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   253篇
  免费   4篇
  国内免费   1篇
安全科学   3篇
废物处理   36篇
环保管理   16篇
综合类   20篇
基础理论   22篇
环境理论   1篇
污染及防治   61篇
评价与监测   82篇
社会与环境   14篇
灾害及防治   3篇
  2023年   19篇
  2022年   26篇
  2021年   14篇
  2020年   5篇
  2019年   3篇
  2018年   19篇
  2017年   11篇
  2016年   20篇
  2015年   8篇
  2014年   18篇
  2013年   24篇
  2012年   9篇
  2011年   10篇
  2010年   19篇
  2009年   22篇
  2008年   12篇
  2007年   7篇
  2004年   1篇
  2003年   3篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1996年   1篇
  1991年   1篇
排序方式: 共有258条查询结果,搜索用时 15 毫秒
81.
Concentrations of heavy metals (Ag, Cd, Cr, Cu, Fe, Ni, Pb ve Zn) were measured in running water and in tissues (muscle, liver, gill, skin and gonads) of one commercially valuable fish species (Carasobarbus luteus) from the Orontes (Asi) River (Güzelburç region) in Hatay (Southeastern Turkey). Results for levels in water compared with national and international water quality guidelines were found at the highest concentrations in international criteria’s WHO, EC and EPA, but Cd, Cu, Ni and Pb were found to exceed permissible level of drinking water in national criteria TSE-266 whereas Fe, Zn and Cr concentrations were within the permissible levels for drinking. The present study showed a significant seasonal variation (p?p?>?0.05), which showed seasonal variation of only Zn (p?C. luteus were below the permissible limit for human consumption, level of Cu being very close to the permissible limit. Consequently, continuous monitoring of heavy metal concentration in edible freshwater fish will be needed in Orontes River.  相似文献   
82.
83.
The surface water quality of the Euphrates river basin in Turkey are evaluated by using the multivariate statistical techniques known as factor analysis (FA) and multidimensional scaling (MDS) analysis. When FA was applied to the water quality data obtained from the 15 different surface water quality monitoring stations, two factors were identified, which were responsible from the 86.02% of the total variance of the water quality in the Euphrates river basin. The first factor called the urban land use factor explained 44.20% of the total variance and the second factor called the agricultural use factor explained 41.81% of the total variance. MDS technique showed that electrical conductivity (EC), percent sodium (Na%) and total salt are the most important variables causing difference in the water quality analysis.  相似文献   
84.
Because of their intense vegetation and the fact that they include areas of coastline, deltas situated in the vicinity of big cities are areas of great attraction for people who wish to get away from in a crowded city. However, coasts, with their fertile soil and unique flora and fauna, need to be protected. In order for the use of such areas to be planned in a sustainable way by local authorities, there is a need for detailed data about these regions. In this study, the changes in land use of the area between Topburnu and Uçburun Musa Bey Harbour on the Çe?me peninsula, which is to the immediate west of Turkey’s third largest city ?zmir, from 1976 up to the present day, were investigated. In the study, using aerial photographs taken in 1976, 1995 and 2000 and an IKONOS satellite image from the year 2007, the natural and cultural characteristics of the region and changes in the coastline were determined spatially. Using aerial photographs from 1976, 1995 and 2000 and an IKONOS satellite image from the year 2007, together with “1/25,000 scale Conservation-Oriented Development Plans” prepared in 1979, 1990 and 2000 by the committee for the Preservation of Natural and Cultural Entities attached to the Ministry of Culture and Tourism of the Turkish Republic, the natural and cultural characteristics of the region and the land use changes and their connection with conservation rulings were determined spatially. In this study, spatial changes in land use over the years were compared with changing conservation rulings over the years and the emerging results have brought a new perspective to the subject in contrast to other similar studies.  相似文献   
85.
Environmental conditions affect human life in various ways. One of the domains of environmental conditions is buildings, and amongst them, a major and important group is the historical buildings. To keep this inheritance alive, one needs to determine the effects of environmental conditions. In this work, effects of lichens and NOx on 7 historical buildings in Erzurum were investigated. Historical buildings are readily available for lichen growth, which takes a long time, and this growth was investigated as a sample of environmental effect that occurs through long periods of time. NOx, main source of which is traffic in Erzurum, were considered as the environmental effect of daily life.  相似文献   
86.
In this study, the relationship among water quality, soil properties, and plant coverage in the region of the Akarçay stream was examined. Correlation analyses were carried out between soil samples taken from each of four plant communities in the Akarçay basin and water in the Akarçay stream. The four plant communities in the study area are as follows: Limonium lilacinum (Boiss. et Bal.) Wag., Alhagi pseudalhagi (M. Bieb.) Desv. Peganum harmala L., and Hordeum marinum Huds. subsp. marinum. B, Cl, EC, K, Mg, Na, pH, and SO4 data from both soil and water samples were subjected to statistical analysis, and significant correlations were obtained (p < 0.05). These correlations indicated that the chemical features of the soil had a major effect on water quality. The important parameters were B, Cl, EC, K, Mg, Na, pH, and SO4 for Limonium lilacinum communities; Ca, K, and pV for Peganum harmala; and B, Cl, Mg, pH, and pV for Alhagi pseudalhagi. There were also statistically significant relationships (p < 0.05) among the parameters examined. These findings strongly suggested that these plant communities can be used as indicators for soil chemistry and water quality.  相似文献   
87.
The aim of this study was to determine the origin and quality of waters in Troia. For this purpose total of 25 water samples including 2 springs, 14 surfaces and 9 groundwaters, were collected at eight different times. Global positioning system (GPS) was used to determine to coordinates of sampling points. The concentration of 6 minor elements (B, Cu, F, Fe, Pb and Zn), 9 major anions and cations (Na(+), Ca(2+), K(+), Mg(2+), SO(4)(2-), PO(4)(3-), HCO(3)(-), Cl(-) and, CO(3)(2-)) were determined by spectrometric, colorimetric and volumetric methods. Water pH, EC, DO, ORP and TDS were measured in situ using probes. The data showed that the concentrations of most of minor elements were below the EPA and TSE limits except Pb which ranged between 0.001 and 4.832 mg L(-1). Statistically significant relationships (P<0.01 and r>0.70) were observed between Fe and Cu, Cu and K(+), Cu and Ca(2+), B and Na(+), Na(+) and K(+). Assessing the water based on irrigation using Wilcox model showed that some well waters were not suitable for irrigation. Troia water was found to be highly corrosive and the average corrosion coefficients varied from 0.5 to 4.6. According to the Piper and Schoeller diagrams results, the water in Troia was classified as mixed water type.  相似文献   
88.
Spatial variability of salinity and alkalinity is important for site-specific management since they are the most important factors influencing soil quality and agricultural production. The objectives of this study were to analyze spatial variability in salinity and alkalinity and some soil properties affecting salinity and alkalinity, using classical statistics and geostatistical methods, in an irrigated field with low-quality irrigation water diverted from drainage canals. A field of 5 da was divided into 10 m x 10 m grids (5 lines in the east-west direction and 10 lines in the north-south direction). The soil samples were collected from three depths (0-30, 30-60 and 60-90 cm) at each grid corner. The variation coefficients of OM and sand contents were higher than other soil properties. OM had the maximum variability, with a mean of 1.63% at 0-30 cm depth and 0.71% at 30-60 cm depth. Significant correlations occurred between ESP, EC and each of Ca, Mg, K and CaCO(3) contents of the soils (p<0.01). Experimental semivariograms were fitted to spherical and gaussian models. All geostatistical range values were greater than 36 m. The soil properties had spatial variability at small distances at 60-90 cm depth. EC was variable within short distances at 30-60 cm depth. The nugget effect of ESP increased with soil depth. Kriged contour maps revealed that soils had a salinisation and alkalisation tendency at 60-90 cm depth based on spatial variance structure of the EC and ESP values. Spatial variability in EC and ESP can depend on ground water level, quality of irrigation water, and textural differences.  相似文献   
89.
This paper focuses on the environmental flow assessment (EFA) methods that maintain the river ecosystem and its integrity for hydropower plants (HPP) with their implementations on a run-off river type HPP. EFA is a crucial phenomenon in terms of electricity production and sustaining river integrity simultaneously. The novelty of this study is that it consists both a comparison of widely used preferred EFA methods and a detailed investigation of the river with pre and post-dam flow regimes. The research shows that by expanding the content and scope of the methods, their relative reliabilities increase. However, this situation requires much more expert, money, and time. Apart from most of the relevant literature, pre and post-dam situations are investigated with a flow duration curve (FDC). It is concluded that the dramatic difference between the flow characteristics of pre and post-dam situations affects long-term aquatic life. Furthermore, a case study is conducted using the selected hydrological flow assessment methods, Tennant and Tessman methods, and comparisons are made. The calculated flows are compared with monthly average flow values before dam construction, projected environmental flow data, and the current situation. Accordingly, Tennant’s “good classification” is proposed to determine the environmental flow (EF) for the considered case study.  相似文献   
90.
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