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931.
降雨条件下典型岩溶流域地下水中的物质运移   总被引:16,自引:13,他引:3  
通过对2008年4月下旬降雨期间,重庆青木关地下河系统出口姜家泉泉水的水文过程、浊度、悬浮颗粒物、主要阳离子和TOC浓度的监测,结合悬浮颗粒物的扫描电镜和能谱分析图,来研究岩溶流域地下水中悬浮颗粒物浓度、浊度、主要阳离子和TOC等物质的运移特征.结果表明,在单一岩溶管道较发育的地下河出口,泉水流量、浊度、悬浮颗粒物浓度、主要阳离子和TOC浓度对降雨事件响应迅速;与碳酸盐岩溶解有关的Ca2+、Mg2+和Sr2+等在流量上升的过程中表现为稀释效应;降雨期间,地下河中受雨水侵蚀的土壤输入量增大,引起泉水中浊度和悬浮颗粒物浓度的增大;泉水中Al3+、Fe、Mn、Ba2+和TOC等物质是悬浮颗粒物的伴生物,其浓度随浊度的增大而增大;在研究的2场降雨期间,地下水携带悬浮颗粒物(0.45μm)的总量约为9.7t;在泉水流量的上升和衰减的过程中,水质较差或极差;降雨期间流域内土壤侵蚀和养分的流失,不但严重破坏了脆弱的岩溶生态环境,而且极易造成地下水由土壤侵蚀引起的非点源污染,对当地居民的饮水安全造成严重的威胁.  相似文献   
932.
CuO-CeO2/γ-Al2O3粒子电极对垃圾渗滤液降解特性   总被引:2,自引:0,他引:2  
岳琳  王启山  石岩  何士忠 《环境科学》2008,29(6):1582-1586
研制了负载型CuO-CeO2/γ-Al2O3粒子电极,并与活性炭颗粒混合填充于主阴阳极之间,实现三维电催化氧化反应,采用XRD、SEM对粒子电极进行表征.结果表明, CuO-CeO2/γ-Al2O3粒子电极对垃圾渗滤液显示了良好的电催化活性和稳定性,在pH为7.0、槽电压10V、空气流速0.04m3·h-1反应条件下,150min后, COD、氨氮去除率达到87.8%、45.4%,去除效果较传统二维平板、三维复极性电解槽更高,经20次反复使用后仍具有一定催化活性.研究了电-多相催化氧化体系对垃圾渗滤液降解的动力学规律,表明渗滤液降解符合准一级反应动力学规律;并在此条件下,体系以直接氧化占优.  相似文献   
933.
土壤中砷和硒的测定有多种方法,一般对两种元素含量进行单独测定,过程比价繁琐,不利于批量分析。本文提出了一种可同时测定土壤中砷、硒含量的方法,该方法采用盐酸和高氯酸一次消解土样,用原子荧光光度法同时测定土壤中的砷、硒,具有操作简便、测定结果准确等特点。  相似文献   
934.
沿海城市灰霾天气与海盐氯损耗机制的关系   总被引:5,自引:0,他引:5  
随着经济规模迅速扩大和城市化进程加快,大气气溶胶污染日趋严重,由细粒子气溶胶造成的能见度恶化事件越来越多,这些人类活动排放的污染物,可形成灰霾天气致使能见度下降。尤其值得注意的是沿海城市灰霾天气增长较快,沿海城市灰霾天气增多与海盐气溶胶粒子的氯损耗机制关系密切。我国30年前在粉尘污染时代建立的空气质量评价体系,已经远远不能描述新型复合空气污染类型,尤其是不能描述细粒子污染的情况,能见度的恶化主要与细粒子的浓度关系比较大,而与气溶胶的质量浓度关系不大。能见度与PM2.5尤其是PM1有非常好的关系,因而目前用能见度来描述灰霾天气是最好的指标。  相似文献   
935.
A field lysimeter/mini plot experiment was established in a silt loam soil near Lincoln, New Zealand, to investigate the effectiveness of urea fertilizer in fine particle application (FPA), with or without the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT - “Agrotain”), in decreasing nitrogen (N) losses and improving N uptake efficiency. The five treatments were: control (no N) and 15N-labelled urea, with or without NBPT, applied to lysimeters or mini plots (unlabelled urea), either in granular form to the soil surface or in FPA form (through a spray) at a rate equivalent to 100 kg N ha−1. Gaseous emissions of ammonia (NH3) and nitrous oxide (N2O), nitrate (NO3) leaching, herbage dry-matter (DM) production, N-response efficiency, total N uptake and total recovery of applied 15N in the plant and soil varied with urea application method and with addition of NBPT. Urea with NBPT, applied in granular or FPA form, was more effective than in application without NBPT: N2O emissions were reduced by 7-12%, NH3 emissions by 65-69% and NO3 leaching losses by 36-55% compared with granular urea. Urea alone and with NBPT, applied in FPA form increased herbage DM production by 27% and 38%, respectively. The N response efficiency increased from 10 kg DM kg−1 of applied N with granular urea to 19 kg DM kg−1 with FPA urea and to 23 kg DM kg−1 with FPA urea plus NBPT. Urea applied in FPA form resulted in significantly (P < 0.05) higher 15N recovery in the shoots compared with granular treatments and this was improved further when urea in FPA form was applied with NBPT. These results suggest that applying urea with NBPT in FPA form has potential as a management tool in mitigating N losses, improving N-response efficiency and increasing herbage DM production in intensive grassland systems.  相似文献   
936.
以马鞍山钢铁公司高炉瓦斯泥为对象,采用微波改性方法对高炉瓦斯泥的粒度分布、微观形貌及化学变化进行表征分析,揭示了微波作用对瓦斯泥吸附特性的影响.结果表明,高炉瓦斯泥的主要组分为含铁烧结矿和焦炭颗粒,经微波改性的瓦斯泥颗粒,在形貌上显示出粗糙度增大,孔隙结构明显,比表面积增大和活性点增多的特征.通过对亚甲基蓝的吸附测试,...  相似文献   
937.
Xiamen,located on the southeastern coastal line of China,is undergoing rapid urbanization and industrialization,so its air quality has a trend of degradation.However,studies on level,temporal and spatial changes of fine particles (PM2.5) and their carbonaceous fractions are scarce.In this article,abundance,sources,seasonal and spatial variations,distribution of organic carbon (OC) and elemental carbon (EC) in PM2.5,were studied at suburban,urban and industrial sites in Xiamen during four season-representative months in 2009-2010.PM2.5 samples were collected with middle volume sampler and were analyzed for OC and EC with thermal optical transmittance (TOT) method.Results showed that the annual average PM2.5 concentrations were 63.88-74.80 μg/m3 at three sites.While OC and EC concentrations were in the range of 15.81-19.73 μg/m3 and 2.74-3.49 μg/m3,respectively,and clearly presented the summer minima and winter maxima in this study.The carbonaceous aerosol accounted for 42.8%-47.3% of the mass of PM2.5.The annual average of secondary organic carbon (SOC) concentrations in Xiamen were 9.23-11.36 μg/m3,accounting for approximately 56% of OC.Strong correlations between OC and EC was found in spring (R2 = 0.50) and autumn (R2 = 0.73),suggesting that there were similar emission and transport processes for carbonaceous aerosols in these two seasons,while weak correlations were found in summer (R2 = 0.33) and winter (R2 = 0.41).The OC/EC ratios in PM2.5 varied from 2.1 to 8.7 with an annual average of 5.7,indicating that vehicle exhaust,coal smoke and biomass burning were main source apportionments of carbonaceous fractions in Xiamen.  相似文献   
938.
Field investigations were conducted to measure subsoil trace element content and factors influencing content in an intensive periurban market garden in Chenggong County, Yunnan Province, South-West China. The area was divided into three di erent geomorphological units: specifically, mountain (M), transition (T) and lacustrine (L). Mean trace element content in subsoil were determined for Pb (58.2 mg/kg), Cd (0.89 mg/kg), Cu (129.2 mg/kg), and Zn (97.0 mg/kg). Strong significant relationships between trace element content in topsoil and subsoil were observed. Both Pb and Zn were accumulated in topsoil (RTS (ratio of mean trace element in topsoil to subsoil) of Pb and Zn >1.0) and Cd and Cu in subsoil (RTS of Cd and Cu 61.0). Subsoil trace element content was related to relief, stoniness, soil color, clay content, and cation exchange capacity. Except for 7.5 YR (yellow-red) color, trace element content increased with color intensity from brown to reddish brown. Significant positive relationships were observed between Fe content and that of Pb and Cu. Trace element content in mountain unit subsoil was higher than in transition and lacustrine units (M > T > L), except for Cu (T > M > L). Mean trace element content in calcareous subsoil was higher than in sandstone and shale. Mean trace element content in clay texture subsoil was higher than in sandy and sandy loam subsoil, and higher Cu and Zn content in subsoil with few mottles. It is possible to model Pb, Cd, Cu, and Zn distribution in subsoil physico-chemical characteristics to help improve agricultural practice.  相似文献   
939.
The particle characterization from the influent and effluent of a chemical-biological flocculation (CBF) process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment (CEPT) process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes. The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.  相似文献   
940.
滇东南岩溶区土壤有效态微量元素丰度特征及其影响因素   总被引:1,自引:0,他引:1  
为了解滇东南岩溶区土壤有效态微量元素丰度特征及其影响因素,采用对角线取样法对研究区土壤进行采样并进行了测试分析.结果表明,不同地层土壤有效硼质量比由小到大为奥陶系、泥盆系、寒武系,有效铜质量比由小到大为寒武系、奥陶系、泥盆系,有效锌和有效铁质量比由小到大为寒武系、泥盆系、奥陶系.pH值、有机质是影响土壤有效态微量元素的重要因素,有效硼、有效铜、有效锌质量比与pH值呈正相关,有效铁质量比与pH值呈负相关;有效硼、有效铜质量比与有机质质量比呈极显著正相关(p<0.01),有效锌质量比与有机质质量比呈显著正相关(p<0.01),而有效铁质量比与有机质质量比相关性不明显.根据中科院微量元素组制定的标准,不同地层土壤有效硼、有效锌质量比级别为极低或低,有效铜质量比级别为中,有效铁质量比为高或极高.  相似文献   
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