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   81篇
  免费   3篇
  国内免费   2篇
安全科学   8篇
废物处理   4篇
环保管理   19篇
综合类   21篇
基础理论   11篇
污染及防治   20篇
评价与监测   1篇
社会与环境   2篇
  2022年   2篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2015年   2篇
  2014年   2篇
  2013年   6篇
  2012年   7篇
  2011年   4篇
  2010年   10篇
  2009年   1篇
  2008年   5篇
  2007年   1篇
  2006年   12篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2000年   5篇
  1999年   3篇
  1997年   1篇
  1996年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1985年   1篇
  1982年   1篇
  1981年   2篇
  1978年   1篇
排序方式: 共有86条查询结果,搜索用时 263 毫秒
31.
Backyard garden sharing projects can be viewed as a small-scale alternative to traditional community gardens. These shared spaces are able to overcome some of the pressures on community gardens such as competing demands for housing and other services and amenities while still providing many of the health-promoting benefits community gardens are noted for. This study is a small-scale participatory qualitative project that explores three backyard garden sharing partnerships. The aim of this study is to explore the benefits and challenges of these shared spaces and to discuss the overall feasibility of shared backyard gardens. Partnerships comprised an older adult homeowner (i.e., greater than age 65) and a non-senior gardener. At an individual level, the results suggest that backyard garden sharing can promote physical activity, psychosocial well-being, and social connectedness for both older adult homeowners and volunteer garden partners. To be successful, partners benefit from an established agreement about what to grow and how to share the garden's produce. In addition, a dedicated project coordinator and a limited amount of community resources can ensure the viability of these small-scale projects.  相似文献   
32.
ABSTRACT

Originating in the UK in 2006, the Transition movement is oriented to local grassroots citizen-led efforts that prepare for and support a societal energy transition to a low-carbon future in response to climate change, peak oil, ecological degradation, and economic instability. Overlapping significantly with relocalization, degrowth/slow growth, local food, and related movements, and based on permaculture principles and a distributed network model, it embraces the opportunity to turn crisis into an opportunity to build more resilient, convivial, and vibrant local communities, declaring that “if it’s not fun, it’s not sustainable”. The Transition approach has spread rapidly around the world, including initiatives in over 100 communities and cities in Canada. This paper reports on the methods and results of a Canadian community-based research study aimed at understanding how and where the movement has taken root across the country, what Transition practice looks like, challenges and opportunities encountered, and lessons learned that could be applied within the movement and by others interested in the role of citizen-led initiatives for sustainability transition. Utilising a practice theory lens, drawing on an extensive web-scan of the movement’s online presence, a survey and interviews with initiative (co)founders, an e-survey of Transition members/participants, regional “structured story-dialogue” workshops, and key informant interviews, and informed by input from a Movement Advisory Group, we describe the research process and explore what success and impact mean to those most active in the movement.  相似文献   
33.
An electromechanical drill with titanium barrels was used to recover a 63.7 m long firn core from Devon Island Ice Cap, Nunavut, Canada, representing 155 years of precipitation. The core was processed and analysed at the Geological Survey of Canada by following strict clean procedures for measurements of Pb and Cd at concentrations at or below the pg g(-1) level. This paper describes the effectiveness of the titanium drill with respect to contamination during ice core retrieval and evaluates sample-processing procedures in laboratories. The results demonstrate that: (1) ice cores retrieved with this titanium drill are of excellent quality with metal contamination one to four orders of magnitude less than those retrieved with conventional drills; (2) the core cleaning and sampling protocols used were effective, contamination-free, and adequate for analysis of the metals (Pb and Cd) at low pg g(-1) levels; and (3) results from 489 firn core samples analysed in this study are comparable with published data from other sites in the Arctic, Greenland and the Antarctic.  相似文献   
34.
35.
This longitudinal field study examined the combined effects of dispositions, entry stressors, and behavioral plasticity theory in predicting newcomers' adjustment to work after four and 10 months of organizational entry. Recent graduates completed a questionnaire prior to entry that measured two dispositions (negative affectivity and general self‐efficacy), and a questionnaire four months after entry that measured four entry stressors (role conflict, role ambiguity, role overload, and unmet expectations). Measures of work adjustment were taken after four and 10 months. Based on behavioral plasticity theory, it was expected that the effects of the entry stressors would be most negative for the adjustment of newcomers with low general self‐efficacy. Limited support was found for behavioral plasticity theory. Those interactions that were significant indicated that increasing levels of role conflict were associated with lower organizational commitment and identification for newcomers with low general self‐efficacy. The results also provided weak support for a dispositional theory of work adjustment. The dispositions only predicted three of seven adjustment variables at four and 10 months. However, the entry stressors significantly predicted all seven adjustment measures. The results are discussed in terms of the predominant role played by the organizational setting in predicting newcomers' adjustment to work. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   
36.
37.
珠三角地区大气中HCFC-22的浓度观测和变化趋势初步研究   总被引:4,自引:0,他引:4  
通过罐采样和预浓缩-色谱/质谱方法,对珠三角地区广州城区和鼎湖山大气中HCFC-22进行了初步的观测和分析.结果表明,2005年广州城区HCFC-22年平均体积分数达到(479.5±241.4)×10-12,鼎湖山仅为(244.4±51.3)×10-12.广州城区大气HCFC-22日变化幅度夏秋季节相对较大,而鼎湖山日变化不明显;广州城区大气HCFC-22的体积分数夏秋季节高于冬春季节,鼎湖山则相反.与城区HCFC-22排放的季节性有关,夏秋季节广州城区与鼎湖山HCFC-22体积分数差别很大,冬春季节则比较接近.初步研究结果表明,广州城区和鼎湖山大气HCFC-22的体积分数呈现快速增长趋势,年增长率分别达到6.57%和7.28%,约为一些全球基准观测站(NOAA/CMDL)的1.9~2.8倍.  相似文献   
38.
Ambient halocarbon mixing ratios in 45 Chinese cities   总被引:4,自引:0,他引:4  
During this study 158 whole air samples were collected in 45 Chinese cities in January and February 2001. The spatial distribution of different classes of halocarbons in the Chinese urban atmosphere, including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), Halon-1211, and other chlorinated compounds is presented and discussed. Most of these compounds were enhanced compared to background levels. However, the mean enhancement of CFCs was relatively small, with CFC-12 and CFC-11 increases of 6% (range 1–31%) and 10% (range 2–89%), respectively, with respect to the global background. On the contrary, strongly enhanced levels of CFC replacement compounds and halogenated compounds used as solvents were measured. The average Halon-1211 concentration exceeded the background of 4.3 pptv by 75% and was higher than 10 pptv in several cities. Methyl chloride mixing ratios were also strongly elevated (78% higher than background levels), which is likely related to the widespread use of coal and biofuel in China.  相似文献   
39.
Contamination with oil poses a threat to the environment and to human health worldwide. Biological methodologies have proved to be economical, versatile and efficient for the remediation of pollutants. In this paper, a highly efficient oil-degrading bacterial strain USTB-2 was isolated from an oil production well of Dagang oil field in Tianjin, China. The 16S rRNA sequence of USTB-2 showed 100% similarity with that of Bacillus subtilis BSn5. Hexadecane is one of the most important components in petroleum. The half inhibitory ratio (IC50) of hexadecane inhibited organisms, determined by microcalorimetry, was lower in USTB-2 than in B. BSn5. The results indicate that the strain USTB-2 degrades hexadecane to make it less toxic compared with the normal strain. RT-PCR was used to evaluate the expression of oil-degrading enzymes, specifically 4-hydroxyphenylacetate 3-monooxygenase genes (HPMO). A sharp increase in the expression of HPMO genes was observed for USTB-2, while the expression of HPMO genes in reference strain B. BSn5 remained relatively stable. These methods can be used to study the metabolic potential of microorganisms for in situ oil decontamination.  相似文献   
40.
Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems, heritage and climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HOx chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed.  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