全文获取类型
收费全文 | 688篇 |
免费 | 14篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 66篇 |
废物处理 | 32篇 |
环保管理 | 99篇 |
综合类 | 126篇 |
基础理论 | 156篇 |
污染及防治 | 140篇 |
评价与监测 | 42篇 |
社会与环境 | 43篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 14篇 |
2019年 | 7篇 |
2018年 | 16篇 |
2017年 | 33篇 |
2016年 | 27篇 |
2015年 | 28篇 |
2014年 | 30篇 |
2013年 | 51篇 |
2012年 | 30篇 |
2011年 | 55篇 |
2010年 | 27篇 |
2009年 | 37篇 |
2008年 | 42篇 |
2007年 | 54篇 |
2006年 | 25篇 |
2005年 | 30篇 |
2004年 | 26篇 |
2003年 | 29篇 |
2002年 | 20篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有711条查询结果,搜索用时 250 毫秒
561.
Surveys in emergency settings are important for the accountability of food aid. Four household surveys conducted between 1994 and 1997 measured the performance of the Bosnia food aid programme, covering a random sample of clusters in Bosnia and Herzegovina and the Republica Srpska. The team calculated coverage, exclusion and inclusion errors, programme misses, and under-supply. Despite intended universal coverage from 1994-96, 15, 19, and 31 per cent, respectively, did not receive food across the three-year time frame. Households categorised as vulnerable were somewhat more likely to receive food. Programme misses were rare, whereas under-supply fell from 30 per cent in 1994 to four per cent in 1997, as the availability of other food increased. Extrapolation suggested that 61 per cent of the food distributed did not reach households. The programme introduced priority categories for targeting in 1997, yet nearly one-half of the highest priority households did not receive food. Incomplete coverage and weak targeting were related to political constraints. 相似文献
562.
Jackson AK Evers DC Folsom SB Condon AM Diener J Goodrick LF McGann AJ Schmerfeld J Cristol DA 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3302-3308
Mercury (Hg) is a persistent environmental contaminant found in many freshwater and marine ecosystems. Historical Hg contamination in rivers can impact the surrounding terrestrial ecosystem, but there is little known about how far downstream this contamination persists. In 2009, we sampled terrestrial forest songbirds at five floodplain sites up to 137 km downstream of an historical source of Hg along the South and South Fork Shenandoah Rivers (Virginia, USA). We found that blood total Hg concentrations remained elevated over the entire sampling area and there was little evidence of decline with distance. While it is well known that Hg is a pervasive and long-lasting aquatic contaminant, it has only been recently recognized that it also biomagnifies effectively in floodplain forest food webs. This study extends the area of concern for terrestrial habitats near contaminated rivers for more than 100 km downstream from a waterborne Hg point source. 相似文献
563.
Hinger G Brinkmann M Bluhm K Sagner A Takner H Eisenträger A Braunbeck T Engwall M Tiehm A Hollert H 《Environmental science and pollution research international》2011,18(8):1297-1304
Purpose
Heterocyclic aromatic compounds containing nitrogen, sulfur, or oxygen heteroatoms (NSO-HET) have been detected in air, soil, marine, and freshwater systems. However, only few publications are available investigating NSO-HET using in vitro bioassays. To support better characterization of environmental samples, selected NSO-HET were screened for dioxin-like activity in two bioassays. 相似文献564.
A congeneric set of 58 substituted anilines and phenols was tested using the 72-h algal growth inhibition assay with Pseudokirchneriella subcapitata and 15-min Vibrio fischeri luminescence inhibition assay. The set contained molecules substituted with one, two or three groups chosen from -chloro, -methyl or -ethyl. For 48 compounds there was no REACH-compatible algal toxicity data available before. The experimentally obtained EC50 values (mg L−1) for algae ranged from 1.43 (3,4,5-trichloroaniline) to 197 (phenol) and for V. fischeri from 0.37 (2,3,5-trichlorophenol) to 491 (aniline). Only five of the tested 58 chemicals showed inhibitory effect to algae at concentrations >100 mg L−1, i.e. could be classified as “not harmful”, 32 chemicals as “harmful” (10-100 mg L−1) and 21 as “toxic” (1-10 mg L−1). The occupied para-position tended to increase toxicity whereas most of the ortho-substituted congeners were the least toxic. As a rule, the higher the number of substituents the higher the hydrophobicity and toxicity. However, in case of both assays, the compounds of similar hydrophobicity showed up to 30-fold different toxicities. There were also assay/organism dependent tendencies: phenols were more toxic than anilines in the V. fischeri assay but not in the algal test. The comparison of the experimental toxicity data to the data available from the literature as well as to QSAR predictions showed that toxicity of phenols to algae can be modeled based on hydrophobicity, whereas the toxicity of anilines to algae as well as toxicity of both anilines and phenols to V. fischeri depended on other characteristics in addition to logKow. 相似文献
565.
Chin A Daniels MD Urban MA Piégay H Gregory KJ Bigler W Butt AZ Grable JL Gregory SV Lafrenz M Laurencio LR Wohl E 《Environmental management》2008,41(6):893-903
This article reports a study of the public perception of large wood in rivers and streams in the United States. Large wood
is an element of freshwater aquatic ecosystems that has attracted much scientific interest in recent years because of its
value in biological and geomorphological processes. At the heart of the issue is the nature of the relationship between scientific
recognition of the ecological and geomorphological benefits of wood in rivers, management practices utilizing wood for river
remediation progress, and public perceptions of in-channel wood. Surveys of students’ perceptions of riverscapes with and
without large wood in the states of Colorado, Connecticut, Georgia, Illinois, Iowa, Missouri, Oregon, and Texas suggest that
many individuals in the United States adhere to traditionally negative views of wood. Except for students in Oregon, most
respondents considered photographs of riverscapes with wood to be less aesthetically pleasing and needing more improvement
than rivers without wood. Analysis of reasons given for improvement needs suggest that Oregon students are concerned with
improving channels without wood for fauna habitat, whereas respondents elsewhere focused on the need for cleaning wood-rich
channels for flood risk management. These results underscore the importance of public education to increase awareness of the
geomorphological and ecological significance of wood in stream systems. This awareness should foster more positive attitudes
toward wood. An integrated program of research, education, and policy is advocated to bridge the gap between scientific knowledge
and public perception for effective management and restoration of river systems with wood. 相似文献
566.
Morrice JA Danz NP Regal RR Kelly JR Niemi GJ Reavie ED Hollenhorst T Axler RP Trebitz AS Cotter AM Peterson GS 《Environmental management》2008,41(3):347-357
A better understanding of relationships between human activities and water chemistry is needed to identify and manage sources
of anthropogenic stress in Great Lakes coastal wetlands. The objective of the study described in this article was to characterize
relationships between water chemistry and multiple classes of human activity (agriculture, population and development, point
source pollution, and atmospheric deposition). We also evaluated the influence of geomorphology and biogeographic factors
on stressor-water quality relationships. We collected water chemistry data from 98 coastal wetlands distributed along the
United States shoreline of the Laurentian Great Lakes and GIS-based stressor data from the associated drainage basin to examine
stressor-water quality relationships. The sampling captured broad ranges (1.5–2 orders of magnitude) in total phosphorus (TP),
total nitrogen (TN), dissolved inorganic nitrogen (DIN), total suspended solids (TSS), chlorophyll a (Chl a), and chloride; concentrations were strongly correlated with stressor metrics. Hierarchical partitioning and all-subsets
regression analyses were used to evaluate the independent influence of different stressor classes on water quality and to
identify best predictive models. Results showed that all categories of stress influenced water quality and that the relative
influence of different classes of disturbance varied among water quality parameters. Chloride exhibited the strongest relationships
with stressors followed in order by TN, Chl a, TP, TSS, and DIN. In general, coarse scale classification of wetlands by morphology (three wetland classes: riverine, protected,
open coastal) and biogeography (two ecoprovinces: Eastern Broadleaf Forest [EBF] and Laurentian Mixed Forest [LMF]) did not
improve predictive models. This study provides strong evidence of the link between water chemistry and human stress in Great
Lakes coastal wetlands and can be used to inform management efforts to improve water quality in Great Lakes coastal ecosystems. 相似文献
567.
Schnitzler F Lavorenti A Berns AE Drewes N Vereecken H Burauel P 《Environmental pollution (Barking, Essex : 1987)》2007,147(1):4-13
The amount of non-extractable residues and the distribution of benazolin and its metabolites were evaluated three months after herbicide application (14C-labelled) in physically extracted soil fractions of topsoil layers of undisturbed soil columns with and without incorporated maize straw (14C-labelled). In addition, a variety of wet-chemical and spectroscopic methods were used to characterise the structure of organic carbon within the different soil fractions. The addition of crop residues increased the amount of dissolved organic carbon, enhanced the aromaticity of the organic carbon structure and enforced the aggregation of organomineral complexes. After incorporation of crop residues, an increase in the formation of metabolic compounds of benazolin and of non-extractable residues was detected. These results indicate that the addition of crop residues leads to a decrease in mobility and bioaccessibility of benazolin and its metabolites. 相似文献
568.
569.
The waste hierarchy is being widely discussed these days, not only by cost-benefit analysts, but a growing number of life cycle assessments (LCA) have also begun to question it. In this article, we investigate the handling of waste paper in Denmark and compare the present situation with scenarios of more waste being recycled, incinerated or consigned to landfill. The investigations are made in accordance with ISO 14040-43 and based on the newly launched methodology of consequential LCA and following the recent guidelines of the European Centre on Waste and Material Flows. The LCA concerns the Danish consumption of paper in 1999, totalling 1.2 million tons. The results of the investigation indicate that the waste hierarchy is reliable; from an environmental point of view recycling of paper is better than incineration and landfilling. For incineration, the reason for the advantage of landfilling mainly comes from the substitution of fossil fuels, when incinerators provide heat and electricity. For recycling, the advantage is related to the saved wood resources, which can be used for generating energy from wood, i.e., from renewable fuel which does not contribute to global warming. 相似文献
570.
Megan MH Nash MS Neale AC Pitchford AM 《Environmental monitoring and assessment》2007,124(1-3):141-156
The objective of this study was to assess the applicability of using landscape variables in conjunction with water quality
and benthic data to efficiently estimate stream condition of select headwater streams in the Mid-Atlantic Coastal Plains.
Eighty-two streams with riffle sites were selected from eight-two independent watersheds across the region for sampling and
analyses. Clustering of the watersheds by landscape resulted in three distinct groups (forest, crop, and urban) which coincided
with watersheds dominant land cover or use. We used non-parametric analyses to test differences in benthos and water chemistry
between groups, and used regression analyses to evaluate responses of benthic communities to water chemistry within each of
the landscape groups. We found that typical water chemistry measures associated with urban runoff such as specific conductance
and dissolved chloride were significantly higher in the urban group. In the crop group, we found variables commonly associated
with farming such as nutrients and pesticides significantly greater than in the other two groups. Regression analyses demonstrated
that the numbers of tolerant and facultative macroinvertebrates increased significantly in forested watersheds with small
shifts in pollutants, while in human use dominated watersheds the intolerant macroinvertebrates were more sensitive to shifts
in chemicals present at lower concentrations. The results from this study suggest that landscape based clustering can be used
to link upstream landscape characteristics, water chemistry and biotic integrity in order to assess stream condition and likely
cause of degradation without the use of reference sites. Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency
policy. 相似文献