little cost, no strategies could be identified to reduce nitrate leaching rate on some soils.  相似文献   
45.
Relational demography research has emphasized a similarity–attraction paradigm in explaining employees' reactions to demographic differences from other organizational members. This study examined similarity–attraction (nondirectional age differences) and status incongruence (directional age differences) predictions of age difference effects. The nondirectional and directional differences between the age of a subordinate and the ages of his or her immediate and higher‐level supervisors were used to predict employee absenteeism, citizenship, and work change behaviors. Results revealed that there were more significant and marginally significant directional age difference effects than nondirectional age difference effects on work outcomes. The implications of these results for organizations are discussed. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
46.
This research explored ironic evaluation processes initiated by suppression instructions conveyed during diversity training. Raters watched one of three training videos: a video providing information about age diversity and recommending that they try to suppress age‐related thoughts; a video providing information about age, sex, race, and ethnic diversity and recommending that they try to suppress demography‐related thoughts; or a control video containing no suppression recommendations. All raters then evaluated a series of job applicants. During the evaluation task, some raters were cognitively busy while others were not. Ironically, busy raters instructed to suppress age‐related thoughts evaluated an older applicant less favorably than raters in other conditions. These results suggest that organizational diversity training including instructions to suppress stereotypic thoughts may have detrimental effects on evaluations of non‐traditional job applicants if raters are cognitively busy when they implement these instructions. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   
47.
Many causes for falls from ladders in construction are related to the user’s activities; however, the extent to which users comply with ladder use best practices is unknown and has not been well quantified before. We developed and tested an audit tool that assesses compliance with best practices guidelines for portable-ladder-use designed for applications in the construction industry. Implemented on a hand-held computer, the assessment tool consisted of a series of check-lists categorized in four groups; ladder condition, setup, moving on a ladder, and completing tasks from a ladder. For these four observational categories, the resulting tool contained 31 and 33 questions for step and extension ladders, respectively. Three individuals trained to use the tool scored a set of photographs and videos depicting 25 ladder conditions, 20 ladder setups, 10 users moving on ladders, and 13 users completing tasks from a ladder for a total of 78 observations. The assessment tool had good agreement across and within raters. For the three raters, agreement ranged from 79% to 97% across the questions. Within one subject, kappa coefficients for the intra-rater reliability ranged from 0.67 to 0.91. The tool offers a practical method to quantify best practices associated with ladder use that can ultimately inform targeted intervention efforts.  相似文献   
48.
Linear regression of high volume air sampler data and various meteorological parameters was used to determine a suspended particulate air pollution climatology for Albany, NY. A new method for exhibiting associations between wind direction and pollutant levels using correlation coefficients is presented. Correlations between wind direction distribution frequency and other meteorological parameters is employed to help explain differences in correlations for direction with suspended particulate levels. Results show that high particulate concentrations correlate well with southerly wind flow throughout the study area, regardless of relative location of receptor to local sources. This suggests that ambient background concentrations inherent in different air masses more consistently affected suspended particulate levels than did the diffusion from local sources during the study period. Maximum particulate advection occurs under conditions of good mixing of the boundary layer and moderate wind speeds and is enhanced further in the absence of removal processes such as rainout and washout. Trajectory analysis of selected days indicates a definite relationship between path and origin of the wind flow and regional average particulate concentration.  相似文献   
49.
50.
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