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881.
This study investigated the removal of Reactive Black 5 (RB5) textile dye from aqueous solutions using cotton (Gossypium hirsutum) seed shell (CSS) as low cost adsorbents. The data were described according to the Freundlich and Langmuir isotherm models. Of these, the Langmuir model provided the best fit for the experimental data. The highest measured adsorption density was 12.19 mg/g at pH 2. An equilibrium adsorption rate of RB5 by CSS (q(e) = 11.879 mg/g) was observed at 30 minutes. In order to evaluate the adsorption kinetic mechanisms, pseudo first and second order rate kinetic models and an intraparticle diffusion model were applied, with the pseudo second order model providing an excellent fit for the data. 相似文献
882.
883.
García FP García MA Drożdżak J Ruiz-Samblás C 《Environmental science and pollution research international》2012,19(8):3317-3326
Purpose
Exploratory data analysis (EDA) is applied in this research to study the behavior of radioactive aerosols present in the surface atmosphere of Granada, using 7Be as radiotracer. The reason for this study is to reduce the large number of parameters involved in understanding their behavior, given the complexity of the atmosphere.Methods
Aerosol particles were collected weekly in Granada (Spain) over a 5-year period. Low-background gamma spectrometry was used to determine concentrations of 7Be-aerosol activity. The variables studied were: 7Be concentration, cosmic ray intensity, temperature, temperature interval, rainfall, relative humidity, and Saharan intrusions. Least significant difference test (LSD), hierarchical cluster analysis (HCA), and principal component analysis (PCA) with varimax rotation have been applied to study the datasets.Results and discussion
The results of our study reveal that aerosol behavior is represented by two principal components which explain 86.23?% of total variance. Components PC1 and PC2 respectively explain 74.61 and 11.62?% of total variance. PC1 explains the cyclical and seasonal pattern of the samples, while PC2 is related to the production of 7Be. In addition, PCA and HCA show good distribution of the samples by families with two groups, summer and winter, at the extremes and spring?Cautumn in the middle. This result corroborates that there are no differences between spring and autumn in the climate of Granada.Conclusions
EDA has been found to be quite useful in studying the behavior of radioactive aerosols in the surface atmosphere of a city with the climate and geographical characteristics of Granada. 相似文献884.
Başak S Cokgör EU Insel G Orhon D 《Environmental science and pollution research international》2012,19(8):3412-3420
Background
This study investigated the acute effect of benzo[a]anthracene, a significant compound among polycyclic aromatic hydrocarbons, on the biodegradation of a synthetic organic substrate??a peptone/meat extract mixture??under aerobic conditions.Methods
A laboratory-scale sequencing batch reactor was sustained at steady state at a sludge age of 10?days with substrate feeding. Inhibition tests involved running a series of batch reactors initially seeded with the biomass obtained from the parent reactor. After the biomass seeding, the reactors were started with the peptone mixture and a range of initial benzo[a]anthracene concentrations between 0.5 and 88?mg/L. Experimental profiles of oxygen uptake rates and polyhydroxyalkanoates were evaluated by calibration of a selected model.Results
Lower doses of benzo[a]anthracene had no effect on process kinetics. The noticeable acute impact was only observed with the addition of 88?mg/L of benzo[a]anthracene, but it was limited with the storage mechanism: the amount of organic substrate diverted to polyhydroxyalkanoates was significantly reduced with a corresponding decrease in the maximum storage rate, k STO, from 2.7 down to 0.6?day?1. Similarly, the maximum growth rate from internally stored polyhydroxyalkanoates was lowered from 2.3 to 1.0?day?1.Conclusion
Among the mechanisms for direct substrate utilization, only the hydrolysis rate was slightly reduced, but otherwise, the overall COD removal efficiency was not affected. 相似文献885.
J Molnar J Agbaba B Dalmacija S Rončević M Prica A Tubić 《Environmental science and pollution research international》2012,19(8):3079-3086
This study investigated the effects of pH (6-10) and ozone dose [0.4-3.0?mg O(3)/mg dissolved organic carbon (DOC)] on the content and structure of haloacetic acid (HAA) precursors in groundwater rich in natural organic matter (NOM; DOC 9.85?±?0.18?mg/L) during drinking water treatment. The raw water was ozonated in a 2 L glass column. NOM fractionation was carried out using XAD resins. HAA formation potential (HAAFP) was determined according to standard EPA Method 552. NOM characterization revealed it is mostly hydrophobic (65?% fulvic and 14?% humic acids). Hydrophobic NOM significantly influences HAA formation, as confirmed by the high HAAFP (309?±?15?μg/L). Ozonation at pH?6-10 led to changes in NOM structure, i.e. complete humic acid oxidation, and increased the hydrophilic NOM fraction content (65-90?% achieved using 3.0?mg O(3)/mg DOC). The highest degree of NOM oxidation and HAA precursor removal was achieved at pH?10 (up to 68?% HAAFP). Ozonation pH influenced the distribution of HAA precursor content, as increasing the pH from 6 to 10 increased the reactivity of the hydrophilic fraction, with the HAAFP increasing from 19.1?±?6.0?μg/mg DOC in raw water to 152?±?8?μg/mg DOC in ozonated water. The degree of HAA precursor removal depends on the dominant oxidation mechanism, which is related to the applied ozone dose and the pH of the oxidation process. Ozonation at pH?10 favours the mechanism of radical NOM oxidation and was the most effective for HAAFP reduction, with the efficacy of the process improving with increasing ozone dose. 相似文献
886.
Kristian H?yer Toft 《Journal of Agricultural and Environmental Ethics》2012,25(2):223-237
Proponents of using genetically modified (GM) crops and food in the developing world often claim that it is unjust not to
use GMOs (genetically modified organisms) to alleviate hunger and malnutrition in developing countries. In reply, the critics
of GMOs claim that while GMOs may be useful as a technological means to increase yields and crop quality, stable and efficient
institutions are required in order to provide the benefits from GMO technology. In this debate, the GMO proponents tend to
rely on a simple utilitarian type of calculus that highlights the benefits of GMOs to the poor, but that overlooks the complex
institutional requirements necessary for GMO production. The critics, recognizing the importance of institutional conditions,
focus primarily on the negative impacts of institutional deficiencies, thereby overlooking the basically Rawlsian claim that
institutions per se may generate claims to justice. This article investigates how GMOs might generate claims to global justice and what type
of justice is involved. The paper argues that the debate on GMOs and global justice can be categorized into three views, i.e.,
the cosmopolitan, the pluralist, and the sceptic. The cosmopolitan holds that GMOs can and should be used for alleviating
global hunger, whereas the sceptic rejects this course of action. I will argue here for a moderately cosmopolitan approach,
relying on the pluralist view of institutions and the need to exploit the benefits of GMOs. This argument rests on the premise
that global cooperation on GMO production provides the relevant basis for assessing the use of GMOs by the standard of global
distributive justice. 相似文献
887.
In early 2009, few would have expected that the Intergovernmental Panel on Climate Change (IPCC) would come under such massive attack. The IPCC had enjoyed a pristine reputation and had even advanced to become a
role model for biodiversity and food security assessments (Loreau et al. 2006; Watson 2005). However, public trust and, with it, the organization’s credibility eroded dramatically after November 2009 with the events
that became known as ‘climategate’. This article seeks to contribute to current debates about how to reform the IPCC. It argues
that there are major flaws in the design of the IPCC which are rooted in the linear model of expertise and which are helping
to stoke the backlash against the IPCC. The article analyzes the ways in which the IPCC’s activities conform to the linear
model of expertise and considers the consequences of this for integrating adaptation into the IPCC assessments. It explains
why adaptation played only a marginal role up until the IPCC Third Assessment Report. It then demonstrates why the use of
the linear model of expertise constrains the scientific and political debate about adaptation and leads to proxy debates about scientific evidence, which result in depoliticizing the politics of adaptation and
politicizing science. Finally, the article calls for the debate to be opened up to accommodate alternatives that are both politically more feasible
and at the same time more appropriate to the specific needs of adaptation policies at different levels of decision-making. 相似文献
888.
Structuring sustainability science 总被引:2,自引:2,他引:0
Anne Jerneck Lennart Olsson Barry Ness Stefan Anderberg Matthias Baier Eric Clark Thomas Hickler Alf Hornborg Annica Kronsell Eva L?vbrand Johannes Persson 《Sustainability Science》2011,6(1):69-82
It is urgent in science and society to address climate change and other sustainability challenges such as biodiversity loss, deforestation, depletion of marine fish stocks, global ill-health, land degradation, land use change and water scarcity. Sustainability science (SS) is an attempt to bridge the natural and social sciences for seeking creative solutions to these complex challenges. In this article, we propose a research agenda that advances the methodological and theoretical understanding of what SS can be, how it can be pursued and what it can contribute. The key focus is on knowledge structuring. For that purpose, we designed a generic research platform organised as a three-dimensional matrix comprising three components: core themes (scientific understanding, sustainability goals, sustainability pathways); cross-cutting critical and problem-solving approaches; and any combination of the sustainability challenges above. As an example, we insert four sustainability challenges into the matrix (biodiversity loss, climate change, land use changes, water scarcity). Based on the matrix with the four challenges, we discuss three issues for advancing theory and methodology in SS: how new synergies across natural and social sciences can be created; how integrated theories for understanding and responding to complex sustainability issues can be developed; and how theories and concepts in economics, gender studies, geography, political science and sociology can be applied in SS. The generic research platform serves to structure and create new knowledge in SS and is a tool for exploring any set of sustainability challenges. The combined critical and problem-solving approach is essential. 相似文献
889.
Arun?Rijal Carsten?Smith-HallEmail author Finn?Helles 《Environment, Development and Sustainability》2011,13(1):121-140
Rural households throughout the Himalayas are regarded as dependent on non-timber forest products (NTFPs), but very few studies
have quantified this dependency. This case study, undertaken in two villages in the Central Himalayan foot hills in Nepal,
documents the absolute and relative importance of commercial NTFPs to rural household economies. Data were collected in a
one-year period and included interviews with 250 households using a semi-structured questionnaire and monthly interviews with
four sub-local NTFP traders, two local traders and two central wholesalers. The conservative estimate of NTFP-derived cash
income showed this to be a cornerstone in poorer household livelihood strategies and thus in poverty prevention. An annual
average of 578 kg of commercial NTFPs was collected in the wild per household, providing poorer households with a cash income
share of 44–78%. Better off households are not NTFP dependent but rely on income from crop production and livestock. Based
on a net marketing margin analysis, showing that harvesters capture a large share of the Indian wholesaler price, it is argued
that there is scope for pursuing NTFP-based strategies for poverty reduction through leasehold forestry and agroforestry.
Both these options are compatible with conserving forest cover and forest corridor functions and may thus present a win–win
scenario for livelihood improvement and conservation. 相似文献
890.
Ali?Mohammed?OumerEmail author Andreas?de Neergaard 《Environment, Development and Sustainability》2011,13(3):547-564
The aim of this paper is to disclose livelihood strategy-poverty links and gain a better understanding by developing typologies
of rural households. Based on qualitative and quantitative data, we group households into different typologies and explore
interactions. We identified six main agronomic strategies, four dominant livelihood diversification strategies, and income
quartiles (proxies for poverty) using cluster and principal component factor analysis. We found that nearly 82% of the surveyed
farmers in the study area belong to the bottom income quartiles while about 18% are on the upper quartiles. Households in
the bottom income quartiles engaged in casual off-farm work and cereal-dominated livelihood strategies that tend to pursue
subsistence farming by growing cereals and oil crops. Contrarily, farmers in the upper income quartiles adapted intensive
agronomic strategies by integrating root crops, legumes, and vegetables with livestock. This was largely attributed to access
to key livelihood assets such as land, livestock, education, and institutional support in which the upper quartiles were more
endowed. Improving availability of the key assets for the bottom income quartiles might be a way out of poverty and ensuring
sustainable development. It is crucial to recognize local-level heterogeneities of rural households when targeting development
interventions. 相似文献