全文获取类型
收费全文 | 744篇 |
免费 | 37篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 42篇 |
废物处理 | 121篇 |
环保管理 | 119篇 |
综合类 | 109篇 |
基础理论 | 175篇 |
环境理论 | 4篇 |
污染及防治 | 122篇 |
评价与监测 | 36篇 |
社会与环境 | 44篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 16篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 30篇 |
2017年 | 28篇 |
2016年 | 40篇 |
2015年 | 33篇 |
2014年 | 19篇 |
2013年 | 60篇 |
2012年 | 30篇 |
2011年 | 46篇 |
2010年 | 39篇 |
2009年 | 45篇 |
2008年 | 38篇 |
2007年 | 45篇 |
2006年 | 40篇 |
2005年 | 27篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1986年 | 6篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1961年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1957年 | 5篇 |
1955年 | 5篇 |
1954年 | 2篇 |
1940年 | 2篇 |
1937年 | 1篇 |
1934年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有785条查询结果,搜索用时 421 毫秒
321.
Ingrid born Anna-Karin Modin-Edman Helena Bengtsson Gunnela M. Gustafson Eva Salomon S.Ingvar Nilsson Johan Holmqvist Simon Jonsson Harald Sverdrup 《Ambio-人类环境杂志》2005,34(4)
通过把全面的农田试验和矿质风化释放养分以及微量元素循环具体研究结合起来,用一个系统分析方法来评价农场尺度上的养分和微量元素可持续性.为了比较有机和常规农业管理方式,在瑞典北部的Ojebyn奶牛场进行了一个包括磷、钾和锌在内的农场尺度上的实例研究.通过结合不同的元素平衡法(农场总体尺度、畜舍尺度和农田尺度)以及进一步把这些方法应用到FARMFLOw模型,我们能够把子系统内质量流和库结合起来并建立子系统之间联系,来进行农场尺度上的预测.研究发现农场内部的元素流动大,而且农场有内部源(锌)和损失项(钾).在Ojebyn奶牛场形成并得到验证的方法是很有前途的,认为可以应用到任何农场. 相似文献
322.
323.
324.
325.
Bates MN Buckland SJ Garrett N Ellis H Needham LL Patterson DG Turner WE Russell DG 《Chemosphere》2004,54(10):1431-1443
Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and organochlorine pesticides were measured in the serum of a sample of the New Zealand population aged 15 years and older. This was the first study to obtain representative measures of PCDDs, PCDFs and PCBs in the adult population of an entire country. Serum samples were obtained in 1996-1997. Potentially occupationally exposed individuals were excluded. Serum samples were pooled according to stratification criteria for area of residence, ethnicity, age, and sex. Of the 80 possible strata, sufficient serum for chemical analysis was available for 60, to which 1,834 individual samples contributed. For the PCDDs and PCDFs, most 2,3,7,8-chlorinated congeners were measured in all strata, with a mean toxic equivalents concentration across all strata of 12.8 ng TEQ kg(-1) lipid. Seven PCB congeners were frequently measured, including the coplanar congeners #126 and #169, quantified in all strata. Of the pesticides and their metabolites, only beta-HCH, dieldrin and pp'-DDE were consistently detected across strata. There was a general trend of increasing concentration with age. There were no consistent differences between the sexes, or between people of Maori (the indigenous people of New Zealand) and non-Maori ethnicity. Concentrations of PCDDs and PCDFs tended to increase in a North-South direction, possibly reflecting greater levels of industrialization and population concentration, and concentrations of the pesticide products were highest in the South, possibly reflecting historical use patterns. Results were consistent with a recent study of concentrations of these compounds in the milk of first-time mothers. 相似文献
326.
An elemental analyzer in combination with stable isotope ratio mass spectrometry (EA-IRMS) was used to demonstrate that two samples of the chloropesticide Melipax discovered in two countries varied only by 0.1 per thousand in their delta 13C values. Gas chromatography interfaced to a stable isotope mass spectrometer (GC-IRMS) was used to study the delta 13C values of individual congeners in two technical polybrominated diphenyl ether products, i. e. DE-71 and DE-79, at three different concentration levels. Injections of 4 microg and 5.2 microg of DE-71 and DE-79 were most suited for the determinations. In both products, the delta 13C values were usually the more negative the higher the degree of bromination was. The delta 13C values of three hexabromo isomers BDE 138, BDE 153, and BDE 154 could be determined in both products. In all cases the delta 13C values of the three hexaBDEs were more depleted in delta 13C in the higher brominated technical octabromo diphenyl ether DE-79. 相似文献
327.
We present a model for benchmarking risk analysis and risk based decision making practice within organisations. It draws on behavioural and normative risk research, the principles of capability maturity modelling and our empirical observations. It codifies the processes of risk analysis and risk based decision making within a framework that distinguishes between different levels of maturity. Application of the model is detailed within the selected business functions of a water and wastewater utility. Observed risk analysis and risk based decision making practices are discussed, together with their maturity of implementation. The findings provide academics, utility professionals, and regulators a deeper understanding of the practical and theoretical underpinnings of risk management, and how distinctions can be made between organisational capabilities in this essential business process. 相似文献
328.
Gray D Pollard SJ Spence L Smith R Gronow JR 《Environmental pollution (Barking, Essex : 1987)》2005,133(3):587-599
Generalised source term data from UK leachates and a probabilistic exposure model (BPRISC(4)) were used to evaluate key routes of exposure from chemicals of concern during the spraying irrigation of landfill leachate. Risk estimates secured using a modified air box model are reported for a hypothetical worker exposed to selected chemicals within a generalised conceptual exposure model of spray irrigation. Consistent with pesticide spray exposure studies, the key risk driver is dermal exposure to the more toxic components of leachate. Changes in spray droplet diameter (0.02-0.2 cm) and in spray flow rate (50-1000 l/min) have little influence on dermal exposure, although the lesser routes of aerosol ingestion and inhalation are markedly affected. The risk estimates modelled using this conservative worst case exposure scenario are not of sufficient magnitude to warrant major concerns about chemical risks to workers or bystanders from this practice in the general sense. However, the modelling made use of generic concentration data for only a limited number of potential landfill leachate contaminants, such that individual practices may require assessment on the basis of their own merits. 相似文献
329.
Justin?C.?WilliamsEmail author Charles?S.?ReVelle Simon?A.?Levin 《Environmental Modeling and Assessment》2005,10(3):163-181
A variety of decision models have been formulated for the optimal selection of nature reserve sites to represent a diversity
of species or other conservation features. Unfortunately, many of these models tend to select scattered sites and do not take
into account important spatial attributes such as reserve shape and connectivity. These attributes are likely to affect not
only the persistence of species but also the general ecological functioning of reserves and the ability to effectively manage
them. In response, researchers have begun formulating reserve design models that improve spatial coherence by controlling
spatial attributes. We review the spatial attributes that are thought to be important in reserve design and also review reserve
design models that incorporate one or more of these attributes. Spatial modeling issues, computational issues, and the trade-offs
among competing optimization objectives are discussed. Directions for future research are identified. Ultimately, an argument
is made for the development of models that capture the dynamic interdependencies among sites and species populations and thus
incorporate the reasons why spatial attributes are important. 相似文献
330.
Oborn I Modin-Edman AK Bengtsson H Gustafson GM Salomon E Nilsson SI Holmqvist J Jonsson S Sverdrup H 《Ambio》2005,34(4-5):301-310
A systems analysis approach was used to assess farmscale nutrient and trace element sustainability by combining full-scale field experiments with specific studies of nutrient release from mineral weathering and trace-element cycling. At the Ojebyn dairy farm in northern Sweden, a farm-scale case study including phosphorus (P), potassium (K), and zinc (Zn) was run to compare organic and conventional agricultural management practices. By combining different element-balance approaches (at farmgate, barn, and field scales) and further adapting these to the FARMFLOW model, we were able to combine mass flows and pools within the subsystems and establish links between subsystems in order to make farm-scale predictions. It was found that internal element flows on the farm are large and that there are farm internal sources (Zn) and loss terms (K). The approaches developed and tested at the Ojebyn farm are promising and considered generally adaptable to any farm. 相似文献