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1.
The drivers for increasing incineration of sewage sludge and the characteristics of the resulting incinerated sewage sludge ash (ISSA) are reviewed. It is estimated that approximately 1.7 million tonnes of ISSA are produced annually world-wide and is likely to increase in the future. Although most ISSA is currently landfilled, various options have been investigated that allow recycling and beneficial resource recovery. These include the use of ISSA as a substitute for clay in sintered bricks, tiles and pavers, and as a raw material for the manufacture of lightweight aggregate. ISSA has also been used to form high density glass–ceramics. Significant research has investigated the potential use of ISSA in blended cements for use in mortars and concrete, and as a raw material for the production of Portland cement. However, all these applications represent a loss of the valuable phosphate content in ISSA, which is typically comparable to that of a low grade phosphate ore. ISSA has significant potential to be used as a secondary source of phosphate for the production of fertilisers and phosphoric acid. Resource efficient approaches to recycling will increasingly require phosphate recovery from ISSA, with the remaining residual fraction also considered a useful material, and therefore further research is required in this area.  相似文献   
2.
Water-insoluble organic compounds(WIOCs) are an important fraction of atmospheric fine particulate matters(PM2.5), which could affect the climate system and threaten human health potentially. In this study, molecular characterization of WIOCs in PM2.5 were investigated by 15 T Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) with atmospheric pressure photoionization(APPI) source in positive ion mode. A total of 2573 and1875 molecular formulas were iden...  相似文献   
3.
Nowadays, more people tend to spend their recreational time in large national parks, and trace metal(loid)s in soils have attracted long-term attention due to their possible harm to human health. To investigate the pollution levels, potential sources and health risks of trace metal(loid)s in road soils, a total of eight trace metal(loid)s (including As, Cd, Cr, Cu, Ni, Pb, Zn and Hg) from 47 soil samples along roads were studied in the Huangshan National Park in Southeast China. The results showed that the concentrations of As, Cd, Pb, Zn and Hg appeared different degrees of pollution compared with their corresponding background values. According to the pollution indices, Hg and Cd were recognized as significant pollutants presenting moderate to high ecological risk. Combining principal component analysis and positive matrix factorization model, the results showed that traffic, industrial, agricultural and natural sources were the potential origins of trace metal(loid)s in this area, with contribution rates of 39.93%, 25.92%, 10.53% and 23.62%, respectively. Non-carcinogenic risks were all negligible, while the carcinogenic risk of As was higher than the limit (1 × 10−6). Moreover, children were more susceptible to trace metal(loid)s by ingestion which appeared to be a more important exposure pathway than dermal contact and inhalation. The contribution rates of different sources to non-carcinogenic risks and carcinogenic risks were similar among children and adults, while traffic and industrial sources have a significant impact on health risks. This study will give more insights to control the environmental risks of trace metal(loid)s in national parks.  相似文献   
4.
Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous priority pollutants that cause great damage to the natural environment and health. Average genome size in a community is critical for shedding light on microbiome’s functional response to pollution stress within an environment. Here, microcosms under different concentrations were performed to evaluate the selection of PAHs stress on the average genome size in a community. We found the distinct communities of significantly larger genome size w...  相似文献   
5.
In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray fluorescence spectroscopy and energy-dispersive X-ray spectroscopy were used to determine Cr, Mn, Ni, Cu, Zn, Cd and Pb and their mean concentrations were 162.27 ± 29.46, 721.18 ± 180.14, 35.65 ± 12.55, 104.56 ± 128.33, 515.32 ± 321.90, BDL, and 342.82 ± 591.20 mg/kg, respectively. Among the heavy metals, highest concentrations of Cu, Zn and Pb were found at urban sites-7 (municipal waste dumping) and 8 (medical waste incineration). Highest concentration of Cr followed by Cu and Zn was found at site-5 (Tejgaon, urban). Principal component analysis revealed that anthropogenic activities are the potential sources for Cr, Ni, Cu, Zn and Pb while earth crust for Mn. Pollution index and pollution load index results suggested that all the sites were contaminated and/or degraded by Cr, Cu, Zn and Pb except sites-9 (urban), 10 (sub-urban), 11 (rural) while sites-7 and 8 (urban) were extremely degraded. For noncarcinogenic health risk, hazard quotient values for dermal were higher compared to that of inhalation/ingestion. Though hazard index values were less than 1 at all the sites, these were at least one order of magnitude higher for children group than that of adult group, thus the children group may face more noncarcinogenic health risk at sites-7 and 8. Values of incremental lifetime cancer risk were from 10−9 to 10−11 showed no carcinogenic health risk by road dusts contaminated with the heavy metals.  相似文献   
6.
不同类型竹种光合特性的比较研究   总被引:7,自引:0,他引:7  
光合作用是植物生长和物质积累的基础,其光合特性是高光效竹种选育的重要生理指标。为了更好开发利用我国丰富的竹种资源,确定不同类型竹种的光合性能,掌握其合成有机同化物的能力是必须探索的一个重要问题。文章采用Li-6400光合测定仪,通过对不同地下茎类型的6个竹种光合参数和光响应的测定分析,进一步探讨不同类型竹种存在差异的生理基础,以期对不同类型竹种的选育和经营管理提供依据。试验结果表明:不同竹种净光合速率(Pn)差异显著,大木竹Bambusa wenchouensis(Wen)Q.H.Dai的净光合速率最高,Pn值平均达到8.379μmol·m-2·s-1,毛竹Phyllostachys heterocycla cv.pubescens和雷竹P.praecox cv.prevernalis次之,斑苦竹Arundinaria oleosa和苦竹Pleioblastus amarus最低,总体呈现丛生竹>散生竹>混生竹的趋势,1~2 a生竹净光合速率高于3~4 a生竹,但没有显著差异。气孔导度(Cond)、胞间C02浓度(Ci)、蒸腾速率(Tr)综合说明丛生竹的光合固碳能力最强,其中蒸腾速率与气孔导度与净光合速率关系最为紧密,是影响净光合速率的主导因子。光响应曲线表明当光强刚开始增强时,各竹种间差异较小,但随着光强的继续增加,不同竹种出现很大的差异,其中绿竹Dendrocalamus.oldhami(Munro)Keng的潜在光合能力最高,远高于其他竹种,同样表现为丛生竹>散生竹>混生竹,进一步说明丛生竹种较强的光合固碳能力,从而为今后不同类型竹种,尤其是优良丛生竹种的筛选和开发利用提供理论参考。  相似文献   
7.
庐山不同森林植被类型土壤特性及其健康评价   总被引:2,自引:0,他引:2  
土壤作为森林生态系统的一个重要因子,评价森林土壤健康状况对森林健康的维护经营以及森林系统功能的发挥具有重要意义。在系统调查和分析庐山8种森林植被类型土壤特性的基础上,评价指标分别从物种多样性以及不同的森林土壤特性中进行筛选,包括物种多样性系数、枯落物层厚度、腐殖质层厚度、土层厚度、容重、粘粒含量、有机质、p H值、阳离子交换量、全氮、水解氮、有效磷、速效钾、磷酸酶活性等指标,基于SPSS19.0软件对所获得数据进行差异性检验和相关分析,确定各项指标的权重,应用合适的土壤健康评分函数,将测得的指标值转换为对应指标的分值,最后通过加权综合法,计算其土壤健康指数,并对不同森林植被类型土壤健康状况进行评价。结果表明,8种森林植被类型下最终的土壤健康指数大小排序为:针阔混交林(0.78)常-落混交林(0.72)灌丛(0.69)常绿阔叶林(0.67)落叶阔叶林(0.64)竹林(0.59)马尾松林(0.53)黄山松林(0.46)。  相似文献   
8.
Conservation and development practitioners increasingly promote community forestry as a way to conserve ecosystem services, consolidate resource rights, and reduce poverty. However, outcomes of community forestry have been mixed; many initiatives failed to achieve intended objectives. There is a rich literature on institutional arrangements of community forestry, but there has been little effort to examine the role of socioeconomic, market, and biophysical factors in shaping both land‐cover change dynamics and individual and collective livelihood outcomes. We systematically reviewed the peer‐reviewed literature on community forestry to examine and quantify existing knowledge gaps in the community‐forestry literature relative to these factors. In examining 697 cases of community forest management (CFM), extracted from 267 peer‐reviewed publications, we found 3 key trends that limit understanding of community forestry. First, we found substantial data gaps linking population dynamics, market forces, and biophysical characteristics to both environmental and livelihood outcomes. Second, most studies focused on environmental outcomes, and the majority of studies that assessed socioeconomic outcomes relied on qualitative data, making comparisons across cases difficult. Finally, there was a heavy bias toward studies on South Asian forests, indicating that the literature on community forestry may not be representative of decentralization policies and CFM globally.  相似文献   
9.
采用数值模拟方法研究典型型号公交车的火灾发展过程,探讨车门打开对火情发展和人员逃生的影响.通过描述火源、公交车的结构及其内饰物的属性,研究车厢内关键位置的温度分布、能见度及CO和O2体积分数的变化规律,以揭示公交车的火灾发展、烟气运动过程及对人员安全逃生的影响.结果表明:车门打开后由于供氧充足,明显加速了火势的蔓延和烟气扩散,并使得燃烧温度显著提高;打开车门后20 s内,车门附近能见度和O2体积分数显著增高,CO体积分数有所降低,是乘客逃生的关键时间.  相似文献   
10.
通过向黏土中添加重金属试剂,模拟煅烧试验制作烧结砖.采用酸消解试验研究烧结砖中重金属的总量,采用欧盟NEN7371方法测试烧结砖中重金属的有效释放量,采用NEN7375方法进行块状烧结砖浸出试验,研究烧结砖样品中Cr、Ni、As、Cd和Pb的释放特性.结果表明:烧结砖中重金属的有效释放量低于总量,释放率从大到小为Cd、As、Pb、Ni、Cr;在块状浸出过程中,Cr、Ni、As累积释放量达到平衡的时间为16 d,Pb为4d,而Cd的累积释放量一直有上升的趋势;Cr、Ni、As的释放机理主要为扩散控制,Cd为溶解作用,Pb为表面冲刷作用;5种重金属释放速率从大到小为Ni、Cr、Pb、As、Cd.  相似文献   
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