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   107篇
  免费   19篇
  国内免费   102篇
安全科学   32篇
废物处理   1篇
环保管理   11篇
综合类   148篇
基础理论   15篇
污染及防治   7篇
评价与监测   4篇
社会与环境   9篇
灾害及防治   1篇
  2024年   3篇
  2023年   16篇
  2022年   29篇
  2021年   8篇
  2020年   30篇
  2019年   16篇
  2018年   9篇
  2017年   8篇
  2016年   8篇
  2015年   10篇
  2014年   7篇
  2013年   11篇
  2012年   12篇
  2011年   8篇
  2010年   5篇
  2009年   7篇
  2008年   3篇
  2007年   9篇
  2006年   6篇
  2005年   9篇
  2004年   2篇
  2003年   3篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1989年   1篇
  1986年   1篇
排序方式: 共有228条查询结果,搜索用时 281 毫秒
41.
为了解大连市环境空气挥发性有机物(VOCs)污染特征及来源,基于2020年6~8月高时间分辨率VOCs在线观测数据,对大连市大气VOCs的浓度水平、组成特征、反应活性及来源情况进行了分析.结果表明φ(VOCs)的平均值为(10.21±5.71)×10-9,其中烷烃占比为66.35%,烯烃为11.89%,炔烃为7.75%,芳香烃为14.01%.VOCs和NOx呈现夜间高,白天低的特征,而O3变化趋势相反.综合考虑物种活性,确定甲苯、乙烯、间/对-二甲苯、1-己烯、正丁烷、异戊烷、正戊烷和异戊二烯是影响大连市大气VOCs的关键物种,优先控制烯烃和芳香烃类化合物的排放是改善大连市夏季O3污染的关键.PMF源解析结果显示交通源(26.38%)、燃烧源(22.75%)、工业排放源(17.09%)、溶剂使用源(14.59%)、天然源(11.72%)和其他(7.47%)为监测期间VOCs的主要来源,交通源和燃烧源排放是大连市夏季O3防控的重点污染源.  相似文献   
42.
金属元素是大气PM2.5的重要组成成分,对人群危害性极强且兼具源特异性,分析不同经济模式地区大气细颗粒物中金属污染状况及来源差异,可以为科学规划城市产业布局和保护大气环境提供参考.通过霾/非霾期大气PM2.5采样,使用电感耦合等离子体发射光谱仪(ICP-OES)测定成都市及仁寿县样品中18种金属元素质量浓度,分析其污染水平,并基于正定矩阵因子分解模型(PMF)解析两地大气PM2.5中金属元素的来源.结果表明,成都市扬尘源、移动源和燃煤源特征元素占元素总和的比值大于仁寿县,而仁寿县生物质燃烧源、工业源以及燃油源特征元素占比则较高.两地Cr、Cd和As元素浓度均超标,表明PM2.5中重金属污染严重.随着霾污染加剧,两地PM2.5中金属元素总量上升,但增幅远低于PM2.5浓度增长.此外,不同元素在霾期和非霾期浓度比值存在差异,成都市变化范围为0.7(Al)~2.8(Ba),仁寿县介于0.8(Al)~3.1(Mn)之间,但总的来说两地大致呈现出燃煤和工业活动排放元素增幅较大,机动车污染源次之,扬尘源增幅较缓的状况.受地区产业布局、经济规模和发展模式的影响,大气PM2.5中金属元素污染水平及来源呈现出不同的区域特征.在重点发展第三产业的大型城市,如成都,更易遭受交通运输和城市建设等带来的大气污染,而在仁寿等第二产业占比不断增加的郊县,其污染主要受化石燃料燃烧和工业过程排放的影响.  相似文献   
43.
在高职高专教育环境下,大学语文课程的日益边缘化已经成为不争的事实。大学语文重不重要这一问题,原则性的答案和事实上的回答截然对立。2004年3月,内地及港澳台学者在“大学语文教学研讨会”上达成共识,他们认为:“只要不把大学办成技校,只要大学还是大学,大学语文的作用就不容忽视。”因而,现在的主要问题不是论证大学语文多么重要,而是要研究教学效果的达成。本文将通过对大学语文课程的性质定位、教学内容、教学方法和考核方式进行分析和研究,进而论证大学语文对高职学生素质和能力培养的积极意义。  相似文献   
44.
The incessant demand and consumption of energy services among individuals’ is increasing throughout the world. Individuals’ electricity consumption in Northern Cyprus has risen considerably. However, the demand for electrical energy services on the island is heavily reliant on imported fossil fuels. Burning fossil fuels has adverse effects on its environment. Therefore, sustainable energy consumption is required and individuals are targeted for energy conservation to reduce electricity consumption. Against this background, using the Structural Equation Modeling approach, this research incorporates social‐psychological factors; personal norms, positive and negative emotions into the theory of planned behaviour (TPB) model to assess the relationships among the variables, explain their impact on consumers’ electricity conservation intentions and enhance the explanatory power of the model. Data was conveniently obtained from a quantitative sample of 400 electricity consumers. The results indicate that negative emotions have the strongest significant influence on intentions, but personal norms have the least effect on intentions to save electricity. Furthermore, the study revealed that our expanded TPB model can provide improved explanatory power more than the original TPB. Policy implications, limitations and future research are discussed.  相似文献   
45.
Conservation operates within complex systems with incomplete knowledge of the system and the interventions utilized. This frequently results in the inability to find generally applicable methods to alleviate threats to Earth's vanishing wildlife. One approach used in medicine and the social sciences has been to develop a deeper understanding of positive outliers. Where such outliers share similar characteristics, they may be considered exceptional responders. We devised a 4‐step framework for identifying exceptional responders in conservation: identification of the study system, identification of the response structure, identification of the threshold for exceptionalism, and identification of commonalities among outliers. Evaluation of exceptional responders provides additional information that is often ignored in randomized controlled trials and before–after control‐intervention experiments. Interrogating the contextual factors that contribute to an exceptional outcome allow exceptional responders to become valuable pieces of information leading to unexpected discoveries and novel hypotheses.  相似文献   
46.
Building on the broaden‐and‐build theory and research on the negativity bias, this study examines how trait affectivity, as a stable predisposition predicting the pattern of emotional responding, shapes newcomers' perceptions of supervisor support and experience of organizational commitment. Using latent growth modeling and data collected at four points in time from newcomers (N = 158), we found the initial level of perceived supervisor support to mediate a negative relationship between negative affectivity and the level of commitment. Moreover, although newcomers experienced a general decrease in perceived supervisor support and a related decrease in commitment, those with high positive affectivity experienced a weaker decrease in perceived supervisor support, which led to a weaker decrease in commitment. Incidentally, positive affectivity was also positively related to the initial level of commitment. Two post hoc studies indicated that positive and negative affectivity exerted their effects controlling for state affect and replicated the relationship between change in perceived support and commitment. We discuss how these findings inform our understanding of trait affectivity's influence on newcomers' work attitudes.  相似文献   
47.
以安徽省涡阳县为例,从分析煤炭资源开采对县域经济发展的正负效应影响和辩证关系转化的角度,提出煤炭资源对涡阳县域经济可持续发展的具体建议。  相似文献   
48.
The objective of mutagenicity assays in regulatory toxicology is the decision on non-mutagenicity or mutagenicity. An inherent problem of statistical tests is the possibility of false decisions, i.e., a mutagenic substance will be falsely labeled as non-mutagenic or a non-mutagenic substance will be falsely labeled as mutagenic. These probabilities of false negative (consumer's risk=type II error) and/or false positive decision (producer's risk=type I error) can be limited by using suitable testing procedures as well as a design including an appropriate positive control. Using the proof of hazard concept the well-known many-to-one procedures with total order restriction for increasing effect differences are used, while using the proof of safety concept procedures on equivalence with total order restriction are discussed. Both approaches are demonstrated on a real data example.  相似文献   
49.
Surface acting has been widely studied in organizational research owing to its impact on organizational behaviors and outcomes. Past research almost exclusively has focused on employees' interactions with external parties such as customers, clients, and patients. This study sought to extend this literature by examining the effects of employees' surface acting in interactions with parties internal to the organization (i.e., leaders and peers). Data were collected from 40 work groups (129 focal participants, 40 leaders, and 40 peers) from a large real estate agency company located in Beijing, China. Results showed that employees' surface acting influenced various emotional, relational, and behavioral outcomes. In addition, the present findings revealed that the consequences of employees' surface acting differed across leaders versus peers. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
50.
中远船务构筑特色安全文化的探索与实践   总被引:2,自引:2,他引:0  
本文主要阐述了在企业核心价值理念孵化牵引下生发的安全文化理念,总结和提炼了具有企业特色的“严、细、真、实、慎”的安全文化,并从制度建设、行为规范以及体现执行力的十大主要措施上,进行了比较系统的论述,对进一步促进企业安全文化建设提出了4个方面的对策。  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