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   139篇
  免费   0篇
安全科学   4篇
废物处理   23篇
环保管理   15篇
综合类   16篇
基础理论   20篇
污染及防治   26篇
评价与监测   28篇
社会与环境   7篇
  2023年   5篇
  2022年   5篇
  2021年   5篇
  2020年   3篇
  2019年   1篇
  2018年   6篇
  2017年   7篇
  2016年   5篇
  2015年   2篇
  2014年   6篇
  2013年   16篇
  2012年   6篇
  2011年   8篇
  2010年   11篇
  2009年   10篇
  2008年   7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
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1996年   1篇
排序方式: 共有139条查询结果,搜索用时 46 毫秒
51.
The distribution of some heavy metals in three different organs of mullet, Liza abu, and catfish, Silurus triostegus, from Atatürk Dam Lake located on Euphrates (Turkey) was studied. Co and Mo concentrations were below limits of detection in all fish organs, whereas Ni was also below limits in organs of mullet. The metal accumulation in the liver and gill of L. abu and S. triostegus was found to be quite high in comparison with the muscle. In general, the concentrations are similar to those previously observed on other fish studied in Atatürk Dam Lake and lower than those determined in Tigris River. The analysed metals (Co, Cu, Fe, Mn, Mo, Ni and Zn) were found in fish muscle at mean concentrations under the permissible limits proposed by FAO.  相似文献   
52.
Impacts of land use conversion on soil properties and soil erodibility   总被引:1,自引:0,他引:1  
Land use conversion can affect natural ecological processes such as surface runoff and erosion. Therefore, it has potential to change soil stability To investigate this process in depth, Iskalan creek catchment in the Black sea region, where excessive land use applications and erosion events have often occured, was selected as the study area. The objective was to determine the effects of land use conversion on soil properties, soil erodibility and the relationships among soil properties and some erodibility indices. Duplicate topsoil samples were taken by using steel cylinders at 100 different sampling points from three different land use types; 34 of them are in farmlands, 34 in rangelands and 32 in forestlands. Soil particle size distribution, loss of ignition, pH, electrical conductivity skeleton percentage and three erodibility indices were determined. Data were analysed by using Pearson correlation analysis (at 95% and 99% significance level), ANOVA and Tukey's test at 95 % significance level. According to study results, land use conversion affects some properties of soils significantly Loss of ignition of soils in forests was significantly higher than soils in farmlands and rangelands. Soil skeleton percentage in rangelands and farmlands were significantly different. The study results showed that there was significant difference between pH of soils in forests and farmlands (p < 0.05). Pearson correlation analysis results showed significant correlations among erodibility indices and certain soil properties such as clay and sand fraction of soils (p < 0.05 and p < 0.01). Topsoils of the study area were sensitive to erosion according to all three erodibility indices. The most sensitive soils were in farmlands.  相似文献   
53.
This study was performed between January 2004 and December 2004 in 13 stations in the Pediatric Unit of Edirne Government Hospital in order to determine the outdoor and indoor airborne microfungal and bacterial contents. The results of air samplings revealed that 1,376 microfungal and 2,429 bacterial colonies in total were isolated. The isolated microfungal specimens were identified and 65 species from 16 genera were determined. Among these, the most frequent genus was Cladosporium with 462 colonies (33.58%) followed by Alternaria with 310 (22.53%) and Penicillium with 280 (20.35%) colonies. The isolated bacterial samples were grouped based on their Gram-staining properties. The most frequent ones were Gram (+) cocci with 1,527 colonies (62.87%) followed by Gram (+) bacilli with 828 colonies (34.09%) and Gram (−) bacilli with 74 colonies (3.05%). Staphylococcus, Bacillus, Corynebacterium, and Microccus appeared to be the common genera isolated for all months. Statistical analyses were performed in order to see if there existed a relationship between meteorological conditions and the microfungal and bacterial species and their concentrations.  相似文献   
54.
Landfill bottom liners are generally constructed with natural clay soils due to their high strength and low hydraulic conductivity characteristics. However, in recent years it is increasingly difficult to find locally available clay soils that satisfy the required engineering properties. Fine grained soils such as sepiolite and zeolite may be used as alternative materials in the constructions of landfill bottom liners. A study was conducted to investigate the feasibility of using natural clay rich in kaolinite, sepiolite, zeolite, and their mixtures as a bottom liner material. Unconfined compression tests, swell tests, hydraulic conductivity tests, batch and column adsorption tests were performed on each type of soil and sepiolite–zeolite mixtures. The results of the current study indicate that sepiolite is the dominant material that affects both the geomechanical and geoenvironmental properties of these alternative liners. An increase in sepiolite content in the sepiolite–zeolite mixtures increased the strength, swelling potential and metal adsorption capacities of the soil mixtures. Moreover, hydraulic conductivity of the mixtures decreased significantly with the addition of sepiolite. The utilization of sepiolite–zeolite materials as a bottom liner material allowed for thinner liners with some reduction in construction costs compared to use of a kaolinite-rich clay.  相似文献   
55.
Environmental Science and Pollution Research - Trihalomethanes (THMs), which is one of the major classes of DBP known to be highly cytotoxic and genotoxic, were formed and modeled under controlled...  相似文献   
56.
We use a relatively new approach to endogenously detect the volatility shifts in the returns of four major precious metals (gold, silver, platinum and palladium) from 1999 to 2013. We reveal that the turbulent year of 2008 has no significant effect on volatility levels of gold and silver however causes an upward shift in the volatility levels of palladium and platinum. Using the consistent dynamic conditional correlations, we show that precious metals get strongly correlated with each other in the last decade which reduces the diversification benefits across them and indicates a convergence to a single asset class. We endogenously detect the shifts in these dynamic correlation levels and reveal uni-directional volatility shift contagions among precious metals. The results show that gold has a uni-directional volatility shift contagion effect on all other precious metals and silver has a similar effect on platinum and palladium. However, the latter two do not matter in terms of volatility shift contagion. Thus, investors that hedge with precious metals should, in particular, monitor the volatility levels of gold and silver.  相似文献   
57.
We present a case of esophageal and ileal duplications at 18 weeks of gestation. Transabdominal ultrasonography of the fetus showed multiple cystic masses of 12 to 17 mm in diameter and continuity with each other in the abdomen and a unilocular cystic mass of 15 mm in diameter in the posterior mediastinum. The cystic mass filled the abdominal cavity with signs of intestinal obstruction. The thoracic cystic mass was tubular, sausage-shaped and behind the heart, which was displaced to the antero-lateral wall of the chest. Amniocentesis revealed a normal fetal karyotype 46,XY. Peristaltic movements in the abdominal cystic structure at 30 weeks of gestation suggested dilated intestinal loops. Follow-up ultrasound examinations showed polyhydramnios with amniotic fluid index of 30 cm and gradual enlargement of the cystic structures to 50 mm in the abdomen and 30 mm in the posterior mediastinum at 38 weeks of gestation. A male infant weighing 3900 g was delivered. Postnatal ultrasonographic examination and the findings of magnetic resonance imaging also suggested enteric duplication cysts. Prenatal diagnosis allowed prompt neonatal evaluation and surgical treatment of the esophageal and the ileal duplications, which was confirmed by pathological examination. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
58.
Based on social cognitive theory (SCT), we develop and test a model that links ethical psychological climate to ethically focused proactive behavior (i.e., ethical voice and ethical taking charge) via two distinct mechanisms (i.e., duty orientation and moral potency). Results from multi-wave field studies conducted in the United States, Turkey, France, Vietnam, and India demonstrate that an ethical psychological climate indirectly influences employees' ethical voice and ethical taking charge behaviors through the dual mechanisms of duty orientation and moral potency. Additionally, we find that individuals' moral attentiveness strengthened these mediating processes. Together, these findings suggest that ethical psychological climate is an important antecedent of ethically focused proactive behavior by stimulating individuals' sense of duty and enhancing their moral potency, particularly when employees are already highly attuned to moral issues.  相似文献   
59.
As a major biotic component of many lotic ecosystems, macrophytes consist a major component of running waters are often used as indicators within the European Water Framework Directive (WFD) to establish ecological quality. In this study, we investigated macrophyte community structure (e.g. composition, abundance and diversity) in Ceyhan River Basin located in the Southeastern Anatolian Region in Turkey. Data was collected during 2014–2015 from river sites located throughout the basin to evaluate the relationship between aquatic vegetation and river physico-chemical factors. The ecological status of the river basin was also calculated based on Macrophyte Biological Index for River (IBMR). In total, 33 macrophyta taxa were observed. According to their biological classification (life form), filamentous algae (FA), free floating (FF), floating leaved (FL) and submersed (S) macrophytes reached their maximum abundance value in summer, while emergent (E) macrophytes were at their maximum abundance in both summer and autumn. The ecological status of the Ceyhan River basin ranged from moderate to bad. The values found are reasonably comparable to IBMR scores recorded in rivers of other Mediterranean countries. IBMR index may be suitable to some extent to establish a basis for ecological quality assessment in Turkish River systems.  相似文献   
60.
The Istanbul composting and recycling plant, constructed in 2001, is one of the few composting plants in Turkey. During test operations of the plant, it was reported that the weight of the oversize materials (OM) above a 80-mm sieve was about 40% of the total incoming waste. They mainly consist of plastic bags that were full of garbage, which resulted in operational problems in the plant. In this paper, the composition of OM was determined and evaluated, particularly to find the economic losses in the plant. It was determined that approximately 58% of the OM transferred to the landfill area due to operational failures and interruptions could be used at the plant with improved operational conditions. Otherwise, the plant would realize an annual economic loss of about 640,800 US$. Compost quality in the plant has been satisfactory, but source separated collection, at least the separation of the wet from the dry fraction, is needed to increase the amount of compost and recovered materials.  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