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   86篇
  免费   4篇
安全科学   10篇
废物处理   1篇
环保管理   20篇
综合类   8篇
基础理论   26篇
污染及防治   11篇
评价与监测   8篇
社会与环境   3篇
灾害及防治   3篇
  2022年   1篇
  2018年   2篇
  2017年   2篇
  2016年   5篇
  2015年   5篇
  2014年   1篇
  2013年   3篇
  2012年   7篇
  2011年   1篇
  2010年   5篇
  2009年   3篇
  2008年   1篇
  2007年   7篇
  2006年   6篇
  2005年   2篇
  2004年   6篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  1999年   2篇
  1998年   1篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1981年   2篇
  1970年   1篇
排序方式: 共有90条查询结果,搜索用时 15 毫秒
21.
Ambrym in Vanuatu is a persistently degassing island volcano whose inhabitants harvest rainwater for their potable water needs. The findings from this study indicate that dental fluorosis is prevalent in the population due to fluoride contamination of rainwater by the volcanic plume. A dental survey was undertaken of 835 children aged 6–18 years using the Dean’s Index of Fluorosis. Prevalence of dental fluorosis was found to be 96% in the target area of West Ambrym, 71% in North Ambrym, and 61% in Southeast Ambrym. This spatial distribution appears to reflect the prevailing winds and rainfall patterns on the island. Severe cases were predominantly in West Ambrym, the most arid part of the island, and the most commonly affected by the volcanic plume. Over 50 km downwind, on a portion of Malakula Island, the dental fluorosis prevalence was 85%, with 36% prevalence on Tongoa Island, an area rarely affected by volcanic emissions. Drinking water samples from West Ambrym contained fluoride levels from 0.7 to 9.5 ppm F (average 4.2 ppm F, n = 158) with 99% exceeding the recommended concentration of 1.0 ppm F. The pathway of fluoride-enriched rainwater impacting upon human health as identified in this study has not previously been recognised in the aetiology of fluorosis. This is an important consideration for populations in the vicinity of degassing volcanoes, particularly where rainwater comprises the primary potable water supply for humans or animals.  相似文献   
22.
Research findings suggest that maternal employment exerts no consistent detrimental effects on children. In this study, the moderating role of employment commitment and child sex on the relationship between maternal employment status and child behavior is investigated. Mothers and teachers provided behavioral ratings for 185 elementary school children (M age = 9.42 years). Employment commitment moderated the influence of employment status on mothers' and teachers' ratings of children's attention problems and immaturity: Children whose mothers' employment status and commitment were not congruent were less attentive and more immature than those whose mothers' employment status and commitment were congruent. The statistical and applied significance of these results is suggested, as is the possibility that mother-child interactions mediate the manner in which incongruencies between employment status and employment commitment influence children's inattention-immaturity.  相似文献   
23.
Despite the rapid uptake of multi‐source multi‐rater (MSMR) feedback systems by UK organizations, comparatively little research exists describing the actual impact on participant managers, in terms of changes in management competence. Ratings of 104 target managers (by self assessments, bosses‐, first‐ and second‐level subordinates) were investigated within the context of a developmental feedback programme in operation within an organization. The study compared ratings over two administrations (with two years between administrations) to determine: (1) changes in co‐workers' perceptions of their target manager's competence, (2) changes in target managers' development needs over time, (3) factors influencing a target manager's revised self‐assessment and co‐workers ratings, (4) changes in congruence between self and co‐workers ratings and (5) the relationship of feedback to the organization's formal performance appraisal process. Significant increases in managers' competence were perceived by the managers' themselves and by their subordinates, development needs were seen to reduce and self and co‐workers ratings were largely seen to become more congruent. However, polynomial regression analyses revealed co‐workers feedback at Time One was not predictive of targets' self‐assessments at Time Two. The implications of these findings with regard to the utility of MSMR feedback as a tool for management development are discussed. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
24.
The detection of trace levels of a range of organic contaminants (including pesticides, toxins and an explosive) in potable water, using cryoprobe NMR spectroscopy with limited sample preparation and rapid acquisition times, is described. Emphasis is placed on the applicability of NMR spectroscopy for use in emergency scenarios as the unbiased nature of the technique facilitates the detection and characterization of unknown compounds at levels as low as 50 microg L(-1).  相似文献   
25.
Anyone who has been involved in the application of IEC 61508 and IEC 61511 by undertaking the Safety Integrity Level (SIL) determination for Safety Instrumented Systems (SIS) will appreciate the amount of effort and tenacity that is required to undertake the task. SIL determination of Safety Instrumented Systems requires considerable commitment and tenacity to get the job done, but it is like climbing to the top of a hill only to be faced with a mountain when we come to consider what is involved in reviewing or configuring a typical alarm system.A medium sized process facility may have a few hundred or so primary Safety Instrumented Functions (SIF) or trips configured into a Safety Instrumented System, but the number of alarms configured into a process control system (PCS), that need to be assessed and prioritised, can often run into the thousands.There is synergy between safety instrumented functions and alarms because they both make a contribution to reduce the risk of having unwanted events, and both need an assigned appropriate criticality.This paper details various methods of criticality assessment which have been successfully applied to set the appropriate priority, identify the critical alarms that need to be upgraded to trips and to rationalise those of no value. It will also cover the use of software tools which can significantly reduce the effort involved in this process.  相似文献   
26.
Detection of soil element deficiencies is time consuming, requiring a major commitment for field work and analysis. Bees concentrate some elements in their honey which could allow soil element concentrations to be predicted without having to take large numbers of soil samples. We measured 14 element concentrations in soil, sunflower, acacia flower and honey samples from two different regions of Hungary. Across sites, the elements with significant correlation coefficients between honey and soil concentrations, in descending order of probability, were Cu > Ba >Sr = Ni > Zn > Mn = Pb >As. Bioconcentration from soil to honey was similar for areas with acacia and sunflower flowers. In the macroelements, it was the greatest for K, S and P and least for Mg and Na, and in the microelements, greatest for B, then Zn, then Cu, then As, Mo and Sr and least for Fe, Ba, Mn and Pb. It is concluded that in acacia and sunflower-growing regions, honey can give an accurate estimate of soil element concentrations for Cu and Ba and provides relevant information for Sr, Ni, Zn, Mn, Pb and As.  相似文献   
27.
Chang W  Whyte L  Ghoshal S 《Chemosphere》2011,82(6):872-878
Temporal atmospheric temperature changes during summers at sub-Arctic sites often cause periodic fluctuations in shallow landfarm and surface soil temperatures. However, little information is available on the effect of site-relevant variations on biodegradation performance in cold climates. This study compares the rate and extents of biodegradation of petroleum hydrocarbons at variable site temperatures (1-10 °C) representative of summers at a sub-Arctic site reported previously with those obtained under a constant average temperature of 6 °C. The biodegradation was evaluated in pilot-scale landfarming experiments with field-aged petroleum-contaminated soils shipped from Resolution Island (61°30′N, 65°00′W), Nunavut, Canada. Under the variable site temperature conditions biodegradation rate constants of semi- (F2) and non-volatile (F3) hydrocarbon fractions were enhanced by over a factor of two during the 60-d experiment, compared to the constant temperature mode. The decrease in total petroleum hydrocarbons (TPH) under the variable site temperature mode was 55% compared to only 19% under the constant average temperature mode. The enhanced biodegradation is attributable to the non-linear acceleration of microbial activity between 4.7 and 10 °C and faster growth of indigenous hydrocarbon-degrading microbial populations. The first-order biodegradation rate constants of 0.018, 0.024 and 0.016 d−1 for TPH, F2 and F3 fractions at the variable site temperature were in agreement with those determined by an on-site experiment at the same site.  相似文献   
28.
29.
30.
Animal welfare scientific literature has accumulated rapidly in recent years, but bias may exist which influences understanding of progress in the field. We conducted a survey of articles related to animal welfare or well being from an electronic database. From 8,541 articles on this topic, we randomly selected 115 articles for detailed review in four funding categories: government; charity and/or scientific association; industry; and educational organization. Ninety articles were evaluated after unsuitable articles were rejected. The welfare states of animals in new treatments, conventional treatments or control groups with no treatment were classified as high, medium or low according to one or more. More articles were published in which the welfare of animals in new treatments was better than that of animals in the conventional or no treatment groups, demonstrating a positive result bias. Failure to publish studies with negative or inconclusive results may lead to other scientists unnecessarily repeating the research. The authors’ assessments of the welfare state of the groups were similarly rated high, medium or low, and it was found that new treatments were rated lower if the research was funded by industry, and higher when funded by charities, with government funding agencies intermediate. These differences were not evident in the Five Freedoms assessment, demonstrating an authors’ assessment bias that appeared to support the funding agencies’ interests. North American funded publications rated the welfare of animals in New treatments higher and those in a Conventional or No Treatment lower, compared with European-funded publications. It is concluded that preliminary evidence was provided of several forms of publication bias in animal welfare science.  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