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841.
A comparative chemometric study for water quality expertise of the Athenian water reservoirs 总被引:1,自引:0,他引:1
Eleni G. Farmaki Nikolaos S. Thomaidis Vasil Simeonov Constantinos E. Efstathiou 《Environmental monitoring and assessment》2012,184(12):7635-7652
The aim of the present study is to compare the application of unsupervised and supervised pattern recognition techniques for the quality assessment and classification of the reservoirs used as the source for the domestic and industrial water supply of the city of Athens, Greece. A new optimization strategy for sampling, monitoring, and water management is proposed. During the period of October 2006 to April 2007, 89 samples were collected from the three water reservoirs (Iliki, Mornos, and Marathon), and 13 parameters (metals and metalloids) were analytically determined. Generally, all the elements were found to fluctuate at very low levels, especially for Mornos that comprises the main water reservoir of Athens. Iliki and Marathon showed relatively elevated values, compared to Mornos, but below the legislative limits. Multivariate unsupervised statistical techniques, such as factor analysis/principal components analysis, and cluster analysis and supervised ones, like discriminant analysis and classification trees, were applied to the data set, and their classification abilities were compared. All the chemometric techniques successfully revealed the critical variables and described the similarities and dissimilarities among the sampling points, emphasizing the individual characteristics in every sample and revealing the sources of elements in the region. New data from posterior samplings (November and December 2007) were used for the validation of the supervised techniques. Finally, water management strategies were proposed concerning the sampling points and representative parameters. 相似文献
842.
Waliszewski SM Caba M Herrero-Mercado M Saldariaga-Noreña H Meza E Zepeda R Martínez-Valenzuela C Gómez Arroyo S Villalobos Pietrini R 《Environmental monitoring and assessment》2012,184(9):5613-5621
The objective of the present study was to monitor the levels of organochlorine pesticides HCB; α-, β-, γ-HCH; pp'DDE; op'DDT; and pp'DDT in blood serum of Veracruz, Mexico inhabitants. Organochlorine pesticides were analyzed in 150 blood serum samples that constituted that which remained after clinical analyses, using gas chromatography-electron-capture detection (GC-ECD). The results were expressed as milligrams per kilogram on fat basis and micrograms per liter on wet weight. Only the following pesticides were detected: p,p'-DDE was the major organochlorine component, detected in 100% of samples at mean 15.8 mg/kg and 8.4 μg/L; p,p'-DDT was presented in 41.3.% of monitored samples at mean 3.1 mg/kg and 1.4 μg/L; β-HCH was found in 48.6% of the samples at mean 4.9 mg/kg and 2.7 μg/L; op'DDT was determined to be in only 3.3% of monitored samples at mean 2.7 mg/kg and 1.4 μg/L. The pooled samples divided according to sex showed significant differences of β-HCH and pp'DDE concentrations in females. The samples grouped according to age presented the third tertile as more contaminated in both sexes, indicating age as a positively associated factor with serum organochlorine pesticide levels in Veracruz inhabitants. 相似文献
843.
Muhammad BG Jaafar MS Abdul Rahman A Ingawa FA 《Environmental monitoring and assessment》2012,184(8):5043-5049
Soil serves as a major reservoir for contaminants as it posseses an ability to bind various chemicals together. To safeguard the members of the public from an unwanted exposure, studies were conducted on the sediments and soil from water bodies that form the major sources of domestic water supply in northern peninsular Malaysia for their trace element concentration levels. Neutron Activation Analysis, using Nigeria Research Reactor-1 (NIRR-1) located at the Centre for Energy Research and Training, Zaria, Nigeria was employed as the analytical tool. The elements identified in major quantities include Na, K, and Fe while As, Br, Cr, U, Th, Eu, Cs, Co, La, Sm, Yb, Sc, Zn, Rb, Ba, Lu, Hf, Ta, and Sb were also identified in trace quantities. Gamma spectroscopy was also employed to analyze some soil samples from the same area. The results indicated safe levels in terms of the radium equivalent activity, external hazard index as well as the mean external exposure dose rates from the soil. The overall screening of the domestic water sources with relatively high heavy metals concentration values in sediments and high activity concentration values in soil is strongly recommended as their accumulation overtime as a consequence of leaching into the water may be of health concern to the members of the public. 相似文献
844.
JF Sauvé C Beaudry D Bégin C Dion M Gérin J Lavoué 《Journal of environmental monitoring : JEM》2012,14(9):2512-2520
A quantitative determinants-of-exposure analysis of respirable crystalline silica (RCS) levels in the construction industry was performed using a database compiled from an extensive literature review. Statistical models were developed to predict work-shift exposure levels by trade. Monte Carlo simulation was used to recreate exposures derived from summarized measurements which were combined with single measurements for analysis. Modeling was performed using Tobit models within a multimodel inference framework, with year, sampling duration, type of environment, project purpose, project type, sampling strategy and use of exposure controls as potential predictors. 1346 RCS measurements were included in the analysis, of which 318 were non-detects and 228 were simulated from summary statistics. The model containing all the variables explained 22% of total variability. Apart from trade, sampling duration, year and strategy were the most influential predictors of RCS levels. The use of exposure controls was associated with an average decrease of 19% in exposure levels compared to none, and increased concentrations were found for industrial, demolition and renovation projects. Predicted geometric means for year 1999 were the highest for drilling rig operators (0.238 mg m(-3)) and tunnel construction workers (0.224 mg m(-3)), while the estimated exceedance fraction of the ACGIH TLV by trade ranged from 47% to 91%. The predicted geometric means in this study indicated important overexposure compared to the TLV. However, the low proportion of variability explained by the models suggests that the construction trade is only a moderate predictor of work-shift exposure levels. The impact of the different tasks performed during a work shift should also be assessed to provide better management and control of RCS exposure levels on construction sites. 相似文献
845.
Paul AG Scheringer M Hungerbühler K Loos R Jones KC Sweetman AJ 《Journal of environmental monitoring : JEM》2012,14(2):524-530
The sources, distribution, levels and sinks of perfluorooctane sulfonate (PFOS) estimated to be released from areas of high population density, have been explored using the river Rhine as a case study. A comparison between modelled and measured data is presented, along with analysis of the importance of PFOS sorption in riverine systems. PFOS releases into the Rhine were estimated to be 325-690 kg/yr based on per capita emission rates of 27-57 μg day(-1) from a population of 33 million living within a 50 km zone either side of the river. Sorption of PFOS to suspended particles and sediments may alter its fate in the aquatic environment. Therefore available measured and modelled partitioning data was assessed, and K(d) values (sorption coefficient) of 7.5 and 20 were selected. This resulted in sediment-water ratios of 23-76 : 1, which are similar to ratios reported in the literature, and resulted in modelled estimates that <20% of the total PFOS entering the Rhine binds to sediments or suspended particles. The calculated discharge from the Rhine to the North Sea based on measured data was 420-2200 kg/yr; our model predictions are in good agreement with these estimates. Emission trends were accurately predicted, suggesting population density can be effectively used as a surrogate for diffuse PFOS emissions from product use, while predicted concentrations were a factor of 2-4 below measured data showing the importance of other sources. Transfer of PFOS to sediment is estimated to be minimal, and consequently discharges to the North Sea are roughly equal to PFOS releases to river water. 相似文献
846.
Arruda-Neto JD Nieto L Righi H Cotta MA Carrer H Rodrigues TE Genofre GC 《Journal of environmental monitoring : JEM》2012,14(8):2108-2113
Persistent harmful scenarios associated with disposal of radioactive waste, high-background radiation areas and severe nuclear accidents are of great concern regarding consequences to both human health and the environment. Of particular concern is the extracellular DNA in aquatic environments contaminated by radiological substances. Strand breaks induced by radiation promote decrease in the transformation efficiency for extracellular DNA. The focus of this study is the quantification of DNA damage following long-term exposure (over one year) to low doses of natural uranium (an alpha particle emitter) to simulate natural conditions, since nothing is known about alpha radiation induced damage to extracellular DNA. A high-resolution Atomic Force Microscope was used to evaluate DNA fragments. Double-stranded plasmid pBS as a model for extracellular DNA was exposed to different amounts of natural uranium. It was demonstrated that low concentrations of U in water (50 to 150 ppm) produce appreciable numbers of double strand breaks, scaling with the square of the average doses. The importance of these findings for environment monitoring of radiological pollution is addressed. 相似文献
847.
The concentrations of heavy metals and metals (Zn, Pb, Bi, Cd, Ni, Co, Fe, Mn, Mg, Cu, Cr, Ca, Sr, Na, Li, K) were measured in muscle of five species Cyprinus carpio (from I??kl? dam), Scardinius erythrophthalmus (from I??kl? dam), Tinca tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), Carassius carassius (from Karaca?ren dam) caught from I??kl? and Karaca?ren. The highest metal was Na (466.95 μg/g) in C. carassius, while the lowest levels were Fe (0.37 μg/g) and Cu (0.37 μg/g) in C. carpio from I??kl? dam. The mean concentrations μg/g d.w. some of heavy metals in muscle of C. carpio (from I??kl? dam), S. erythrophthalmus (from I??kl? dam), T. tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), C. carassius (from Karaca?ren dam) were as follows: Cd 2.00-2.10-1.95-2.06-2.27, Zn 4.36-2.64-13.13-13.33-24.47, Pb 1.65-1.24-1.90-2.37-2.41, Co 2.46-2.37-2.48-2.58-2.80, Mg 138.51-154.35-218.59-204.58-202.16, Fe 0.37-2.62-3.17-3.01-12.33, respectively. 相似文献
848.
Luis Fernando Cáceres Choque Oswaldo E. Ramos Ramos Sulema N. Valdez Castro Rigoberto R. Choque Aspiazu Rocío G. Choque Mamani Samuel G. Fernández Alcazar Ondra Sracek Prosun Bhattacharya 《Environmental monitoring and assessment》2013,185(12):9979-9994
Chemical weathering is one of the major geochemical processes that control the mobilization of heavy metals. The present study provides the first report on heavy metal fractionation in sediments (8–156 m) of Lake Titicaca (3,820 m a.s.l.), which is shared by the Republic of Peru and the Plurinational State of Bolivia. Both contents of total Cu, Fe, Ni, Co, Mn, Cd, Pb, and Zn and also the fractionation of these heavy metals associated with four different fractions have been determined following the BCR scheme. The principal component analysis suggests that Co, Ni, and Cd can be attributed to natural sources related to the mineralized geological formations. Moreover, the sources of Cu, Fe, and Mn are effluents and wastes generated from mining activities, while Pb and Zn also suggest that their common source is associated to mining activities. According to the Risk Assessment Code, there is a moderate to high risk related to Zn, Pb, Cd, Mn, Co, and Ni mobilization and/or remobilization from the bottom sediment to the water column. Furthermore, the Geoaccumulation Index and the Enrichment Factor reveal that Zn, Pb, and Cd are enriched in the sediments. The results suggest that the effluents from various traditional mining waste sites in both countries are the main source of heavy metal contamination in the sediments of Lake Titicaca. 相似文献
849.
Mike Williams Anupama Kumar Christoph Ort Michael G. Lawrence Adam Hambly Stuart J. Khan Rai Kookana 《Environmental monitoring and assessment》2013,185(11):9321-9332
The assessment of potential impacts of wastewater effluent discharges in freshwater systems requires an understanding of the likely degrees of dilution and potential zones of influence. In this study, four tracers commonly present in wastewater effluents were monitored to compare their relative effectiveness in determining areas in freshwater systems that are likely to be impacted by effluent discharges. The four tracers selected were the human pharmaceutical carbamazepine, anthropogenic gadolinium, fluorescent-dissolved organic matter (fDOM), and electrical conductivity (EC). The four tracers were monitored longitudinally in two distinct freshwater systems receiving wastewater effluents, where one site had a high level of effluent dilution (effluent <1 % of total flow) and the other site had a low level of effluent dilution (effluent ~50 % of total flow). At both sites, the selected tracers exhibited a similar pattern of response intensity downstream of discharge points relative to undiluted wastewater effluent, although a number of anomalies were noted between the tracers. Both EC and fDOM are non-specific to human influences, and both had a high background response, relative to the highly sensitive carbamazepine and anthropogenic gadolinium responses, although the ease of measuring EC and fDOM would make them more adaptable in highly variable systems. However, the greater sensitivity and selectivity of carbamazepine and gadolinium would make their combination with EC and fDOM as tracers of wastewater effluent discharges highly desirable to overcome potential limitations of individual tracers. 相似文献
850.
Alam R Munna G Chowdhury MA Sarkar MS Ahmed M Rahman MT Jesmin F Toimoor MA 《Environmental monitoring and assessment》2012,184(1):573-580
In rural areas in Bangladesh, groundwater is the principal source of water supply. This underground water is available in
considerable amount in shallow aquifers. It is free from pathogenic microorganisms and hence water-borne diseases. In plain
lands, other than hilly areas, water supply to 97% rural population comes from tube-wells, which is regarded to be a phenomenal
achievement in preserving public health. Besides, a dependable water supply system all throughout the country is offset by
two factors: (a) high salinity in surface plus groundwater in coastal areas; (b) want of suitable groundwater aquifers in
hilly areas and the high cost of setting up tube-wells due to deep underground water table and stony layers. However, presence
of arsenic in underground water now poses a serious threat to the success once made in water supply by setting up of manually
operated tube-wells in the village areas—the achievement is now on the brink of total collapse. In about 61 districts out
of 64, presence of arsenic exceeds a quantity of 0.05 mg/1, a permissible limit as per Bangladeshi water quality standard.
Harvesting rainwater can be a pragmatic solution to this problem, which is common in many places in Sylhet especially in the
hilly areas on the north eastern part of the city. This can be an alternative source of drinking water because of availability
of rainwater from March to October. Heavy rain occurs from end of May till mid September, which is commonly known as the rainy
season. This paper focuses on the possibility of harvesting rainwater in rural communities and thickly populated urban areas
of Sylhet. It also demonstrates the scopes of harvesting rainwater using simple and low-cost technology. With setting up of
a carefully planned rainwater storage tank, a family can have all of its drinking water from rain. Planned use of rainwater
through rainwater harvesting in the roof catchments may fulfill the entire annual domestic water demand of a family in the
rural areas of Bangladesh. 相似文献