首页 | 官方网站   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   41篇
  免费   2篇
环境安全   43篇
  2023年   2篇
  2022年   1篇
  2020年   1篇
  2018年   5篇
  2017年   4篇
  2016年   2篇
  2015年   3篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1995年   1篇
  1991年   2篇
  1983年   1篇
排序方式: 共有43条查询结果,搜索用时 15 毫秒
1.
2.
Graduated Driver Licensing (GDL) inserts between the leaner permit and full licensure an intermediate or "provisional" license that allows novices to drive unsupervised but subject to provisions intended to reduce the risks that accompany entry into highway traffic. Introduction of GDL has been followed by lowered accident rates, resulting from both limiting exposure of novices to unsafe situations and by helping them to deal with them more safely. Sources of safer driving include extended learning, early intervention, contingent advancement, and multistage instruction. To extend the learning process, most GDL systems lengthen the duration of the learner phase and require a specified level of adult-supervised driving. Results indicate that extended learning can reduce accidents substantially if well structured and highly controlled. Early intervention with novice traffic violators have shown both a general deterrent effect upon novice violators facing suspension and a specific effect upon those who have experienced it. Making advancement to full licensure contingent upon a violation-free record when driving on the provisional license has also evidenced a reduction in accidents and violations during that phase of licensure. Multistage instruction attempts development of advanced skills only after novices have had a chance to master more basic skills. Although this element of GDL has yet to be evaluated, research indicates crash reduction is possible in situations where it does not increase exposure to risk. While the various elements of GDL have demonstrated potential benefit in enhancing the safety of novice drivers, considerable improvement in the nature and enforcement of GDL requirements is needed to realize that potential.  相似文献   
3.
This paper presents evidence relating to a forecast-based cash and non-food item distribution among vulnerable herder households during the 2017–18 dzud (extreme winter) season in Mongolia, and analyses the results of a quasi-experimental study evaluating its impacts. An innovative approach in disaster risk reduction, forecast-based financing (FbF) can have short- and long-term benefits to vulnerable households but remains understudied. The paper contributes information on a multimodal FbF programme offering one-off cash grants and in-kind veterinary kits. The data found significant effects of reduced mortality and increased offspring survival in some types of livestock, and that the timing of FbF assistance is crucial, as reported early assistance correlated to positive outcomes in terms of reduced animal mortality. These findings can be used to design more effective FbF interventions, to understand better the appropriateness of FbF designs, and to use early warnings and early actions to help people prepare and withstand disasters such as dzuds.  相似文献   
4.
Sustainable environmental management is contingent on having an effective environmental planning system. A new methodology for designing and evaluating environmental planning systems is described and applied to a case study evaluation of the Canadian environmental planning process. The methodology is based on eight international best practice principles for environmental planning and 45 indicators. The research illustrates the benefits of the evaluation methodology in identifying how to improve environmental planning systems to achieve desired results. The methodology is applicable to a wide variety of jurisdictions.  相似文献   
5.
Animal color patterns often reflect a compromise between natural selection for crypsis or inconspicuousness to predators and sexual selection for conspicuousness to potential mates. In leaf litter-dwelling wolf spider species like Schizocosa ocreata, body coloration often closely matches the background coloration of a generally brown environment. However, body parts used in communication should exhibit high contrast against background coloration. We used spectral analysis to examine male and female S. ocreata for matching and contrasting coloration against leaf litter. Values were plotted in multivariate color space, based on reflectivity in different frequency ranges. When viewed from above, colors of both males and females overlap with values for dead brown leaf litter and soil, suggesting cryptic coloration when viewed by potential predators. However, when viewed from a lateral perspective, both males and females show color values that are polar opposites of litter backgrounds, suggesting higher contrast when viewed by other spiders. Moreover, male secondary characters used in visual signaling by S. ocreata (tibia brushes) show the highest level of background contrast. These findings suggest that S. ocreata wolf spiders have color patterns that provide both crypsis and background contrast at the same time, depending on receiver viewing perspective.  相似文献   
6.
A 26 year old nulligravida presented at 24 weeks gestation for the second opinion of abnormal fetal profile and mid-face views on ultrasound at another institution. A detailed fetal anatomic ultrasound at our facility revealed the absence of fetal lens and globes bilaterally consistent with bilateral anophthalmia (HP: 0000528) without other anomalies. Karyotype and chromosomal microarray analysis were completed from amniocentesis sample. After these results, duo exome testing with paternal sequencing was completed from proband amniotic fluid sample and parental blood samples. A pathogenic variant in SOX2 (NM_003106.3: c.513C>G p.(Tyr171*Ter)) with heterozygous autosomal dominant inheritance resulted. On duo exome testing with paternal segregation analysis, the variant was found to be consistent with likely sporadic de novo inheritance. The SOX2 variant reported is consistent with the fetal phenotype in this case. While germline mosaicism could exist, this identified variant provided the family with a likely explanation for this proband's finding. This ultrasound and genetic testing allowed the family to make decisions related to planning in current and future pregnancies.  相似文献   
7.
Objective: Studies of alcohol-related harm (violence, injury, illness) suggest that the most significant risk factors are the amount of alcohol consumed and whether obviously intoxicated patrons continue to be served. This study's objective was to investigate the effects of a responsible beverage service (RBS)/enhanced alcohol enforcement intervention on bars, bar patrons, and impaired driving.

Method: Two communities—Monroe County, New York, and Cleveland, Ohio—participated in a demonstration program and evaluation. The intervention applied RBS training, targeted enforcement, and corrective actions by law enforcement to a random sample of 10 identified problem bars in each community compared to 10 matched nonintervention problem bars. Data were collected over 3 waves on bar serving practices, bar patron intoxication, drinking and driving, and other alcohol-related harm from intervention and control bars and treatment and comparison communities.

Results: In Monroe County, New York, of the 14 outcome measures analyzed, 7 measures showed statistically significant differences from pre- to postintervention. Six of those measures indicated changes in the desired or positive direction and 2 measures were in the undesired or negative direction. Of note in the positive direction, the percentage of intervention bar patrons who were intoxicated decreased from 44 to 27% and the average blood alcohol concentration of patrons decreased from 0.097 to 0.059 g/dL pre- to postintervention. In Cleveland, Ohio, 6 of the 14 measures showed statistically significant changes pre- to postintervention with 6 in the positive direction and 4 in the negative direction. Of note, the percentage of pseudo-intoxicated patrons denied service in intervention bars increased from 6 to 29%.

Conclusions: Of the 14 outcome measures that were analyzed in each community, most indicated positive changes associated with the intervention, but others showed negative associations. About half of the measures showed no significance, the sample sizes were too small, or the data were unavailable. Therefore, at best, the results of these demonstration programs were mixed. There were, however, some positive indications from the intervention. It appears that when bar managers and owners are aware of the program and its enforcement and when servers are properly trained in RBS, fewer patrons may become intoxicated and greater efforts may be made to deny service to obviously intoxicated patrons. Given that about half of arrested impaired drivers had their last drink at a licensed establishment, widespread implementation of this strategy has the potential to help reduce impaired driving.  相似文献   

8.
D epth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and Conductivity of the aquifer). Using such an approach allows one to investigate the potential for groundwater contamination on a regional, rather than site-specific, scale. Based upon data from variables such as soil permeability, depth to water, aquifer hydraulic conductivity, and topography, subjective numerical weightings have been assigned according to the variable's relative importance in regional groundwater quality. The weights for each variable comprise a GIS map layer. These map layers are combined to formulate the final groundwater pollution potential map. Using this method of investigation, the pollution potential map for the study area classifies 47% of the area as having low pollution potential, 26% as having moderate pollution potential, 22% as having high pollution potential, and 5% as having very high pollution potential.  相似文献   
9.
Immediately following Hurricane Katrina, the Mississippi Governor's Commission for Recovery, Rebuilding and Renewal provided planning teams to work with coastal communities to prepare long-range rebuilding plans followed by further community-initiated plans. Eighteen months after Katrina, this paper examines the degree to which environmental protection has been incorporated into the long-range plans developed in Harrison County, Mississippi. This study finds that environmental protection has not been adequately integrated into the plans. It concludes by offering recommendations on how these communities can improve their plans relative to environmental protection measures as they move into their next phase of planning.  相似文献   
10.
Since the turn of the century, copper sulfate has been used extensively as an algicide to control nuisance algal blooms in drinking water reservoirs Recent experimental results have shown that the toxicity of copper to algae is determined by the activity of ionic copper, and not the total copper concentration The sensitivity of algae to ionic copper has been found to vary considerably for different algal species Chemical processes such as precipitation, complexation by dissolved organic substances, and adsorption by suspended material can be important in controlling the chemical speciation of copper added to drinking water reservoirs The copper sulfate dosage required for effective treatment of a reservoir is shown to depend on water chemistry and the copper sensitivity of nuisance algal species By evaluating copper chemistry and copper sensitivity of nuisance algal species it may be possible to obtain effective treatment with lower copper sulfate dosages in some reservoirs  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-23

京公网安备 11010802026262号