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301.
302.
The impact of wake wash from high-speed ferries on the coastal environment in non-tidal seas is analysed in terms of wave
energy and power, and properties of the largest waves. Shown is that hydrodynamic loads caused by heavy high-speed traffic
may play a decisive role not only in low-energy coasts but also in certain areas with high wind wave activity. For example,
ship-generated waves form, at least, about 5–8% from the total wave energy and about 18–35% from the wave power in the coastal
areas of Tallinn Bay exposed to dominating winds. The periods of wake waves from high-speed ships frequently are much larger
than dominating periods of wind waves. The leading waves typically have a height of about 1 m and a period of 10–15 s. Such
waves extremely seldom occur in natural conditions in many regions of semi-enclosed seas. They cause unusually high hydrodynamic
loads in the deeper part of the nearshore. The fast ferry traffic thus is a qualitatively new forcing component of vital impact
on the local ecosystem. It is demonstrated that wakes from high-speed ferries may trigger considerable changes of the existing
balance of coastal processes. Owing to their low decay rates combined with their exceptional compactness after crossing many
kilometres of the sea surface, such wakes may cause considerable remote impact of the ship traffic. This feature has to be
addressed in the analysis of the impact of harbours and associated ship traffic in the neighbourhood of vulnerable areas. 相似文献
303.
This paper presents a mathematical model of local pollutant dispersion designed to compute the concentration field above and
around the Marcoule nuclear site. The model is based on integrating the classical turbulent diffusion equation, corrected
(prior to integration) by experimental wind tunnel data obtained for a scaled-down model of the site. The computed results
are compared with full-scale experimental observations at Marcoule in the case of neutral atmosphere. A comparison with the
standard Gaussian model is also made. Finally, a critical analysis of the model is presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
304.
基于利用AMDAR数据确定大气混合层高度进而对飞机不同工作状态下的时间进行修正的计算方法,核算了2017年华北地区6座典型机场大气污染物排放量.结果显示,6座机场NOx、CO、VOC、SO2与PM2.5的排放总量分别为21504.2,7074.8,1424.0,1283.6和323.2t.飞机源NOx、CO、VOC与SO2的排放量远高于机场内其他污染源,而对PM2.5的排放贡献相差较小.HC与CO的排放主要集中在滑行阶段,占比分别为90.6%与90.2%,而NOx、SO2与PM2.5的排放主要集中在爬升阶段,排放占比分别为58.9%、38.7%和43.5%.6座机场1月份污染物排放量较低,在8月份达到峰值.基于本研究建立的天津滨海国际机场大气污染物排放清单,利用WRF-CAMQ模型研究机场排放对周边区域PM2.5浓度的影响.结果表明机场区域小时最大贡献浓度为3.24μg/m3;距离机场5km处的年均贡献浓度与小时最大贡献浓度分别为0.08和2.84μg/m3. 相似文献
305.
沿海飞机铝合金结构腐蚀与防护 总被引:1,自引:0,他引:1
依据地处沿海的19架飞机受海洋大气和海水影响的腐蚀形态和防护方法的调查,分析研究了铝合金结构的腐蚀机理.探寻其腐蚀规律。针对飞机结构设计中的不足,采取了减少电位差、绝缘电极、隔离盐雾海水、减少结构缝隙、增加保护层抗蚀能力的改进防护措施.为飞机设计和维修提供了参考。 相似文献
306.
Edwards G. C. Dias G. M. Thurtell G. W. Kidd G. E. Roulet N. T. Kelly C. A. Rudd J. W. M. Moore A. Halfpenny-Mitchell L. 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):447-454
Methane emissions were measured from a bog andlake in the Experimental Lakes Area in Northern Ontario in 1992and 1993, prior to and following flooding. Bog fluxes were smallin 1992 (0.27 mg m-2 d-1) but increased 5-fold in 1993 afterflooding. Over the bog, there was a diel cycle of nighttimeemission and daytime uptake in 1992 in contrast to constantemission in 1993. Lake emissions decreased after flooding butwere much greater than bog emissions in both years (average = 7.3 mg m-2 d-1). Seasonally, the bog flux was correlated withground temperatures after flooding. In 1992, lake fluxes werecorrelated with air temperature on a daily basis. In contrast,seasonal lake fluxes were correlated with water and sedimenttemperatures in 1992, but only with sediment temperatures in1993. These results are explained with respect to the effects offlooding on lake and bog dynamics. 相似文献
307.
Tuovinen J.-P. Simpson D. Mikkelsen T. N. Emberson L. D. Ashmore M. R. Aurela M. Cambridge H. M. Hovmand M. F. Jensen N. O. Laurila T. Pilegaard K. Ro-Poulsen H. 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):263-274
The performance of a new dry deposition module, developedfor the European-scale mapping and modelling of ozone flux to vegetation, was tested against micrometeorological ozone and water vapour flux measurements. The measurement data are for twoconiferous (Scots pine in Finland, Norway spruce in Denmark) and one deciduous forest (mountain birch in Finland). On average, themodel performs well for the Scots pine forest, if local inputdata are used. The daytime deposition rates are somewhat over-predicted at the Danish site, especially in the afternoon. The mountain birch data indicate that the generic parameterisationof stomatal responses is not very representative of this northernspecies. The module was also tested by using modelled meteorological data that constitute the input for a photochemical transport model. 相似文献
308.
中国生态环境的新特点及其对策 总被引:25,自引:0,他引:25
在分析我国生态环境现状的基础上 ,提出了生态环境发展的 3个新特点 :①由单纯的工业污染过渡到工业和大众消费形成的污染并存阶段 ,而且乡镇企业污染问题越来越突出 ;②水体污染由工业污染发展到工业污染加农业污染的复合污染 ;③生态恶化问题正在由局部扩展到更大范围 ,从流域的一部分扩到全流域 .针对目前生态环境目前出现的新特点 ,在对策上提出了应实现 3个方面的转变 :①在环境污染控制上 ,应从末端治理发展到清洁生产 ;②在生态保护上 ,应从生态赤字到生态建设 ;③在污染治理上 ,从“谁污染、谁治理”转变到“谁污染、谁付费”、“谁治理、谁收益”. 相似文献
309.
ABSTRACTCarbon fiber-reinforced polymers (CFRPs) have attracted attention from the aerospace industry due to their light weight, excellent mechanical properties, and resistance to corrosion. However, CFRP composites are difficult to recycle as their recycling process must be performed under extreme conditions; end-of-life regulations do not directly address the problem with reusing these composites. Thus, the objective of this study is to explore solutions that minimize the use of CFRPs and prolong their useful life in the airline industry. To achieve this goal, this work conducted a review of the state of the art of CFRP fiber recycling, emphasizing the recycling processes, restrictions, and regulations. One solution is to develop a CFRP recycling market that would allow the sequential use of recycled materials among industries in descending order of the required structural performance of the composite. 相似文献
310.
为解决飞机结冰防御系统能力评估中不确定因素较多导致结果不准确的问题,提出基于不确定语言的评估方法。在介绍区间数和语言评估标度的基础上,给出将语言评估标度转化为区间数的方法,并阐述不确定语言变量的定义及运算法则。建立飞机结冰防御系统能力评估指标体系,采用区间数特征向量法确定各指标的区间数权重,并利用区间集结(IA)算子和区间加权矢量和法实现指标的聚合。最后,分析某飞机结冰防御系统,以区间数评估其结冰防御能力。 相似文献