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531.
532.
混合堆肥过程中自由空域(FAS)的层次效应及动态变化 总被引:5,自引:0,他引:5
城市污泥、猪粪混合堆肥试验表明:升温期和高温期FAS分别为42.3%、26.2%,在这2个堆肥期内堆体上部的FAS明显高于下部,堆体内的空气能满足微生物的需求;降温期FAS为52.4%,堆体上部的FAS高于中部,中部高于下部,FAS呈明显的层次效应;腐熟期FAS为54.7%,FAS的层次效应减弱,堆体上部和中部的通气性明显好于下部.不同堆肥期剖面上下部FAS的差异由大到小分别为:降温期>高温期>后熟期>升温期;堆体内FAS由高到低为:上部>中部>下部.FAS随时间的变化满足二级反应动力学方程. 相似文献
533.
Luyu Ding Qikun Lu Lina Xie Jie Liu Wei Cao Zhengxiang Shi 《Journal of the Air & Waste Management Association (1995)》2016,66(3):267-279
The open lots and manure stockpiles of dairy farm are major sources of greenhouse gas (GHG) emissions in typical dairy cow housing and manure management system in China. GHG (CO2, CH4 and N2O) emissions from the ground level of brick-paved open lots and uncovered manure stockpiles were estimated according to the field measurements of a typical dairy farm in Beijing by closed chambers in four consecutive seasons. Location variation and manure removal strategy impacts were assessed on GHG emissions from the open lots. Estimated CO2, CH4 and N2O emissions from the ground level of the open lots were 137.5±64.7 kg hd-1 yr-1, 0.45±0.21 kg hd-1 yr-1 and 0.13±0.08 kg hd-1 yr-1, respectively. There were remarkable location variations of GHG emissions from different zones (cubicle zone vs. aisle zone) of the open lot. However, the emissions from the whole open lot were less affected by the locations. After manure removal, lower CH4 but higher N2O emitted from the open lot. Estimated CO2, CH4 and N2O emissions from stockpile with a stacking height of 55±12 cm were 858.9±375.8 kg hd-1 yr-1, 8.5±5.4 kg hd-1 yr-1 and 2.3±1.1 kg hd-1 yr-1, respectively. In situ storage duration, which estimated by manure volatile solid contents (VS), would affect GHG emissions from stockpiles. Much higher N2O was emitted from stockpiles in summer due to longer manure storage.Implications: This study deals with greenhouse gas (GHG) emissions from open lots and stockpiles. It’s an increasing area of concern in some livestock producing countries. The Intergovernmental Panel on Climate Change (IPCC) methodology is commonly used for estimation of national GHG emission inventories. There is a shortage of on-farm information to evaluate the accuracy of these equations and default emission factors. This work provides valuable information for improving accounting practices within China or for similar manure management practice in other countries. 相似文献
534.
选取优级纯化学试剂Cd Cl2和As2S3来模拟危险废物中的重金属,按一定比例将其与烧结矿原料均匀混合后进行共处置煅烧。主要研究了在煅烧过程中Cd和As的挥发规律,同时对煅烧所得烧结矿进行消解实验求得固化的重金属量。实验结果表明,Cd的挥发率随着温度的升高和时间的增加而不断增大,直到达到一个平衡而不再继续增大,对Cd的挥发进行动力学模拟得到挥发率α与煅烧温度T和煅烧时间t的关系式为α=1-exp(-0.669exp(-3567.6/T)t)。而As则呈现出温度越高挥发率越低的规律,当温度为1 200℃时,煅烧75 min后As的挥发率仅为9.8%,即共处置过程中As与烧结矿原料发生化学反应而固化下来,挥发较少,可认为对人体健康和环境造成的危害较小。 相似文献
535.
采用UV_(185 nm)-H_2O_2组合工艺处理高浓度棘白菌素类抗生素发酵废水。结果表明:UV_(185 nm)-H_2O_2组合工艺较好地实现了高浓度棘白菌素类抗生素发酵废水的强化处理,其处理效果明显优于单独UV_(185 nm)光氧化工艺;在废水pH为2.50、光照时间为60 min、H_2O_2投加量为5 g/L、反应温度为室温的条件下,UV_(185 nm)-H_2O_2组合工艺对废水色度和COD的去除率分别高达96.4%和46.9%;该联合氧化过程需在酸性体系中进行;联合氧化过程中产生了大量蜂王浆提取物类黑褐色物质,处理出水中显色物质的种类明显减少,实现了废水的高效脱色。 相似文献
536.
Polyoxometalate, K6TiW11O39Sn·7H2O (TiW11Sn), was synthesized and characterized. TiW11Sn and K6ZrW11O39Sn·12H2O (ZrW11Sn) were evaluated for their photocatalytic degradation of triarylmethane (brilliant green and acid blue 9), bisazo (C.I. reactive black 5), and monoazo dyestuffs (C.I. reactive red 24, C.I. reactive red 194, and C.I. reactive orange 5) with natural sunlight in homogeneous aqueous solutions. TiW11Sn and ZrW11Sn effectively and photocatalytically decolorized the dyestuffs. The TiW11Sn- and ZrW11Sn-mediated photocatalytic degradation of the dyestuffs involved a pseudo-first-order reaction and was modeled by Langmuir–Hinshelwood-type kinetics. The observed pseudo-first-order rate constants (K/) of triarylmethane dyestuffs were generally bigger than that of the azo dyestuffs. Quantitative structure–property relationship models of the K/ of the dyestuffs were developed using partial least-square regression. The cumulative variance of the dependent variable explained by the partial least-square components was > 0.753 for each optimal model. This value indicated that the model had good predictive ability and robustness. The K/ values of the dyestuffs were related to the energy of the lowest unoccupied molecular orbital, and the most positive net atomic charges on a sulfur atom of dyestuffs. The linear correlation coefficients between the predicted and experimental values were all > 0.9950. 相似文献
537.
Altitude dependence of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in surface soil from Tibetan Plateau, China 总被引:5,自引:0,他引:5
Pu Wang Qinghua Zhang Yawei Wang Thanh Wang Xiaomin Li Yingming Li Lei Ding Guibin Jiang 《Chemosphere》2009,76(11):1498-1504
Remote mountain areas besides high latitude regions are beginning to receive increased attention in studying the transport and behavior of persistent organic pollutants (POPs). In the present work, surface soil samples were collected from the Tibetan Plateau, the highest plateau in the world which includes the northern slope of Mt. Qomolangma, to investigate the levels and trends of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) along the altitudinal gradient. The average PCB and PBDE concentrations were 185.6 ng kg−1 dry weight (dw) (range 47.1–422.6 ng kg−1 dw) and 11.1 ng kg−1 dw (range 4.3–34.9 ng kg−1 dw), respectively. Regression analysis between the log-transformed TOC-normalized concentrations and the altitudes of the sampling sites showed two opposite trends with regard to altitude dependence: negative relationship with altitude below about 4500 m followed by a positive altitude dependence above this point. Considering minimum anthropogenic activities and very sparse precipitation in the north of Himalayas, the trends above 4500 m imply that the significant altitude dependence of these two groups of POPs were irrespective of pollution sources, but could be predicted by the global distillation effect involving cold condensation in high altitude mountain areas. Increasing levels of heavier congeners were found in higher altitude sites, although the lighter congeners were the main contributors to the total amount, suggesting that less volatile congeners seem to become enriched easier than those more volatile at higher altitudes in this region. 相似文献
538.
含铬钻井泥浆固化及影响因素 总被引:3,自引:0,他引:3
固化技术是含铬钻井泥浆无害化处理最有效的方法。以四川西部某钻井泥浆为研究对象,选取水泥、石灰、聚铝和水玻璃作为固化处理剂,运用正交试验研究了含铬钻井泥浆实验条件。最佳试验配方是:先将泥浆含水率调整为46%,水泥、聚铝、石灰和水玻璃的添加量分别为10%、1%、3%和0.5%。固化72 h,该试验配方对六价铬和总铬的固化率分别达到93%和95%,浸出六价铬浓度符合地下水三类水标准(GB/T14848-9),浸出总铬浓度符合国家污水综合排放标准(GB5085.3-1996)。 相似文献
539.
540.