全文获取类型
收费全文 | 47篇 |
免费 | 2篇 |
国内免费 | 34篇 |
专业分类
安全科学 | 11篇 |
环保管理 | 4篇 |
综合类 | 40篇 |
基础理论 | 23篇 |
污染及防治 | 1篇 |
评价与监测 | 1篇 |
社会与环境 | 3篇 |
出版年
2024年 | 4篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 1篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 1篇 |
1995年 | 1篇 |
排序方式: 共有83条查询结果,搜索用时 452 毫秒
51.
Mercury in sediments and vegetation in a moderately contaminated salt marsh
(Tagus Estuary, Portugal) 总被引:1,自引:1,他引:0
Jo?ao Can′ario Carlos Vale Laurier Poissant Marta Nogueir Martin Pilote Vasco Branco 《环境科学学报(英文版)》2010,22(8):1151-1157
Depth variations of total mercury (Hg) and methylmercury (MeHg) concentrations were studied in cores from non-colonized
sediments, sediments colonized by Halimione portulacoides, Sarcocornia fruticosa and Spartina maritima and belowground biomass,
in a moderately contaminated salt marsh (Tagus Estuary, Portugal). Concentrations in belowground biomass exceeded up to 3 (Hg) and
15 (MeHg) times the levels in sediments, and up to 198 (Hg) and 308 (MeHg) times those found in aboveground parts. Methylmercury
in colonized sediments reached 3% of the total Hg, 50 times above the maximum values found in non-colonized sediments. The absence
of correlations between total Hg concentrations in sediments and the corresponding MeHg levels suggested that methylation was only
dependent on the environmental and microbiological factors. The analysis of belowground biomass at high-depth resolution (2 cm)
provided evidence that Hg and MeHg were actively absorbed from sediments, with higher enrichment factors at layers where higher
microbial activity was probably occurring. The results obtained in this study indicated that the biotransformation of Hg to the toxic
MeHg could increase the toxicity of plant-colonized sediments. 相似文献
52.
本文综述了近年来国内外大量文献,对有关水体和大气中汞的存在形态、特性及水/气间汞交换通量的影响因素进行了总结,描述了目前国内外相关领域的研究现状,并对该领域下一步的研究方向进行了探讨. 相似文献
53.
The architectural complexity of ecosystems can greatly influence their capacity to support biodiversity and deliver ecosystem services. Understanding the components underlying this complexity can aid the development of effective strategies for ecosystem conservation. Caribbean coral reefs support and protect millions of livelihoods, but recent anthropogenic change is shifting communities toward reefs dominated by stress-resistant coral species, which are often less architecturally complex. With the regionwide decline in reef fish abundance, it is becoming increasingly important to understand changes in coral reef community structure and function. We quantify the influence of coral composition, diversity, and morpho-functional traits on the architectural complexity of reefs across 91 sites at Cozumel, Mexico. Although reef architectural complexity increases with coral cover and species richness, it is highest on sites that are low in taxonomic evenness and dominated by morpho-functionally important, reef-building coral genera, particularly Montastraea. Sites with similar coral community composition also tend to occur on reefs with very similar architectural complexity, suggesting that reef structure tends to be determined by the same key species across sites. Our findings provide support for prioritizing and protecting particular reef types, especially those dominated by key reef-building corals, in order to enhance reef complexity. 相似文献
54.
River restoration success: a question of perception 总被引:1,自引:0,他引:1
J?hnig SC Lorenz AW Hering D Antons C Sundermann A Jedicke E Haase P 《Ecological applications》2011,21(6):2007-2015
What defines success and failure of river restoration measures is a strongly debated topic in restoration science, but standardized approaches to evaluate either are still not available. The debate is usually centered on measurable parameters, which adhere to scientific objectivity. More subjective aspects, such as landscape aesthetics or recreational value, are usually left out, although they play an important role in the perception and communication of restoration success. In this paper, we show that different perceptions of restoration success exist by analyzing data from 26 river restoration measures in Germany. We addressed both objective parameters, such as hydromorphological changes and changes in fish and benthic invertebrate assemblages, from field investigations, and subjective parameters, such as opinions and perceptions, from water managers via an online survey. With regard to the objective hydromorphological and biotic parameters, our results agree with many studies that have reported improvements in the hydromorphology following restoration; however, there is no similar agreement between results concerning changes in the benthic invertebrate and fish assemblages. The objective results do not correspond to the subjective parameters because self-evaluation of the restoration projects by water managers was overly positive. Indeed, 40% of the respondents admitted that their evaluation was based on gut feeling, and only 45% of the restoration measures were monitored or occasionally checked. This lack of objectively recorded data meant that the water managers were not able to reasonably evaluate restoration success. In contrast, some self-evaluation responses reflected a different perception of the restoration success that was based on landscape aesthetic values or on benefit for the public; others adopted a general "condemned to success" attitude. Based on our data, we argue (1) that goals should be thoughtfully formulated prior to restoration implementation and (2) that it is necessary to monitor river restoration success from different perspectives. 相似文献
55.
56.
Skoglind-?hman I Kjellberg K 《International journal of occupational safety and ergonomics》2011,17(4):433-444
The aim of this pilot study was to explore whether home care service personnel used knowledge and skills in transfer technique in their daily work; knowledge and skills gained by participating in training programmes, and to identify factors that may hinder and support their use. Focus group interviews were held with 2 home care service groups in 2 Swedish towns. Individual interviews were conducted with the personnel's managers, unit leaders and safety representatives. Qualitative content analysis was used. The findings revealed that the personnel tried to use their knowledge and skills. However, there were both hindering and supporting factors for the use of safe work technique. The findings indicate that training programmes in transfer technique should not be implemented as isolated actions without considering the physical environment, the wishes of persons receiving care and their relatives, the work organisation, the safety culture and the role of managers. 相似文献
57.
58.
利用生理毒物代谢动力学(PBTK)对小鼠静脉注射农药氰戊菊酯后,氰戊菊酯在体内分布转化代谢过程进行模拟,为评价农药暴露风险提供依据。小鼠静脉注射氰戊菊酯的PBTK模型构建分为5个房室:肝脏、肺、肾脏、充分灌注室和不充分灌注室,各房室内氰戊菊酯的浓度变化率由质量守恒微分方程表示。根据欧拉数值计算方法,对小鼠静脉注射氰戊菊酯后的毒物代谢动力学数据进行模拟。结果模拟预测了小鼠静脉注射0.5 mg·kg-1、2.5 mg·kg-1、10 mg·kg-1氰戊菊酯后血液、肝脏和肺中氰戊菊酯浓度变化曲线。为验证该模型的准确性,对小鼠静脉注射0.77 mg·kg-1氰戊菊酯后血液、肝脏和肺中氰戊菊酯的浓度值变化模拟值与前人的实验测量值进行比较,结果显示模拟值与实验值之间不存在显著性差异。因此利用该方法可以估测小鼠静脉注射氰戊菊酯的毒物代谢动力学数据,为评估农药暴露体内剂量数据提供了便利途径。 相似文献
59.
Mountain lakes are usually sensitive to the effects of global and regional environmental changes. Since the second half of the 20th century, surface-water acidification has become a significant ecological problem, and many lakes in Europe and North America have anthropogenically acidified. Additionally, following reduction in emissions of sulfur (S) and nitrogen (N) compounds, recovery from acidification has been observed in many lakes. In this study, we used changes in diatom communities to reconstruct the pH histories based on changes recorded in nine Tatra lakes (Western Carpathians, Poland) since approximately 1850 AD. Overall, results indicate that acidic precipitation had little influence on lake-water pH in the Tatra Mountain lakes. Changes in diatom-inferred pH (DI-pH) generally were small and showed little evidence of acidification during the time of the highest air pollution (since the 1960s), and have shown little change since the reduction of acidic deposition since the 1990s. Lakes that showed some evidence of acidification included dystrophic lakes with low acid neutralizing capacity. However, as illustrated by the PCA trajectories of the diatom assemblages, the majority of the lakes currently contain diatom assemblages that are unlike the diatom floras that existed ca. 1850. 相似文献
60.
Vali? B Kos B Gaj?ek P 《International journal of occupational safety and ergonomics》2012,18(2):161-170
Occupational exposure caused by large broadcasting transmitters exceeds current reference levels. As it is common for different radio and TV transmitters to share the location, we analysed combined exposure on a 40-m high mast. The frequency modulation (FM) transmitter, located between the 10th and 30th metre, had the power of 25 kW, whereas an ultra-high frequency (UHF) transmitter of 5 kW occupied the top 8 m of the mast. Measured and calculated values of the electric field strength exceeded the reference levels up to 10 times; however, the results for the specific absorption rate (SAR) values show that the reference levels are very conservative for FM exposure, i.e., basic restrictions are not exceeded even when the reference levels are exceeded 10 times. However, for UHF exposure the reference levels are not conservative; they give a good prediction of real exposure. 相似文献