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   2985篇
  免费   182篇
  国内免费   391篇
安全科学   345篇
废物处理   182篇
环保管理   480篇
综合类   1402篇
基础理论   320篇
环境理论   4篇
污染及防治   455篇
评价与监测   264篇
社会与环境   80篇
灾害及防治   26篇
  2024年   4篇
  2023年   33篇
  2022年   44篇
  2021年   69篇
  2020年   96篇
  2019年   86篇
  2018年   63篇
  2017年   83篇
  2016年   113篇
  2015年   101篇
  2014年   135篇
  2013年   242篇
  2012年   231篇
  2011年   256篇
  2010年   155篇
  2009年   230篇
  2008年   198篇
  2007年   214篇
  2006年   177篇
  2005年   134篇
  2004年   119篇
  2003年   139篇
  2002年   130篇
  2001年   86篇
  2000年   93篇
  1999年   66篇
  1998年   57篇
  1997年   63篇
  1996年   41篇
  1995年   41篇
  1994年   20篇
  1993年   13篇
  1992年   9篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   3篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1981年   1篇
  1979年   3篇
  1970年   1篇
排序方式: 共有3558条查询结果,搜索用时 31 毫秒
991.
为防治油气泄漏事件,长庆油田以重点环境保护目标为对象,按照层级防护、标本兼治、数字预警、分级响应、就地控制的原则,建设油气泄漏防治体系,明确和落实油田公司、厂处、作业区、生产岗位四个层级的防治范围和职责,构建系统参数预警报警、阀门截断、基础防护三道防线,全面提升安全环保的防范能力和水平。保证事故状态下,能够在最短时间、最小范围内进行最有效的处置,实现重点环境保护目标的安全。  相似文献   
992.
Natural gamma radiation of beach sand deposits was measured along the south coast of Rio de Janeiro State, Brazil, with the aim of studying the provenance and transport processes of sediments in this area. Concentrations of thorium, uranium and potassium were evaluated using γ-ray spectrometry and a behavioral study of eTh/eU and eTh/K cross plots was performed, reflecting the mineralogical properties of beach sands, as well as their history of transport and sorting processes. The results show that such technique can be efficiently used to map heavy mineral distributions and to distinguish the different origins of coastal sediments disclosing the influence of nearby rivers.  相似文献   
993.
The paper addresses the wear particles released from commercially available “low-metallic” automotive brake pads subjected to brake dynamometer tests. Particle size distribution was measured in situ and the generated particles were collected. The collected fractions and the original bulk material were analyzed using several chemical and microscopic techniques. The experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm were released into the air. The numbers of nanoparticles (<100 nm) were by three orders of magnitude larger when compared to the microparticles. A significant release of nanoparticles was measured when the average temperature of the rotor reached 300 °C, the combustion initiation temperature of organics present in brakes. In contrast to particle size distribution data, the microscopic analysis revealed the presence of nanoparticles, mostly in the form of agglomerates, in all captured fractions. The majority of elements present in the bulk material were also detected in the ultra-fine fraction of the wear particles.  相似文献   
994.
Foliage dust contains heavy metal that may have harmful effects on human health. The elemental contents of tree leaves and foliage dust are especially useful to assess air environmental pollution. We studied the elemental concentrations in foliage dust and leaves of Acer pseudoplatanus along an urbanization gradient in Vienna, Austria. Samples were collected from urban, suburban and rural areas. We analysed 19 elements in both kind of samples: aluminium, barium, calcium, copper, iron, potassium, magnesium, sodium, phosphor, sulphur, strontium and zinc. We found that the elemental concentrations of foliage dust were significantly higher in the urban area than in the rural area for aluminium, barium, iron, lead, phosphor and selenium. Elemental concentrations of leaves were significantly higher in urban than in rural area for manganese and strontium. Urbanization changed significantly the elemental concentrations of foliage dust and leaves and the applied method can be useful for monitoring the environmental load.  相似文献   
995.
Dispersant use in nearshore areas is likely to increase the exposure of aquatic organisms to petroleum. To measure the toxicity of this controversial response technique, golden grey mullets (Liza aurata) were exposed to mechanically dispersed oil, chemically dispersed oil, dispersant alone in seawater, water-soluble fraction of oil and to seawater as a control treatment. Several biomarkers were assessed in the gills (enzymatic antioxidant activities, glutathione content, lipid peroxidation) and in the gallbladder (polycylic aromatic hydrocarbons metabolites). The significant differences between chemically dispersed oil and water soluble fraction of oil highlight the environmental risk to disperse an oil slick when containment and recovery can be conducted. The lack of significance between chemically and mechanically dispersed oil suggests that dispersant application is no more toxic than the natural dispersion of the oil slick. The results of this study are of interest in order to establish dispersant use policies in nearshore areas.  相似文献   
996.
The effect of cable oil concentration, nutrient amendment and bioaugmentation on cable oil component biodegradation in a pristine agricultural soil was investigated. Biodegradation potential was evaluated over 21 d by measuring cumulative CO2 respiration on a Micro-Oxymax respirometer and 14C-phenyldodecane mineralisation using a 14C-respirometric assay. Cable oil concentration had a significant effect upon oil biodegradation. Microbial respiratory activity increased with increasing cable oil concentration, whereas 14C-phenydodecane mineralisation decreased. Bioaugmentation achieved the best cable oil biodegradation performance, resulting in increases in cumulative CO2 respiration, and maximum rates and extents of 14C-phenyldodecane mineralisation. Generally, nutrient amendment also enhanced cable oil biodegradation, but not to the extent that degrader amendment did. Cable oil biodegradation was a function of (i) cable oil concentration and (ii) catabolic ability of microbial populations. Bioaugmentation may enhance cable oil biodegradation, and is dependent upon composition, cell number and application of catabolic inocula to soil.  相似文献   
997.
The concentrations of heavy metals (Cr, Cd, Hg, Cu, Zn, Pb and As) in the water, sediment, and fish were investigated in the middle and lower reaches of the Yangtze River, China. Potential ecological risk analysis of sediment heavy metal concentrations indicated that six sites in the middle reach, half of the sites in the lower reach, and two sites in lakes, posed moderate or considerable ecological risk. Health risk analysis of individual heavy metals in fish tissue indicated safe levels for the general population and for fisherman but, in combination, there was a possible risk in terms of total target hazard quotients. Correlation analysis and PCA found that heavy metals (Hg, Cd, Pb, Cr, Cu, and Zn) may be mainly derived from metal processing, electroplating industries, industrial wastewater, and domestic sewage. Hg may also originate from coal combustion. Significant positive correlations between TN and As were observed.  相似文献   
998.
We measured the concentration of several elements (arsenic [As], calcium [Ca], cadmium [Cd], copper [Cu], nickel [Ni], lead [Pb], selenium [Se] and zinc [Zn]) in adult and nestling pied flycatchers (Ficedula hypoleuca) and great tits (Parus major) at different distances to a Cu-Ni smelter in 2009. Feces of nestlings generally failed to correspond with internal element concentrations but reflected the pollution exposure, indicating an increased stress by removal of excess metals. The uptake of Cu and Ni were regulated, but As, Cd, Pb and Se accumulated in liver tissue. Pied flycatchers had generally higher element concentrations than great tits. The higher accumulation of As and Pb in pied flycatcher livers was explained by a more efficient absorption, whereas the higher Cd concentration was primarily due to different intake of food items. Age-related differences occurred between the two species, though both Cd and Se accumulated with age.  相似文献   
999.
Lead isotopes and heavy metal concentrations were measured in two sediment cores sampled in estuaries of Xiangjiang and Lishui Rivers in Hunan province, China. The presence of anthropogenic contribution was observed in both sediments, especially in Xiangjiang sediment. In the Xiangjiang sediment, the lower 206Pb/207Pb and higher 208Pb/206Pb ratio, than natural Pb isotope signature (1.198 and 2.075 for 206Pb/207Pb and 208Pb/206Pb, respectively), indicated a significant input of non-indigenous Pb with low 206Pb/207Pb and high 208Pb/206Pb. The corresponding concentrations of heavy metals (As, Cd, Zn, Mn and Pb) were much higher than natural values, suggesting the contaminations of heavy metals from extensive ore-mining activities in the region.  相似文献   
1000.
利用化学强化分离-无害化技术处理废弃油基钻井液   总被引:12,自引:2,他引:10  
废弃油基钻井液因其含有油类、重金属、有机物等污染物,属国家危险废弃物,处理难度大.通过大量室内实验研究,首次采用化学强化分离-无害化技术处理废弃油基钻井液,研制了新型清油剂和无害化处理药剂,回收了废弃油基钻井液中的油类,油回收率达90%以上.回收油的品质好,除机械杂质和灰分指标外,所测的几项指标均达到GB252-200...  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