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311.
Five priority areas of potential impact by contaminants (API) were investigated at the Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil with the following aims: (i) to identify both organic and inorganic contaminants present in soil and groundwater; (ii) to define the environmental conditions relevant for microbial activity at the site and (iii) to evaluate the feasibility of employing natural attenuation for treatment of the hydrocarbon contamination. One area (API 1) was an uncontrolled landfill, where waste materials from the refinery were deposited between 1954 and 1986, and four areas (API 4, 5, 7 and 11) were located in the operational section of the refinery. Soil contamination by regulated BTEX compounds (benzene, toluene, total xylenes) was restricted to two samples from API 1. Nonregulated ethylbenzene was detected in one soil sample from API 4, one from API 5 and two from API 1. No soil contained regulated PAH above threshold levels. Several nonregulated PAHs were found in 6 soil samples from API 1, 3 soil samples from API 4 and 1 soil sample from API 5. Site soils contained very high aluminium concentrations, but metal contamination was restricted to one soil sample from API 1, which contained nickel above threshold limits. BTEX contamination of groundwater was due mostly to benzene. Of the 17 PAH molecules tested, only naphthalene and 2-methylnaphthalene occurred in groundwater. The sum of total BTEX and total PAH exceeded 200 μg/L in only a few monitoring wells in API 4, 5 and 11 and was always below 2.640 μg/L. Be, Cd, Cr, Cu, Hg, Ni, Se, Ag, Tl and Zn were not detected in groundwater, which was contaminated in a few locations by aluminium (mostly below 1 mg/L), lead (<0.066 mg/L) and arsenic (<0.056 mg/L). S, K, Ca, Mg and Fe were present in groundwater in excess of physiological requirements for microbial growth, but low concentrations of N and P could become growth limiting. However, BTEX were efficiently degraded in saturated and unsaturated zone microcosms and nutrient amendments did not stimulate biodegradation rates measurably. The inorganic carbon pool in groundwater was up to one order of magnitude larger than the organic carbon pool. Total inorganic carbon (TIC) in API groundwater exceeded TIC of clean groundwater by factors of 2 (API 4), 6 (API 5, 7 and 11) or 10 (API 1). Most of the inorganic carbon incorporated into groundwater beneath the refinery originated from biodegradation in the unsaturated soil, which contained a microbiota (106 cells/g on average) capable of growth with most of the pure (benzene, toluene, ethylbenzene and xylene) and mixed hydrocarbons tested (diesel oil, gasoline, naphtha, condensate, aromatic residue and fuel oil). A viscous hydrocarbon paste uncovered in API 1 was insoluble in water but dissolved in dichloromethane. Many organic components of this paste were biodegradable as evidenced by weight reduction of the hydrocarbon paste and by the growth of suspended and attached biomass in saturated zone microcosms, where the paste was the only carbon source. This study indicates that monitored natural attenuation may be a technically feasible and efficient means for plume control in API 1, 4 and 5, provided the plumes in API 4 and 5 are not expanding. This technique is not suitable for contaminant reduction in API 11.  相似文献   
312.
Herein, a novel direct Z-scheme photocatalyst was accomplished by hybridization of 0D MoS2 quantum dots (MSQDs) and 3D honeycomb-like conjugated triazine polymers (CTP) (namely, CTP-MSQD). The unique 0D/3D hierarchical structure significantly enhanced the exposure of active sites and light harvesting property, while the formed p-n junction enabled the direct strong interface coupling without the necessity of any mediators. The optimized CTP-MSQD3 exhibited continuously increased visible-light-driven photocatalytic activity and strong durability both in Cr(VI) reduction and H2 evolution, featured a rate of 0.069 min−1 and 1070 µmol/(hr∙g), respectively, which were 8 times than those of pure 3D-CTP (0.009 min−1 and 129 µmol/(hr∙g)). We believe that this work provides a promising photocatalyst system that combines a 0D/3D hierarchical structure and a Z-scheme charge flow for efficient and stable photocatalytic conversion.  相似文献   
313.
扁挤压筒受力的有限元分析及试验   总被引:1,自引:0,他引:1  
对 8 5 0mm× 2 5 0mm扁挤压筒 ,采用双层预应力结构模型 ,模型尺寸按实际尺寸的 1/10设计 ,用有限元方法进行受力分析 ,并进行了模拟试验 ,得到的结果与实际情况基本一致 ,为进一步对扁挤压筒结构的优化设计提供了依据。  相似文献   
314.
为研究持久性有机污染物(POPs)的长距离传输和边远山区POPs的区域分布与来源,于2005年10月—2008年4月在四川西部山区的卧龙自然保护区内沿巴朗山迎风坡1个海拔梯度(1 242~4 475 m)采集表层土壤和大气被动采样样品.对色谱-高分辨质谱(GC-HRMS)的数据分析表明,在卧龙山区2 800 m以上的高海拔地区,土壤和大气中HCB,HCHs和DDTs具有浓度低、分布均匀的特点,这可归因于大气长距离传输的贡献;在有人居住和活动的地区,也观测到HCHs和DDTs的浓度异常和污染情况.通过对有机氯污染物浓度水平、相对化学组成、浓度空间分布特征和季节变化等情况的综合分析,可以区分大气长距离传输和局地污染源排放2种源贡献.大气被动采样技术能够提供边远山区有机氯污染物大气浓度水平和时空分布的信息. 结合大气和土壤的现场数据,可以综合观测和表征山区环境有机氯污染物的浓度异常现象.   相似文献   
315.
危险废物管理区域决策支持系统的研究与开发   总被引:9,自引:0,他引:9  
在系统分析危险废物管理系统和环境信息系统发展现状与趋势的基础上,讨论了中国危险废物管理区域决策支持系统的设计原则并进行了系统分析与设计。研究采用将系统分化为子系统的设计方法,可以更方便的增加信息,增加功能,保证系统的可持续发展性。该区域决策支持系统的设计方法和结构框架对其他环境信息系统开发与设计具有借鉴意义。  相似文献   
316.
采用取条法和化学浸蚀法相结合对不锈钢 /铝 (铝合金 ) /不锈钢多层复合板的残余应力值进行了测量。结果表明外层不锈钢受到长度和宽度方向的残余拉应力作用 ,随着轧制复合变形量的增加 ,多层复合板的残余应力值会逐渐增大。此外还通过热 力耦合的弹塑性有限元法对不锈钢 /铝 (铝合金 ) /不锈钢多层复合板的残余应力场进行了模拟仿真 ,并将模拟结果与试验测量值进行了分析和对比。  相似文献   
317.
采取荧光定量PCR技术及ELISA酶联免疫吸附法,以mcyD基因和PC-IGS基因为靶基因对夏季蓝藻暴发期间海河天津市区段的产毒微囊藻种群丰度和毒素含量进行了研究.结果表明:夏季海河天津市区段微囊藻种群丰度具有明显差异性:产毒微囊藻种群丰度为1.16×104~2.48×107copies/mL占总微囊藻种群的4.25%~28.59%.藻毒素含量最高点为8号采样点天津站,每升水体中藻细胞共含毒素195.51μg,除去藻细胞水中毒素浓度为0.97μg/L.总的来说,海河天津市区段微囊藻总基因拷贝数较高,产毒微囊藻丰度在不同采样点间差异较大,影响水体中微囊藻丰度的最主要环境因素是pH值.海河水体中毒素含量没有超过安全阈值,但是单位体积水体中藻细胞内毒素含量很高,具有较高的毒素释放潜力,可能对下游河口生态系统造成潜在威胁.  相似文献   
318.
工业废液中镍钴的回收及在锂离子电池正极材料中的应用   总被引:1,自引:0,他引:1  
邹正光  麦立强 《环境与开发》2000,15(4):31-32,34
探索了从废液中回收镍钴在空气气氛下合成锂离子电池正级材料LiNi2Co1-xO2的方法和工艺。结果表明,合成材料的充放电性能都比较好,LiNi0.3Co0.7O2在600℃6h-750℃16h时制得的产物初始充电容量达154.938mAh/g,接近用分析纯的镍钴原料合成的正级材料LiNi0.3Co0.7O2的首次充电容量(156.146mAh/g),采用镍钴废液合成锂离子电池正极材料,化害为利,经  相似文献   
319.
三层复合板的r值研究   总被引:1,自引:0,他引:1  
通过拉伸实验测试了不锈钢 /铝合金 /不锈钢三层复合板的厚向异性系数r,并分析了扩散退火对r值的影响及r值对板材成形性能的影响。分析表明 :扩散退火会降低r值和提高n值。用平均r值和rmin 来判断拉延危险断面的抗拉强度其误差在 6 %左右。  相似文献   
320.
A novel insight on the role of interactions between target pollutants and the catalyst in the copper-containing layered double oxide(LDO)-catalyzed persulfate(PS) system was elucidated in the present study.4-Chlorophenol(4-CP),as a representative benzene derivative with a hydroxyl group,was completely removed within 5 min,which was much faster than the reaction of monochlorobenzene(MCB) without a hydroxyl group,with the degradation efficiency of 31.7% in 240 min.Through the use of radical quench...  相似文献   
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