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961.
可见光照射下土壤光催化降解有毒有机污染物 总被引:2,自引:0,他引:2
在可见光(vis,λ>420 nm)照射下,用天然土壤粉末(Soil)做催化剂降解酸性桃红(Sulforhodamine B,SRB)和2,4二氯苯酚(2,4-Dichlorophenol,DCP),分析了催化剂的用量、H2O2初始浓度对降解反应的影响,并通过紫外可见分光光度法(UV-Vis)、荧光检测(FL)、红外光谱(IR)等方法对降解反应动力学及反应机制进行了研究.结果表明,Soil/H2O2/vis体系能有效地降解SRB,反应240 min可脱色完全,10 h COD去除率达90.44%,反应240 min,DCP的去除率达到80.55%;荧光检测发现反应中产生了高活性氧化物种·OH,红外光谱结果表明目标底物最终被氧化降解为胺类、羧酸类小分子;催化剂具有比较好的稳定性,循环使用5次,催化性能无明显变化.反应机制主要是涉及·OH的异相类Fenton过程. 相似文献
962.
963.
964.
桂林大气降水化学特征及其经树木枝叶淋滤后的变化 总被引:1,自引:0,他引:1
大气降水经过茂密的树木枝叶后,其化学成分含量会发生改变,本文通过于2011年4、5月份在桂林理工大学校园内接收未经植被淋滤的普通雨水和经过铁树、桂花树、竹子3种树木枝叶淋滤的雨水,测定其K+、Na+、Mg+、Ca2+、SO24-、Cl-、PO34-和TN的含量,分析其基本特征和变化规律。大气降水在经过以上3种树木枝叶淋滤后,其总氮含量及各种离子含量和未经树木淋滤的普通雨水相比都是增加的。由于各种综合因素影响,其变化规律呈多样性。 相似文献
965.
Synthesis and high adsorption and selectivity performance of lead ion-imprinted micro-beads with combination of two functional monomers. 相似文献
966.
The e ects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts (DBPs) during chlorination
were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were
used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower
content of total organic carbon (TOC) and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions,
four trihalomethanes (THMs), nine haloacetic acids (HAAs), total organic halogen (TOX) and its halogen species fractions, including
total organic chlorine (TOCl) and total organic bromide (TOBr), were determined. The results showed that co-existent ferric and
bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of
bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species,
which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide
ions in raw water samples produced higher percentages of unknown TOBr. 相似文献
967.
968.
Michael G. Dosskey Zeyuan Qiu 《Journal of the American Water Resources Association》2011,47(4):662-671
Dosskey, Michael G. and Zeyuan Qiu, 2011. Comparison of Indexes for Prioritizing Placement of Water Quality Buffers in Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 47(4):662‐671. DOI: 10.1111/j.1752‐1688.2011.00532.x Abstract: Five physically based, spatially distributed, empirical indexes were compared for the degree to which they identified the same or different locations in watersheds where vegetative buffers would function better for reducing agricultural nonpoint source pollution. All five indexes were calculated on a 10 m × 10 m digital elevation grid on agricultural land in the 144‐km2 Neshanic River watershed in New Jersey. The indexes included the topography‐based Wetness Index (WI) and Topographic Index (TI) and three soil survey‐based indexes (sediment trapping efficiency [STE], water trapping efficiency [WTE], and groundwater interaction [GI]). Results showed that each index associated higher pollution risk and mitigation potential to a different part of the landscape. The WI and TI identified swales and riparian areas where runoff converges, whereas STE and WTE identified upland sites. The STE and WTE lack the fine scale of slope resolution and the accounting for convergent runoff patterns that can be important for properly locating buffers in some watersheds. The GI index indicates the existence of a shallow water table but the correspondence with WI‐ and TI‐identified sites was only modest. For watersheds where pollutant loading is generated by both saturation‐excess (emphasized by TI and WI) and infiltration‐excess processes (emphasized by STE and WTE), the indexes could be complementary. However, techniques would be needed for properly apportioning priority among sites identified by each index. 相似文献
969.
基于供应链和可拓决策的食品安全预警模型及其应用 总被引:2,自引:0,他引:2
为提高食品安全预警能力,改善食品安全状况,以食品原料供应环境质量、生产加工、流通加工、销售食品质量、食品安全管理与监测作为食品安全预警的关键因素,提出一种基于供应链和可拓决策的食品安全预警模型。从供应链的角度建立食品安全预警指标体系,确定食品安全的经典域、节域和预警对象;建立食品安全预警模型并给出食品安全预警的方法和步骤;结合A省2010年的食品安全数据,定量评价A省食品安全预警状态,结合模型评价结果进行单指标和综合安全预警分析,验证该模型的合理性和适用性。研究结果表明:针对食品安全状况与预警特征,运用基于供应链和可拓决策的食品安全预警模型,能够对食品安全状态进行快速判断并有效预警。 相似文献
970.
Identification of microcystins contamination in surface water samples from the Three Gorges Reservoir, China 总被引:1,自引:0,他引:1
Xu C Chen JA Huang YJ Qiu ZQ Luo JH Zeng H Zhao Q Cao J Shu WQ 《Environmental monitoring and assessment》2011,180(1-4):77-86
Physicochemical and biological parameters related to water quality and microcystins (MCs) contamination in aquatic environment of the Three Gorges Reservoir were investigated in August 2004 and January 2005. A solid-phase extraction method and an HPLC equipped with photodiode array were used for MC-LR detection. A quantitative analysis showed the total MC-LR concentrations of water samples ranged from non-detectable to 0.57 μg L?1 among the seven sampling sites. The highest MC-LR concentration was found at sampling site G (Wushan), which was followed by F (Kaixian), E (Wanzhou), D (Fuling), C (Cuntan), and A (Daxigou). The correlation analysis showed the MC-LR concentration was positively correlated with chlorophyll-a concentration. This result suggests that MC concentration in water can be indirectly estimated by analyzing the chlorophyll-a concentration. Overall, the results of this study suggest that more importance should be placed on monitoring of MC contamination and water quality in the Three Gorges Reservoir to ensure drinking water safety and reduce the potential exposure of people to these health hazards. 相似文献