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731.
Adamu Mustapha Ahmad Zaharin Aris Hafizan Juahir Mohammad Firuz Ramli Nura Umar Kura 《Environmental science and pollution research international》2013,20(8):5630-5644
Jakara River Basin has been extensively studied to assess the overall water quality and to identify the major variables responsible for water quality variations in the basin. A total of 27 sampling points were selected in the riverine network of the Upper Jakara River Basin. Water samples were collected in triplicate and analyzed for physicochemical variables. Pearson product-moment correlation analysis was conducted to evaluate the relationship of water quality parameters and revealed a significant relationship between salinity, conductivity with dissolved solids (DS) and 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and nitrogen in form of ammonia (NH4). Partial correlation analysis (r p) results showed that there is a strong relationship between salinity and turbidity (r p?=?0.930, p?=?0.001) and BOD5 and COD (r p?=?0.839, p?=?0.001) controlling for the linear effects of conductivity and NH4, respectively. Principal component analysis and or factor analysis was used to investigate the origin of each water quality parameter in the Jakara Basin and identified three major factors explaining 68.11 % of the total variance in water quality. The major variations are related to anthropogenic activities (irrigation agricultural, construction activities, clearing of land, and domestic waste disposal) and natural processes (erosion of river bank and runoff). Discriminant analysis (DA) was applied on the dataset to maximize the similarities between group relative to within-group variance of the parameters. DA provided better results with great discriminatory ability using eight variables (DO, BOD5, COD, SS, NH4, conductivity, salinity, and DS) as the most statistically significantly responsible for surface water quality variation in the area. The present study, however, makes several noteworthy contributions to the existing knowledge on the spatial variations of surface water quality and is believed to serve as a baseline data for further studies. Future research should therefore concentrate on the investigation of temporal variations of water quality in the basin. 相似文献
732.
Abundance of denitrification genes under different peizometer depths in four Irish agricultural groundwater sites 总被引:1,自引:0,他引:1
Maria Barrett Mohammad M. R. Jahangir Changsoo Lee Cindy J. Smith Niamh Bhreathnach Gavin Collins Karl G. Richards Vincent O’Flaherty 《Environmental science and pollution research international》2013,20(9):6646-6657
This study examined the relationship between the abundance of bacterial denitrifiers in groundwater at four sites, differing with respect to overlaying land management and peizometer depth. Groundwater was sourced from 36 multilevel piezometers, which were installed to target different groundwater zones: (1) subsoil, (2) subsoil to bedrock interface, and (3) bedrock. The gene copy concentrations (GCCs), as gene copies per liter, for bacterial 16S rRNA genes and the denitrifying functional genes, nirK, nirS, and nosZ, were determined using quantitative polymerase chain reaction assays. The results were related to gaseous nitrogen emissions and to the physicochemical properties of the four sites. Overall, nirK and nirS abundance appeared to show no significant correlation to N2O production (P?=?0.9989; P?=?0.3188); and no significant correlation was observed between nosZ and excess N2 concentrations (P?=?0.0793). In the majority of piezometers investigated, the variation of nirK and nirS gene copy concentrations was considered significant (P?<?0.0001). Dissolved organic carbon (DOC) decreased with aquifer depth and ranged from 1.0–4.0 mg l?1, 0.9–2.4 mg l?1, and 0.8–2.4 mg l?1 within piezometers located in the subsoil, subsoil/bedrock interface, and bedrock depths, respectively. The availability of increasing DOC and the depth of the water table were positively correlated with increasing nir and nosZ GCCs (P?=?0.0012). A significant temporal correlation was noted between nirS and piezometer depth (P?<?0.001). Interestingly, the nirK, nirS, and nosZ GCCs varied between piezometer depths within specific sites, while GCCs remained relatively constant from site to site, thus indicating no direct impact of agricultural land management strategies investigated on denitrifier abundance. 相似文献
733.
Mohammad Arhami Nima Kamali Mohammad Mahdi Rajabi 《Environmental science and pollution research international》2013,20(7):4777-4789
Recent progress in developing artificial neural network (ANN) metamodels has paved the way for reliable use of these models in the prediction of air pollutant concentrations in urban atmosphere. However, improvement of prediction performance, proper selection of input parameters and model architecture, and quantification of model uncertainties remain key challenges to their practical use. This study has three main objectives: to select an ensemble of input parameters for ANN metamodels consisting of meteorological variables that are predictable by conventional weather forecast models and variables that properly describe the complex nature of pollutant source conditions in a major city, to optimize the ANN models to achieve the most accurate hourly prediction for a case study (city of Tehran), and to examine a methodology to analyze uncertainties based on ANN and Monte Carlo simulations (MCS). In the current study, the ANNs were constructed to predict criteria pollutants of nitrogen oxides (NOx), nitrogen dioxide (NO2), nitrogen monoxide (NO), ozone (O3), carbon monoxide (CO), and particulate matter with aerodynamic diameter of less than 10 μm (PM10) in Tehran based on the data collected at a monitoring station in the densely populated central area of the city. The best combination of input variables was comprehensively investigated taking into account the predictability of meteorological input variables and the study of model performance, correlation coefficients, and spectral analysis. Among numerous meteorological variables, wind speed, air temperature, relative humidity and wind direction were chosen as input variables for the ANN models. The complex nature of pollutant source conditions was reflected through the use of hour of the day and month of the year as input variables and the development of different models for each day of the week. After that, ANN models were constructed and validated, and a methodology of computing prediction intervals (PI) and probability of exceeding air quality thresholds was developed by combining ANNs and MCSs based on Latin Hypercube Sampling (LHS). The results showed that proper ANN models can be used as reliable metamodels for the prediction of hourly air pollutants in urban environments. High correlations were obtained with R 2 of more than 0.82 between modeled and observed hourly pollutant levels for CO, NOx, NO2, NO, and PM10. However, predicted O3 levels were less accurate. The combined use of ANNs and MCSs seems very promising in analyzing air pollution prediction uncertainties. Replacing deterministic predictions with probabilistic PIs can enhance the reliability of ANN models and provide a means of quantifying prediction uncertainties. 相似文献
734.
This study was navigated to examine the effects of fungicide-stress on the activities of plant-growth-promoting rhizobacterium Pseudomonasputida with inherent phosphate solubilizing activity. The fungicide-tolerant and phosphate solubilizing P.putida strain PS9 was isolated from the mustard rhizosphere and tentatively identified following standard morphological, physiological and biochemical tests. To further consolidate the identity of the strain PS9, the 16S rDNA sequence analysis was performed. Following the BLAST program, the strain PS9 was identified as P.putida. In the presence of the varying concentrations (0-3200 μg mL−1; at a two fold dilution interval) of four fungicides of different chemical families (tebuconazole, hexaconazole, metalaxyl and kitazin) amended in minimal salt agar medium, the P.putida strain PS9 showed a variable tolerance levels (1400-3200 μg mL−1) against the tested fungicides. The strain PS9 produced plant-growth-promoting (PGP) substances in significant amount in the absence of fungicides. In general, fungicides applied at the recommended, two and three times of the recommended rates, decreased the PGP attributes of P.putida the strain PS9 and affected the PGP activities in concentration-dependent manner. Fungicides at the recommended dose had minor reducing effect while the doses higher than the recommended dose significantly reduced the PGP activities (phosphate solubilization, salicylic acid, 2,3-dihydroxy benzoic acid, and indole-3-acetic acid production except exo-polysaccharides, hydrogen cyanate and ammonia production). Of the four fungicides, tebuconazole generally, showed maximum toxicity to the PGP activities of the strain PS9. This study inferred that fungicides must be examined in vitro for their possible adverse effects on soil micro flora before their application in agricultural fields. Moreover, the results also suggested the prerequisite of application of fungicide-tolerant PGPR strains as bioinoculants so that their PGP activities may not be suppressed under fungicide stress. 相似文献
735.
Chronic exposure of arsenic via drinking water and its adverse health impacts on humans 总被引:1,自引:0,他引:1
Mohammad Mahmudur Rahman Jack C. Ng Ravi Naidu 《Environmental geochemistry and health》2009,31(Z1):189-200
Worldwide chronic arsenic (As) toxicity has become a human health threat. Arsenic exposure to humans mainly occurs from the
ingestion of As contaminated water and food. This communication presents a review of current research conducted on the adverse
health effects on humans exposed to As-contaminated water. Chronic exposure of As via drinking water causes various types
of skin lesions such as melanosis, leucomelanosis, and keratosis. Other manifestations include neurological effects, obstetric
problems, high blood pressure, diabetes mellitus, diseases of the respiratory system and of blood vessels including cardiovascular,
and cancers typically involving the skin, lung, and bladder. The skin seems to be quite susceptible to the effects of As.
Arsenic-induced skin lesions seem to be the most common and initial symptoms of arsenicosis. More systematic studies are needed
to determine the link between As exposure and its related cancer and noncancer end points. 相似文献
736.
Rasoul Kharazmi Ali Tavili Mohammad Reza Rahdari Lyudmila Chaban Evgeny Panidi Jesús Rodrigo-Comino 《Environmental monitoring and assessment》2018,190(6):356
The availability of Landsat data allows improving the monitoring and assessment of large-scale areas with land cover changes in rapid developing regions. Thus, we pretend to show a combined methodology to assess land cover changes (LCCs) in the Hamoun Wetland region (Iran) over a period of 30-year (1987–2016) and to quantify seasonal and decadal landscape and land use variabilities. Using the pixel-based change detection (PBCD) and the post-classification comparison (PCC), four land cover classes were compared among spring, summer, and fall seasons. Our findings showed for the water class a higher correlation between spring and summer (R2?=?0.94) than fall and spring (R2?=?0.58) seasons. Before 2000, ~?50% of the total area was covered by bare soil and 40% by water. However, after 2000, more than 70% of wetland was transformed into bare soils. The results of the long-term monitoring period showed that fall season was the most representative time to show the inter-annual variability of LCCs monitoring and the least affected by seasonal-scale climatic variations. In the Hamoun Wetland region, land cover was highly controlled by changes in surface water, which in turn responded to both climatic and anthropogenic impacts. We were able to divide the water budget monitoring into three different ecological regimes: (1) a period of high water level, which sustained healthy extensive plant life, and approximately 40% of the total surface water was retained until the end of the hydrological year; (2) a period of drought during high evaporation rates was observed, and a mean wetland surface of about 85% was characterized by bare land; and (3) a recovery period in which water levels were overall rising, but they are not maintained from year to year. After a spring flood, in 2006 and 2013, grassland reached the highest extensions, covering till more than 20% of the region, and the dynamics of the ecosystem were affected by the differences in moisture. The Hamoun wetland region served as an important example and demonstration of the feedbacks between land cover and land uses, particularly as pertaining to water resources available to a rapidly expanding population. 相似文献
737.
Mohammad Nafees Fawad Ahmad Muhammad Naeem Butt Mohammad Khurshed 《Environmental monitoring and assessment》2018,190(6):359
Kabul River is a shared resource of Pakistan and Afghanistan and is a major source of economy for both countries. It is used for irrigation, power generation, fishery, hunting, and recreation. This study explored human-induced impact on Kabul River and its associated wetlands. For an in-depth study, the area situated between the two tributaries of Kabul River, i.e., Shalam and Naguman Rivers, was selected. The focus of the study was to find out reduction in the wetland areas, its causes, and associated impacts. For this purpose, a survey was conducted in 10 villages selected randomly in 10 union councils. The study revealed that anthropogenic activities, such as wetland farming, grazing residential encroachment, and industrial development, have caused severe alteration in the wetland of the study areas. The results revealed that before the 1990s, 33.55% area of the study area was wetland. Due to regular decrease in the flow of the Kabul River System and human encroachment, it has engulfed 68.40% of the total wetland leaving behind only 10.60% wetland. This can be termed as a big ecological disturbance. In the long run, this will have negative effects on both the countries. It is therefore recommended to give proper attention to this important wetland, positioning between Shalam and Naguman Rivers and to conserve it. One of the solutions is to regulate the natural flow of Kabul River. 相似文献
738.
Rawat M Singh UK Mishra AK Subramanian V 《Environmental monitoring and assessment》2008,137(1-3):67-74
In this study, an attempt has been made to study methane flux and quantification of heavy metals from Municipal Solid Waste
(MSW) landfill areas of selected cities in India. During the period of study, the average value of methane flux was estimated
from these landfill areas varied from 146–454 mg/m2/h. Methane emission from landfill is of serious environmental global concern
as it accounts for approximately 15 percentages of current Greenhouse gas emissions. It has been estimated that methane emission,
from landfill areas in the world, in next two decades would be same as that what is emitted from paddy fields presently. Besides,
the estimation of methane flux, quantification of some heavy metals was conducted to analyse the suitability of using MSW
as compost. The average values for metals were observed to be both within the range of USEPA and Indian standards for MSW
disposal in landfill areas and to be used as compost respectively. 相似文献
739.
This study was carried out to determine the noise-reduction effectiveness of the Pinus sylvestris L. and Populus nigra L. trees along the E-80 State highway in Erzurum-Turkey. Noise values were taken at three measurement points; open (without trees and taken as control), the urban forests of pure P. sylvestris L. and P. nigra L. areas, and at four different distances; 0 (near the noise source), 25, 50 and 75 m from the noise source. At the distance of 25 m from the source, the noise value was 78.5 dB(A) in the control area, which was reduced 75.5 dB(A) and 69.2 dB(A) in the P. nigra L. and P. sylvestris L. areas, with the reduction rates of 24.7 and 31% compared to the control, respectively. This value was 69.6, 67.1 and 64.3 at the distance of 50 m and 64.9, 62.5 and 59.2 at 75 m for the naked, P. nigra L. and P. sylvestris L. areas, respectively. From the results of the study, it was suggested that for the noise pollution from the traffic flow on the roads, in especially the big cities, noise reduction zones with suitable width and plant species should be formed along the main arteries of the cities. 相似文献
740.
Determination of landscape beauties through visual quality assessment method: a case study for Kemaliye (Erzincan/Turkey) 总被引:1,自引:0,他引:1
Kemaliye (Erzincan/Turkey) is the member of European Association of Historic Towns and Regions. The aim of this study was
to reveal the visual richness of the town; to identify the relationship between landscape spatial pattern and visual quality
of the landscape and to offer some suggestions for the future planning in regarding to these visual beauties. The visual quality
assessment method was used in this study. The results of the study revealed three landscape types that have the highest visual
quality. Among those, the highest one is urban scenery 3 (US3; VQP = 5.9400), the second is geological structure scenery 5
(GSS 5; VQP = 5.9200) and the third natural scenery 3 (NS3; VQP = 5.9133). Visual quality assessment showed that urban pattern,
geological structure and natural resources of the region also have visual value. The relationships between landscape spatial
pattern and visual quality of landscape indicated that certain characteristics of landscape affected the quality. For instance,
as the texture level decreased in natural landscapes and as the green areas increased in geological structure, visual preferences
ratio increased. Some suggestions were also made regarding the visual resources use in the region. 相似文献