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711.
Lijin Lin Jun Shi Qihua Liu Ming’an Liao Luoyin Mei 《Environmental monitoring and assessment》2014,186(7):4051-4056
In a preliminary study, we found that the cadmium (Cd) concentrations in shoots of the winter farmland weeds Cardamine hirsuta Linn. and Gnaphalium affine D. Don exceeded the critical value of a Cd-hyperaccumulator (100 mg kg?1), indicating that these two farmland weeds might be Cd-hyperaccumulators. In this study, we grew these species in soil containing various concentrations of Cd to further evaluate their Cd accumulation characteristics. The biomasses of C. hirsuta and G. affine decreased with increasing Cd concentrations in the soil, while the root/shoot ratio and the Cd concentrations in shoot tissues increased. The Cd concentrations in shoots of C. hirsuta and G. affine reached 121.96 and 143.91 mg kg?1, respectively, at the soil Cd concentration of 50 mg kg?1. Both of these concentrations exceeded the critical value of a Cd-hyperaccumulator (100 mg kg?1). The shoot bioconcentration factors of C. hirsuta and G. affine were greater than 1. The translocation factor of C. hirsuta was less than 1 and that of G. affine was greater than 1. These findings indicated that C. hirsuta is a Cd-accumulator and G. affine is Cd-hyperaccumulator. Both plants are distributed widely in the field, and they could be used to remediate Cd-contaminated farmland soil in winter. 相似文献
712.
Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions 总被引:1,自引:0,他引:1
Jun Xiao Ya-Feng Wang Peng Shi Lei Yang Li-Ding Chen 《Environmental monitoring and assessment》2014,186(11):8037-8048
Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant community. During the recovery period, the plant community in the work area of the pipeline is replaced by some species that are rare or uncommon in the resident plant community because of human disturbance, thereby increasing the plant diversity in the work area. In terms of plant succession, the duration of the recovery period has a direct effect on the composition and structure of the plant community. The findings provide a theoretical basis and scientific foundation for improving the environmental impact assessment (EIA) of oil and gas pipeline construction as it pertains to the desert steppe ecosystem, and provide a reference point for recovery and management of the eco-environment during the pipeline construction period. 相似文献
713.
714.
环境监测中确定最佳点位的关键技术 总被引:2,自引:0,他引:2
环境监测网络设计的关键问题是确定最佳的环境监测点位 ,而最优的监测点位必须既能代表所在区域环境质量的平均水平 ,又能反映该区域环境质量的变化状况。为此提出一个兼容样本贴近与相似程度的统计量——近似度 ,不仅在理论上证明了其合理性 ,而且在厦门的应用中得到满意的结果 ,从而解决了如何确定环境监测中最佳点位的问题 相似文献
715.
716.
生态工程治理玄武湖水污染效果的监测与评价 总被引:10,自引:1,他引:9
选取总磷、总氮、叶绿素a、浮游生物、浮游植物等多项环境监测指标,对利用生态工程治疗玄武湖水环境污染的效果进行了环境监测与评价。指出生态工程治理玄武湖水环境污染效果显著,经过治理使湖水中生物多样性大大增加,浮游植物大幅减少,湖水透明度增加,总磷、总氮等主要指标大幅下降,生态工程区中的水环境已从高度富营养化降到中度富营养化。 相似文献
717.
718.
Size and resin fractionations of dissolved organic matter and trihalomethane precursors from four typical source waters in China 总被引:3,自引:0,他引:3
Wei Q Wang D Wei Q Qiao C Shi B Tang H 《Environmental monitoring and assessment》2008,141(1-3):347-357
Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during drinking water treatment raise
challenges to water quality control. Understanding both chemical and physical characteristics of DOM in source waters is key
to better water treatment. In this study, the DOM from four typical source waters in China was fractionated by XAD resin adsorption
(RA) and ultrafiltration (UF) techniques. The trihalomethane formation potential (THMFP) of all fractions in the DOM were
investigated to reveal the major THM precursors. The fraction distributions of DOM could be related to their geographical
origins in a certain extent. The dominant chemical fraction as THM precursors in the DOM from south waters (East-Lake reservoir
in Shenzhen and Peal rivers in Guangzhou) was hydrophobic acid (HoA). The size fraction with molecular weight (MW) <1 kDa
in both south waters had the highest THMFP. The results of cluster analysis showed that the parameters of fractions including
DOC percentage (DOC%), UV254%, SUVA254 (specific UV254 absorbance) and THMFP were better for representing the differences of DOM from the studied waters than specific THMFP (STHMFP).
The weak correlation between SUVA254 and STHMFP for either size or XAD fractions suggests that whether SUVA254 can be used as an indicator for the reactivity of THM formation is highly dependent on the nature of organic matter. 相似文献
719.
Regional differences and sources of organochlorine pesticides in soils surrounding chemical industrial parks 总被引:1,自引:0,他引:1
Wang G Lu Y Li J Wang T Han J Luo W Shi Y Jiao W 《Environmental monitoring and assessment》2009,152(1-4):259-269
Concentrations of organochlorine pesticides (OCPs; dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB)) were investigated in 105 soil samples collected in vicinity of the chemical industrial parks in Tianjin, China. OCP concentrations significantly varied in the study area, high HCH and DDT levels were found close to the chemical industrial parks. The intensity of agricultural activity and distance from the potential OCP emitters have important influences on the OCP residue distributions. Principal component analysis indicates that HCH pollution is a mix of historical technical HCH and current lindane pollution and DDT pollution input is only due to technical DDT sources. The significant correlations of OCP compounds reveal that HCHs, DDTs and HCB could have some similar sources of origin. 相似文献
720.
Luo W Lu Y Wang B Tong X Wang G Shi Y Wang T Giesy JP 《Environmental monitoring and assessment》2009,158(1-4):507-517
Fifty-seven typical surface soils and 108 deeper soils were collected from five former industrial sites in Beijing and concentrations of total Hg (SigmaHg) as well as pH, total carbon (TC), total nitrogen (TN), total sulfur, and dissolved organic carbon concentrations determined. The mean concentration of SigmaHg in surface soils was significantly greater than background concentrations in the vicinity of Beijing. Forty-eight percent of the samples exceeded the "critical" concentration of 1.0 mg Hg/kg, dry weight in soils, which has been established by the Chinese government. At depths of 0-80 cm in the soil, profile concentrations of SigmaHg also exceeded the background value. There were significant correlations between concentrations of SigmaHg, TC, and TN in the industrial soils. The greater concentration of SigmaHg in most soils could have been due in part to combustion of coal and leakage from industrial processes. 相似文献