全文获取类型
收费全文 | 845篇 |
免费 | 80篇 |
国内免费 | 238篇 |
专业分类
安全科学 | 56篇 |
废物处理 | 29篇 |
环保管理 | 166篇 |
综合类 | 513篇 |
基础理论 | 160篇 |
污染及防治 | 111篇 |
评价与监测 | 40篇 |
社会与环境 | 58篇 |
灾害及防治 | 30篇 |
出版年
2024年 | 6篇 |
2023年 | 26篇 |
2022年 | 43篇 |
2021年 | 50篇 |
2020年 | 56篇 |
2019年 | 41篇 |
2018年 | 36篇 |
2017年 | 38篇 |
2016年 | 44篇 |
2015年 | 54篇 |
2014年 | 43篇 |
2013年 | 80篇 |
2012年 | 60篇 |
2011年 | 66篇 |
2010年 | 50篇 |
2009年 | 57篇 |
2008年 | 47篇 |
2007年 | 60篇 |
2006年 | 40篇 |
2005年 | 24篇 |
2004年 | 27篇 |
2003年 | 31篇 |
2002年 | 25篇 |
2001年 | 22篇 |
2000年 | 21篇 |
1999年 | 10篇 |
1998年 | 15篇 |
1997年 | 18篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1163条查询结果,搜索用时 671 毫秒
321.
322.
Thodoris Dantsis Angeliki Loumou Christina Giourga 《Journal of Agricultural and Environmental Ethics》2009,22(3):197-216
Up to now, several scientific works have noted that the organic sector resembles more and more conventional farming’s structures,
what is widely known as the “conventionalization” thesis. This phenomenon constitutes an area of conflict between organic
farming’s original vision and its current reality and raises ethical and social questions concerning the structure of agricultural
systems of production and their interactions with the socio-economic and natural environment. The main issue of this dialogue
is the concept of sustainable agriculture, which for scientists and policymakers is a means to express their vision of a better
agriculture. In this article we focus on agricultural sustainability in the context of capitalist production as conducted
by the two subsystems of agro-industrial system. As we have proposed in this article, the relationship between organic agriculture,
defined by two essential components (prevention and direct marketing), and the agro-industrial complex, defined by two subsystems,
indicates the degree of agricultural sustainability. The investigation of this relationship can be extremely useful as it
may lead those involved in the discussion of sustainability to identify the key aspects of sustainable agriculture. In order
to investigate the interaction of organic farming with the agro-industrial complex, a survey was conducted in Central Macedonia,
Northern Greece, involving local organic farms. The results of our study indicate that a large proportion of organic producers
did not differ substantially from their counterparts in conventional agriculture in so far as their relationship with the
agro-industrial complex is concerned. Finally, this research highlights two scenarios for the evolution of organic farming.
The first is the full absorption of organic farming to the existing economic system and the second one is the development
of organic farming in a radically opposite direction to conventional farming. 相似文献
323.
324.
325.
326.
Agriculture can be a major nonpoint source (NPS) of nutrient and pesticide contamination in the environment. Available databases
do not provide accurate and dynamic data on fertilizer and pesticide application, which limits the ability of complex watershed
models to simulate contaminant loads into impaired water bodies. A model for estimating agricultural nutrient and pesticide
input for watershed modeling has been developed. Climate, soils, and major agricultural operations are considered within the
model, so that it can be adapted to any watershed or subregion within a watershed. The timing of the agricultural operations
is a function of the weather data, providing realistic results at daily, monthly, or annual application rates. The model also
predicts irrigation demand and biomass production, which can be used to calibrate the model. Model output can be used in any
watershed model that considers agricultural land uses. Two case studies were evaluated, using grape vineyards in the Napa
River and strawberry production in Newport Bay as examples. The predicted time to maturity corresponded well with actual data.
Irrigation and fertilizer needs were very sensitive to weather input. Although the model can generate weather from long-term
averages, the simulated results are best when at least observed precipitation and temperature are provided, to capture extreme
events. The model has data for 98 crops and 126 pesticides, based on the California Department of Pesticide Regulation database.
The databases are easily modifiable by the user to adapt them to local conditions. The output from AgInput is much needed
for watershed modeling and for development of total maximum daily loads (TMDLs), based on realistic targets of irrigation,
nutrient, and pesticide inputs. The model is available for free download at . 相似文献
327.
328.
Pentabromocyclododecanols (PBCDOHs) are potential environmental transformation products of hexabromocyclododecanes (HBCDs). They are also potential stage one metabolites of biological HBCD transformations. Herein, we present analytical evidence that PBCDOHs are also constituents of technical HBCDs and flame-proofed polystyrenes (FP-PSs). PBCDOHs are possibly formed during the synthesis of technical HBCD, presumably during the bromination of cyclododecatrienes in aqueous isobutanol together with isobutoxypentabromocyclododecanes (iBPBCDs), which have been identified in these materials recently. Of the 64 stereoisomers possible, eight pairs of enantiomers, named α-, β-, γ-, δ-, ε-, ζ-, η-, and θ-PBCDOHs were separated with a combination of normal-, reversed- and chiral-phase LC. Crystal structure analysis revealed the stereochemistry of the α-PBCDOH pair of enantiomers, which was assigned to (1S,2S,5R,6S,9S,10R)-2,5,6,9,10-pentabromocyclododecanol and its enantiomer. Mass spectrometric data are in accordance with the expected isotope patterns. On a C18-RP-column, the polar PBCDOHs eluted before the HBCD and iBPBCD classes of compounds. PBCDOHs were also found in FP-PS materials. The stereoisomer patterns varied considerably in these materials like those of HBCDs and iBPBCDs. Expanded polystyrenes were rich in late-eluting stereoisomers, similar to technical HBCD mixtures. Extruded polystyrenes contained more of the polar, faster-eluting isomers. The presented chromatographic and analytical methods allow a stereoisomer-specific search for PBCDOHs in biota samples, which might have experienced metabolic HBCD transformation reactions. Besides this potential source, it has to be recognized that PBCDOHs are by-products in technical HBCDs and in flame-proofed polystyrenes. Therefore, it is likely that PBCDOHs and iBPBCDs are released to the environment together with HBCD-containing plastic materials. 相似文献
329.
环境公平问题既有研究述评及研究框架思考 总被引:2,自引:0,他引:2
环境不公平问题,日益成为经济发展现实中的一个重要问题,也日益成为环境经济学的一个着重关注领域,但既有的研究尚缺乏系统性和理论基础。本文系统梳理了国内外关于环境公平定义的代表性观点,在此基础上提出了作者对环境公平的认识。然后笔者在各种形式的环境不公平研究(包括不同群体间的环境不公平问题的研究和不同区域间的环境不公平问题的研究)、环境公平问题的研究方法(主要指基于地理信息系统获取相应的变量数据进而用计量模型的方法和借鉴收入差距的分析方法)等既有研究进行梳理和简要评述的基础上,提出:环境不公平问题的实质是经济利益不公平问题的转化与延伸,应在这一认识前提下来探讨环境公平问题、来建立环境公平问题的研究框架。进而提出:以经济学方法讨论利益主体之间如何实现公平享有环境利益、公平分配使用环境容量、公平承受环境破坏后果、公平分担环境维护责任、公平分担环境治理成本,是环境公平问题研究的主要方向。 相似文献
330.
Manel Araoud Wahiba Douki Mohamed Fadhel Najjar Abderraouf Kenani 《Journal of environmental science and health. Part. B》2013,48(3):242-248
The aim of this study was to develop an analytical method for the determination of residues of organophosphorus and carbamate pesticides which are widely used in Tunisia. This method involves a liquid-liquid extraction procedure followed by liquid chromatography tandem mass spectrometry (LC/MS/MS) for the identification and quantification of compounds. Ionization of molecules was performed by the electrospray mode. Multiple reactions monitoring (MRM) was the acquisition mode used for the monitoring of two MS/MS transitions for each compound. The average recoveries obtained, at three different fortification levels, ranged between 65% and 106% for most of the pesticides studied, except for methamidophos (lower than 25%).The linearity of the method was in the range of 5 to 50 μ g/L with a correlation coefficient from 0.995 to 0.999, depending on the analyte. The estimated limit of detection and limit of quantification were 2 μ g/L and 5 μ g/L, respectively. The precision of the analytical procedure was satisfactory and the coefficients of variation, evaluated at three concentration levels were lower than 15% for most pesticides studied. The application of the method was investigated in a population of agricultural workers chronically exposed to various pesticides some of which, such as carbofuran, carbendazim, methomyl and pirimicarb, were detected in some serum samples. 相似文献