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21.
采用强制放电技术,通过对东北制药总厂部分车间的废炭进行吸附能力恢复试验,找出一种废炭再生方法.此工艺简单、易于操作,所需人员少,吸附能力恢复率400%以上,每千克炭能耗2.5kW/h,再生温度850℃.  相似文献   
22.
本文介绍了测定土壤中碘的淀粉显色分光光度法。该法操作简便、快速、准确、容易掌握。平均回收率为100.5%,标准偏差为0.3mg kg~(-1),变异系数为4.8%(n=5)。  相似文献   
23.
碘是人体必需的微量元素之一,高碘或低碘均能引起人类或动物的各种疾病。对天津东部地区水土环境中碘地球化学特征及成因进行了研究,结果表明,研究区表层土壤碘含量变化范围是0.89~17.09 mg/kg,平均为5.11 mg/kg,是天津市背景值的1.92倍,是全国背景值的1.36倍。深层土壤碘含量在0.64~34.55 mg/kg之间,平均为10.73 mg/kg,是天津市深层土壤基准值的3.93倍,是研究区表层土壤的2.1倍,研究区表层和深层土壤碘均处于富集状态。表层土壤碘高背景区分布面积较大,主要集中分布在东丽区、宁河区南部、滨海新区北部。浅层地下水碘含量范围在0.03~4.00 mg/L之间,平均为0.56mg/L,高碘地下水分布面积较大,主要分布在东丽区、津南区、宁河区南部、滨海新区(除去西南部)。研究区历史上海陆交互作用强烈,海水提供的大量碘物质在此残留富集,可能是造成水土环境中碘元素整体偏高的自然原因。  相似文献   
24.
珠三角新会地区表层土壤硒、氟、碘地球化学特征研究   总被引:1,自引:0,他引:1  
以珠江三角洲新会地区西江、潭江下游的三江、睦州、古井三镇土壤为主要研究对象,测试分析所采集的1 567件表层土壤样品全氮(N)、有机碳(Org.C)、pH等理化指标和二氧化硅(SiO_2)、三氧化二铝(Al_2O_3)、硒(Se)、氟(F)、碘(I) 5种元素组分含量,以及60件稻谷样的硒(Se)含量。重点探讨了研究区Se、F、I的含量、分布及其影响因素等地球化学特征。结果表明,研究区土壤呈现强酸性-酸性,Se、F、I的含量均值分别为0. 50 mg/kg、617. 39 mg/kg、3. 57 mg/kg,Se、F高于全国土壤背景值,I低于全国土壤背景值; Se、F、I均与Al_2O_3、Org.C以及pH相关,F与Se不相关,F与I负相关。Se、F、I的含量、分布等地球化学特征受地层控制:不同成土母质中,基岩区和花岗岩区Se、I含量较高;第四纪沉积区F含量较高。推测Se和I主要源于燕山期的火山活动,F主要源于三角洲的沉积作用。总体上研究区土壤呈现足硒、富硒,碘适量,氟过剩的特征,稻谷富硒率也高,具备开发天然富硒农产品的条件。  相似文献   
25.
本文探讨了离子色谱法分析海苔食品中的碘含量的分析方法,采用戴安IGC-1500型,RFC-30淋洗液发生器,直接电导检测(电位:0.15V),对海苔进行定性,定量分析。该方法相对标准偏差RSD<0.8%(n=8),碘的回收率在94.0%~106.7%之间。方法简便、快速。  相似文献   
26.
The fate of exogenous iodine in pot soil cultivated with vegetables   总被引:1,自引:0,他引:1  
A pot experiment was conducted to explore a more effective approach to enhancing vegetable uptake of soil iodine, with the ultimate goal of using agricultural fortification as a measure to prevent iodine deficiency disorders in local communities. Two types of iodine fertilizers were added separately to pot soil samples at various dosages. The fortified soil in each of the flower pots was seeded with one of four test crops (pakchoi, celery, pepper, and radish) in an effort to examine the effect of vegetable cultivation. The fate and residual levels of the exogenous iodine in the fortified soil samples were then monitored and quantified. The data showed that the soil iodine contents decreased with time (and hence with plant growth as well). At the second cutting, iodine from the inorganic form (KI) as the exogenous source was reduced to approximately 50% (41.6–61.0%) of the applied dose, whereas that in soil fortified with the seaweed fertilizer was down to approximately 60% (53.9–71.5%). The abilities of the edible portion of the four vegetables in accumulating the soil iodine were as follows: pakchoi > celery > radish > pepper. On the whole, iodine residues were found less in soil cultivated with vegetables. Vegetable cultivation appeared to have enhanced the soil content of the water-soluble form of iodine somewhat, especially in soil fortified with the inorganic forms. There also appeared to be a significant negative correlation between the residual iodine and its dissolution rate in soil. Overall, the results of the present study pointed toward the direction that the seaweed fertilizer tends to be a (more) preferred source of agricultural fortification in promoting human iodine nutrition.  相似文献   
27.
This paper attempts to discuss the links between the geochemical composition of rocks and minerals and the geographical distribution of diseases in human beings in Nigeria. We know that the natural composition of elements in our environment (in the bedrock, soils, water, and vegetation) may be the major cause of enrichment or depletion in these elements and may become a direct risk to human health. Similarly, anthropogenic activities such as mining and mineral processes, industrial waste disposal, agriculture, etc., could distort the natural geochemical equilibrium of the environment. Thus, the enrichment or depletion of geochemical elements in the environment are controlled either by natural and/or anthropogenic processes. The increased ingestion of toxic trace elements such as As, Cd, Hg, Pb, and F, whether directly or indirectly, adversely affects human health. Of these, Cd has most dangerous long-term effect on human health. Environmental exposure to As and Hg is a causal factor in human carcinogenesis and numerous cancer health disorders. Available information on iodine deficiency disorder (IDD) in Nigeria indicates goiter prevalence rates of between 15% and 59% in several affected areas. There have been reported cases of dental fluorosis resulting from intake of water with fluoride content >1.5 ppm. Dental caries among children shows an overall prevalence rate of 39.9%. Within the Younger Granite province in central Nigeria, cases of cancer and miscarriages in pregnant women have been linked to natural radiation These examples and a number of others from the existing literature underscore the pressing need for the development of collaborative research to increase our understanding of the relationship between the geographical distribution of human and animal diseases in Nigeria and environmental factors. We submit that such knowledge is essential for the control and management of these diseases.  相似文献   
28.
Natural organic matter, such as humic and fulvic acids and humin, plays a key role in determining the fate and mobility of radioiodine in soil and sediments. The radioisotope 129I is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter.Due to its long half-life (15.7 million years), 129I builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of 129I and 127I chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine bound to humic acid, fulvic acid and to humin and minerals. This is the first study to identify 129I in humic and fulvic acid and humin. The results show that 30-56% of the total 127I and 42-60% of the total 129I are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0-5.5, 127I and 129I in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 129I was mostly found to be bound to fulvic acid. Anoxic conditions seem to increase the mobility and availability of iodine compared to oxic, while subaerial conditions (soils) reduces the availability of water soluble fraction compared to subaqueous (marine) conditions.  相似文献   
29.
李建华 《火灾科学》1999,8(2):14-20
对四种同脂发热自燃性进行了试验研究,采用回归分析方法,建立了环境温度与油脂发热诱导期之间的定量关系式,即lgT/a/t+b,提出油脂自燃性能可用a和b两参数描述。研究表明,碘值与油脂自燃性能常数a和b存在密切关系,可分别用对数和直线方程表示。  相似文献   
30.
Sri Lanka provides an ideal opportunity for the study of the effect of geology on human health. The vast majority of the people of Sri Lanka still live in rural areas within areas termed geochemical provinces. Very broadly, one could say that a geochemical province has characteristic chemical composition in soil, water stream sediments and rocks, enabling their delineation from others. The chemical composition is presumed to be have an impact on the health of the inhabitants of the particular geochemical province, particularly because of the fact that their food and water are obtained mostly from the terrain itself. This leads to the concept of “diseases of geochemical origin”. Among these are dental fluorosis, iodine deficiency disorders (IDDs) and selenium-based diseases. The Dry Zone of Sri Lanka has several areas rich in groundwater fluoride, the ingestion of which leads to dental fluorosis. Iodine deficiency diseases are more common in the Wet Zone, though their aetiologies are more complicated. Interestingly, it has also been observed that significant proportions of the female population of Sri Lanka are selenium-deficient, which could well be related to the geological environment. Chronic renal failure (CRF) has been observed in some areas of the Dry Zone of Sri Lanka, where there is a relationship of CRF with the mineral content of drinking water. This subject matter falls under the auspices of Medical Geology, a scientific discipline still in its infancy, and much more concerted studies are needed to attract the attention of medical research.  相似文献   
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