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   1300篇
  免费   3篇
  国内免费   50篇
安全科学   42篇
废物处理   110篇
环保管理   107篇
综合类   130篇
基础理论   212篇
污染及防治   520篇
评价与监测   130篇
社会与环境   90篇
灾害及防治   12篇
  2023年   67篇
  2022年   168篇
  2021年   146篇
  2020年   48篇
  2019年   49篇
  2018年   62篇
  2017年   65篇
  2016年   68篇
  2015年   38篇
  2014年   63篇
  2013年   118篇
  2012年   53篇
  2011年   51篇
  2010年   38篇
  2009年   44篇
  2008年   40篇
  2007年   36篇
  2006年   37篇
  2005年   26篇
  2004年   21篇
  2003年   12篇
  2002年   15篇
  2001年   9篇
  2000年   11篇
  1999年   5篇
  1996年   3篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1991年   2篇
  1987年   2篇
  1986年   1篇
  1984年   5篇
  1983年   7篇
  1982年   6篇
  1981年   2篇
  1979年   3篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   2篇
  1964年   2篇
  1963年   1篇
排序方式: 共有1353条查询结果,搜索用时 15 毫秒
131.
132.
133.
Chronic exposure to heavy metals has long been recognized as being capable of increasing head and neck cancer (HNC) incidence, such as laryngeal (LC) and nasopharyngeal (NPC), among exposed human populations. The aim of the present study was to evaluate the concentrations of arsenic (As) and cadmium (Cd) in the blood of 145 patients (LC and NPC) and 351 controls in order to establish a potential relationship between these factors and the occurrence of LC and NPC. Mean blood levels of As and Cd in patients (5.67 and 3.51 μg/L, respectively) were significantly higher than those of controls (1.57 and 0.74 μg/L, respectively). The blood levels of As and Cd were mostly significantly higher than those of controls (p?<?0.05) after controlling the other risk factors of HNC including tobacco smoking and chewing, and alcohol drinking. Cd levels in blood increase significantly with the number of occupational exposure years for patients (p?<?0.05). However, seafood was not found to be contributing as an exposure source. Among these risk factors, smoking (>30 pack years) and occupational exposure (>20 years) presented the most significant association with HNC (OR?=?10.22 and 10.38, respectively, p?<?0.001). Cd level in blood sample of cases that are occupationally exposed/tobacco users (smokers and chewers) were higher than that of non-occupationally exposed/nontobacco users (p?<?0.001). The logistic regression model illustrated that HNC (LC?+?NPC) was significantly associated with blood levels of As (OR?=?2.41, p?<?0.001) and Cd (OR?=?4.95, p?<?0.001).  相似文献   
134.
The general public, government regulators, and environmental organizations are increasingly demanding industries to reduce their environmental impacts and report progress. This in turn resulted in numerous requirements for reporting environmental data. Environmental assessments are a useful tool in gathering and documenting this data. The assessments also assist decision makers to quantify impacts of their activities and plan for appropriate mitigation measures. There are different types of environmental assessments, each having specific purpose(s) and addressing specific audience(s). This paper gives an overview of common environmental concerns associated with oil and gas industry and shares insights on types of environmental assessments that are widely used. It discusses general methodologies to define the scope, approach, measurement standards, and reporting. Potential challenges encountered in conducting these assessments in an international arena and under a wide variety of regulatory requirements are addressed. Practical approach in execution of these assessments is described here, and strategy in dealing with the challenges is presented.  相似文献   
135.
Climate change poses water resource challenges for many already water stressed watersheds throughout the world. One such watershed is the Upper Neuse Watershed in North Carolina, which serves as a water source for the large and growing Research Triangle Park region. The aim of this study was to quantify possible changes in the watershed’s water balance due to climate change. To do this, we used the Soil and Water Assessment Tool (SWAT) model forced with different climate scenarios for baseline, mid‐century, and end‐century time periods using five different downscaled General Circulation Models. Before running these scenarios, the SWAT model was calibrated and validated using daily streamflow records within the watershed. The study results suggest that, even under a mitigation scenario, precipitation will increase by 7.7% from the baseline to mid‐century time period and by 9.8% between the baseline and end‐century time period. Over the same periods, evapotranspiration (ET) would decrease by 5.5 and 7.6%, water yield would increase by 25.1% and 33.2%, and soil water would increase by 1.4% and 1.9%. Perhaps most importantly, the model results show, under a high emission scenario, large seasonal differences with ET estimated to decrease by up to 42% and water yield to increase by up to 157% in late summer and fall. Planning for the wetter predicted future and corresponding seasonal changes will be critical for mitigating the impacts of climate change on water resources.  相似文献   
136.
Environmental Science and Pollution Research - Harmful cyanobacterial blooms (HCB) have severe impacts on marine and freshwater systems worldwide. They cause oxygen depletion and produce potent...  相似文献   
137.
The widespread contamination of surface and ground water quality from the heavy use of fertilizer in modern agriculture is the current concern. Therefore, this study was carried out to develop a slow-release fertilizer using charcoal. The morphology of the charcoal impregnated fertilizer was investigated by scanning electron microscopy (SEM). This study also evaluated the release patterns of N, P, and K from impregnated charcoal using a simulated soil solution and distilled water as leaching solutions. The patterns of N, P, and K releases were examined in both static and continuous-flow conditions for 360 h. Releases of N, P, and K from impregnated charcoal were found to be slow and steady. However, the release trends of N, P, and K were higher in soil solution than distilled water under both the above conditions. Dissolution occurred when N, P, and K were released in the above leached solutions. As a result, the fertilizer impregnated charcoal could be developed as slow-release type fertilizer to minimize the contamination.  相似文献   
138.
Journal of Polymers and the Environment - This study aims to improve low intrinsic ductility of poly (lactic acid) (PLA) by using a novel bio-sourced plasticizer environmentally friendly and...  相似文献   
139.
Journal of Polymers and the Environment - Starch-polyacrylic acid-polyvinylsulfonic acid (St-g-PAA-PVSA) graft copoymer was synthesized by gamma radiation as an initiator. The chemical structure,...  相似文献   
140.

The present study investigates the feasibility of using two types of municipality solid wastes incineration ashes, namely, fly ash and bottom ash in the production of sustainable alkali-activated binder. The ashes are collected from the incineration plant and characterized to determine their particle size distribution, specific gravity, chemical composition, and heavy metals content. The ashes are then used as either fly ash or sand replacement with five replacement ratios 0%, 5%, 10%, 15%, and 20% to produce the binder. The produced binder are characterized in terms of strength, workability, density, water absorption, thermal conductivity and stability, chemical composition, and heavy metals content. The results reflect the ability of producing sustainable alkali-activated binder with small dosage of MSWI ashes as either fly ash or sand replacement without negatively affecting its strength, workability, density, and water absorption. The ashes enhance the thermal insulation capability of the binder.

  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