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
151.
In this study, surface water quality of the Ceyhan River basin were assessed and examined with 13 physico-chemical parameters in 31 stations in 3 months during the period of 2005. Multivariate statistical techniques were applied to identify characteristics of the water quality in the studied stations. Nutrients, Cl??? and Na?+? affected mostly to the stations of Erkenez 2, S?r 2, and S?r 3 in the ordination diagram of correspondence analysis. Three factors were extracted by principal component analysis, which explains 79.14% of the total variation. The first factor (PC1) captures variables of EC, DO, NO $_{2}^{\; -}$ , PO $_{4}^{\; \equiv }$ , Cl???, SO $_{4}^{\; =}$ , Na?+?, and Ca?+?+?. The second factor (PC2) is significantly related to pH, NH $_{3}^{\; -}$ , and Mg?+?+?, while water temperature (T) and NO $_{3}^{\; -}$ accounted for the greatest loading for factor 3 (PC3). The stations were divided into three groups for PC1, two groups for PC2, and three groups for PC3 by hierarchical cluster analysis. The stations in the vicinity of cities presented low dissolved oxygen and high concentration of physico-chemical parameter levels. The stations of Erkenez 2, S?r 2, S?r 3, and Aksu 4 located near the city of Kahramanmara? were characterized by an extremely high pollution due to discharge of wastewater from industry and domestic. P?narba?? and Elbistan stations were also influenced by household wastewater of the city of Elbistan. According to criteria of Turkish Water Pollution Control Regulation, Erkenez 2, S?r 2, and S?r 3 stations have high polluted water. This study suggests that it is urgent to control point pollutions, and all wastewater should be purified before discharge to the Ceyhan River basin.  相似文献   
152.
Ships are significant air pollution sources as their high powered main engines often use heavy fuels. The major atmospheric components emitted are nitrogen oxides, particulate matter (PM), sulfur oxide gases, carbon oxides, and toxic air pollutants. Shipping emissions cause severe impacts on health and environment. These effects of emissions are emerged especially in territorial waters, inland seas, canals, straits, bays, and port regions. Candarli Gulf is one of the major industrial regions on the Aegean side of Turkey. The marine environment of the region is affected by emissions from ships calling to ten different ports. In this study, NO x , SO2, CO2, hydrocarbons (HC), and PM emissions from 7,520 ships are estimated during the year of 2007. These emissions are classified regarding operation modes and types of ships. Annual shipping emissions are estimated as 631.2 t year???1 for NO x , 573.6 t year???1 for SO2, 33,848.9 t year???1 for CO2, 32.3 t year???1 for HC, and 57.4 t year???1 for PM.  相似文献   
153.
This study aims to investigate the change in spatial-temporal configuration of secondary forest succession and generate measurements for monitoring the changes in structural plant diversity in Yaln?zçam Scots pine forest in NE Turkey from 1972 to 2005. The successional stages were mapped using the combination of Geographic Information System (GIS), Global Positioning System (GPS), aerial photos and high resolution satellite images (IKONOS). Forest structure and its relationship with structural plant diversity along with its changes over time were characterized using FRAGSTATS. In terms of spatial configuration of seral stages, the total number of fragments increased from 572 to 735, and mean size of patch (MPS) decreased from 154.97 ha to 120.60 ha over 33 years. The situation resulted in forestation serving appropriate conditions for plant diversity in the area. As an overall change in study area, there was a net increase of 1823.3 ha forest during the period with an average annual forestation rate of 55.25 ha year?1(0.4% per year). In conclusion, the study revealed that stand type maps of forest management plans in Turkey provide a great chance to monitor the changes in structural plant diversity over time. The study further contributes to the development of a framework for effective integration of biodiversity conservation into Multiple Use Forest Management (MUFM) plans using the successional stages as a critical mechanism.  相似文献   
154.
Soils are complex mixtures of organic, inorganic materials, and metal compounds from anthropogenic sources. In order to identify the pollution sources, their magnitude and development, several X-ray analytical methods were applied in this study. The concentrations of 16 elements were determined in all the soil samples using energy dispersive X-ray fluorescence spectrometry. Soils of unknown origin were observed by scanning electron microscopy equipped with a Si(Li) X-ray detector using Monte Carlo simulation approach. The mineralogical analyses were carried out using X-ray diffraction spectrometry. Due to the correlations between heavy metals and oxide compounds, the samples were analyzed also by electron probe microanalyzer (EPMA) in order to have information about their oxide contents. On the other hand, soil pH and salinity levels were identified owing to their influence between heavy metal and soil-surface chemistry. Moreover, the geoaccumulation index (I geo) enables the assessment of contamination by comparing current and pre-industrial concentrations.  相似文献   
155.
Industrial enterprises constitute a major portion of the world’s economy, as well as a large proportion of a country’s businesses and total employment. In Turkey, industrial enterprises are underdeveloped in terms of knowledge, skill, capital, and particularly accessing and benefiting from the advantages provided by modern information and communication technologies. Aluminum manufacturing has been reported to be the largest industry in Turkey with respect to production volumes and application fields. However, aluminum production is known to be an important contributor to environmental pollution, and the relative contribution of other related enterprises to the total industrial environmental impact is unknown. Environmental pollution sources can typically be classified into three categories: gaseous emissions, solid wastes, and wastewaters. The types of wastes produced by aluminum production vary based on the process line used, the variety of target products produced, and the production capacity of a given plant. As the capacities of facilities grow, the type and amount of waste become more variable. Therefore, the primary objective of this study is to determine the priority of each waste type in aluminum manufacturing industries. This study was conducted in the Industrial Zone of Kayseri in Turkey. Three different facilities that range in size from large to small based on their production volume, plant capacity, and variety of production are selected for this study. The priority of waste types was determined by combining the AHP and PROMETHEE II multicriteria decision methods. While wastewater was categorized as having the highest priority in large facilities, solid waste was determined to be the highest priority in medium and small facilities.  相似文献   
156.
This paper concentrates on determining the areas for afforestation and the development of conservation strategies and actions in the case where there is high demand for the conservation of a particular land area. The analysis of hydrological landscape structure and of erodibility was prerequisite in the methodological design considering the site-specific natural landscape characteristics of the study area. The Gölba?? Specially Protected Area (SPA) being the case area has many local environmental disturbances, especially with respect to its hydrological system, and the area is beset by increasing demands for its use by the burgeoning human population. It is obviously clear that the present intensive demand for recreational use will be forecasted further increase in the future. The count of rural residences is estimated to increase by 50% over the next decade. This intensive demand shall further strain the carrying capacity of the ecological milieu, which has already suffered to a significant degree because of the present urban and rural activities. The Gölba?? district is located only 20 km from the city center of Ankara, and its surroundings were legally designated to be a Specially Protected Area primarily for the existence of lacustral and fluvial systems where two interconnected lakes exist: Mogan and E?mir Lakes. Essentially, the continuity of the lacustral and fluvial system of Lakes Mogan and E?mir depends on the preservation and improvement of the water sources. However, interconnected surface water bodies of these lakes are actually quite contaminated, and a decline in the water flow from Mogan to E?mir has been observed. For the elaboration of the present method, required conventional maps (at 1/25,000 scale) of topography (for slope analysis) and geology (for erodibility and permeability analysis) were transferred to computer media using AutoCAD® R.14 software. The rectification of the transferred data was done using ERDAS® Imagine 8.3. All data were then transferred into a GIS engine (Arcview® 3.2). This software provided the ability to create, manipulate, analyze and display topologically correct geographic data in digital form. The method proceeded according to the following phases: 1. Analysis of the hydrologic landscape structure; 2. Permeability of the soil structure; 3. Permeability of the geological structure; 4. Conservation zones.  相似文献   
157.
In this study, aluminium (Al), lead (Pb), cadmium (Cd), selenium (Se) and arsenic (As) contents in milk and different dairy product samples were measured. Pb, Cd, As, Al and Se contents in the milk and different dairy products ranged from 0.054 mg/kg (milk powder)?1.100 mg/kg (Ka?ar cheese), 0.009 mg/kg (whey powder and yogurt)?1.051 mg/kg (Tulum cheese), 0.010 mg/kg (whey powder)?0.146 mg/kg (butter), 2.848 mg/kg (ice cream)?8.778 (drained yogurt) and n.d. (ice cream, milk and whey powder, yogurt, ayran and Lor cheese)?0.434 mg/kg (Tulum cheese), respectively. The 75% of White and Ka?ar cheeses, 50% of Lor and 12.5% of Tulum cheese samples contained higher Pb according to the legal limits established by the Turkish Food Codex and European Communities regulation and 12.5% of Tulum cheese sample contained Cd. It was concluded that Pb contents of milk and dairy products from this region might be highly hazardous to human  相似文献   
158.
The aim of this study was to determine if high concentrations of any heavy metals exist in the sediment of Seyhan Dam reservoir to be considered toxic to the aquatic environment. Surface sediment samples from five stations in the Seyhan dam were collected quarterly from 2004 to 2005 and examined for metal content (Cr, Zn Cu, Mn, Cd, Fe, Ca, K, and Na), organic matter, and grain size. Correlation analyses showed that metal content of Seyhan dam sediment was affected by organic matter and grain size. The results have been compared with values given in the literature. The evaluation of the metal pollution status of the dam was carried out by using the enrichment factor and the geoaccumulation index. A comparison with sediment quality guideline values has also been made. Based on the enrichment factor, dam sediments were treated as a moderately severe enrichment with Cd and minor enrichment with Cr and Mn. The results of geoaccumulation index reveal that sediments of Seyhan Dam were strongly polluted in stations 1, 2, 4, and 5, and were moderately polluted in station 3 with Cd. Moreover, Cd and Cr concentrations in the sediments were above TECs except ERL for Cd.  相似文献   
159.
160.
Polycyclic aromatic hydrocarbons are known for their carcinogenic and mutagenic effects on human health. This therefore calls for the regulation of their concentrations in air, water, and soil. Naphthalene as the simplest in structure of the polycyclic aromatic hydrocarbons is mainly used as a starter material for other chemicals but also has impacts on human health. A method is therefore proposed for the determination of naphthalene in water samples by gas chromatography mass spectrometry after liquid-liquid extraction. The extraction method was optimized to improve the extraction output, thereby lowering the limit of detection. The limits of detection and quantification obtained for naphthalene were 4.4 and 14.6 ng mL?1, respectively. Deuterated anthracene was used as internal standard to enhance the precision of the method, for which a relative standard deviation of 4.3% was obtained. The percent recovery of naphthalene obtained from tap water was ranged between 93.8 and 102.2.  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