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31.
利用微机制作土壤环境研究中的趋势面等值线图 总被引:2,自引:0,他引:2
介绍一种利用微机制作土壤环境元素含量趋势面等值线图的实用方法,其中包括地理背景底图,趋势面等值线图及两图的套绘技术。本法简便易操作勿需复杂的硬,软件支撑,利用普遍流行的常用软件,不但能进行趋势面分析及绘图中所需的坐标转换,耐用可解决图件套绘中的定位问题,对拥有微机和小型绘图仪的单位均可适用。 相似文献
32.
研究气候变化下林地植被生态需水量的时空变化,对于保护涵养水源的林地植被系统,合理规划管理流域水资源有着重要作用。以汉江上游流域11个气象站点1971~2010年的气象资料为依据,采用结合[1]土壤含水量与植物类型修正蒸散发量得到植被生态需水量的方式,从时空角度定量研究了在生长季4~10月份流域林地植被生态需水量及其趋势性变化,并且分析了生态需水量对各气象因子变化的敏感性程度。结果表明:汉江上游流域林地植被多年平均生长季生态需水量为6.915 8×109 m3,整体上呈现非显著性增加趋势,在空间分布上具有明显的地带性特征。生态需水量对不同气象因子有不同程度的敏感性:最高温度水汽压太阳辐射风速最低温度,生态需水量对各气象因子敏感程度的地带性分布特征还与各区域的纬度、海拔、植被类型和下垫面情况有关。 相似文献
33.
34.
Zhang H 《Environmental monitoring and assessment》2007,127(1-3):429-434
The Huangpu River supplies eighty percent of daily water used for life and industry for about 20 million people in Shanghai,
China. Industry and human sewerage from the metropolis is mainly released into the Huangpu River, which flows past the Shanghai
city area. The pollution caused by city life and production in the Huangpu River has occurred for years. In this paper, the
contents of heavy metals (Cu, Pb, Cr, Cd, and Hg), total organic carbon (TOC), and polynuclear aromatic hydrocarbons (PAHs)
in the Huangpu River are discussed. Data from environmental monitoring from 1991 to 2002 are compared to understand the variation
and trends of the pollution. Results indicate that metals have been reduced efficiently, but organic pollutants develop in
aggravating trend as human sewage increase. The variation of the organic pollutant concentration, which are lower than other
similar river's of China, US, and Canada, in the Huangpu River suggests that the organic pollution maybe a problem of water
quality evolvement in metropolis river protection, which should be accentuated in the world today. 相似文献
35.
The analysis of data of the ground-level ozone concentration and accumulated ozone exposure over a threshold of 40 ppb (AOT40)
in the rural areas of Lithuania is presented. Trends in the annual ozone mean, 95{th} and 25{th} percentiles were determined
as statistically not significant at Preila and Rugsteliskes sites during the 1994hbox{–}2004 period. Trends in the ozone concentration
and its percentiles in the air masses arriving to Preila station in “polluted” and “unpolluted” sectors have been examined.
Statistically significant changes in the ozone annual mean and 25th percentile were found in air masses in both “polluted”
and “unpolluted” sectors in the 1988hbox{–}2002 period. The trend analysis in the ozone monthly mean and percentiles for each
month of the year revealed the main changes in the ozone level in both sectors during January-May. Insignificant downward
trends in monthly 95th percentile in “unpolluted” sector and upward trends in “polluted” sector were found during summer months.
Values of AOT40 for the protection of forests as well as crops and semi-natural vegetation were determined during the 1994–2004
period. The estimated AOT40 values for the protection of forests were lower than the critical level at Lithuanian rural sites
but AOT40 values for the protection of crops and semi-natural vegetation were found to be higher than the critical level at
both sites. 相似文献
36.
Sicard P Dalstein-Richier L Vas N 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):351-362
In the South-Eastern French Mediterranean region, high ozone concentrations were measured since many years and specific symptoms like chlorotic mottles were detected on Arolla pines. We presented results for the 2000-2008 period concerning the trend analysis for ambient ozone concentrations and related forest damages, with the Mann and seasonal Kendall tests. Ozone precursor’s emissions from Europe have been reduced over the last 20 years. Decreases in annual averages, median, 25th and 98th percentiles and maxima values were found. The seasonal trend analysis for the high-lying stations showed a decreasing trend for the warm season, when main ozone production is the photochemistry, and an increase for the cold period, caused by a reduced ozone titration. Statistics on Arolla Pine reveal strong correlations between mottling intensity and the high ozone concentrations. Finally, decreases for the ozone concentrations, and associated statistics, AOT40 values and for the mottling intensity on conifers needles were observed. 相似文献
37.
文章在对长江下游铜陵硫铁矿集中开采区矿山地质环境系统调查的基础上,分析阐述了主要矿山地质环境问题及其成因、分布特征,其中地面塌陷、含水层破坏和水土污染较为严重;结合矿山地质环境现状、保护治理政策及成效,分析预测了矿山地质环境问题的发展趋势,为矿山地质环境恢复治理提供了基础支撑作用。 相似文献
38.
介绍了几种在环境质量评价中关键污染因子的确定方法,在此基础上提出了一种新的关键污染因子的确定方法--动态污染指数判别法。经过实例运用分析表明,该方法物理意义明确,简便易用。通过对某个时间段内污染物原始监测数据的灰色处理,从动态演变中找出关键因子,客观地判别各污染因子所起的作用,对各因子在下一个时间段的发展趋势作出预测判断,增加了评价的准确性。 相似文献
39.
以可降解塑料替代普通塑料作包装材料和农用薄膜,已成为发展的方向和趋势。本文比较详细地介绍了国内外对可降解塑料的研制现状和应用前景,并指出了可降解塑料在开发和应用方面所存在的一些问题。 相似文献
40.
灰色拓扑分析方法在海上溢油趋势预测上的应用 总被引:5,自引:0,他引:5
依据1973~1996 年间中国海域船舶溢油的历史数据,利用灰色系统理论的灰色拓扑分析方法,以10 个不同的溢油总量作为分析采用的阈值,建立相应的GM(1,1)分析模型,对未来的溢油趋势进行预测分析。分析的结果显示未来年份的溢油量较1996 年以前的溢油量要高,表明未来的溢油趋势仍不可乐观。必须加强以大溢油量(单次溢油量>50 000 kg) 溢油事件的防止工作。 相似文献