全文获取类型
收费全文 | 475篇 |
免费 | 38篇 |
国内免费 | 232篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 16篇 |
环保管理 | 47篇 |
综合类 | 309篇 |
基础理论 | 187篇 |
污染及防治 | 96篇 |
评价与监测 | 40篇 |
社会与环境 | 29篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 16篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 20篇 |
2017年 | 22篇 |
2016年 | 17篇 |
2015年 | 28篇 |
2014年 | 28篇 |
2013年 | 58篇 |
2012年 | 34篇 |
2011年 | 48篇 |
2010年 | 33篇 |
2009年 | 36篇 |
2008年 | 44篇 |
2007年 | 56篇 |
2006年 | 37篇 |
2005年 | 32篇 |
2004年 | 21篇 |
2003年 | 27篇 |
2002年 | 20篇 |
2001年 | 19篇 |
2000年 | 24篇 |
1999年 | 8篇 |
1998年 | 15篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有745条查询结果,搜索用时 602 毫秒
361.
Carlos Garcia Teresa Hernandez Ascension Barahona Francisco Costa 《Environmental management》1996,20(1):133-141
Twenty-one severely eroded soils of SE Spain (Torriorthent xeric soils) were studied. These soils form a fragile system characterized
by soils with a low density of plant cover (<5%), are loamy and occur in a semiarid climate. The soils formerly were used
for agricultural purposes but were abandoned at least 15 years ago. These eroded soils had a low total organic carbon content,
and their humic substances, humic acid carbon, and carbohydrates were lower compared with soils that had never been cultivated
(natural soils). The variables in which the effects of erosion were particularly noted were those related with the active
organic matter (respiration and water-soluble organic matter). Those eroded soils with higher salt content showed lower organic
matter and carbohydrate contents. Only total nitrogen was correlated with the carbon fractions in the eroded soils. 相似文献
362.
Clean-up techniques, which were developed for removing cationic heavy metals from contaminated soils, are inappropriate for the metalloid As, which is a common and highly toxic pollutant. Because arsenic is mainly found associated with the hydrous ferric oxides of the soil, a possible mechanism for the mobilisation of this element is the reductive dissolution of Fe(III) oxyhydroxides. In this paper we investigate the possibility to mobilise arsenic, using the Fe(III)-reducing bacterium Desulfuromonas Palmitatis. The initial experiments were carried out using a crystalline ferric arsenate as model compound, i.e. scorodite (FeAsO4.2H2O). D. palmitatis was found able to reduce the trivalent iron of scorodite at a percentage of 80% within 16 days, but arsenic remained in the pentavalent state, and reprecipitated with Fe(II) in the form of low solubility ferrous arsenates. To avoid the precipitation of ferrous arsenates the subsequent experiments with soil were conducted by combining the reducing ability of D. palmitatis with the chelating strength of EDTA (ethylenediamine tetracetic acid), which can form strong aqueous complexes with Fe(II). Approximately 60% of Fe and 75% of As were recovered in the aqueous solution in the presence of EDTA, while in the simple biological treatment no Fe was dissolved and only a 3% of As was mobilised. 相似文献
363.
The goal of this research was to evaluate the relative effects of root density, freeze/thaw cycling, and soil properties on the erodibility and critical shear stress of streambanks. The erodibility and critical shear stress of rooted bank soils were measured in situ at 25 field sites using a submerged jet test device; several soil, vegetation, and stream chemistry characteristics shown to influence soil erosion were also assessed. Multiple linear regression analysis was conducted to determine those factors that most influenced streambank erodibility and the relative impact of riparian vegetation. Study results indicated that soil erosion is a complex phenomenon that depends primarily on soil bulk density. Freeze/thaw cycling, soil antecedent moisture content, the density of roots with diameters of 2 to 20 mm, soil texture, and the interaction of soil pore water and stream water had a significant impact on soil erodibility and critical shear stress, depending on soil type. Riparian vegetation had multiple significant effects on soil erodibility. In addition to reducing soil erodibility through root reinforcement, the streamside vegetation affected soil moisture and altered the local microclimate, which in turn affected freeze/thaw cycling (FTC). This study represents the first in situ testing of the erodibility of vegetated streambanks and provides a quantitative analysis on the effects of vegetation on streambank erosion, relative to other soil physical and chemical parameters. 相似文献
364.
Impacts of algal blooms removal by chitosan-modified soils on zooplankton
community in Taihu Lake, China 总被引:1,自引:0,他引:1
Jiajia Ni Yuhe Yu Weisong Feng Qingyun Yan Gang Pan Bo Yang Xiang Zhang Xuemei Li 《环境科学学报(英文版)》2010,22(10):1500-1507
It is important to assess the e ect on zooplankton when perform the environmental protection or restoration technology, especially
removing algal blooms, because algae were the major primary producer in algal lakes. The influence on zooplankton community after
half a year of algal blooms removed by chitosan-modified soils in Taihu Lake was assessed and the rationality of carrying out the
process semiannually was evaluated in the present study. Morphological composition and genetic diversity of zooplankton community
were investigated by microscope checkup and polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE). A total
of 44 zooplankton taxa (23 protozoa, 17 rotifers, 3 copepoda and 1 cladocera) were detected by microscope checkup, and a total of
91 bands (28 bands amplified by primers F1427-GC and R1616, 63 bands amplified by primers Fung-GC and NS1) were detected by
PCR-DGGE. The results of cluster analysis or detrended correspondence analysis indicated that there was no considerable di erence
in morphological composition of zooplankton and DGGE profiles between experimental and control sites, and DGGE profiles could
represent the biologic diversity. The study showed that zooplankton community could recover original condition after half year of algal
blooms removed by chitosan-modified soils and it was acceptable to apply this process semiannually. In addition, the results revealed
that PCR-DGGE could be applied to investigate the impacts of the environmental protection or restoration engineering on zooplankton
community diversity. 相似文献
365.
366.
367.
连霍高速郑商段路旁土壤重金属积累及潜在风险 总被引:9,自引:3,他引:6
以连霍高速郑商段不同通车时间的湾刘(通车11 a)和小王庄断面(通车4 a)为研究对象,根据距离公路远近不同布设土壤采样点,用原子吸收分光光度法测定土壤Cd、Cu、Pb、Zn、Ni和Cr含量.在计算表层土壤重金属积累速率和通量的基础上,探讨了路旁土壤重金属的分布特征、积累状况及潜在污染风险.结果表明,Cu、Pb和Cd是典型的交通源重金属,其含量在公路两侧随距离的增加呈先增加后减少的趋势,含量峰值出现在离路基25~50 m之间.湾刘断面土壤Pb、Cd、Cu的平均含量分别为14.52、 1.32、 73.54 mg·kg-1,小王庄断面分别为12.41、 0.98、 43.64 mg·kg-1.大部分样点Pb、Cu和Cd的积累速率和通量为正值,且Cu>Pb>Cd,小王庄断面大于湾刘断面. 2个断面土壤Cd已经发生污染;Cu的潜在污染风险在百年时间尺度之内,大部分样点在未来5~30 a中可能发生污染,潜在风险大;Pb的潜在污染风险都在千年尺度以上,潜在风险极小. 相似文献
368.
Effects of maize root exudates and organic acids on the desorption of
phenanthrene from soils 总被引:2,自引:0,他引:2
The effects of maize root exudates and low-molecular-weight-organic anions (LMWOAs) on the desorption of phenanthrene from eight artificially contaminated soils were evaluated. A significant negative correlation was observed between the amounts of phenanthrene desorbed and the soil organic carbon (SOC) contents (P<0.01), and the influences of soil pH and clay content on phenanthrene desorption were insignificant (P>0.1). Neither maize root exudates nor oxalate and citrate anions influenced desorption of phenanthrene with the addition of NAN3. A faster phenanthrene desorption occurred without the addition of NaN3 in the presence of maize root exudates than oxalate or citrate due to the enhanced degradation by root exudates. Without the addition of NaN3, oxalate or citrate at different concentrations could inhibit phenanthrene desorption to different extents and the inhibiting effect by citrate was more significant than by oxalate. This study leads to the conclusion that maize root exudates can not enhance the desorption under abiotic condition with the addition of NaN3 and can promote the desorption of phenanthrene in soils without the addition of NAN3. 相似文献
369.
湿地土壤Fe与N耦合过程研究进展 总被引:3,自引:1,他引:2
地球系统的耦合过程研究是目前地球表层系统地理过程研究的重点内容,湿地是地球表层生态系统重要的组成部分.湿地土壤季节性或长期处于积水的厌氧状态,这一厌氧环境中的Fe、N在氧化还原过程中存在微生物作用下的耦合过程.这种耦合过程主要表现在3个方面,即微生物利用NO 3-氧化Fe2+、利用Fe3+氧化NH 4+以及湿地厌氧土壤中NO 3-对于Fe3+还原的抑制作用.这一耦合过程的研究对于认识湿地中Fe、N的循环具有重要意义.文章从3个方面综述了湿地土壤Fe与N耦合过程的研究现状.总体看来,目前对于NO 3-氧化Fe2+方面的研究较另外两方面更深入,因此应加强Fe3+氧化NH 4+的微生物机制、Fe与N耦合过程的综合评价等方面的研究,从而为人们更好地了解和掌握湿地生物地球化学循环过程提供理论依据. 相似文献
370.
Fabrizio Monaci Eduardo O. Leidi Maria Dolores Mingorance Benito Vald′es Sabina Rossini Oliv Roberto Bargagli 《环境科学学报(英文版)》2011,23(3):444-452
To assess the ecophysiological traits and the phytoremediation potential of the endemic heather Erica andevalensis,we determined the concentrations of major and trace elements in different plant parts and in rizosphere soils from Riotinto mining district (Huelva,Spain).The results showed that E.andevalensis may grow on substrates with very high As,Cu,Fe and Pb concentrations (up to 4114,1050,71900 and 15614 μg/g dry weight,respectively),very low availability of macro-and micronutrients and with pH values ra... 相似文献