全文获取类型
收费全文 | 1307篇 |
免费 | 30篇 |
国内免费 | 36篇 |
专业分类
安全科学 | 73篇 |
废物处理 | 3篇 |
环保管理 | 307篇 |
综合类 | 504篇 |
基础理论 | 201篇 |
环境理论 | 1篇 |
污染及防治 | 78篇 |
评价与监测 | 140篇 |
社会与环境 | 50篇 |
灾害及防治 | 16篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 12篇 |
2021年 | 30篇 |
2020年 | 58篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 33篇 |
2016年 | 43篇 |
2015年 | 31篇 |
2014年 | 55篇 |
2013年 | 49篇 |
2012年 | 45篇 |
2011年 | 84篇 |
2010年 | 49篇 |
2009年 | 102篇 |
2008年 | 80篇 |
2007年 | 78篇 |
2006年 | 72篇 |
2005年 | 50篇 |
2004年 | 41篇 |
2003年 | 60篇 |
2002年 | 47篇 |
2001年 | 34篇 |
2000年 | 46篇 |
1999年 | 40篇 |
1998年 | 28篇 |
1997年 | 18篇 |
1996年 | 17篇 |
1995年 | 22篇 |
1994年 | 13篇 |
1993年 | 20篇 |
1992年 | 16篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有1373条查询结果,搜索用时 46 毫秒
711.
712.
黄玉源 《环境与可持续发展》2015,(4)
本文基于第一线调研和多年参政议政工作基础上,对珠三角区域的城市工业生态经济战略实施的过程、途径,可行性、原理及获得的重大效益进行了介绍与总结分析。研究指出,在实践过程中为更快更大规模地把生态经济战略与各地实际发展进程相结合加以推广和实施,则必须具备高度的社会责任感,勇于运用各种机会把生态经济的战略思路和实施策略很好地向社会各层面以及政府部门反映和建言,才能取得最好及更大的成效。 相似文献
713.
The flash point is one of the most important physicochemical parameters used to characterize the fire and explosion hazard for flammable liquids. The flash points of ternary miscible mixtures with different components and compositions were measured in this study. Four model input parameters, being normal boiling point, the standard enthalpy of vaporization, the average number of carbon atoms and the stoichiometric concentration of the gas phase for mixtures, were employed and calculated based on the theory of vapor–liquid equilibrium. Both multiple linear regression (MLR) and multiple nonlinear regression (MNR) methods were applied to develop prediction models for the flash points of ternary miscible mixtures. The developed predictive models were validated using data measured experimentally as well as taking data on flash points of ternairy mixtures from the literature. Results showed that the obtained average absolute error of both the MLR and the MNR model for all the datasets were within the range of experimental error of flash point measurements. It is shown that the presented models can be effectively used to predict the flash points of ternary mixtures with only some common physicochemical parameters. 相似文献
714.
The different toxicity characteristics of arsenic species result in discrepant ecological risk. The predicted no-effect concentrations (PNECs) 43.65, 250.18, and 2.00 × 103 μg/L were calculated for As(III), As(V), and dimethylarsinic acid in aqueous phase, respectively. With these PNECs, the ecological risk from arsenic species in Pearl River Delta in China and Kwabrafo stream in Ghana was evaluated. It was found that the risk from As(III) and As(V) in the samples from Pearl River Delta was low, while much high in Kwabrafo stream. This study implies that ecological risk of arsenic should be evaluated basing on its species. 相似文献
715.
Influence evaluation of ionic liquids on the alteration of nitrification waste for thermal stability
Nitrification waste (NW) is the processed product of nitro compounds, flammable and explosive, and is prone to accidents due to thermal runaway. Ionic liquids (ILs) are widely used as flame retardants and have a good inhibitory effect. The effect of 1-butyl-3-methylimidazole hexafluorophosphate and 1-butyl-3-methylimidazole tetrafluoroborate as humectants on the thermal stability of NW was investigated in this paper. The microstructure and properties of the ionic liquid hybrid NW were first investigated using scanning electron microscopy. Secondly, thermogravimetric experiments were carried out on the ionic liquid mixed NW by thermogravimetric-infrared spectroscopy to analyze the decomposition law. Finally, six advanced linear regression thermokinetic models were used to calculate its apparent activation energy, pre-exponential factor, and other thermokinetic parameters, and the reaction model was simulated through multiple linear regression. The experimental research results in this paper can provide a reference for the storage and disposal of nitro compounds and their wastes. 相似文献
716.
陈秀梅 《环境监测管理与技术》2023,(4):72-75
运用相关性分析、因子分析及多元线性回归模型对南通市2020—2021年15个监测井第Ⅲ承压层地下水的监测数据进行分析,研究深层地下水中氨氮的主要影响因素。结果表明,氨氮的主要来源是地下水沉积物中有机质的矿化及一部分工业开采引入的氮污染,地下水的还原性环境是氨氮赋存的主要成因;地下水中As、Fe及总硬度含量的同时增加也能反映氨氮含量的提高;硝态氮(NO-3-N)与NH3-N在深层地下水中是竞争关系,当地下水环境处于还原性时,更易于NH3-N的富集。降低深层地下水中氨氮的主要方法是减少有机污染物输入及还原性废水的入渗。 相似文献
717.
生态足迹方法在中国应用的案例初探 总被引:3,自引:0,他引:3
生态足迹方法通过估算维持人类生存的自然资源消费量和同化人类产生的废弃物所需要的生态性生产空间面积大小,并与给定人口区域的生态承载力进行比较,衡量区域的可持续发展状况。本文介绍了生态足迹模型的理论依据和计算方法,从模型方法应用范围,计算所需资料和模型自身三方面分析了生态足迹方法在我国应用中存在的问题和方法本身的不足。详细分析和比较了生态足迹方法在我国不同省市及地区的应用案例,结果表明,经济比较发达地区很大程度上需要通过地区贸易从不发达地区输入生态足迹,因而加重了不发达地区的生态负担。 相似文献
718.
This paper presents the main results of two studies of contrasting natural and man-induced conditions along the Pacific coast
of Baja California (Mexico), based on the assumption that ecological insight can be obtained from man-induced modifications
insofar as relevant activities are explicitly addressed as parts of the systems under study. The study is concerned with a
fragmented coastal succulent-sage scrub and showed that several patches of different size and age may harbor as many species
as non-fragmented areas, and that 83% of the original species assemblage persisted in the fragments, in which the invasion
by opportunistic exotic species may not progress beyond certain limits. The study of dune-backed and urban-backed beaches
showed a significantly greater abundance of the Snowy Plover (Charadrius alexandrinus) at the dune-backed beach, where a much more active back-shore feeding of adult birds and the only evidences of breeding
occurred. Both studies refer to landscape features of regional concern and its results may be used in conservation management.
The results on fragmented coastal succulentsage scrub may encourage alternative urban designs that keep patches of the original
landscape, thus meeting existing requirements of low density urban development for most of the coastal succulent-sage scrub
area. The evidence presented on the negative effects of dune destruction on the abundance, feeding and reproductive performance
of a threatened bird species has a bearing on the topic of biodiversity management. It may also contribute to the conservation
of the coastal dunes system. 相似文献
719.
The simplicity of many bioeconomic models has been criticised several times, due to their lack of realism resulting from a deterministic nature and a single-species focus. In this context it was interesting to test the financial sensitivity of bioeconomic modelling against fairly well documented ecological effects in mixed forests. For this purpose our study linked existing results of ecological research with bioeconomic modelling. The presented methodological approach could not only show the importance of considering ecological effects in bioeconomic models; it in fact enabled prioritising ecological research from a financial point of view.In a first step, the possible influence of the tree species mixture on forest stand resistance, productivity and timber quality was derived from existing studies. In a second step, the available Monte Carlo simulations for Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.), simulated under site conditions and risks typical of southern Germany, were extended by the mentioned ecological effects and then evaluated from a financial perspective.The results showed a clear influence of all tested ecological effects on the financial indicators, financial risk and return. While testing each ecological effect separately, an increased resistance against wind, snow and insect attacks had the greatest influence on financial risk and return. It over-proportionally enhanced the financial return while simultaneously the financial risk was reduced. In contrast, a degraded timber quality could eliminate the positive effect of risk compensation in mixed forests almost completely. The least influence on the financial indicators finally showed a changed volume growth in mixed forests.A combination of the separately tested ecological effects (increased resistance, changed volume growth and decreased timber quality), between both tree species, underlined the dominating importance of the stand resistance. The integration of ecological effects, induced by interdependent tree species, in our bioeconomic model resulted in significantly lower financial risk than ignoring these effects. Moreover, the financial return of mixed stand variants with a proportion of Norway spruce greater than 60% even exceeded that of the most profitable pure stand.In conclusion this paper clearly confirmed that ignoring ecological effects in bioeconomic models could lead to seriously biased financial results. While a changed volume growth proved rather to be of minor importance for European beech/Norway spruce stands, tree resistance and timber quality may change the financial results significantly. 相似文献
720.