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951.
通过遥感与GIS技术,研究了lOa间于田地区的土地覆盖类型变化,通过对于田绿洲生态脆弱带的预警线提取,分析了该地区的生态脆弱带的开发利用现状,有针对性地提出相应的绿洲生态脆弱带生态环境建设的建议和保护措施。 相似文献
952.
国家加大了对环境影响评价技术服务机构和专业技术人员的考核与监督以及环境评价审批力度,因而有关服务机构和技术人员在日常工作中必须进行关键技术储备和技术培训。文章阐述了当前环境影响评价的目的、主要内容以及进行环境影响评价必须的技术储备重点。 相似文献
953.
本文通过在生产实践中发现的人的不安全行为及不安全因素,认识到安全教育的重要性,推想到安全教育在教学课程中的设置问题。 相似文献
954.
Speciation of heavy metals in marine sediments from the East China Sea by ICP-MS with sequential extraction 总被引:22,自引:0,他引:22
Twelve elements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Sn, Cd and Pb) in 24 sediment samples at eight sites (S1-S8) from the East China Sea were analyzed with the BCR sequential extraction (SE) protocol to obtain the metal distribution patterns in this region. The results showed that the heavy metal pollutions in S4 and S8 were more severe than in other sampling sites, especially Cd and Pb pollution. In the top sediments at S4 and S8, both the total contents and the most dangerous non-residual fractions of Cd and Pb were extremely high. More than 90% of the total concentrations of V, Cr, Mo and Sn existed in the residual fraction. Fe, Co, Ni, Cu and Zn mainly (more than 60%) occurred in the residual fraction. While Mn, Pb and Cd dominantly presented in the non-residual fractions in the top sediments. The metal distribution patterns with depth and the correlations between total organic carbon (TOC) and the total Fe-Mn content were also investigated. The results showed that, for most of the elements except Fe, the concentration of elements in fraction A in the top sediments was higher than that in other depth. The similar rule was also found in fraction B but not in fraction C. Besides, the distributions of V, Cd in fraction B and Pb, Cd, Cu in fraction C might be affected by TOC. 相似文献
955.
Wei Wang Jianguo Jiang Xuelong Wu Shunwen Liang 《Journal of Material Cycles and Waste Management》2000,2(2):65-69
In China, controlling environmental pollution resulting from solid waste (SW) and hazardous waste (HW) has become one of the
most pressing tasks in the field of environmental engineering. It is reported that the annual generation of industrial solid
waste (ISW) in China exceeded 0.6 billion tons in the 1990s, and is increasing every year. Although ISW management has been
strengthened in recent years, about 40% of SW is put in uncontrolled landfill without appropriate treatment. According to
statistics from the national Environmental Protection Agency, the cumulative ISW uncontrolled landfill in China had reached
6.6 billion tons by the end of 1995, occupying around 55 000 hectares of land. Although some major uncontrolled landfills
were constructed, nonetheless groundwater contamination resulted from the use of low-standard liners and poor management.
Furthermore, about 20 million tons of ISW was discharged into the environment illegally, and a third of this waste was discharged
directly into water bodies, making ISW one of the greatest pollution sources for surface water and ground water. Environmental
pollution accidents resulting from SW occur about 100 times a year in China, and environmental issues frequently arise because
of ISW pollution. The practices of SW management, treatment, and disposal started relatively late in China, and for a long
time the management of SW pollution has received little attention compared with water and air pollution management. China
faces problems such as the insufficiency of management laws and regulations, insufficient investment, inadequate treatment
and disposal technology, and a lack of qualified technicians. At present, most treatment and disposal technology cannot meet
the requests for solid waste pollution control. In order to protect, restore, and improve environmental quality in China and
to realize sustainable development, the safe management and disposal of solid and hazardous wastes is a pressing challenge.
In recent years, much attention has been paid to SW management in China, and investment to develop management and treatment
technologies has increased. In 1995, the Law for Solid Waste Pollution Protection was issued, and work on solid waste treatment
and disposal began to be legally managed. SW treatment and disposal facilities have been constructed, and now operate in some
large and medium-sized cities. In particular, rapid improvements have been seen in ISW recycling, collection, and disposal
of municipal solid waste and regional HW management. All the figures in this paper are from 1995, and represent the situation
in China in that year.
Received: April 18, 2000 / Accepted: May 15, 2000 相似文献
956.
957.
Soil Fertility Quality and Agricultural Sustainable Development in the Black Soil Region of Northeast China 总被引:2,自引:0,他引:2
The black soil in northeast China is considered one of the most fertile soils in China. Consequently, the black soil region has become one of the most important regions for cereal grain production in China. Agriculture has developed rapidly since the early part of the nineteenth century. To date, approximately 70 percent of total land in the area is cultivated. Even though the agricultural production in this region is increasing continuously, some soil fertility quality problems have become serious. This is hampering agricultural development and sustainability in the region. A brief history of population growth and agricultural development in the region is presented. Major soil quality problems, particularly soil degradation and soil erosion, are analyzed. Based on studies, suggestions for improving soil quality and for promoting sustainable agricultural development in the region are presented. These suggestions include improving agricultural landscape patterns, developing conservation cultivation, promoting combinations of crop production with combinations of forestry and animal husbandry, and implementing integrated management for soil and water conservation. 相似文献
958.
对某厂办公楼裂缝产生的原因进行了分析 ,并对其沉降情况和墙体裂缝发展情况进行了监测 ,指出了某办公楼现状及其隐患发展的趋势 相似文献
959.
根瘤菌、丛枝菌根(AM)真菌与宿主植物共生的分子机理 总被引:2,自引:0,他引:2
丛枝菌根(AM)真菌和根瘤菌是两类重要的共牛微生物,分别能够与宿主植物形成丛枝菌根和根瘤,其中,对二者共有的宿主植物--豆科植物而言,则能够形成AM真菌-豆科植物-根瘤菌三重共生体.两类微生物与宿主植物共生关系建立的关键是二者之间的相互识别以及随后的侵染,其相互识别过程就是它们相互交换信号分子、相互作用的过程,而这两类微生物与宿主植物的识别过程具有许多相似之处.本文就根瘤菌、AM真菌与宿主植物在分子水平上的共生机理进行了综述,在对宿主植物分泌信号分子识别的基础上,提出植物根系对两类微生物侵染的感应机制,分析了共生体形成过程中相关基因的转录与表达,进而阐明了共生体的形成过程,并对本领域的未来发展提出了建议. 相似文献
960.
Shunwen Liang Jianguo Jiang Yan Zhang Xin Xu 《Frontiers of Environmental Science & Engineering》2008,2(3):358-363
The leaching characteristics of heavy metals in products of cement stabilization of fly ash from a municipal solid waste incinerator were investigated in this paper. The stabilization of heavy metals such as Cd, Pb, Cu, and Zn in fly ash from such incinerators was examined through the national standard method in China based on the following factors: additive quantity of cement and Na2S, curing time, and pH of leaching liquor. The results showed that as more additives were used, less heavy metals were leached except for Pb, which is sensitive to pH of the leachate, and the worse effect was observed for Cd. The mass ratio of cement to fly ash = 10% is the most appropriate parameter according to the national standard method. When the hydration of cement was basically finished, stabilization of heavy metals did not vary after curing for 1 d. The mixtures of cement and fly ash had excellent adaptability to environmental pH. The pH of leachate was maintained at 7 when pH of leaching liquor varied from 3 to 11. 相似文献