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   131篇
  免费   16篇
  国内免费   7篇
安全科学   40篇
环保管理   21篇
综合类   31篇
基础理论   31篇
污染及防治   3篇
评价与监测   2篇
社会与环境   19篇
灾害及防治   7篇
  2023年   1篇
  2022年   7篇
  2021年   5篇
  2020年   9篇
  2019年   6篇
  2018年   6篇
  2017年   14篇
  2016年   10篇
  2015年   3篇
  2014年   11篇
  2013年   10篇
  2012年   9篇
  2011年   6篇
  2010年   6篇
  2009年   6篇
  2008年   4篇
  2007年   6篇
  2006年   4篇
  2005年   2篇
  2004年   2篇
  2003年   2篇
  2002年   3篇
  2001年   2篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1996年   2篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1989年   1篇
  1987年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1970年   1篇
排序方式: 共有154条查询结果,搜索用时 15 毫秒
91.
ABSTRACT: Increasingly, residential development in urbanizing areas is accomplished by large housing projects, composed of clusters of townhouses or garden partments. It is hypothesized that the runoff from such developments should carry more pollution than that from the same number of housing units on separate plots, because the runoff is conveyed directly to drainage channels rather than being drained across lawns and gardens, which may absorb part of the pollutants. In order to evaluate this effect, storm event data were obtained from a planned unit development near Hightstown, N. J., using samples taken every 10 minutes throughout the storm at two different storm sewers. Results show heavy metals pollution about what had been anticipated, in accordance with the hypothesis given above, and BOD ammonia and phosphates higher than predicted. The results are significant for areawide water quality planning in metropolitan areas, where projections of future pollution loadings depends upon the land use.  相似文献   
92.
On the basis of the source attribution perspective of work–family conflict, this study aims to first test whether threat to the family role mediates the relationship between work‐to‐family conflict and job satisfaction. We then examine boundary conditions of the source attribution perspective by drawing on boundary management and gender role orientation theories to examine whether role segmentation enactment and gender role orientation moderate the relationship between work‐to‐family conflict and job satisfaction. Using a scenario‐based experiment in Study 1, we find that threat to the family role mediates the relationship between work‐to‐family conflict and job satisfaction. This finding provides evidence supporting the appraisal process proposed by the perspective of source attribution. Using survey data collected from 216 Chinese managers and their spouses in Study 2, we find that work‐to‐family conflict has a negative relationship with job satisfaction only among people with high levels of role segmentation between work and home. In addition, for male managers, the negative moderating effect of role segmentation enactment on the relationship between work‐to‐family conflict and job satisfaction is stronger for those with a nontraditional gender role orientation, compared with those with a traditional gender role orientation. Theoretical and managerial implications are discussed.  相似文献   
93.
This study investigates the relationship between coworker work hours and perceived work‐to‐family conflict (WFC) in a multinational sample of professional service employees. Building on recent research on the ways in which workgroups influence individual WFC, we demonstrate that the average hours worked by coworkers has a significant relationship to reported WFC independent of an employee's own work hours. Although this finding is universal across the multinational sample, national cultural differences were found to moderate the relationship, such that employees in more collectivist countries are more strongly influenced by average coworker hours than their counterparts in less collectivist countries. The multilevel analysis was conducted using a sample of 7,600 professional service employees in 497 different workgroups across 20 countries. The results provide support for the effect of culture on the relationship between group average hours and perceptions of WFC. We conclude with a discussion of how national culture affects WFC.  相似文献   
94.
为了研究家用小型汽车室内多溴联苯醚(PBDEs)的存在状态,对上海市7辆使用2 a以上的不同型号家用轿车进行了调查。采集形成于车窗玻璃内表面的有机膜,采用气相色谱-质谱联用仪(GCMS)对有机模样品进行了定性及定量分析,并根据表面膜-空气分配模型计算汽车室内空气中PBDEs的质量浓度。结果表明:13种待测多溴联苯醚(PBDEs)目标化合物均被检出;在车窗玻璃内表面有机膜中,Σ13PBDEs含量为19.63~26.13 ng/m2;家用小型汽车室内空气中Σ13PBDEs质量浓度为376.61~961.24 pg/m3;由于PBDEs的正辛醇-空气分配系数KOA与PBDEs的溴代度正相关,高溴代PBDEs在有机膜中的含量较高(实测BDE-209是其最主要的污染物),而低溴代PBDEs在空气中的含量较高(BDE-28是其最主要的污染物);与家庭、办公场所、公共场所等室内环境相比,家用小型汽车室内空气中PBDEs质量浓度处于较高水平。  相似文献   
95.
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   
96.
Accounting for Uncertainty in Making Species Protection Decisions   总被引:1,自引:0,他引:1  
Abstract:  Uncertainty gives rise to two decision errors in implementing the U.S. Endangered Species Act: listing species that are not in danger of extinction and delisting species that are in danger of extinction. I evaluated four methods (minimum standard, precautionary principle, minimax regret criterion, adaptive management) for deciding whether to list or delist a species when there is uncertainty about how those decisions are likely to influence survival of the species. A safe minimum standard criterion preserves some minimum amount or safe standard (population) of a species unless maintaining that amount generates unacceptable social cost. The precautionary principle favors not delisting a species when there is insufficient evidence on the efficacy of state management plans for protecting them. A minimax regret criterion selects the delisting decision that minimizes the maximum loss likely to occur under alternative ecosystem states. When the cost of making a correct decision is less than the cost of making an incorrect decision, the minimax regret criteria indicates that delisting is the optimal decision. Active adaptive management employs statistically valid experiments to test hypotheses about the likely impacts of delisting decisions. Safe minimum standard and minimax regret criterion are not compatible with the U.S. Endangered Species Act. The precautionary principle comes closest to describing how federal agencies make delisting decisions. Active adaptive management is scientifically superior to the other methods but is costly and time consuming and may not be compatible with the U.S. National Environmental Policy Act.  相似文献   
97.
Composite sampling offers the great promise of efficiency and economy in environmental decision making. However, if careful attention is not paid to matching the support of the sample to that required for making the desired decision, the promise is unfulfilled. Obviously this attention must be applied in the design phase of a composite sampling strategy. Less obvious is the potential for alteration of the design sample support during sample collection and assay. The consequences of not paying attention to these aspects of sample design and assay are discussed in this issue paper illustrated with a series of examples taken from the authors consulting experience.  相似文献   
98.
为使合成旅后装保障方案的决策过程量化,达到决策结果更加符合客观事实的目的,通过引入模糊评价方法,结合分析后装保障方案决策的选择影响因素,确定了不同指标因素下对应的隶属函数,进而建立了针对后装保障方案决策评价问题的定量分析评价模型,最后给出该评价方法的实例运用,结果分析可知该模型在一定程度上保证了后装保障方案决策的科学合理性。  相似文献   
99.
Reproductive success within populations often varies with the timing of breeding, typically declining over the season. This variation is usually attributed to seasonal changes in resource availability and/or differences in the quality or experience of breeders. In colonial species, the timing of breeding may be of particular importance because the costs and benefits of colonial breeding are likely to vary over the season and also with colony size. In this study, we examine the relationship between timing of breeding and reproductive performance (clutch size and nest success) both within and between variable sized colonies (n = 18) of fairy martins, Petrochelidon ariel. In four of these colonies, we also experimentally delayed laying in selected nests to disentangle the effects of laying date and individual quality/experience on reproductive success. Within colonies, later laying birds produced smaller clutches, but only in larger colonies. The general seasonal decline in nest success was also more pronounced in larger colonies. Late laying birds were generally smaller than earlier laying birds, but morphological differences were also related to colony size, suggesting optimal colony size also varies with phenotype. Experimentally delayed clutches were larger than concurrently produced non-delayed clutches, but only in larger colonies. Similarly, delayed clutches were more likely to produce fledglings, particularly later in the season and in larger colonies. We suggest that the reduced performance of late breeding pairs in larger colonies resulted primarily from inexperienced/low quality birds preferring to settle in larger colonies, possibly exacerbated by an increase in the costs of coloniality (e.g., resource depletion and ectoparasite infestations) with date and colony size. These findings highlight the importance of phenotype-related differences in settlement decisions and reproductive performance to an improved understanding of colonial breeding and variation in colony size.  相似文献   
100.
周伟  米红  余潇枫  封宁 《中国环境科学》2013,33(10):1904-1910
从人口的家庭结构、年龄结构、城乡结构变化的角度对城镇建筑能耗的变化进行了分析.根据测算,2010~2030年,中国20~39岁的人口从4.46亿下降到3.28亿,减少约1.18亿;2030年全国的平均家庭规模从3.10人下降到2.48人,全国家庭数量将突破5.5亿户;按照现有模式发展,2030年城市化率达到64.2%.人口结构变化的影响下,2020年的城镇建筑需求总面积为3.14′1010m2,人均住宅面积为37m2,建筑能耗达到1.72′109tce;2030年的建筑需求总面积为3.84′1010m2,人均住宅面积为42m2,能耗为2.13′109tce. 从需求角度看,未来建筑规模的增长速度将逐步放缓.如果不能及时调整发展战略,未来会出现较大规模的住宅空置和资源浪费.  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