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101.
中国沿海地区台风灾害损失评估研究   总被引:4,自引:1,他引:3  
沿海地区作为人口积聚、国民经济和社会发展的重要区域和战略中心,在台风灾害中遭受的损失往往是惨重和致命的,所以亟待开展沿海地区台风灾害损失评估研究。根据1990-2007年的台风灾情资料,选取代表性指标尝试构建了台风灾情评估模型,并对沿海省市的台风灾害损失及其与致灾因子的关系进行分析评价。结果显示:除个别区域外,沿海地区台风灾害损失都呈下降趋势,但各区域下降的幅度不等,其中浙江省、江苏省和海南省下降幅度较低,均不足10%;浙江省、福建省和广东省18年间平均台风灾害损失较大;上海市以南各区域台风大风和暴雨的频次多、强度大,灾害损失大。  相似文献   
102.
Knowledge of the effects of climate factors on net primary production (NPP) is pivotal to understanding ecosystem processes in the terrestrial carbon cycle. Our goal was to evaluate four different categories of effects (physical, climatic, NDVI, and all effects[global]) as predictors of forest NPP in eastern China. We developed regression models with data from 221 NPP in eastern China and identified the best model with each of the four categories of effects. Models explained a large part of the variability in NPP, ranging from 46.8% in global model to 36.5% in NDVI model. In the most supported global model, winter temperature and sunshine duration negatively affected NPP, while winter precipitation positively affected NPP. Thus, winter climate conditions play an important role in modulating forest NPP of eastern China. Spring temperature had a positive affect on NPP, which was likely because a favorable warm climate in the early growing season promotes forest growth. Forest NPP was also negatively affected by summer and autumn temperatures, possibly because these are related to temperature induced drought stress. In the NDVI model, forest NPP was affected by NDVI in spring (positive), summer (negative) and winter (negative) seasons. Our study provides insight into seasonal effects of climate and NPP of forest in China, as well as useful knowledge for the development of climate-vegetation models.  相似文献   
103.
Researches on the removal of dicofol catalyzed by immobilized cellulase were conducted. Factors, such as acidity, temperature, enzyme activity, and initial concentration of dicofol, which could influence the removal were studied. The optimal pH for dicofol removal by immobilized cellulase was approximately 4–7, broader than that for free enzymes. The removal efficiencies for immobilized and free cellulase both decreased with increasing initial concentration of dicofol. The Km for immobilized cellulase was slightly lower than that of free cellulase, suggesting that substrate affinity may be enhanced by immobilization. The optimum temperatures for immobilized and free cellulase were 45 °C and 50 °C. The removal reaction for immobilized cellulase was found to be a first-order reaction. The activation energy was 64.3 kJ mol−1. The continuous oxidation of dicofol carried out in the static system of immobilized cellulase showed that the removal efficiency of immobilized cellulase remained after six cycles of operation. Thus, the catalytic efficiency of cellulase was improved greatly. As evidenced by infrared and gas chromatography–mass spectrometry data, the mechanism of reaction might involve an attack by the OH free radical of cellulase at a weak location of the dicofol molecule, resulting in the removal of three chlorine atoms from dicofol, thus oxygenizing dicofol and producing 4,4′-dichloro-dibenzophenone.  相似文献   
104.

Copper oxide nanoparticles (CuO NPs) have received considerable attention for their toxic effects on crops and potential application in agriculture. In order to investigate the biological effects of CuO NPs on plants, we exposed cucumber (Cucumis sativus) to two sizes of CuO NPs (510 nm, μCuO and 43 nm, nCuO). Results indicated that with concentration increased, the available Cu content in soil increased significantly. The addition of CuO NPs increased Cu content and other nutrient element (e.g., K, P, Mn, and Zn) content in plants. However, diverse particle sizes had different effects. The nCuO treatment had larger translocation factor, higher nutrient element content in fruits, and lower oxidative damage than μCuO treatment. Moreover, nCuO of 100 mg/kg could stimulate cucumber growth, while μCuO had no obvious effects on growth. Conclusively, CuO NPs could be used as copper fertilizer to supply copper to cucumber. The nCuO had better effects on improving the bioavailability of Cu and nutritional value of fruits. These results can help develop strategies for safe disposal of CuO NPs as agricultural fertilizer.

  相似文献   
105.
随着人类社会的进步,经济文明的发展,全球的环境问题日益严重,建设绿色的家园成为全世界人民的迫切愿望和各国政府的责任。我国作为一个发展大国,如何保护环境,解决环境污染问题,笔者认为解决环境问题的基本思路是首先政府要转变观念,通过立法、税收等强制性手段来保护环境,通过技术创新来解决环保中的技术问题,将环境污染的程度降到最低。  相似文献   
106.
季宗 《防灾博览》2005,(4):31-31
1976年7月28日唐山7.8级地震时,在极震区(烈度Ⅺ)内有许多平房居民,来不及跑出屋外,避于炕前,依赖炕墙的掩蔽得以生存。他们亲身体验到:炕前避震,简单易行,快速有效.是个人临震应急良策。以下是几位幸存者的自述。  相似文献   
107.
The disposal, recycling, and part salvaging of discarded electronic devices such as computers, printers, televisions, and toys are now creating a new set of waste problems. This study is aimed at identifying the sources and quantifying the pollution levels generated from electronic waste (e-waste) activities at Guiyu, Guangdong Province, China, and their potential impacts on the environment and human health. The preliminary results indicate that total polycyclic aromatic hydrocarbons (PAHs) in soil obtained from a printer roller dump site was 593 μg/kg dry weight (dry wt.) and in sediment from a duck pond, the PAH concentration was 514 μg/kg (dry wt.). Sediment from the Lianjiang River was found to be contaminated by polychlorinated biphenyls (743 μg/kg) at a level approaching three times the Canadian Environmental Quality Guidelines probable effect level of 277 μg/kg. Total mono- to hepta-brominated diphenyl ether homologue concentrations (1140 and 1169 μg/kg dry wt.) in soils near dumping sites were approximately 10–60 times those reported for other polybrominated diphenyl ether-contaminated locations in the world. In-house study on the open burning of cable wires showed extremely high levels of polychlorinated dibenzo-p-dioxins and dibenzofurans resulting in 12419 ng toxic equivalents (TEQ)/kg of waste input and 15 610 ng TEQ/kg for two separate tests, respectively, which were about three orders of magnitude higher than those for the open burning of household waste. High levels of Cu (712, 528, and 496 mg/kg), exceeding the new Dutch list action value, were determined for soil near the printer roller dumping area, sediment from Lianjiang River, and soil from a plastic burn site, respectively. A more thorough study is underway to elucidate the extent of contamination of toxic pollutants in different ecological compartments to establish whether these pollutants are bioaccumulated and biomagnified through food chains. Assessments of human health impacts from oral intake, inhalation, and dermal contact will be subsequently investigated. An erratum to this article is available at.  相似文献   
108.
针对故障仿真预测技术的现状和发展,分析了ADAMS仿真平台和专家系统的优缺点.根据自行火炮系统结构的特殊性,提出基于ADAMS(Automatic Dynamic Analysis Mechanical System)仿真平台和专家系统的故障仿真系统的建模方法和设计思想.仿真过程根据用户输入的初始状态真实体现出系统在服役状态的量变,产生动态模糊关系矩阵,并由动态模糊综合评判得到系统可能出现的故障,由预测结果调用知识库中的诊断知识产生实际发生的故障部件.这样建立的仿真模型不仅能表达领域对象的动态属性、行为特性,又能表达专家的经验、判断决策等知识,还具备较强的数值计算及过程控制能力.  相似文献   
109.
辽宁省产业结构对环境影响的初探   总被引:1,自引:0,他引:1  
产业结构影响着一个地区社会经济以及环境等诸多方面。本文对辽宁省产业结构现状,主要行业产值及污染贡献率,以及产业结构调整对污染物排放强度变化影响进行剖析,较系统地分析了一个地区的产业结构对环境的影响,对环境管理及经济建设具有一定的借鉴意义。  相似文献   
110.
采用介质阻挡强电离放电技术制取高浓度臭氧 ,使用射流器和气液溶解分离器溶解臭氧制取高浓度臭氧水。讨论了应用臭氧量、气液比、系统压力和气液溶解方式对臭氧水浓度和臭氧有效溶解效率的影响  相似文献   
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