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   300篇
  免费   1篇
  国内免费   1篇
安全科学   18篇
废物处理   9篇
环保管理   32篇
综合类   68篇
基础理论   48篇
污染及防治   102篇
评价与监测   12篇
社会与环境   13篇
  2023年   4篇
  2022年   2篇
  2020年   3篇
  2019年   2篇
  2018年   9篇
  2017年   7篇
  2016年   15篇
  2015年   9篇
  2014年   5篇
  2013年   32篇
  2012年   9篇
  2011年   22篇
  2010年   4篇
  2009年   16篇
  2008年   7篇
  2007年   14篇
  2006年   22篇
  2005年   16篇
  2004年   11篇
  2003年   9篇
  2002年   10篇
  2001年   3篇
  1999年   3篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1993年   3篇
  1992年   4篇
  1991年   5篇
  1990年   2篇
  1989年   2篇
  1986年   4篇
  1985年   5篇
  1984年   2篇
  1982年   6篇
  1981年   3篇
  1980年   1篇
  1977年   1篇
  1972年   1篇
  1970年   1篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
  1961年   1篇
  1953年   1篇
  1951年   3篇
  1948年   1篇
  1942年   1篇
  1941年   1篇
  1914年   1篇
排序方式: 共有302条查询结果,搜索用时 203 毫秒
261.
Sixty healthy non-smoking white collar employees, aged 30–50, from a large corporation in Sweden participated in the study. There were four groups: 15 male and 15 female middle managers, 15 male and 15 female clerical workers. Each participant was examined individually with regard to cardiovascular and neuroendocrine functions and self-reports for 12 consecutive hours under each of two conditions: (1) a normal day at work (9 a.m.–5 p.m.) and after work (6–9 p.m.), and (2) for the same time period during work-free conditions at home. In addition, everyone was given a videotaped type A-interview and a general health check-up including blood-lipid determination. Attitudes towards work, total workload (including responsibilities outside the paid work) and sex role identity were examined by questionnaires. As expected, all groups showed a moderate increase in cardiovascular and neuroendocrine activity during the day at work. After work, however, interesting group differences emerged, suggesting slower unwinding in female managers. Differences related to occupational level and/ or sex were found for autonomy and social support at work, competitiveness, sex role and reported conflict between demands from paid work and other responsibilities. The stress profile of the female managers was considered in terms of possible long-term health risks.  相似文献   
262.
With the depletion of many natural resources, we are growing aware of the need to understand the risks that stem from different management decisions. Here, we outline an approach to test the ability of different dynamical signatures to characterize time-series data: how likely is it that a natural population is declining, sustainable, or increasing, and at what rates are these temporal changes likely occurring? These dynamical signatures can serve as a robust foundation on which to formulate alternative scenarios in a decision analysis. They take account of much of the uncertainty in model parameters and have precise mathematical underpinnings with associated risks. We present methods to evaluate the likelihood of these scenarios, and ways that the analysis can be graphically represented. We discuss different ecological factors such as climate variability, life history, ecosystem interactions, and a changing population age structure, all of which impact the dynamics of natural populations. Considering the types of dynamical signatures that emerge from these factors can change our understanding of risk and the decisions that we make.  相似文献   
263.
264.
Marianne Törner 《Safety Science》2011,49(8-9):1262-1269
This paper aims at contributing to a comprehensive perspective on occupational safety by integrating research on different specific organisational psychological concepts found to contribute to different types of organisational performance, and apply these to an occupational safety context. A second aim was to present perspectives on how occupational safety may be promoted within an organization. The following mechanisms are suggested. A leadership style promoting co-operation, inspiring, fostering group goals, as well as providing individualized support and empowering workers may intrinsically be expected to comprise rich and open communication and thus support the development of high-quality interactions between managers and employees. Such interaction and communication may promote the development of mutual trust, and the development of a good workgroup climate. Trust, in turn, may further promote communication and interaction. Mutual trust, high-quality relations, and a strong group climate may promote workers’ motivation and intentions to contribute to the organisational goals. Managers successful in demonstrating true and consistent priority of workers’ safety may promote the development of workers’ trust but also convince that safety is a prime organisational goal. This may promote workers’ motivation to behave safely. Trustful relations characterized by empowerment and participation are then likely also to support the realization of safety intentions into safe behavior.  相似文献   
265.
This paper clarifies how polymers are dealt with under the Directive 67/548/EEC. Polymers are a particular group of substances under the Directive 67/548/EEC [1] and amendments [2,3] as they are not listed in the European INventory of Existing Commercial chemical Substances (EINECS [4]) which otherwise lists all substances which were on the European Community Market between 1 January 1971 and 18 September 1981, the ‘existing substances’. Instead, in EINECS polymers are registered under their ultimate building blocks. With the 6th amendment to the Directive [2] polymers became notifiable substances if containing 2% or more of new substance(s) (i.e. as a general rule substances not listed in EINECS), and the reporting criteria were used as definition. With the 7th amendment to the Directive [3] an exact definition was introduced and a special test package, given in Directive 93/105/EEC [5], was designed for polymers to take into account their particular properties. Changing the definition of polymers created a group of substances which under the 6th amendment had been defined as polymers, and could no longer be regarded as polymers under the 7th amendment, the No‐Longer‐Polymers.  相似文献   
266.
This study investigates the influence of the two different clay minerals kaolinite and smectite as well as of organic matter on the cation sorption and desorption behaviour of three imidazolium based ionic liquids -1-butyl-3-methyl-imidazolium tetrafluoroborate (IM14 BF(4)), 1-methyl-3-octyl-imidazolium tetrafluoroborate (IM18 BF(4)) and 1-butyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide (IM14 (CF(3)SO(2))(2)N) - in soil. The German standard soil Lufa 2.2 - a natural soil classified as a loamy sand - was the basis substrate for the different soil compositions and also served as a reference soil. The addition of organic matter and clays increases the sorption of the substances and in particular smectite had striking effects on the sorption capacity for all three ionic liquids indicating that ionic interactions play an important role for sorption and desorption processes of ionic liquids in soil. One exception was for kaolinite-containing soils and the IM14 cation: with (CF(3)SO(2))(2)N(-) as an anion the sorption was identical at either 10 wt% or 15 wt% clay content, and with BF(4)(-) sorption was even lower at 15 wt% kaolinite than at 10 wt%. Desorption was weak for IM18 BF(4), presumably owing to the longer alkyl side chain. With regard to the influence of kaolinite on desorption, the same pattern was observed as it was found for the sorption of IM14 BF(4) and IM14 (CF(3)SO(2))(2)N.  相似文献   
267.
Nielsen KE  Degn HJ  Damgaard C  Bruus M  Nygaard B 《Ambio》2011,40(7):819-823
A new species has recently invaded coastal dune ecosystems in North West Europe. The native and expansive inland grass, Deschampsia flexuosa, progressively dominating inland heaths, has recently invaded coastal dunes in Denmark, occasionally even as a dominant species. A total of 222 coastal locations with 5,000 random sample plots have been investigated. These findings are in contrast to historical records, and D. flexuosa has never been considered belonging to coastal dune ecosystems. The occurrence of the typical inland grass in the coastal dunes is a strong indication of increase in nutrient level and that human influences may cause a native species to be invasive in new ecosystems. This could be a radical example of change in species composition due to a long lasting exceedance of critical load of nitrogen. The investigation also showed a general increase in cover of the most dominant species.  相似文献   
268.
The presence of sewage-borne micro contaminants in environmental waters is directly related to the discharge of treated effluents from wastewater treatment plants (WWTP) and the flow rate of the receiving river waters. Mediterranean rivers, in particular, are characterized by important fluctuations in the flow rates and heavy pollution pressures resulting from extensive urban, industrial and agricultural activities. This translates into contamination levels in these rivers often higher than those in other larger European basins. The present work provides an overview of the occurrence of five groups of organic contaminants (131 compounds) namely pharmaceuticals, illicit drugs, polar pesticides, estrogens, alkylphenols and related ethoxylates in WWTP tertiary treatment effluents. Data gathered during a period of water reuse carried out in the lower stretch of the Llobregat river (NE Spain), in the surroundings of the town of Barcelona as a consequence of the severe drought that took place along the years 2007-2008 are presented as illustrative example. In general, measured concentrations of the target compounds were in the low to mid ng L−1 range. The total concentration of each compound class downstream to the discharge point was similar or slightly higher than that found upstream. Regarding the loads calculated for each compound, the relative contribution from the river upstream and the tertiary effluent were highly compound depending with no apparent trend. However, estimation of the overall bulk loads for each compound class determined in the Llobregat river showed the following rank order: pharmaceuticals > alkylphenols > pesticides > illicit drugs ? estrogens.  相似文献   
269.
Analysis of a European Union funded biotechnology project on plant genomics and marker assisted selection in Solanaceous crops shows that the organization of a dialogue between science and society to accompany technological innovations in plant breeding faces practical challenges. Semi-structured interviews with project participants and a survey among representatives of consumer and other non-governmental organizations show that the professed commitment to dialogue on science and biotechnology is rather shallow and has had limited application for all involved. Ultimately, other priorities tend to prevail because of high workload. The paper recommends including results from previous debates and input from societal groups in the research design phase (prior to communication), to use appropriate media to disseminate information and to make explicit how societal feedback is used in research, in order to facilitate true dialogue between science and society on biotechnology.  相似文献   
270.
Volatile organic compounds (VOCs) are emitted from anthropogenic and natural (biogenic) sources into the atmosphere. Characterizing their ambient mixing ratios or concentrations is a challenge because VOCs comprise hundreds of species, and accurate measurements are difficult. Long-term hourly and daily-resolution data have been collected in the metropolitan area of Atlanta, Georgia, a major city dominated by motor vehicle emissions. A series of observations of daily, speciated C2–C10 non-methane organic compounds (NMOC) and oxygenated hydrocarbons (OVOC) in mid-town Atlanta (Jefferson Street, JST) are compared with data from three urban-suburban sites and a nearby non-urban site. Annual-average mixing ratios of NMOC and OVOC at JST declined from 1999 through 2007. Downward trends in NMOC, CO, and NOy corroborate expected emission changes as reflected in emission inventories for Atlanta’s Fulton County. Comparison of the JST NMOC composition with data from roadside and tunnel sampling reveals similarities to motor vehicle dominated samples. The JST annual average VOC-OH reactivities from 1999 to 2007 were relatively constant compared with the decline in annual-average NMOC mixing ratios. Mean reactivity at JST, in terms of concentration*kOH, was approximately 40% alkenes, 22% aromatics, 16% isoprene and 6% other biogenics, 13% C7–C10 alkanes and 3% C2-C6 alkanes, indicating that biogenic NMOCs are important but not dominant contributors to the urban reactive NMOC mix. In contrast, isoprene constituted ~50% of the VOC-OH reactivities at two non-urban sites. Ratios of 24-hour average CO/benzene, CO/isopentane, and CO/acetylene concentrations indicate that such species are relatively conserved, consistent with their low reactivity. Ratios of more-reactive to less-reactive species show diurnal variability largely consistent with expected emission patterns, transport and mixing of air, and chemical processing.  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