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   239篇
  免费   7篇
  国内免费   5篇
安全科学   22篇
废物处理   6篇
环保管理   49篇
综合类   49篇
基础理论   52篇
环境理论   1篇
污染及防治   39篇
评价与监测   18篇
社会与环境   13篇
灾害及防治   2篇
  2023年   1篇
  2022年   5篇
  2021年   5篇
  2020年   3篇
  2019年   3篇
  2018年   6篇
  2017年   6篇
  2016年   14篇
  2015年   5篇
  2014年   8篇
  2013年   18篇
  2012年   13篇
  2011年   22篇
  2010年   10篇
  2009年   11篇
  2008年   8篇
  2007年   13篇
  2006年   17篇
  2005年   10篇
  2004年   5篇
  2003年   13篇
  2002年   5篇
  2001年   5篇
  2000年   5篇
  1999年   4篇
  1998年   1篇
  1997年   3篇
  1996年   5篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
排序方式: 共有251条查询结果,搜索用时 46 毫秒
161.
Research over the last 25 years on the contribution of aloneness to creativity enhancement has had mixed results. Early studies of sensory deprivation generally found negative effects while more recent research on flotation isolation has reported positive influence. Sports performance, for example, has been improved by means of directed imagery and flotation aloneness. However, there has been only one study which has attempted to enhance creativity through the flotation method and while this study reported positive results, it lacked several control features and was based on a very small sample of highly selected subjects.The present study was designed to evaluate directly the potential contribution of floating to creativity enhancement as measured by the Guilford fluency test and other measures. Subjects were male and female university students, half of whom spent one hour in a float environment and the other half in a darkened room. Each was tested before and after experimental trial on the Guilford and other creativity measures and on two personality/affect scales. Float subjects showed significant increases on the Guilford test from the pre- to post-float and meaningful increases on other thinking measures as compared to non-floating control subjects. Floating was associated with a decrease in anxiety/tension, depression, hostility, and fatigue, but with an increase in vigor and a maintenance of curiosity scores, and it is speculated that the creativity benefits may be a result of these state changes.  相似文献   
162.
The paper identifies some of the main ethical issues concerning the protection of the environment from radiation and suggests ways in which ethics can aid in developing a system of protection. After a presentation of background on ethical theory and environmental ethics, three main issues related to environmental protection are discussed: First, the question of valuing the environment and implications for the definition of harm and monetary valuation of environmental goods; second, difficulties with scientific uncertainty and applications of the precautionary principle; and third, issues concerned with the distribution of risk and its relevance for participation in decision-making. In summary, the paper argues that there are strong ethical grounds to provide for the protection of the environment and that, all other things being equal, there is no reason to treat ionising radiation differently to other environmental stressors.  相似文献   
163.
INTRODUCTION: Many injury prevention interventions require changes in human behavior to reduce self-risk or risk to others. Promising injury prevention interventions may be discarded if they lack power to create a significant difference in outcomes when judging their ability to "move a person from nonaction or negative action to positive action (safety)." The transtheoretical model of change (TMC) allows greater sensitivity in detecting along the change process where an intervention may be effective. The stages of change consist of precontemplation, contemplation, preparation, action, maintenance, and termination. Change is not viewed as an "all or none phenomenon." METHOD: Use of the TMC was examined using a quasiexperimental, cross-over design involving high school agriculture students enrolled in 21 schools in Kentucky (n=9), Iowa (n=7), and Mississippi (n=5). A series of physical and narrative simulations (safety training exercises) were developed with a focus on preventing amputation, spinal cord injury, hypersensitivity pneumonitis, and noise-induced hearing loss. Contemplation and action, as part of the TMC, were measured using a 10-item, Likert-type, stages of change (SOC) instrument comprised of two subscales (reliability coefficients were.88 and.81, respectively). The final sample consisted of 790 students (373 treatment and 417 control). RESULTS: There was a significant group effect for both contemplation, F(1,732)=197.4; p<.0001, and action, F(1,730)=106.1; p<.0001. A convenience sample of 29 of the participating students was selected for follow-up farm visits 1 year postparticipation. Of these students, 25 (86%) had made safety behavior changes in their farm work. IMPACT ON INDUSTRY: The use of the TMC model can provide researchers with greater precision in examining intervention effectiveness in promoting change.  相似文献   
164.
A technique for sampling pure fetal blood in twin pregnancies using a single uterine entry with a fetoscope is described. The fetoscope was inserted into one sac and after blood had been obtained from that, twin, the fetus in the other sac was sampled by trans-septal passage of the blood-sampling needle. This was done in six out of seven patients, the first in the series having two separate insertions of the fetoscope, one into each sac. Pure fetal blood was taken from all 14 fetuses, either from the placental insertion of the umbilical cord or the umbilicus, and the volume of the samples ranged from 200 μl to 1200 μl. In six patients the fetuses were at risk of β-thalassaemia and in one of haemophilia A. Some observations are made relating zygosity to the ultrasonic and fetoscopic appearance of the septum between the sacs.  相似文献   
165.
In understanding the safety climate or culture of a workplace, the perceptions and attitudes of the workforce are important factors in assessing safety needs. Safety solutions may fail if they do not take into account these prevailing attitudes and perceptions. Also, changes in attitudes and perceptions about safety are often likely outcomes of safety interventions. The aim of this study was to develop a measure of perception and attitudes about safety as an indicator of safety culture for use with working populations. After reviewing the structure and content of a number of older, related measures of safety attitudes, a 67-item questionnaire was developed. The questionnaire was distributed in a self-administered form to 1560 workers in a wide variety of types of jobs and 660 questionnaires were returned from 7 workplaces with a response rate of 42%. Items were evaluated by Cronbach alpha which showed that the item set shared considerable common variance. Scale development was approached in two ways. First items which were highly skewed were removed, resulting in removal of around half of the items, with very little loss in alpha. The remaining items were then subjected to factor analysis which revealed five factors; personal motivation for safe behaviour, positive safety practice, risk justification, fatalism and optimism. This factor structure showed acceptable psychometric properties. Second, in an effort to produce a unidimensional scale with a small, but representative set of items, additional items were removed which had high correlation with other items. This resulted in loss of around half of the remaining items. The short scale contained 17 items with again overall acceptable psychometric properties. The most striking finding in the development of this questionnaire was that there was little variation between respondents on a very large proportion of the questions originally selected. Clearly there are well-known beliefs about safety in the working community which need to be understood in order to progress the concept of safety culture.  相似文献   
166.
In much of the San Joaquin Valley, California, USA, inadequate drainage of applied irrigation water and accumulating salts in the soil have necessitated the installation of subsurface tile drainage systems to preserve crop productivity. At present, these subsurface drainage waters are disposed of by means of evaporation ponds or discharges into the San Joaquin River. Unfortunately, most of these agricultural drainage waters contain high concentrations of salts and naturally occurring trace elements, such as selenium, and recent evidence indicates that substantial numbers of waterbirds are exposed to contamination by selenium in the evaporation ponds. In order to avoid, minimize, or mitigate the adverse impacts on wildlife using the ponds, alternative pond management methods must be identified and evaluated for implementation. A number of methods have the potential to be cost-effective in significantly reducing the contamination hazard to birds using agricultural evaporation ponds. Twenty general methods were evaluated in this study, and four methods are recommended for implementation: remove levee vegetation, remove windbreaks, deepen the ponds, and haze birds. A number of other methods are recommended for further consideration because they appear to have good prospects for reducing the contamination hazard: steepen interior levee slopes, apply herbicides and insecticides, place netting on pond shorelines, and provide freshwater habitat adjacent to evaporation ponds. It may be necessary to use a combination of methods to effectively control selenium contamination of aquatic birds because it is unlikely that a single affordable pond management method will be able to entirely eliminate the contamination hazard.  相似文献   
167.
Through the Direct/Delayed Response Project (DDRP), the United States Environmental Protection Agency is attempting to assess the risk to surface waters from acidic deposition in three regions of the eastern United States: the Northeast Region, the Southern Blue Ridge Province, and the Mid-Appalachian Region. The central policy question being addressed by the DDRP is: Within the regions of concern, how many surface water systems (lakes, streams) will become acidic due to current or altered levels of acidic sulfur deposition, and on what time scales? The approach taken by the DDRP is to select a statistically representative set of watersheds in each region of concern and to project the future response of each watershed to various assumed levels of acidic deposition. The probability structure will then be used to extrapolate the watershed-specific results to each region. The data will be used also for statistical investigation of hypothesized relationships between current surface water chemistry and watershed characteristics. Because the needed terrestrial data base was not available, regional watershed surveys were conducted to meet the specific data needs of the DDRP. Maps (1∶24,000) of soils, vegetation, land use, depth to bedrock, and bedrock geology were made for each watershed. The soils were grouped into sampling classes based on their hypothesized response to acidic deposition. Randomized sampling of these classes provided regional means and variances of soil properties that can be applied to individual watersheds. Because of DDRP's need for consistency within and among regions, unique quality control/quality assurance activities were developed and implemented. After verification and validation, the DDRP data base will be made publicly available. This will be a unique and useful resource for others investigating watershed relationships on a regional scale. The results of these surveys and the conclusions of the DDRP will be presented in several future papers. The current paper gives an overview of the context, rationale, logistical considerations, and implementation of these surveys, with special emphasis on the field activities of watershed mapping and soil sampling. This discussion should be useful to those planning, implementing, and managing survey activities in support of regional assessments of other environmental concerns, who are likely to face similar choices and constraints.  相似文献   
168.
It seems like a simple enough exercise. After the opening meeting, the audit team embarks on an orientation tour to familiarize itself with the layout of the facility. A simple ?walk about”? as the Australians would say. If the site is bigenough, maybe the team climbs into a vehicle for the tour. Although the orientation tour typically represents only one hour, this hour is as important as any other for the audit team. This article discusses ten steps audit teams can take to maximize the effectiveness of the tour. The ten steps came about as a result of observing audit teams during many training audits and seeing persistent problems arise.  相似文献   
169.
In 1996, the International Standards Organization (ISO) completed work on an environmental management system (EMS) standard: ISO 14001. The standard involves only five required elements, spans less than five pages, and upon initial review, appears relatively uncomplicated. As well, many of the ISO 14001 requirements may already be present in an organization's existing EMS. Nevertheless, the new standard presents a number of challenges to industry implementation. Whether an organization aims to start from scratch in developing an EMS under ISO 14001 or modify its existing EMS to meet the ISO challenge, implementation requires careful planning and analysis. This article provides a summary of the planning required to implement ISO 14001 at the facility level, including the initial planning effort and the identification of significant environmental impacts, objectives, and targets. The aim will be to eliminate some of the “hype” associated with ISO and provide some practical “how to” guidance for implementing the standard. The discussion begins with an overview of the initial planning effort and then turns to key planning requirements.  相似文献   
170.
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