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   242篇
  免费   2篇
  国内免费   1篇
安全科学   5篇
废物处理   17篇
环保管理   29篇
综合类   18篇
基础理论   32篇
污染及防治   64篇
评价与监测   63篇
社会与环境   12篇
灾害及防治   5篇
  2023年   6篇
  2022年   19篇
  2021年   13篇
  2020年   4篇
  2019年   6篇
  2018年   10篇
  2017年   11篇
  2016年   10篇
  2015年   6篇
  2014年   14篇
  2013年   21篇
  2012年   6篇
  2011年   6篇
  2010年   15篇
  2009年   17篇
  2008年   19篇
  2007年   11篇
  2006年   9篇
  2005年   9篇
  2004年   10篇
  2003年   6篇
  2002年   6篇
  2001年   2篇
  2000年   1篇
  1997年   1篇
  1995年   1篇
  1994年   1篇
  1978年   1篇
  1976年   1篇
  1964年   1篇
  1963年   1篇
  1957年   1篇
排序方式: 共有245条查询结果,搜索用时 31 毫秒
121.
During the period 1997-1998, macroalgae, sea snail, mussel, fish and sediment samples were collected at different stations of the Turkish Black Sea coast in order to establish the concentration of selected heavy metals. Heavy metals analyzed were Cd, Co, Cr, Ni, Zn, Fe, Mn, Pb and Cu. The results showed that the Turkish Black Sea coast is facing heavy metal pollution. The metal concentrations in macroalgae, sea snail, mussel and sediment samples are very high. However, Cd, Pb and Cu concentrations in anchovy fish decreased, while Co, Fe, Zn, Cr, Mn and Ni contents had changed when compared previous data. The metal levels in macroalgae did not follow the same pattern as concentrations in sediments at the same station. On the other hand, concentrations of Cd, Co, Cr, Zn, Fe, Mn and Cu in sea snail, mussel and fish samples were related to sediment data in the examined stations.  相似文献   
122.
秦皇岛海滨森林公园森林景观改造探讨   总被引:1,自引:0,他引:1  
秦皇岛海滨森林公园是秦皇岛沿海防护林的重要组成部分,也是秦皇岛重要的城市森林公园之一。针对秦皇岛海滨森林公园阔叶树多、针叶树少、树种单一、林龄老化、景观单调的现状.探讨了森林公园景观改造的原则、措施和技术,并描绘了景观改造后的效果。  相似文献   
123.
PROBLEM: Limited information exists concerning adoption of workplace violence prevention measures by employers and the factors influencing their adoption. METHODS: A weighted sample of North Carolina workplaces (n=210) in operation January 1994 through March 1998 was used to estimate prevalence of 18 measures and identify community and workplace predictors of having >/=5 recommended measures. RESULTS: Location in a metropolitan area most strongly predicted presence of >/=5 administrative safety measures while a history of workplace violence and being in a high crime area were negatively associated. Belonging to an industry considered to be high-risk for workplace homicide was most strongly associated with having >/=5 environmental safety measures. DISCUSSION: Factors influencing high prevalence of violence prevention measures were related to business type, violence history, and location. Knowledge of factors influencing adoption of recommended workplace violence prevention measures can help tailor interventions to diverse industry settings. IMPACT ON INDUSTRY: An important contribution to the understanding and mitigation of workplace homicide is knowledge of the extent of implementation of recommended workplace violence prevention guidelines and factors influencing their adoption. Identifying factors that influence the prevalence and adoption of workplace violence safety interventions can help to tailor development of interventions to address the issue of workplace homicide across diverse industry settings.  相似文献   
124.
Pesticides are widely used throughout the world in agriculture to protect crops and in public health to control diseases. Nevertheless, exposure to pesticides represents a potential risk to humans. This paper describes a study of possible genetic damage in the people living in regions contaminated with complex mixture of pesticides in G?ksu Delta. In this study, used methods were chromosomal aberration (CA), sister chromatid exchange analysis (SCE) in the peripheral blood lymphocytes, and micronucleus (MN) assay in the buccal epithelial cells. In the present investigation, 32 affected subjects consist of 16 smoking and 16 non-smokings and an equal number of control subjects were assessed for genome damage. Micronucleus (MN), Broken egg (BE), Karyorrhexis (KR), Karyolysis (KL) and Binucleus (BN) frequencies were higher in affected subjects than in controls. Smoking had a statistically significant effect on the Micronucleus, Karyorrhexis and Binucleus frequencies for both the control and the exposed group. Also smoking and exposure affected the frequency of sister chromatid exchange and chromosomal aberrations compared with control groups.  相似文献   
125.
Adsorption of diazine dye safranine O (SO) in the presence of Cs+ and Sr2+ ions was investigated onto natural and synthetic zeolites in order to predict competition of cationic organic species with their radionuclides, which are the main fission products released into the environment. Adsorption of SO was measured up to the 40th day and the surface-diffusion coefficients (Ds) were estimated by applying Nernst–Planck approximation based on a homogeneous-surface-diffusion model. The values of Ds were 10 times higher on natural zeolite than those of synthesized zeolite from fly ash (FA) under hydrothermal conditions. Similarly, distribution coefficients (KD) were considerably higher on the clinoptilolite-type natural zeolite. The zeolitized product of FA is mainly composed of analcime and sodalite. SO adsorption on natural zeolite was not influenced by Cs+ and Sr2+ ions, but it decreased at high concentrations on synthetic zeolite. The higher influence of the Sr2+ ions on SO+ adsorption showed that they compete with each other for the same adsorption sites. These results suggested that natural zeolite cannot be used for remediation of wastewater polluted with Cs and Sr radionuclides in the presence of organic cations, whilst FA zeolite has a potential for Sr removal.  相似文献   
126.
This study investigated the process of taking action to mitigate damage and prepare for an earthquake at the individual level. Its specific aim was to identify the factors that promote or inhibit individuals in this process. The study was conducted in Istanbul, Turkey—where an earthquake is expected soon—in May and June 2006 using qualitative methods. Within our conceptual framework, three different patterns emerged among the study subjects. Outcome expectancy, helplessness, a low socioeconomic level, a culture of negligence, a lack of trust, onset time/poor predictability, and normalisation bias inhibit individuals in this process, while location, direct personal experience, a higher education level, and social interaction promote them. Drawing on these findings, the paper details key points for better disaster communication, including whom to mobilise to reach target populations, such as individuals with direct earthquake experience and women.  相似文献   
127.
Carbon dioxide absorption using amine based solvents is a well-known approach for carbon dioxide removal. Especially with the increasing concerns about greenhouse gas emissions, there is a need for an optimization approach capable of multifactor calibration and prediction of interactions. Since conventional methods based on empirical relations are not efficiently applicable, this study investigates use of Response Surface Methodology as a strong optimization tool. A bubble column reactor was used and the effect of solvent concentration (10.0, 20.0 and 30.0 vol%), flow rate (4.0, 5.0 and 6.0 L min−1), diffuser pore size (0.5, 1.0 and 1.5 mm) and temperature (20.0, 25.0 and 30.0°C) on the absorption capacity and also overall mass transfer coefficient was evaluated. The optimization results for maintaining maximum capacity and overall mass transfer coefficient revealed that different optimization targets led to different tuned operational factors. Overall mass transfer coefficient decreased to 34.7 min−1 when the maximum capacity was the desired target. High reaction rate along with the highest absorption capacity was set as desirable two factor target in this application. As a result, a third scenario was designed to maximize both mass transfer coefficient and absorption capacity simultaneously. The optimized condition was achieved when a gas flow rate of 5.9 L min−1, MEA solution of 29.6 vol%, diffuser pore size of 0.5 mm and temperature of 20.6°C was adjusted. At this condition, mass transfer coefficient reached a maximum of 38.4 min−1, with a forecasted achievable absorption capacity of 120.5 g CO2 per kg MEA.  相似文献   
128.
This study reports the optimization of a binary dispersive liquid-liquid microextraction method for the determination of iprodione, procymidone, and chlorflurenol by gas chromatography mass spectrometry. The study was aimed at using two extraction solvents to increase the extraction efficiency of all analytes. The binary solvents recorded results higher than the mono-solvents. After examining the effects of main experimental parameters and their interactions by analysis of variance, 200 μL of binary mixture (dichloromethane and 1,2-dichloroethane), 2.5 mL of ethanol, and 15 s vortex were obtained as optimum parameters. The detection and quantification limits calculated for the analytes were found to be between 0.30–1.6 and 1.0–5.3 ng/mL, respectively. Enhancement in detection power calculated as a ratio of the binary extraction detection limit to the detection limit of direct GC-MS analysis was 105-, 214-, and 233-fold for chlorflurenol, iprodione, and procymidone, respectively. In order to check the accuracy of the developed method, recovery study was performed. Water sampled from a lake and two wastewater samples from treatment facilities were spiked at two concentrations, and the percent recovery calculated for the samples ranged between 87 and 116%. These results confirmed the suitability of the method to real samples for accurate determination of the analytes at trace levels.  相似文献   
129.
This study aims to identify precipitation, throughfall, stemflow, precipitation, and interception processes in pure black pine, pure Scots pine, and mixed black pine–Scots pine forest ecosystems and present the precipitation partitioning according to different stand types. Throughfall and stemflow measurements were performed using five standard precipitation gauges in a pilot area established to represent pure black pine, pure Scots pine, and mixed black pine–Scots pine stands in the Bezirgan Basin. The total precipitation was measured in an open field close to the study area. Throughfall values were calculated as the percentage of precipitation measured in an open field. According to the results of the study, the throughfall values were 69.8% in black pine, 73.9% in Scots pine, and 77.7% in the mixed black pine–Scots pine stands; the stemflow values were 2.6% in black pine, 5.9% in Scots pine, and 3.1% in the mixed black pine–Scots pine stands; the amounts of precipitation reaching the forest floor were 72.3% in black pine, 79.8% in Scots pine, and 80.7% in the mixed black pine–Scots pine stands; and the interception values were found to be 27.7% in black pine, 20.2% in Scots pine, and 19.2% in the mixed black pine–Scots pine stands.  相似文献   
130.
A better public perception and knowledge on land degradation increases the individual and collective responsibility in land use and land management. Based on interviews, this paper presents results of evaluation of public perception and attitude towards degrading phenomena in the central part of Romania, an area prone to geomorphologic processes, with different land uses and a high proportion of degraded land. The research reveals natural causes, improper land use, categories of land owned, socio-economic causes and involvement of institutions as key aspects of public perception. Our research could be useful in the identification and design of measures in regional planning to attract population in prevention, mitigation and rehabilitation actions on degraded land.  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