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   424篇
  免费   13篇
  国内免费   26篇
安全科学   35篇
废物处理   2篇
环保管理   145篇
综合类   151篇
基础理论   44篇
污染及防治   25篇
评价与监测   23篇
社会与环境   22篇
灾害及防治   16篇
  2023年   5篇
  2022年   3篇
  2021年   16篇
  2020年   20篇
  2019年   7篇
  2018年   12篇
  2017年   13篇
  2016年   16篇
  2015年   17篇
  2014年   17篇
  2013年   28篇
  2012年   18篇
  2011年   19篇
  2010年   23篇
  2009年   19篇
  2008年   22篇
  2007年   16篇
  2006年   16篇
  2005年   15篇
  2004年   9篇
  2003年   15篇
  2002年   12篇
  2001年   14篇
  2000年   16篇
  1999年   12篇
  1998年   10篇
  1997年   9篇
  1996年   4篇
  1995年   7篇
  1994年   4篇
  1993年   3篇
  1992年   3篇
  1990年   2篇
  1989年   4篇
  1988年   4篇
  1986年   5篇
  1985年   5篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   3篇
  1979年   4篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1971年   1篇
排序方式: 共有463条查询结果,搜索用时 296 毫秒
291.
蒸汽直埋管道的安全与节能技术近年来日趋成熟,但在南方高水位城市应用中还存在诸多缺陷。本文结合工程实践,针对这些缺陷进行了技术改进,并在多项工程中推广应用,取得了良好的效果。  相似文献   
292.
ABSTRACT

This article draws from the author’s four-year study of five school communities hit by the 2010–2011 earthquake sequence in the Canterbury region of New Zealand to highlight the roles that schools played in supporting their communities in the aftermath of the disaster. The article begins by synthesising the relevant literature on disasters, schools in earthquake disasters, and the importance of schools to their communities, pre- and post-disaster. The following themes from the data are discussed: (a) the role of schools in their communities prior to the earthquakes; (b) the role of schools in immediate rescue and response; (c) the role of schools in short-term relief; and (d) the role of schools in long-term recovery. The author then argues that as more evidence shows that schools play such crucial roles in post-disaster response and recovery, we need to better prepare and support them to undertake these functions. Further, we need to recognise the wider roles schools play supporting local communities to build and sustain resilience as part of on-going community cohesion and connectedness, so that society is better prepared when major disasters occur.  相似文献   
293.
新时期高校实验室安全管理的分析与思考   总被引:25,自引:2,他引:25  
高校实验室是进行实验教学和开展科学研究的重要基地,是理论联系实际,人才培养和科技创新的必备场所。实验室的安全对高校乃至全社会的安全和稳定都至关重要。笔者分析了新时期高校实验室安全管理的现状、特点以及存在的问题;对高校实验室的安全、环保管理发表了自己的见解,提出了“以人为本”、“安全第一,预防为主”,“依法整治”的观点,它是建设和管理高校实验室的基本思路,也是实现高校实验室安全的基本原则;同时调强了保护教师和学生的实验室安全与健康,不仅仅是实验室的安全问题,也是校园安全管理工作的重要组成部分。  相似文献   
294.
1 INTORDUCTIONRivers are the artery of the earth surface system; and it isone of the major components of natural environment incities, whose quantity and quality result from the long-time interaction between environment and human activities(Chen Dechao, et al. 2002; Wang Ying, Sheng Jingfen.2002). As a symbol of reform and opening in China,Pudong New Area plays an important role in the economicdevelopment around Yangtze Delta and even all over thecountry. The 14th congress of the Com…  相似文献   
295.
Access opportunities for outdoor recreation in New Zealand and England and Wales are classified according to their conformity with collective, citizenship or exclusion rights and their degrees of permanence. Alternative criteria for the apportionment of access rights are considered in the context of this classification. Different criteria for rights apportionment are found to be appropriate according to different circumstances in the context of pluralist provision. Policy developments in New Zealand are compared with those in England. After 150 years of a dominance of collective rights in New Zealand current policy is shifting provision towards exclusionary rights. In England, there is a policy shift in the other direction, towards collective rights. Lessons for the development of collective rights in England are drawn from the New Zealand experience in relation to styles of governance, public preferences, public cost, insurance liability and the potential of markets.  相似文献   
296.
This study observed privacy-seeking behavior in an elementary classroom, investigated individual differences in privacy seeking, and compared preferences for private spaces varying in degree of enclosure. Four privacy booths were placed in a fourth-grade classroom. A ticket system was used to assess booth use. Information on personality and background variables was obtained with self-report, peer, teacher, and parent questionnaires. After an initial period of enthusiasm, overall booth use declined sharply. However, analysis revealed substantial individual variation in booth use that remained consistent throughout the study. For boys, booth use was significantly correlated with teachers' ratings of sociability, aggressiveness, and distractibility. For girls, a significant positive relationship was found between privacy seeking at home and in school. Self-reported desire for privacy was uncorrelated with actual privacy-seeking behavior in the classroom. No significant differences in the use of the various booths were found, although self-reported preferences clearly favored the booth that allowed visual access to the rest of the classroom when desired.  相似文献   
297.
ABSTRACT: Land use planning in rapidly developing areas can serve as an effective tool for minimizing water quality impacts on ground water supplies. A land use management model applied to Jackson Township of the New Jersey Pine Barrens was developed. The management model consisted of a simulation model for the transport of nitrates from septic tank systems through the aquifer and a multiobjective, goal programming optimization model to determine population density restrictions using 208 areawide planning population projections. Results showed that growth may have to be curtailed in several areas of Jackson Township and that current population projections over the next 30 years may result in unacceptably high nitrate concentrations downgradient of Jackson Township. The management framework provides a flexible approach to land use planning.  相似文献   
298.
ABSTRACT: A fundamental problem in protecting surface drinking water supplies is the identification of sites highly susceptible to soil erosion and other forms of nonpoint source (NPS) pollution. The New York City Department of Environmental Protection is trying to identify erodible sites as part of a program aimed at avoiding costly filtration. New York City's 2,000 square mile watershed system is well suited for analysis with geographic information systems (GIS); an increasingly important tool to determine the spatial distribution of sensitive NPS pollution areas. This study used a GIS to compare three land cover sources for input into the Modified Universal Soil Loss Equation (MUSLE), a model estimating soil loss from rangeland and forests, for a tributary watershed within New York City's water supply system. Sources included both conventional data (aerial photography) and Landsat data (MSS and TM images). Although land cover classifications varied significantly across these sources, location-specific and aggregate watershed predictions of the MUSLE were very similar. We conclude that using Landsat TM imagery with a hybrid classification algorithm provides a rapid, objective means of developing large area land cover databases for use in the MUSLE, thus presenting an attractive alternative to photo interpretation.  相似文献   
299.
ABSTRACT: To provide a basis for regional hydroclimatic forecasting, New England (NE) precipitation and streamflow are compared with indices for the El Niño/Southern Oscillation, the Pacific North American (PNA) pattern, and the North Atlantic Oscillation (NAO). Significant positive correlations are found between the NAO index and monthly streamflow at western inland locations, with the strongest seasonal correlations occurring in winter. Smoothed records for the winter NAO and winter streamflow are highly correlated at some sites, suggesting that interrelationships are most significant in the low frequency spectrum. However, correlations between the NAO and precipitation are not significant, so further examination of other factors is needed to explain the relationship between the NAO and streamflow. NAO related regional air temperature, sea surface temperature (SST), storm tracking, and snowfall variability are possible mechanisms for the observed teleconnection. Exceptionally cool regional air temperatures, and SSTs, and unique regional storm track patterns characterized NE's climate during the famous 1960s drought, suggesting that concurrent (persistent) negative NAO conditions may have contributed to the severity of that event. Monthly and winter averaged regional streamflow variability are also significantly correlated with the PNA index. This, along with results from previous studies, suggests that tropospheric wave character and associated North Pacific SST anomalies are also related to NE regional drought conditions.  相似文献   
300.
ABSTRACT: Water management in the United States has historically been characterized by a decisionmaking system that is fragmented along three dimensions: (1) physical, (2) institutional, and (3) political-technical. The result is often ‘garbage can’ decision-making in open decisionmaking structures with the attributes of an ‘organized anarchy’ rather than the rational, comprehensive decisionmaking prescribed for water management. A case study of water quality management decisionmaking in the New York Finger Lakes is used to illustrate how the garbage can model can illuminate the forces that operate in fragmented water management. Interorganizational decisionmaking theory and experience from water management integration initiatives are then applied to assess what strategies may be effective in reducing the organizational anarchy that results from fragmented water management institutions.  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