全文获取类型
收费全文 | 3238篇 |
免费 | 16篇 |
国内免费 | 43篇 |
专业分类
安全科学 | 77篇 |
废物处理 | 159篇 |
环保管理 | 380篇 |
综合类 | 427篇 |
基础理论 | 1221篇 |
环境理论 | 1篇 |
污染及防治 | 628篇 |
评价与监测 | 216篇 |
社会与环境 | 188篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 11篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 121篇 |
2017年 | 123篇 |
2016年 | 191篇 |
2015年 | 63篇 |
2014年 | 25篇 |
2013年 | 48篇 |
2012年 | 440篇 |
2011年 | 241篇 |
2010年 | 43篇 |
2009年 | 49篇 |
2008年 | 73篇 |
2007年 | 96篇 |
2006年 | 93篇 |
2005年 | 400篇 |
2004年 | 544篇 |
2003年 | 416篇 |
2002年 | 52篇 |
2001年 | 50篇 |
2000年 | 22篇 |
1999年 | 38篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1961年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有3297条查询结果,搜索用时 46 毫秒
991.
The water-soluble fraction (WSF) of petroleum contains a mixture of polycyclic aromatic hydrocarbons, volatile hydrocarbons, phenols, and heterocyclic compounds, considered deleterious to aquatic biota. Marine “pejerrey” Odontesthes argentinensis (Teleostei: Atherinopsidae) has a great commercial importance in local fisheries and a high potential for aquaculture. The aim of this study was to evaluate the histopathological effects in “pejerrey” larvae exposed to different concentrations of petroleum WSF. The chronic toxicity test was conducted with newly hatched larvae exposed for 21 days to sublethal concentrations of WSF (2.5, 5, 10, and 20 % of WSF), plus one control. Survival and growth were significantly lower in the highest concentration. Several histopathological changes were found in the gills (e.g., hyperplasia, aneurisms, edema, and necrosis), kidney (e.g., nuclear alterations, decrease in the hematopoietic cells), and liver (e.g., hypertrophy, karyorrhexis, and karyopyknosis). An index of branchial lesion was proposed to standardize gill lesions to different pollutants. 相似文献
992.
Concentrations of PCDD/Fs, PCBs and PBDEs were measured in 56 egg samples collected from waterbirds of different species (Great Egret, Little Egret, Night Heron and Chinese Pond Heron) from different regions of Hong Kong (Ho Sheung Heung, Mai Po Village and Mai Po Lung Village) during 2000 and 2006. Dominance of 2,3,4,7,8-PeCDF indicates a signature associated with commercial usage of PCBs. Although no significant variations were observed within- and between-site in the levels of PCDD/Fs, coplanar PCBs and PBDEs, the concentrations of coplanar PCBs were much higher than PCDD/Fs. Similarity in composition profiles of PCDD/F and coplanar PCBs from different egretries is possibly associated with non-point sources of these contaminants to Hong Kong. Predominant accumulation of BDE-47, BDE-99 and BDE-100 suggested the penta-BDE technical mixtures usage in Hong Kong and its vicinity. Toxic equivalency and Monte Carlo simulation technique showed potential risks on waterbirds due to their exposure to PCDD/Fs. 相似文献
993.
Duarte CM Agustí S Wassmann P Arrieta JM Alcaraz M Coello A Marbà N Hendriks IE Holding J García-Zarandona I Kritzberg E Vaqué D 《Ambio》2012,41(1):44-55
The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem. 相似文献
994.
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
995.
Effects of endosulfan exposure and Taura Syndrome Virus infection on the survival and molting of the marine penaeid shrimp, Litopenaeus vannamei 总被引:1,自引:0,他引:1
Molting in crustaceans is an important endocrine-controlled biological process that plays a critical role in growth and reproduction. Many factors can affect this physiological cycle in crustaceans including environmental stressors and disease agents. For example the pathology of Taura Syndrome Virus (TSV) of shrimp is closely related to molting cycle. Similarly, endosulfan, a commonly used pesticide is a potential endocrine disruptor. This study explores interrelationships between pesticide exposure, virus infection and their interactions with physiology and susceptibility of the shrimp. Litopenaeus vannamei (Pacific white shrimp) were challenged with increasing doses of endosulfan and TSV (TSV-C, a Belize reference strain) to determine the respective median lethal concentrations (LC50s). The 96-h endosulfan LC50 was 5.32 μg L−1, while the 7-d TSV LC50 was 54.74 mg L−1. Subsequently, based on their respective LC50 values, a 20-d interaction experiment with sublethal concentrations of endosulfan (2 μg L−1) and TSV (30 mg L−1) confirmed a significant interaction (p < 0.05, χ2 = 5.29), and thereby the susceptibility of the shrimp. Concurrently, molt-stage of animals, both at the time of exposure and death, was compared with mortality. For animals challenged with TSV, no strong correlation between molt-stage and mortality was observed (p > 0.05). For animals exposed to endosulfan, animals in the postmolt stage were shown to be more susceptible to acute toxicity (p < 0.05). For animals exposed to both TSV and endosulfan, interference of endosulfan-associated stress lead to increasingly higher susceptibility at postmolt (p < 0.05) during the acute phase of the TSV disease cycle. 相似文献
996.
997.
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998.
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999.
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
1000.
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