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   64篇
  免费   3篇
安全科学   1篇
废物处理   5篇
环保管理   3篇
综合类   14篇
基础理论   22篇
污染及防治   7篇
评价与监测   10篇
社会与环境   5篇
  2023年   2篇
  2022年   3篇
  2020年   3篇
  2018年   2篇
  2017年   5篇
  2016年   5篇
  2015年   1篇
  2014年   2篇
  2013年   10篇
  2012年   2篇
  2011年   2篇
  2010年   4篇
  2009年   1篇
  2008年   1篇
  2007年   2篇
  2006年   1篇
  2005年   3篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  1997年   1篇
  1995年   1篇
  1994年   1篇
  1990年   1篇
  1983年   1篇
  1979年   3篇
  1978年   1篇
  1975年   1篇
  1969年   1篇
  1968年   1篇
  1963年   1篇
  1962年   1篇
排序方式: 共有67条查询结果,搜索用时 406 毫秒
41.
42.
43.
44.
The aim of this study was to determine the concentrations of nickel and cadmium in blood plasma of the people exposed to cement dust emissions and to investigate the effects of exposure period on the activities of Na+/K+ ATPase enzymes in their erythrocyte membranes. The study was carried out on people living in Eskiehir Çukurhisar rural area, located near a cement factory. Blood samples of the individuals residing in this area were taken from 80subjects (30 for control) following a physical examination. The analysis of plasma samples showed that nickel concentrations in subject group were found to be significantly higher than those of the control group (p < 0.001). Cadmium concentrations were found to be within the reference values for both group and no difference was found between the subjects and controls (p > 0.05). Furthermore, no correlation was observed between the levels of Na+/K+ ATPase activity in erythrocyte membranes of the subject group and the ages of people living in the region (p > 0.05, r = 0.133). It was also observed that nickel concentrations increased by age (p < 0.001, r = 0.646) while no effect was observed in means of cadmium. Na+/K+ ATPase activities in the erythrocyte membranes were not affected.In conclusion although there was no difference between the Na+/K+ ATPase activity in means of age, there was an environmental pollution and may be it was due to the industrial plant.  相似文献   
45.
46.
Abstract: The monitoring of trends in the status of species or habitats is routine in developed countries, where it is funded by the state or large nongovernmental organizations and often involves large numbers of skilled amateur volunteers. Far less monitoring of natural resources takes place in developing countries, where state agencies have small budgets, there are fewer skilled professionals or amateurs, and socioeconomic conditions prevent development of a culture of volunteerism. The resulting lack of knowledge about trends in species and habitats presents a serious challenge for detecting, understanding, and reversing declines in natural resource values. International environmental agreements require signatories undertake systematic monitoring of their natural resources, but no system exists to guide the development and expansion of monitoring schemes. To help develop such a protocol, we suggest a typology of monitoring categories, defined by their degree of local participation, ranging from no local involvement with monitoring undertaken by professional researchers to an entirely local effort with monitoring undertaken by local people. We assessed the strengths and weaknesses of each monitoring category and the potential of each to be sustainable in developed or developing countries. Locally based monitoring is particularly relevant in developing countries, where it can lead to rapid decisions to solve the key threats affecting natural resources, can empower local communities to better manage their resources, and can refine sustainable‐use strategies to improve local livelihoods. Nevertheless, we recognize that the accuracy and precision of the monitoring undertaken by local communities in different situations needs further study and field protocols need to be further developed to get the best from the unrealized potential of this approach. A challenge to conservation biologists is to identify and establish the monitoring system most relevant to a particular situation and to develop methods to integrate outputs from across the spectrum of monitoring schemes to produce wider indices of natural resources that capture the strengths of each.  相似文献   
47.
The aim of this study was to evaluate the effects of copper (Cu) stress on accumulation and transport of trace elements, nitrogen assimilation, and growth parameters of Verbascum olympicum. Eight-week-old seedlings were grown in Hoagland's solution and exposed to 0, 50, 250, or 500?µM CuSO4 for seven days in laboratory conditions. Bioaccumulation of trace elements (boron, bismuth, cobalt, Cu, iron, lithium, manganese, molybdenum, nickel, lead, zinc) in the roots and leaves was determined by inductively coupled plasma–mass spectrometry after one, three, and seven days. Chlorophyll content, nitrate reductase, and glutamine synthetase activities, soluble protein content, and biomass were determined. Copper accumulated in the roots and leaves (up to 19609.8 and 256.2?mg?kg?1 dry weight, respectively). Other trace elements accumulated to higher levels in the roots of Cu-treated plants compared with those of control plants. High Cu concentrations decreased nitrogen-assimilatory enzyme activities. Compared with control plants, those treated with high Cu concentrations showed lower chlorophyll contents, total protein contents, and biomass. Nitrogen assimilation and growth parameters of V. olympicum were negatively affected by Cu treatment but mineral nutrition was not severely disrupted. The results support the suitability of V. olympicum as a candidate for phytoremediation of Cu-contaminated soils.  相似文献   
48.

Goal, scope, and background  

Many studies have focused on measuring fine and course particulate matter (PM) in urban and rural sites around the world. The aim of this research is to gain information on the size distribution of particles. The physical characteristics of PM in the urban air of Istanbul were determined.  相似文献   
49.
Regional Environmental Change - Unfavorable environmental conditions—abiotic stress—constitute one of the key drivers of evolution leading to environmental adaptation. Since the start...  相似文献   
50.
In this study, the size distribution of airborne particles and related heavy metals Co, Cd, Sn, Cu, Ni, Cr, Pb and V in two urban areas in Istanbul: Yenibosna and Goztepe, were examined. The different inhalable particles were collected by using a cascade impactor in eight size fractions (<0.4 μm, 0.4-0.7 μm, 1.1-2.1 μm, 2.1-3.3 μm, 3.3-4.7 μm, 4.7-5.8 μm, 5.8-9 μm and >9 μm) for six months at each station. Samples were collected on glass fiber filters and filters were extracted and analyzed using ICP-MS. Log-normal distributions showed that the particles collected at the Yenibosna site have a smaller size compared to the Goztepe samples and the size distribution of PM was represented the best by the tri-modal. The average total particle concentrations and standard deviations were obtained as 67.7 ± 17.0 μg m(-3) and 82.1 ± 21.2 μg m(-3), at the Yenibosna and G?ztepe sites, respectively. The higher metal rate in fine and medium coarse PM showed that the anthropogenic sources were the most significant pollutant source. Principal component analysis identified five components for PM namely traffic, road dust, coal and fuel oil combustion, and industrial.  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