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   407篇
  免费   17篇
  国内免费   36篇
安全科学   34篇
废物处理   21篇
环保管理   28篇
综合类   149篇
基础理论   39篇
污染及防治   117篇
评价与监测   41篇
社会与环境   23篇
灾害及防治   8篇
  2023年   7篇
  2022年   20篇
  2021年   26篇
  2020年   12篇
  2019年   8篇
  2018年   18篇
  2017年   14篇
  2016年   20篇
  2015年   17篇
  2014年   25篇
  2013年   34篇
  2012年   17篇
  2011年   20篇
  2010年   15篇
  2009年   19篇
  2008年   13篇
  2007年   19篇
  2006年   12篇
  2005年   12篇
  2004年   9篇
  2003年   16篇
  2002年   20篇
  2001年   18篇
  2000年   22篇
  1999年   9篇
  1998年   10篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1993年   2篇
  1991年   1篇
  1989年   2篇
  1988年   1篇
  1986年   3篇
  1984年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1966年   1篇
  1964年   1篇
  1963年   3篇
  1959年   1篇
  1957年   1篇
  1917年   1篇
排序方式: 共有460条查询结果,搜索用时 296 毫秒
31.
Biomarkers are internationally recognized as useful tools in marine coastal biomonitoring, in particular, as early-warning signals at the level of individual organisms to assess biological effects of pollutants and other stressors. In the present study, Mytilus galloprovincialis has been employed as a sentinel organism to assess biological pollution effects in the Mar Piccolo of Taranto (Southern Italy), a coastal lagoon divided into two small inlets, connected to the open sea through one natural and one artificial narrow openings. Mussels were collected in June 2013 at three sites located within each of the two inlets of the Mar Piccolo. Biological effects were investigated through a suite of biomarkers suitable to reflect effects and/or exposure to contaminants at biochemical and cellular levels. Biochemical biomarkers included glutathione-S-transferase (GST) and acetylcholinesterase (AChE) enzyme activities; as histochemical biomarkers, lysosomal membrane stability, lipofuscin and neutral lipid accumulation, and lysosomal structural changes were considered. As a whole, results highlighted differences among the three study sites, particularly for GST, AChE, and lipofuscins, which are consistent with the variations of the chemical pollutants in sediments. The applied biomarkers showed that a stress syndrome likely to be ascribed to environmental pollutants is occurring in mussels living in the Mar Piccolo of Taranto, in particular, the ones inhabiting the first inlet.  相似文献   
32.
This paper examines the anthropogenic factors that have contributed to wetland loss and degradation in the Mekong Delta, Vietnam from 1816 AD to present. Our analysis is framed over five historical periods and highlights the role that seven drivers of wetland degradation have played in the Mekong Delta, including: resettlement and economic development policies; population growth and urbanization; demand for food and reclaiming wetland for agriculture; construction of canals construction of dykes flood protection systems; expansion of travel systems (waterway and roads); and exploitation of wetland natural resources. Of these, government policies for resettlement and economic development seem to have had the greatest impact on wetland loss and degradation in the Mekong Delta throughout the course of history. As a result of these factors, only 0.068 million hectares of the original 4.0 million hectares of the Mekong Delta currently remains as primary swamp forest ecosystem. History suggests that future management of the Mekong Delta should take a holistic approach that includes a better understanding of the implications of past decisions on wetland loss.  相似文献   
33.
通过采用ACE装置与烟气NOx分析仪器联用的实验室评价方法,可在更接近实际催化裂化反应-再生过程的条件下,评价助剂对再生烟气中NOx的催化转化性能,同时还可考察助剂的加入对催化裂化产品分布的影响。采用该方法对几种降NOx助剂的性能进行了评价,结果表明,在催化剂体系中含有Pt基CO助燃剂的情况下,加入4%的RDNO;助剂后,烟气NOx降低幅度约30%~40%,且催化裂化产品分布基本不受影响。  相似文献   
34.
In recent years, growing interest has focused on determining the performance of materials and evaluating the service life of structures exposed to various environmental forces. In this context, the determination of the aggressive potential of marine salts on mortars used as external renders is critical. The present study aimed to evaluate the spatial distribution of marine salts relative to distance from the sea. This was done by monitoring the deposition rate of chlorides and sulfates in wet candle sensors, located at nine stations scattered around the Metropolitan Region of Salvador, state of Bahia, Brazil. The study also determined the effectiveness of water-soluble salts at penetrating three different types of mortars of varying cement content via deposition and diffusion. The methodology employed enabled an evaluation of the efficiency of the monitoring sensors' measurement of the aggressiveness potential of local marine aerosol, and determination of the comparative performance of the three mortars tested, from the standpoint of resistance to salt penetration. The type and amount of salts captured both in solution and in powder samples extracted from the mortars were determined by ion chromatography. The analysis of the various types of mortars tested indicated which types are more resistant to the aggressive potential of the region's marine aerosol and the distance from the shore where local buildings are liable to be most strongly affected.  相似文献   
35.
Little data are available on organochlorine contamination in Chinese terrestrial birds of prey. This study examined the presence of PCBs, DDTs and other organochlorine pesticides in various raptors from northern China. DDE exhibited the highest concentrations among targeted compounds. Greatest levels (23.5-1020 mg/kg lipid weight) were observed in Eurasian sparrowhawks. This may be due to their stopover in southeastern China, where high DDT and dicofol applications have been documented. Residential kestrels exhibited much lower DDE, but similar PCB and HCH concentrations. ΣTEQs and PCB-126/-77 concentration ratios exhibited significant positive correlations with ΣPCB concentrations, respectively. Similar results were also demonstrated by a meta-analysis of previously published data across avian species. Possible hepatic sequestration of coplanar PCB-77, -126, -169 and -118 was observed as liver TEQs increased in Eurasian sparrowhawks. These observations may indicate an induction of CYP1A enzymes, as a result of elevated contamination in some species.  相似文献   
36.
木棉基活性炭纤维吸附性能的研究   总被引:1,自引:0,他引:1  
荣达  周美华 《环境工程学报》2009,3(8):1419-1424
采用浸渍(NH4)2HPO4化学活化法650℃时制备得到3种新型木棉基活性炭纤维,即只浸渍不预氧化方法处理的AK1(activated kapok),先浸渍后预氧化的AK-2和先预氧化后浸渍的AK-3。利用制备得到的活性炭纤维处理苯酚和亚甲基蓝的模拟废水,AK-2具有苯酚最大吸附量(137.00 mg/g),AK-1具有亚甲基蓝最大吸附量(274.11 mg/g)。吸附苯酚时,在静态平衡实验中,更符合Freundlich吸附等温线;在动力学实验中,更符合准一级反应。吸附亚甲基蓝时,在静态平衡实验中,AK-1更符合Langmuir模型,AK-2 、AK-3更符合Freundlich吸附等温线;在动力学实验中,更符合准二级反应。  相似文献   
37.
环境中苯并(a)芘监测技术及建议   总被引:1,自引:0,他引:1  
环境中BaP是引起人们各类癌症的主要诱发物.叙述了环境中BaP的来源及其浓度状况,列举了国家制定的各项标准中的BaP含量的浓度限值,论述了环境水中和空气中BaP的样品采集、保存、前处理、分析测定及定量监测中应注意的几个问题,提出了监测BaP的4点建议.  相似文献   
38.
Based on meteorological data from 1978 to 2007, we investigated the annual, seasonal, and fixed hourly variations of Shanghai urban heat island (UHI) in urban and suburban areas and spatial distribution of UHI. The results demonstrated a remarkable interannual increase of UHI intensity in Shanghai. The UHI was the strongest in autumn and the weakest in summer, as a consequence of the prevailing weather conditions. Similar to previous studies of other cities, the UHI in Shanghai was stronger in the nighttime than in the daytime. The SW–NE cross section followed the general cross section of the typical UHI described by Oke (1987) who defines its characteristic parts as “cliff”, “plateau”, and “peak”. Analysis of the association of UHI and urbanization indicated that the UHI increased with the expansion of population and rapid increase of gross domestic product. The continuous increase of power consumption and area of paved road and decrease of area of cropland caused the growth of UHI intensity. Green land had a positive effect on mitigation of heat island based on an inversed U-shaped curve with UHI intensity.  相似文献   
39.
Swine manure composting by means of experimental turning equipment   总被引:1,自引:0,他引:1  
The purpose of research was to test the effectiveness of a prototype of a turning machine and to evaluate the feasability of a farm-scale composting process of the solid fraction of swine manure. A qualitative evaluation of the process and final product was made by monitoring the following parameters: process temperature, oxygen concentration inside the biomass, gaseous emissions (CH4, CO2, NH3, N2O), respiration index, humification index, total and volatile solids, carbon and nitrogen, pH and microbial load. The prototype proved to be very effective from a technical-operational point of view. The composting process exhibited a typical time-history, characterised by a thermophilic phase followed by a curing phase [Chiumenti, A., Chiumenti, R., Diaz, L.F., Savage, G.M., Eggerth, L.L., Goldstein, N., 2005. Modern Composting Technologies. BioCycle-JG Press, Emmaus, PA, USA]. Gas emissions from compost the windrow were more intense during the active phase of the process and showed a decreasing trend from the thermophilic to the curing phase. The final compost was characterized by good qualitative characteristics, a significant level of humification [Rossi, L., Piccinini, S., 1999. La qualità agronomica dei compost derivanti da liquami suinicoli. (Agronomic quality of swine manure compost). L'informatore Agrario 38, 29-31] and no odor emissions. This method of managing manure represents an effective, low cost approach that could be an interesting opportunity for swine farms.  相似文献   
40.
Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd,) and Al concentrations as well as values of Ca/Al in the tip, middle and base sections, and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.  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