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   136篇
  免费   0篇
安全科学   4篇
废物处理   22篇
环保管理   15篇
综合类   16篇
基础理论   16篇
污染及防治   27篇
评价与监测   30篇
社会与环境   6篇
  2023年   5篇
  2022年   5篇
  2021年   7篇
  2020年   3篇
  2019年   1篇
  2018年   6篇
  2017年   7篇
  2016年   3篇
  2015年   2篇
  2014年   5篇
  2013年   16篇
  2012年   7篇
  2011年   7篇
  2010年   11篇
  2009年   10篇
  2008年   6篇
  2007年   5篇
  2006年   12篇
  2005年   3篇
  2004年   9篇
  2003年   1篇
  2002年   2篇
  2000年   1篇
  1999年   1篇
  1994年   1篇
排序方式: 共有136条查询结果,搜索用时 738 毫秒
31.
This study assesses the level of background radiation for Canakkale province of northwestern Turkey. Radon concentrations in indoor air were determined using CR-39 nuclear track detectors and 222Rn activity was found to be 167 Bq m???3 (equivalent to an annual effective dose of 4.2 mSv). Measurements of outdoor gamma radiation (of terrestrial and cosmic origin) in air were performed using plastic scintillators, and the average absorbed gamma dose rate was found to be 66.4 nGy h???1 (corresponding to an annual effective dose of 81.4 μSv). The radionuclide activity concentrations in soil samples collected from the study area were measured through gamma-ray spectrometry, and the average activities were determined as 94.55, 110.4, and 1,273 Bq kg???1 for the natural radionuclides 238U, 232Th, and 40K, respectively, and 19.39 Bq kg???1 for the fission product 137Cs. The natural radioactivity sources resulted in an annual effective dose of 184 μSv. The radioactivity levels of drinking water samples were measured as 0.0599 Bq l???1 for gross-alpha activity and 0.0841 Bq l???1 for gross-beta activity using a low-background counting technique (equivalent to an annual effective dose of 12.25 μSv). The results of this study show that the activity levels of radon in air, radionuclides in soil, and alpha activities in drinking water are higher compared to the data available for other Turkish cities and the world averages. On the other hand, the outdoor gamma dose rates in air and beta activities in drinking water are within natural limits.  相似文献   
32.
Understanding the human health impacts of ground level ozone requires detailed knowledge of its spatial–temporal distribution beyond that provided by surface monitoring networks. Here, a novel methodology based on unsupervised multivariate statistical techniques has been developed and used to identify the transport and dispersion patterns of tropospheric ozone. The hierarchical clustering method is used to visualize air flow patterns at two time scales relevant for ozone buildup. Sequentially executed statistical methods consider hourly 1-h surface wind field measurements. First, clustering is performed at the hourly time scale to identify 1-h surface flow patterns. Then, sequencing is performed at the daily time scale to identify groups of days sharing similar diurnal cycles for the surface flow. Selection of appropriate numbers of air flow patterns allows inference of regional transport and dispersion patterns for understanding population exposure to ozone. The methods are applied to the Houston, Galveston, and Beaumont-Port Arthur, TX study domain. Representative hourly wind field patterns are determined for the entire 2004 ozone season. Then, sequencing is performed for the 32 days in exceedance of the NAAQS for 8-h ozone. Four diurnal flow patterns capturing different ozone exceedance scenarios are isolated; each scenario is associated with a distinct spatial distribution for atmospheric pollutants.  相似文献   
33.
Coastline mapping and coastline change detection are critical issues for safe navigation, coastal resource management, coastal environmental protection, and sustainable coastal development and planning. Changes in the shape of coastline may fundamentally affect the environment of the coastal zone. This may be caused by natural processes and/or human activities. Over the past 30 years, the coastal sites in Turkey have been under an intensive restraint associated with a population press due to the internal and external touristic demand. In addition, urbanization on the filled up areas, settlements, and the highways constructed to overcome the traffic problems and the other applications in the coastal region clearly confirm an intensive restraint. Aerial photos with medium spatial resolution and high resolution satellite imagery are ideal data sources for mapping coastal land use and monitoring their changes for a large area. This study introduces an efficient method to monitor coastline and coastal land use changes using time series aerial photos (1973 and 2002) and satellite imagery (2005) covering the same geographical area. Results show the effectiveness of the use of digital photogrammetry and remote sensing data on monitoring large area of coastal land use status. This study also showed that over 161 ha areas were filled up in the research area and along the coastal land 12.2 ha of coastal erosion is determined for the period of 1973 to 2005. Consequently, monitoring of coastal land use is thus necessary for coastal area planning in order to protecting the coastal areas from climate changes and other coastal processes.  相似文献   
34.
Concentration of some heavy metals (Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn) were determined in muscle, liver, kidney and gill of two barb, Barbus xanthopterus and Barbus rajanorum mystaceus, which have great economic values, in the Atatürk Dam Lake (Turkey). Heavy metal levels in fish samples were analyzed by inductively coupled plasma spectroscopy (ICP/OES). Heavy metal concentrations vary significantly, depending on the type of the tissue in fish species. The metal accumulation in the liver, kidney and gill of Barbus xanthopterus and Barbus rajanorum mystaceus was found to be quite high in comparison with that in the muscle. The mean concentrations of heavy metals in muscle tissues of Barbus xanthopterus were as follows: Co, 0.09; Cr, 0.12; Cu, 0.27; Fe, 5.26; Mn, 0.20; Ni, 0.08; Pb, 0.68; Zn, 1.39, whereas in muscle tissues of Barbus rajanorum mystaceus were as follows: Co, 0.11; Cr, 0.10; Cu, 1.07; Fe, 3.97; Mn, 019; Ni, 0.04; Pb, 0.66; Zn, 1.70 microg/g wet weight. Cd levels in gill and muscle tissues were below detection limits. All metal levels detected in tissues were safe for human consumption and within the limits for fish proposed by FAO/ WHO, EU and Turkish Food Codes.  相似文献   
35.
The distribution of historical ozone levels for a region is tabulated as a function of its prevailing synoptic and mesoscale influences. Meteorological patterns are determined sequentially from extended records of hourly surface wind measurements sampling relevant low-level flows. A visualization method is presented to readily indicate the likelihoods for exceedances to occur under a variety of meteorological conditions. The study domain is San Joaquin Valley (SJV) of California, which is divided into three subregions (North, Central, and South). Each day from May–October of 1996–2004 is labeled using synoptic (single-day) and mesoscale (intra-day) patterns. Emissions levels are assumed roughly constant for this period following the introduction of reformulated gasoline to California. Synoptic motions largely control the regional SJV ozone pollution potential; the same single-day patterns are identified for all three SJV subregions. Additionally, a unique mesoscale flow feature is identified in each subregion that strongly affects its ozone levels: flows through minor Coast Range gaps for N-SJV, the Fresno Eddy for C-SJV, and flows through Mojave Pass for S-SJV. The strength of each mesoscale feature is characterized using 1-h surface u or v wind components that explain local ozone pollution potentials.  相似文献   
36.
Construction firms all over the world are increasingly seeking to obtain ISO 14001. The rapid growth in the number of ISO 14001 applications in Turkey and the share from the construction sector in this number, as a leading sector, is rather striking. This paper, using a structured questionnaire survey, investigates whether there is any dependence or relation between construction firms characteristics and having ISO 14001 certification and any difference in the perceptions related to ISO 14001 by considering both firm characteristics and two different groups as certified and non-certified firms. Additionally, it examines the perceived benefits of having ISO 14001 for certified construction firms. According to the results of analysis, although there is not any difference in perceptions on ISO 14001 certification in terms of firm characteristics and being as certified and non-certified and their both positive opinions about ISO 14001 certification. There is a relation between firms characteristics and having ISO 14001 certification. ISO 14001 certification contributes to construction firms not only in terms of environmental benefits but also with corporate management and marketing effects, thus verifying that the ISO 14001 has a positive impact on the Turkish construction sector.  相似文献   
37.
Waste marble dusts are obtained by different methods of cutting marble in marble manufacturing companies. However, environmental damage can occur from the uncontrolled spill of these waste materials in natural habitats. In this study, we investigated the utilization of waste marble in the soil improvement of clayey soils, and as a fine aggregate in concrete production. Specifically, we determined the physical, mechanical and physicochemical characteristics of clayey soils with marble dust (MD) additive. The test results showed that some improvement occurred in the behavior of clay soil. Also, the cutting waste of marble sludge can be used as a filler material instead of fine aggregate in concrete production. This will reduce the porosity of the concrete due to the filling of the pores by MD.  相似文献   
38.
Environmental Science and Pollution Research - Wind energy is the most important renewable energy source produced by wind turbines. The optimal placement of wind turbines is a challenging binary...  相似文献   
39.
40.
The objective of this study was to examine the effects of vegetation change from a native broadleaf forest to a coniferous plantation on selected soil properties, including soil texture, pH, organic matter, total nitrogen (N), total phosphorus (P), exchangeable cations (Ca2+, K+, Na+), and cation exchange capacity (CEC). Results showed that the amount of clay particles, Ca2+, and K+ values significantly increased, whereas Na+, total N, and organic matter and soil pH values decreased on the treatment plot after vegetation change. Soil acidity also increased and soil textural group changed from moderately fine-textured soils (clay loam) to medium-textured soils (loam) under both control and treatment plots. Organic matter, total N, and Na+ values increased, whereas Ca2+ concentration decreased through time on the control plot. Soil pH, total P, K+, and CEC did not show significant changes through time on the control plot.  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