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   217篇
  免费   55篇
  国内免费   11篇
安全科学   84篇
废物处理   2篇
环保管理   55篇
综合类   86篇
基础理论   16篇
污染及防治   8篇
评价与监测   10篇
社会与环境   4篇
灾害及防治   18篇
  2023年   1篇
  2022年   5篇
  2021年   13篇
  2020年   3篇
  2019年   13篇
  2018年   9篇
  2017年   15篇
  2016年   17篇
  2015年   7篇
  2014年   19篇
  2013年   13篇
  2012年   25篇
  2011年   12篇
  2010年   9篇
  2009年   9篇
  2008年   6篇
  2007年   10篇
  2006年   6篇
  2005年   8篇
  2004年   6篇
  2003年   11篇
  2002年   6篇
  2001年   5篇
  2000年   7篇
  1999年   6篇
  1998年   7篇
  1997年   6篇
  1996年   4篇
  1995年   3篇
  1994年   5篇
  1993年   2篇
  1992年   3篇
  1988年   2篇
  1983年   1篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
排序方式: 共有283条查询结果,搜索用时 671 毫秒
181.
松花江硝基苯污染事件不仅对松花江干流造成危害,也影响到界河黑龙江的水质.本文通过调查、实验,在界河黑龙江下游对硝基苯污染带到达前、到达期间和过后进行研究,论证了界河黑龙江沿岸井水没有受到硝基苯污染的影响.  相似文献   
182.
Personal initiative training is a promising way to increase entrepreneurial personal initiative, which is a key behavior for successful entrepreneurship. Although personal initiative training has been shown to promote personal initiative, little is known about how this proactive behavior can be maintained over time and what the consequences are. The training transfer literature suggests that training effects usually decline with time. It is not clear, however, which factors contribute to personal initiative maintenance and which benefits go along with it. In a randomized controlled field experiment with 912 microentrepreneurs in Lomé, Togo, we investigate the influence of need for cognition—a cognitive factor driving proactive behavior—on personal initiative maintenance after training. In addition, we examine the effect of need for cognition on the well‐being consequences of personal initiative maintenance. We show that people high in need for cognition tend to maintain posttraining personal initiative longer than those low in need for cognition. However, contrary to our predictions, need for cognition has no effect on the level of well‐being that results from personal initiative maintenance. Our findings contribute to a better understanding of personal initiative and its maintenance and could be used to increase training effectiveness.  相似文献   
183.
针对气井套管环空带压问题,通过研究气体在套管水泥环内的渗流规律,建立了气体渗流的连续性方程和运动方程,并求解出气体在水泥环中的渗流速率。通过分析井口泄压时针型阀处的气体流动状态,得出泄压时的气体泄放速率。以气体渗流速率和泄放速率为基础,结合井口的气体状态方程,分别建立了套管环空压力恢复与泄压预测模型。根据现场A气井实际数据进行实例计算,研究结果表明:所建模型计算的套管环空压力值与现场实测数据吻合,验证了模型的准确性。研究结果对套管环空带压的诊断评估和环空压力的控制具有重要意义。  相似文献   
184.
采油射流泵内流场是具有逆压力梯度的强湍流场,扩散管部分具有不规则边界。采用代数法生成扩散器贴体坐标系统;并选择使用高Re数k-ε。模型及考虑逆压力梯度影响的壁面函数法对射流泵整体流场进行数值模拟。将理论结果与试验值进行对比分析,二者基本符合,数值模拟的可靠性得到了验证。  相似文献   
185.
本文报道了自贡市井矿盐开发所致的辐射水平。井矿盐开发的主要废弃物-卤泥中^238U,^226Ra,^232Th的天然放射性核素比活度比四川省土壤中相应核素平均值高1-2个数量级,且造成卤泥堆积场和局部生产环境陆地γ辐射剂量率高出自贡市环境陆地γ辐射平均值的2.0-48.3倍,最主超过165倍。部份卤泥和盐厂附近江河排放口底泥中天然放射性废物标准。  相似文献   
186.
利用核辐射法治理生物堵塞地下水井,在众多有希望的辐射净水技术中被证明是成功的和具有明显经济效益的工艺方法。描述了此项技术在德国、捷克、美国和俄国的应用和获得的经验.利用核辐射水力屏障法成功地就地净化了被氰化物污染的地下水,使出水中的氰化物浓度降低了一数量级。  相似文献   
187.
Although theory suggests that regulatory focus fluctuates within person and such fluctuations impact employee well‐being, there is little empirical investigation of such propositions. These are important research questions to address because work events may elicit within‐person fluctuations in regulatory focus, which can then affect well‐being. The primary purpose of this study is to examine specific predictors of daily regulatory focus at work and the foci's impact on employee well‐being at work and home as indicated by mood and psychosomatic complaints, respectively. We present and test an overarching theoretical framework that integrates conservation of resources theory, the cognitive‐affective processing system framework, and regulatory focus theory to delineate why and when work events affect regulatory focus and how the foci affect well‐being. Consistent with our expectations, we found that positive work events positively predicted daily promotion focus, but this effect was weaker when employees had high‐quality relationships with leaders. Furthermore, daily regulatory focus was associated with employee well‐being (mood and psychosomatic complaints) such that (i) promotion focus improved well‐being; (ii) prevention focus reduced well‐being; and (iii) the effects of promotion focus on well‐being were strongest when prevention focus was low. We discuss theoretical and practical implications and offer directions for future research. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
188.
Previous research showed that psychological detachment from work during leisure time is beneficial and that reflecting on negative aspects of work is detrimental for employees' well‐being. However, little is known about the role of positive reflection about work during leisure time. In the present research, we examined the effects of positive work reflection on affective well‐being. Additionally, we tested the effectiveness of an intervention to increase positive work reflection and to improve well‐being with a randomized controlled field experiment. Findings from three diary studies showed that positive work reflection was related to an increase in affective well‐being with regard to both positive and negative moods. The results further indicated that the benefits of positive work reflection were incremental to that of psychological detachment and the absence of negative work reflection. Contrary to our expectation, no evidence was found for the effectiveness of the intervention. Theoretical implications of main findings as well as supplementary findings are further discussed. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
189.
Going beyond the relation of work and family, the present three‐wave longitudinal study spanning one year assessed different forms of conflict and facilitation between leisure and the life domains work and family and their relation to subjective well‐being. A sample of N = 277 employed men and women reported their perceived conflict and facilitation between leisure, work, and family and subjective well‐being. Results suggest that leisure is a source of facilitation for work and family, and, at the same time, a major recipient of conflict from work and family. Moreover, leisure conflict was negatively correlated and leisure facilitation was positively associated with concurrent subjective well‐being. Both conflict and facilitation between all three life domains remained highly stable over the course of one year. Only few and non‐systematic lagged effects were found, indicating that the variance of the stability of the constructs and their relations over time leave little room for longitudinal predictions. Taken together, the study demonstrates that, similar to work–family relations, conflict and facilitation with the leisure domain are also associated with subjective well‐being and remain highly stable over the course of a year in the lives of young and middle‐aged adults. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
190.
铀矿井通风系统合理性灰色综合评价模型及应用   总被引:3,自引:0,他引:3  
针对铀矿井通风系统实际特征,合理确定其评价指标体系,建立了基于灰色关联理论的铀矿井通风系统合理性灰色综合评价模型。该模型利用关联度判断评价数据序列与参考数据序列的接近程度,尽量减少个人主观臆断带来的弊端,其评判结果更符合实际,评价结果更可靠。利用该模型对3个铀矿井的通风系统进行评价,方法简便,易于使用,评价结果与实际相符,为铀矿井通风系统合理性评价提供了一种新的方法和思路。  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