全文获取类型
收费全文 | 1063篇 |
免费 | 222篇 |
国内免费 | 14篇 |
专业分类
安全科学 | 154篇 |
废物处理 | 10篇 |
环保管理 | 126篇 |
综合类 | 685篇 |
基础理论 | 133篇 |
污染及防治 | 70篇 |
评价与监测 | 16篇 |
社会与环境 | 85篇 |
灾害及防治 | 20篇 |
出版年
2025年 | 24篇 |
2024年 | 65篇 |
2023年 | 62篇 |
2022年 | 56篇 |
2021年 | 36篇 |
2020年 | 36篇 |
2019年 | 57篇 |
2018年 | 41篇 |
2017年 | 44篇 |
2016年 | 53篇 |
2015年 | 57篇 |
2014年 | 71篇 |
2013年 | 100篇 |
2012年 | 75篇 |
2011年 | 87篇 |
2010年 | 81篇 |
2009年 | 48篇 |
2008年 | 29篇 |
2007年 | 43篇 |
2006年 | 30篇 |
2005年 | 34篇 |
2004年 | 28篇 |
2003年 | 35篇 |
2002年 | 21篇 |
2001年 | 13篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 12篇 |
1997年 | 5篇 |
1995年 | 8篇 |
1994年 | 1篇 |
1993年 | 6篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有1299条查询结果,搜索用时 15 毫秒
101.
Small body size is generally correlated with r‐selected life‐history traits, including early maturation, short‐generation times, and rapid growth rates, that result in high population turnover and a reduced risk of extinction. Unlike other classes of vertebrates, however, small freshwater fishes appear to have an equal or greater risk of extinction than large fishes. We explored whether particular traits explain the International Union for Conservation of Nature (IUCN) Red List conservation status of small‐bodied freshwater fishes from 4 temperate river basins: Murray‐Darling, Australia; Danube, Europe; Mississippi‐Missouri, North America; and the Rio Grande, North America. Twenty‐three ecological and life‐history traits were collated for all 171 freshwater fishes of ≤120 mm total length. We used generalized linear mixed‐effects models to assess which combination of the 23 traits best explained whether a species was threatened or not threatened. We used the best models to predict the probability of 29 unclassified species being listed as threatened. With and without controlling for phylogeny at the family level, small body size—among small‐bodied species—was the most influential trait correlated with threatened species listings. The k‐folds cross‐validation demonstrated that body size and a random effect structure that included family predicted the threat status with an accuracy of 78% (SE 0.5). We identified 10 species likely to be threatened that are not listed as such on the IUCN Red List. Small body size is not a trait that provides universal resistance to extinction, particularly for vertebrates inhabiting environments affected by extreme habitat loss and fragmentation. We hypothesize that this is because small‐bodied species have smaller home ranges, lower dispersal capabilities, and heightened ecological specialization relative to larger vertebrates. Trait data and further model development are needed to predict the IUCN conservation status of the over 11,000 unclassified freshwater fishes, especially those under threat from proposed dam construction in the world's most biodiverse river basins. 相似文献
102.
矿用柴油重卡因工作任务量大和工作环境恶劣,导致其碳排放量巨大。从使用矿用柴油重卡的企业角度出发,采用全生命周期法,理清了矿用柴油重卡全生命周期各个阶段的碳排放量及影响碳排放的因素,建立了矿用柴油重卡碳核算模型。以内蒙古某煤矿4种柴油重卡为案例,对矿用柴油重卡全生命周期碳排放量进行了核算,分析了核算结果,并从车辆重量与经济性角度,分析比较了几种车辆的单位重量排放量和单位价格排放量。结果表明:矿用柴油重卡全生命周期碳排放量由车辆重量和燃料消耗量共同作用,其中燃料消耗量占绝大比重。综合考虑节能减排和经济性,重量为156 t和85 t的车辆是最佳选择,煤矿企业可适当提高该类车辆的占比。在保证工作量的情况下,将138 t和65 t车辆代替为156 t和85 t的车辆,全生命周期内可减少1.275×105 t 的碳排放量,节省9 936.704 万元的花费。本研究结果可为重卡企业开展节能减排工作提供参考。 相似文献
103.
在我国生活垃圾分类和“无废城市”建设持续推进背景下,餐厨垃圾收运与处置利用一体化成为了城市固废资源化产业链的重要环节。本研究以天津市为例,利用地理信息系统(ArcGIS)空间分析天津市餐饮垃圾产排特征,通过实地调研获得收运方式信息并归纳出4条处理技术路线,分别是高温发酵、焚烧发电、单独厌氧以及协同厌氧,并采用生命周期评价方法(LCA)选取6种影响类型为评价指标对餐厨垃圾收运及处置一体化模式进行了环境影响评价。结果显示,4条技术路线均具有环境效益,净环境影响潜力由低到高分别是高温发酵路线(−0.030 8)、协同厌氧路线(−0.029 9)、单独厌氧路线(−0.024 5)、焚烧发电路线(−0.005 7)。敏感性分析表明,提高餐厨垃圾提油率,减少收运距离均能降低环境影响潜力,优化三相分离技术提高提油率是一种更加可行高效的方式。 相似文献
104.
Methods for life cycle assessment of products (LCA) are most often based on the general prevention principle, as opposed to the risk minimization principle. Here, the desirability and feasibility of a combined approach are discussed, along with the conditions for elaboration in the framework of LCA methodology, and the consequences for LCA practice. A combined approach provides a separate assessment of above and below threshold pollution, offering the possibility to combat above threshold impacts with priority. Spatial differentiation in fate, exposure, and effect modelling is identified to play a central role in the implementation. The collection of region-specific data turns out to be the most elaborate requirement for the implementation in both methodology and practice. A methodological framework for the construction of characterization factors is provided. Along with spatial differentiation of existing parameters, two newly introduced spatial parameters play a key role: the sensitivity factor and the threshold factor. The practicability of the proposed procedure is illustrated by an example of its application. Providing a reasonable data availability, the development of separate LCA characterization factors for the respective assessment of pollution levels above and below environmental threshold values seems to be a feasible task that may add to LCA credibility. 相似文献
105.
K.M.S. Sundaram A. Sundaram B.D. Hammock 《Journal of environmental science and health. Part. B》2013,48(5):999-1052
Abstract A commercial formulation of Bacillus thuringiensis Berliner var. kurstaki (BTK), Foray® 48B, was sprayed aerially over four blocks B13, B14, B15A and B15B in an oak forest in Wayne County, Pennsylvania during May 1990. B13 and B14 were sprayed at 75 billion international units (BIU) in 5.91 litres/ha and the other two at 50 BIU in 3.94 litres/ha. Oak foliage was collected at different intervals of time after treatment. Three types of bioassays were conducted against fourth instar gypsy moth larvae, viz., direct feeding of sprayed foliage, feeding on diet containing homogenized foliage, and force‐feeding of foliar extracts. Larval mortalities were converted into international units of BTK activity per unit area (IU/cm2) of foliage. Foliar extracts were also subjected to enzyme‐linked immunosorbent assay (ELISA) to determine the concentration of delta‐endotoxin protein. Regardless of the type of bioassay used, bioactivity of BTK persisted in foliage for about a week in all the blocks. The half‐life of inactivation, DT50, ranged from ca 12 to 22 h. The immunoassay data indicated a shorter duration of persistence (i.e., about 2 d) of the delta‐endotoxin protein, with DT50 values ranging from 10 to 15 h. Formulation ingredients present in Foray 48B played a role in the toxicity of BTK to gypsy moth larvae. 相似文献
106.
Traditionally in toxicological studies time is not studied as quantifiable variable but as a fixed endpoint. The Reduced Life Expectancy (RLE) model which relates exposure time and exposure concentration with lethal toxic effects was tested previously using fish data. In this current paper the effects of exposure time on aquatic toxicity with zooplanktons and various toxicants were evaluated using the RLE model based on ambient exposure concentration. The model was evaluated by plotting ln LT50 against LC50 using toxicity data with zooplanktons from the literature for metal, metalloid and organic compounds. Most of the experimental data sets can be satisfactorily correlated by use of the RLE model, but deviations occurred for some data sets. Those data sets were satisfactorily fitted by a two stage RLE model. This model was based on two phases: one in the peripheral system and other in the central system. Both the single and two stage RLE model support the hypothesis that toxicity is time dependent and decreases in a systematic way with increasing exposure time. A calculated normal life expectancy (NLT) can be obtained from the single stage model and is in accord with reported NLT but those obtained from the two stage RLE model are in excellent agreement. 相似文献
107.
本文论述了我国发泡PS餐盒及其替代品的发展状况和国内外的相关政策 ,采用生命周期评价的方法 ,讨论了从原料开采、生产加工、使用 ,到回收或废弃全过程不同产品的环境负荷 ,指出简单替代并不能真正解决污染问题 ,而PS餐盒的回收再利用更有益于治理白色污染和保护环境 相似文献
108.
运用生命周期评价方法,应用Gabi5.0软件对采用循环流化床锅炉燃煤技术的热电企业进行资源耗竭和环境影响分析,计算各生产单元生命周期清单的全球变暖潜值、酸化效应潜值、富营养化潜值、非生物资源耗竭潜值、人体毒性潜值以及光化学烟雾和臭氧生成潜值等主要环境影响类型,对燃煤发电过程进行生命周期评价。结果表明,全球变暖和非生物资源耗竭为发电运行过程中主要的环境影响因素,分别占53%和15.05%;锅炉燃烧阶段的环境影响最重,占整个生命周期影响值的77.12%,并且除生物耗竭潜值外的其他5项指标均为发电运行阶段各个单元中最高。采用SNCR脱硝技术减少燃烧过程中NOx的排放量,并对该技术方案进行生命周期评价,比较方案实施前后的环境影响。 相似文献
109.
集中收集和跨区域转运制度确立了我国铅酸蓄电池生产者责任延伸制 (EPR) 的实施路径。在危险废物管理框架下,集中收集和跨区域转运改变了废铅酸蓄电池的物质流过程,与之相关的资源环境效应变化也成为当前的重要研究课题。以贵州省为例,基于实地调研和系统模拟,采用物质流分析和生命周期评价方法分析了废铅酸蓄电池的产生特征、物质流过程和碳减排效益。结果表明,在集中收集与跨区域转运制度实施前,83.3%的废铅酸蓄电池进入再生铅企业,16.7%流入非正规处理企业,回收处理1 t废铅酸蓄电池的碳减排效益为923.1 kgCO2eq。开展情景分析发现,相对于无政策驱动的基准情景,集中收集和跨区域转运优化情景均能提升废铅酸蓄电池进入正规回收处理企业的比例,且碳减排效益分别提高到994.44和953.53 kgCO2eq∙t−1。这表明,基于EPR政策驱动的系统情景具有环境正效应,可作为当前废铅酸蓄电池回收处理系统完善和政策优化的方向。 相似文献
110.
化工废盐的资源化处理是化工行业实现可持续发展的重要环节,对于减少环境污染以及固体废物的再生利用具有重要意义。通过生命周期评价(LCA)方法,对化工废盐的热解脱碳-结晶分盐组合工艺进行全面的环境影响评估,以期为化工废盐的资源化及碳减排策略提供科学依据和实践指导。为此,运用GaBi 10软件和CML 2001评价体系,构建了全生命周期评价框架,分析涵盖10项环境影响指标。环境影响评估结果表明,单次工艺运行全球变暖潜势指标为1.76×102 kg (以CO2计),热解和蒸发结晶阶段对环境的影响最为显著,在总影响中占比为60%以上。敏感性分析结果表明,第1次蒸发结晶的电力消耗是决定生命周期评价结果的关键因素。通过工艺流程优化,尤其是减少关键能耗阶段的耗电量,可实现环境污染和碳排放的有效降低。以上研究结果表明,热解脱碳-结晶分盐工艺是一种成熟、高效的技术路径,可有效促进废盐资源化,符合环保和可持续发展要求,对化工行业绿色转型及全球气候变化应对具有重要意义。 相似文献