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   69篇
  免费   1篇
  国内免费   5篇
安全科学   6篇
废物处理   5篇
环保管理   4篇
综合类   31篇
基础理论   9篇
污染及防治   12篇
评价与监测   2篇
社会与环境   2篇
灾害及防治   4篇
  2023年   1篇
  2022年   5篇
  2021年   4篇
  2019年   3篇
  2018年   3篇
  2017年   1篇
  2016年   2篇
  2015年   3篇
  2013年   3篇
  2012年   6篇
  2011年   5篇
  2010年   1篇
  2009年   5篇
  2008年   5篇
  2007年   2篇
  2006年   4篇
  2004年   1篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1999年   3篇
  1997年   1篇
  1996年   3篇
  1993年   2篇
  1991年   1篇
  1990年   1篇
  1965年   1篇
  1955年   1篇
排序方式: 共有75条查询结果,搜索用时 15 毫秒
51.
全民环境意识调查   总被引:7,自引:0,他引:7  
通过“全民环境意识调查”首次获得全国范围公民环境意识、环境保护知识、环境保护态度、环境保护行为等方面的数据与信息,表明近年来环境意识虽有所增强,但总体水平仍然偏低,加强环境宣传与教育、提高全民环境意识是推动环境保护工作、改善环境质量的重要环节。  相似文献   
52.
以我国山东省北部为例 ,研究了冲积物覆盖区土壤中金属的存在形式 ,特别是活动态金属的分配规律。通过研究发现 ,活动态Au在土壤全量Au中大约占到 70 %的比例 ,而Cu、Pb、Zn等元素在土壤中所占的比例相对较小。每种金属在四种活动态中的分配比例也存在较大差别。造成这些差别的主要原因是元素的地球化学性质不同 ,特别是地球化学性质极为不活泼的Au ,反而大部分以活动形式存在 ,主要是因为Au在表生环境中以纳米或亚微米等超微细颗粒形式存在 ,使其化学性质发生了很大的变化。  相似文献   
53.
丁桂冰 《福建环境》2001,18(2):37-38
随着城市化速度的加快,热环境诸因素的变化也更显著。分析城市区域特征所引起的热环境各因素的变化趋势,采取相应防治措施,改善城市环境质量。  相似文献   
54.
应用红外光谱、差热分析和X衍射分析丙烯腈二元共聚物(PAN)超滤膜材料的结构特性,用浸渍对比试验观察了超滤膜在浸渍前后的性能变化。结果表明:PANA大分子侧向排列是有序的,纵向排列是无序的,因而可以制成具有较好分离性能的超滤膜,以PAN制备的超滤膜不仅具有良好的耐化学药品能力(其抗酸性优于抗碱性)和抗氧化能力,而且有较好的耐菌性。  相似文献   
55.
在目前环境问题日益突出的背景下.为研究环境质量变化与经济增长之间的关系.利用齐波夫(Zipf)定律分析了广东省的环境污染事故发生次数与GDP之间的关系.并利用其在图形中规律性幂率区间.结合RBF人工神经网络对未来3年环境污染事故的发生次数进行了预测.结果表明,这2种方法对环境污染与事故预测值均在允许的范围内,平均值分别为6、5、4次.研究结果为有关部门防范未来环境污染事故发生,具有明显的警示作用.  相似文献   
56.
内蒙古毛乌素沙地近年荒漠化动态研究   总被引:1,自引:0,他引:1  
毛乌素沙地是我国西北地区面积较大的沙地,本文利用2000年和2005年的LANSAT TM影像图,结合野外实地调研,运用常规方法深入分析研究研究区的近5年的荒漠化动态变化,阐明变化原因,最后提出相应的生态环境保护建议。  相似文献   
57.
Volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylene (BTEX) along with inorganic gases such as sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) levels were found in the atmosphere of the Kemerburgaz region where environmental issues became a major concern due to nearby incineration plant and waste disposal facility in Istanbul. Ten sampling locations were selected considering possible sources in the study area. The sampling areas were classified as suburban, industrial, rural, and background regions. Sampling campaigns were carried out for four-week periods from March 2011 to August 2012 in all locations. Elevated concentrations of BTEX around roads and the industrial locations indicated that vehicle exhaust and industrial activities were the main sources of these pollutants in the region. Concentrations of NO2 were also high around roads. A much more uniform distribution was observed for SO2 during sampling periods. However higher levels were observed at suburban locations due to the use of coal for local heating especially during winter. Ozone concentrations were low at the industrial locations and roadsides, but high in suburban and rural locations downwind from the sources. The results of these organic and inorganic gases meet the national limit values. Furthermore, a lifetime risk assessment methodology was used to evaluate the potential adverse health effects of BTEX. The mean cancer risk level for benzene was estimated to be 7.71E-07 that is lower than assigned acceptable risk level of 1.0E-04. Toluene, ethylbenzene, and xylenes were lower than the specified level of 1.0 with respect to mean non-carcinogenic risks. The findings reveal that determined BTEX emissions do not pose a health threat to residents in the studied region.  相似文献   
58.
微生物菌剂和鸡粪对蔬菜废弃物堆肥化处理的影响   总被引:13,自引:0,他引:13  
由于我国缺乏适用的蔬菜废物循环利用技术,致使蔬菜产地的生产废物难以处理与再循环利用而被弃置。为获得适用的蔬菜废物堆肥化处理技术,本研究以小麦秸秆为水分调理剂,并分别以鸡粪和微生物菌剂为接种剂,在初始物料含水率65%和C/N为25的条件下,设置了V1(蔬菜残体+小麦秸秆)、V2(V1+鸡粪)、V3(V2+微生物菌剂)和V4(V1+微生物菌剂)等4个处理,通过测定4个不同堆肥处理对温度、含水率、C/N比以及发芽指数(GI)等指标的影响。结果表明:同时加入微生物菌剂和鸡粪的处理(V3)可使堆肥最高温度达到67.5℃,且水分脱除效果最好,最终产品的含水率是最低的;鸡粪也是较好的接种剂,提升堆肥温度且能缩短堆肥周期;发芽率指数(GI)的结果显示,4个处理之间的堆肥腐熟成度为V3>V4>V2>V1,这进一步表明,添加微生物菌剂和鸡粪可降低堆肥产品对后茬植物发芽和生长的不良抑制。  相似文献   
59.
Objective: Rapid urbanization and motorization without corresponding increases in helmet usage have made traumatic brain injury due to road traffic accidents a major public health crisis in Cambodia. This analysis was conducted to quantify the impact of helmets on severity of injury, neurosurgical indication, and functional outcomes at discharge for motorcycle operators who required hospitalization for a traumatic brain injury following a road traffic accident in Cambodia.

Methods: The medical records of 491 motorcycle operators who presented to a major tertiary care center in Cambodia with traumatic brain injury were retrospectively analyzed using multivariate logistic regression.

Results: The most common injuries at presentation were contusions (47.0%), epidural hematomas (30.1%), subdural hematomas (27.9%), subarachnoid hemorrhages (12.4%), skull fractures (21.4%), and facial fractures (18.5%). Moderate-to-severe loss of consciousness was present in 36.3% of patients. Not wearing a helmet was associated with an odds ratio of 2.20 (95% confidence interval [CI], 1.15–4.22) for presenting with moderate to severe loss of consciousness compared to helmeted patients. Craniotomy or craniectomy was indicated for evacuation of hematoma in 20.0% of cases, and nonhelmeted patients had 3.21-fold higher odds of requiring neurosurgical intervention (95% CI, 1.25–8.27). Furthermore, lack of helmet usage was associated with 2.72-fold higher odds of discharge with functional deficits (95% CI, 1.14–6.49). In total, 30.1% of patients were discharged with severe functional deficits.

Conclusions: Helmets demonstrate a protective effect and may be an effective public health intervention to significantly reduce the burden of traumatic brain injury in Cambodia and other developing countries with increasing rates of motorization across the world.  相似文献   

60.
Development of environmentally friendly synthesis of nanoparticles is one of the important areas of research in nanotechnology. In present study silver naopartticles (AgNPs) of root extract of Sageretia thea (S. thea) were synthesized at room temperature. The synthesized AgNPs were characterized by UV. Visible spectroscopy (UV), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier transform infrared (FT-IR) spectroscopy. Formation of AgNPs was confirmed by visual examination the colour change from yellow to brick red due to surface Plasmon resonance band at 435 nm. SEM and TEM analysis of synthesized AgNPs revealed spherical morphology with average particle size 25 nm. Crystalline nature of the AgNPs in face centered cubic structure is evident from the selected area electron diffraction (SAED) and XRD pattern. The presence of elemental Ag was confirmed by EDX analysis at 3kv. Different functional groups which responsible for reduction and stabilization of reaction medium was confirmed by FTIR spectroscopy. The biosynthesized AgNPs showed strong DPPH and dye protection radical scavenging assay while modest hydrogen peroxide radical scavenging assay as compare to crude extract. The present investigations suggest that biosynthesized nanoparticles have a high potential for use in the preparation of drugs used against various diseases and also a promising candidate for many medical applications.  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