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   104篇
  免费   6篇
  国内免费   7篇
  2023年   2篇
  2022年   3篇
  2021年   5篇
  2020年   4篇
  2019年   1篇
  2018年   4篇
  2017年   5篇
  2016年   2篇
  2015年   4篇
  2014年   13篇
  2013年   14篇
  2012年   6篇
  2011年   7篇
  2010年   3篇
  2009年   4篇
  2008年   5篇
  2007年   5篇
  2006年   2篇
  2005年   6篇
  2004年   2篇
  2003年   2篇
  2001年   1篇
  2000年   2篇
  1999年   4篇
  1997年   3篇
  1996年   1篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1987年   1篇
  1981年   1篇
排序方式: 共有117条查询结果,搜索用时 97 毫秒
81.
目的:研究道路交通事故卡车与卡车前部碰撞驾乘人员损伤特征,分析比较驾乘人员的损伤及损伤分布特点。方法:应用统计学方法对2001年-2010年昆明地区卡车与卡车200例前部碰撞人员损伤的法医学鉴定资料进行系统分析性研究。结果:1.驾驶员易发生损伤的部位是下肢、头颈部,其次为胸、腹部损伤。驾驶员易发生右下肢的损伤及骨折。驾驶员易发生颅骨骨折和肋骨骨折。2.前排乘车人员易发生损伤的部位是上肢、头颈部,其次为下肢,而胸腹部损伤较少见。前排乘车人员易发生上肢的损伤及双侧尺桡骨的骨折。前排乘车人员左侧头颈部受伤的几率大于驾驶员的相对部位。前排乘车人员易发生右肱骨骨折。结论:1.与前排乘车人相比,驾驶员易造成胸部、腹部及盆部、右侧下肢的损伤及右股骨胫腓骨的骨折,发生双侧上肢的体表损伤及尺桡骨骨折均明显少。在身体体表出现胸部、腹部及盆部多部位连续的损伤,有助于提高认定卡车驾驶员的准确性。2.与驾驶员相比,前排乘车人易形成左侧头颈部的损伤,上肢双侧尺桡骨骨折,右侧肱骨的骨折。当损伤位于身体左侧头颈部且有右侧肱骨的骨折,有助于提高认定卡车前排乘车人的准确性。  相似文献   
82.
以生长在交通繁忙的东莞大道沿线的4种常见乡土绿化树种山杜英(Elaeocarpus sylvestris)、海南蒲桃(Syzygium hainanense)、小叶榕(Ficus microcarpa var. pusillifolia)和樟树(Cinnamomum philippinense)为材料,研究了城市交通尾气污染对植物的影响以及乡土植物在城市绿化中的适应特征。结果表明,4种植物的气孔形态没有明显差异,但污染环境中的气孔密度均显著增加,其中山杜英增加幅度最大。各树种的叶绿素和类胡萝卜素含量均发生了不同的适应性变化,但变化规律不一致。除樟树外,其它3种植物的最大净光合速率均提高,但气孔导度和胞间二氧化碳浓度的变化不一致。植物对大气污染的响应程度和方式存在种间差异。因此,4种植物通过形态和生理可塑性的改变以适应交通尾气污染环境。  相似文献   
83.
All radiation devices in use nowadays are subject to cause serious incidents and accidents, with potential risks in exposed population groups. These risks may have immediate or long term health implications. The detection of radioactive incidents is a procedure that should be systematized in economically developed societies. International organizations may provide support to other states in the event of a radioactive incident. Prevention, mitigation and treatment of the radiation effects are done by anticipating the moment of exposure and by establishing new efforts for investigation of radioprotective products.In this article we will analyze the causes of radiological incidents, the means to detect them, and the current preventive and therapeutic procedures available, with special emphasis on new biodosimetry methods for triage and investigational radioprotective drugs. Finally, we will explore the most efficient measures, for future prevention.  相似文献   
84.
85.
The present study was performed at a heavy-traffic affected soil to examine the efficacy of bioaccumulation and translocation potentials of heavy metals by the naturally growing weed Plantago major. Heavy metals were analyzed in soil as well as in plant below- and above-ground parts along different distances from a heavy-traffic highway. All the investigated soil heavy metals, except Cd, varied significantly, while pH and E.C had no significant difference, with increasing distance from the highway. Likewise, there was a significant decrease of heavy metals in plant below- and aboveground parts. In addition, no significant difference between most soil and root heavy metals at 20 and 100 m as well as those at 500 and 750 m distance from the highway. The bioaccumulation factor (BF) of all heavy metals, except Cd and Sr, were less than unity at most distances. However, Cd showed relative BF decline with the distance in contrast to Sr, which increases as distance from the highway increases. On the other hand, the translocation factors (TF) of Cd, Co, Cu, Pb and Zn were higher at the distances far from the highway, while that of Fe, Cr and Sr were higher near the highway. Furthermore, the enrichment factor (EF) showed small variations, among the investigated heavy metals, with varying distances from the pollution source. It was found that soil Fe, Al, Cr, Ni, Sr, V and Zn had significant positive correlation with all investigated heavy metals in P. major roots. The higher TFs of Cd, Fe and Pb in P. major shoots makes it suitable for phytoextraction from soil, while the lower ratios of Al, Mn, V, Co, Ni, Cr, Zn, Cu and Sr make it suitable for their phytostabilization. Therefore, this plant can be used as a bioindicator and biomonitor for traffic related heavy metals.  相似文献   
86.
Public use of protected areas is typically encouraged, but visitors arriving by vehicles may alter the natural areas they seek. Vehicle emissions add nitrogen oxides (NOx) and ammonia (NH3) to the air, which can increase the amount of plant-available (reactive) nitrogen, a limiting nutrient. Changes in ecosystem processes as a result of increases in nitrogen availability are at odds with the goals of many protected wilderness areas that are typically accessed by vehicles. In this multi-year study (2003–2019), we tested whether emissions from local vehicles entered the forest ecosystem adjacent to a highway in a protected wilderness valley near a mid-sized city (Calgary, Alberta, Canada). We examined the concentration of NO2 in the air and the abundance of combustion-derived nitrogen isotopes (δ15N) in naturally-occurring forest moss (Hylocomium splendens and Pleurozium schreberi) within 20 m of the highway as a function of traffic levels that varied independently at two scales: along the highway and among years. Within the valley, we observed a gradient in the number of vehicles that was greatest where vehicles enter the valley, with a corresponding pattern for NO2 concentrations in air. Traffic volume also varied among years, with the highest year having almost twice as many vehicles in the summer as the lowest year. δ15N values in forest moss displayed similar patterns as traffic both within and among years, signalling that nitrogen from vehicle emissions entered the local ecosystem corresponding to local traffic levels. Because vehicle emissions enter natural ecosystems that are intended to be conserved, vehicle use must be considered in the management of protected natural areas.  相似文献   
87.
环境噪声会降低动物声信号可探测性,是动物声信号进化的压力。为了避免人工噪声干扰,多数脊椎动物调整其叫声的频谱-时间结构,如采用延长叫声持续时间、提高频率和增加强度等策略。本研究选择回声定位声波频率范围与交通噪声频率范围相互重叠的东方蝙蝠(Vespertilio sinensis)为研究对象,在自然条件下开展实验,研究交通噪声对蝙蝠回声定位声波的影响。本实验选择交通噪声强度存在差异的两个样点,分别录制东方蝙蝠的回声定位声波,分析其结构参数。在交通噪声强度较高的样点,东方蝙蝠回声定位声波的持续时间、斜率均未显著改变,但起始频率、主频、终止频率及带宽均显著提高。结果表明,东方蝙蝠的回声定位行为在交通噪声干扰下具有明显的可塑性。  相似文献   
88.
In 1996, 10 years after Chernobyl accident, a cytogenetic analysis was carried out to assess whether chromosome aberrant cells (CA) were still detectable in the lymphocytes and clastogenic factors (CFs) were present in the plasma of children coming from Gomel (Belarus), one of the most heavily contaminated regions. Furthermore, the possible contribution of plasmatic CFs to the amount of CA was investigated. The presence of CA was examined in the lymphocytes from 29 thyroid tumour-affected children and 41 healthy children (local controls). Thirty healthy children living in Pisa (Italy) were enrolled in the study as additional controls from an uncontaminated area. No significant difference was observed between the two control groups, whereas a significantly increased frequency of CA was found in the tumour-affected children, as compared with Gomel and Pisa controls (χ2-test, p<0.001). However, when soil contamination level was taken into account, the chromosome type CA frequency observed in tumour-affected children coming from the more contaminated areas (>4 Ci/km2) resulted significantly higher than that in other children, either affected or not (p=0.003). The presence of CFs was analyzed on the plasma ultrafiltrate from 41 children. 7/10 (70%) plasma samples from tumour-affected children and 17/23 (74%) Gomel controls resulted to possess clastogenic activity irrespective of soil contamination levels. No activity was detected in the plasma of eight Pisa controls (0%). The difference between both Gomel groups and Pisa controls was highly significant (p=0.002). A borderline, but not statistically significant correlation (p=0.08) was observed between basal CA frequency and CF potency, which became significant (p=0.03) when only chromosome type of aberrations was considered. We conclude that, although the presence of CFs in the plasma of these children might be partly responsible of the cytogenetic effects observed, the main source of damage has considered to be do to the previous and/or continuous exposure to environmental radiocontaminants. Tumour-affected children may represent a subset of the population either more sensitive to clastogenic damage or exposed to higher levels of contaminants.  相似文献   
89.
蔡瑜萱 《生态科学》1996,15(1):63-67
外伶仃岛特大死鱼事件的水动力成因分析蔡瑜萱(广东省环境保护监测中心站)1992年10月16~18日,珠海市伶仃岛石冲湾发生了网箱养殖鱼类大批死亡的严重事件。珠海市担杆镇人民政府向国家环保部门递交了“关于要调查外伶仃岛石冲湾养殖区海水严重受污的申诉书...  相似文献   
90.
Background, Aim, and Scope  The identification and assessment of environmental tradeoffs is a strongpoint of life cycle assessment (LCA). A tradeoff made in many product systems is the exchange of potential for occupational accidents with the additional use of energy and materials. Net benefits of safety measures with respect to human health are best illustrated if the consequences avoided and health impacts induced by additional emissions are assessed using commensurable metrics. Our aim is to develop a human health impact indicator for offshore crane lifts. Crane lifts are a major cause of accidents on offshore oil and gas (O & G) rigs, and health impacts from crane lift accidents should be included in comparative LCA of O & G technologies if the alternatives differ in the use of crane lifts. Materials and methods  Accident records for mobile offshore petroleum installations were used to develop an empirical occupational health indicator for crane lifts in LCA. Probabilistic parameters were introduced in the procedure, and results were calculated by Monte Carlo simulation. The disability adjusted life years (DALY) framework was used to classify health outcome. The characterization factor for offshore crane lifts was applied in three comparisons to evaluate the significance of crane lifts to human health impacts from drilling technology. Results  The mean occupational health impact per crane lift was 4.5∙10−6 DALY, with cumulative percentiles {P 2.5, P 50, P 97.5} = {6.0∙10−7, 3.1∙10−6, 1.7∙10−5}. Analogously, the fatal accident frequency was described by {P 2.5, P 50, P 97.5} = {7.6∙10−9, 3.9∙10−8, 2.0∙10−7}, with mean 5.6∙10−8 lives lost per crane lift. Discussion  The uncertainty in the results is caused mainly by the random nature of accidents, i.e., variability in accident frequency. Applications of the characterization factor indicate that although crane lifts may not be significant to the overall health impact of the life cycle of drilling fluids, they are important to the occupational safety of employees on offshore drilling rigs and contribute significantly to the life cycle health impact of loading technologies used to transport drilling waste to shore. A comparative LCA of technologies for loading and off-loading drilling wastes shows that a recently developed hydraulic system performs better than the traditional crane lift alternative in terms of human health impacts. Conclusions  With the availability of statistics to assess the risk of single mechanical operations, safety aspects may well be included in LCA. For the case of offshore crane lifts, the uncertainty in the characterization factor compares favorably to what is indicated for other human health impact chains. In further work of quantifying occupational health impacts in DALY using accident statistics, it is advised to see if records of non-recoverable injuries (fatalities and amputation cases) can be used to simplify the damage assessment procedure as recoverable injuries were insignificant to the total burden from crane accidents. Recommendations and perspectives  The characterization factor for crane lifts identifies contributions to life cycle health impact from loading technologies that otherwise would have been overlooked in LCA. While many contest the inclusion of occupational accidents in LCA, our results show that such impacts can be included and that their consideration adds valuable insights.  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