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171.
Coastal erosion may be caused by natural causes as well as human factors. Karasu town of the city of Sakarya in Turkey which is a touristic region on the Black Sea coast has been experienced a drastic coastal erosion. In recent years, this erosion reached the threatening dimensions for the structures in the settlement. According to the temporal analyses of Landsat satellite images, the maximum erosion on the coastline was detected 100 m between 1987–2013. The results of the study show that the harbour construct on the Karasu coast has the major impact on this event. The secondary factor is that the amount of the sediment carried by the Sakarya River was decreased in time due to different reasons. To prevent the coastal erosion, a series of offshore breakwaters were planned after the failed application of groins on the coastline. In this study, temporal changes of the coastline are investigated by the Landsat satellite data and land surveys, possible reasons of the erosion are discussed and the solutions are proposed regarding the coastal structures.  相似文献   
172.
Journal of Material Cycles and Waste Management - Nowadays, textile waste arising from increasing clothing production, consumption, and disposal activities has led to environmental, social, and...  相似文献   
173.
In this study, the indicative value of mosses as biomonitors of atmospheric nitrogen (N) depositions and air concentrations on the one hand and site-specific and regional factors which explain best the total N concentration in mosses on the other hand were investigated for the first time at a European scale using correlation analyses. The analyses included data from mosses collected from 2781 sites across Europe within the framework of the European moss survey 2005/6, which was coordinated by the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation). Modelled atmospheric N deposition and air concentration data were calculated using the Unified EMEP Model of the European Monitoring and Evaluation Programme (EMEP) of the Convention on Long-range Transboundary Air Pollution (CLRTAP). The modelled deposition and concentration data encompass various N compounds. In order to assess the correlations between moss tissue total N concentrations and the chosen predictors, Spearman rank correlation analysis and Classification and Regression Trees (CART) were applied. The Spearman rank correlation analysis showed that the total N concentration in mosses and modelled N depositions and air concentrations are significantly correlated (0.53 ≤ rs ≤ 0.68, p < 0.001). Correlations with other predictors were lower than 0.55. The CART analysis indicated that the variation in the total N concentration in mosses was best explained by the variation in NH4+ concentrations in air, followed by NO2 concentrations in air, sampled moss species and total dry N deposition. The total N concentrations in mosses mirror land use-related atmospheric concentrations and depositions of N across Europe. In addition to already proven associations to measured N deposition on a local scale the study at hand gives a scientific prove on the association of N concentration in mosses and modelled deposition at the European scale.  相似文献   
174.

Purpose

The objectives of this research are to identify the functional groups and determine corresponding pK a values of the acidic sites on dried brown algae Cystoseira barbata using FTIR and potentiometric titrations, and to investigate the biosorption ability of biomass towards divalent nickel, cadmium, and lead ions. Adsorption was studied as a function of solution pH and contact time, and experimental data were evaluated by the Langmuir isotherm model.

Methods

CaCl2 pretreatment was applied to the sorbent for enhancing the metal uptake capacity. The effect of solution pH on biosorption equilibrium was investigated in the pH range of 1.5?C5.0. Individual as well as competitive adsorption capacity of the sorbent were studied for metal cations and mixtures.

Results

The retention of the tested metal ions was mostly influenced from pH in the range of 1.5?C2.5, then stayed almost constant up to 5.0, while Ni(II) uptake showed the highest variation with pH. Potentiometric titrations were performed to find the number of strong and weak acidic groups and their acidity constants. The density of strong and weak acidic functional groups in the biomass were found to be 0.9 and 2.26?mmol/g, respectively. The FTIR spectra of the sorbent samples indicated various functionalities on the biomass surface including carboxyl, hydroxyl, and amino and sulphonate groups which are responsible for the binding of metal ions.

Conclusions

The capacity of the biomass for single metal ions (around 1?mmol/g) was increased to 1.3?mmol/g in competitive adsorption, Pb(II) showing the highest Langmuir intensity constant. Considering its extremely high abundance and low cost, C. barbata may be potentially important in metal ion removal from contaminated water and industrial effluents.  相似文献   
175.
A sensitive and accurate analytical method based on dispersive liquid-liquid microextraction was developed for the simultaneous determination of selected pesticides, hormones, and endocrine disruptors by GC-MS. The optimum conditions of the extraction procedure were determined using an experimental design of factors significantly affecting the extraction output. Analysis of variance (ANOVA) was used to evaluate the main effects of experimental factors and their interactions. The limit of detection values determined for the analytes under optimum experimental conditions were found to be between 0.30–2.0 ng/mL. The linear calibration plot of analytes span across a wide concentration range and low %RSD values from replicate measurements indicated good precision of the developed method. Spiked recovery tests were also performed on municipal wastewater, well water, lake water, sea water, and tap water matrices to determine the method’s accuracy and applicability to water samples. The recovery results obtained were satisfactory for all water samples.  相似文献   
176.
The major and trace element component of 48 recent sediment samples in three distinct intervals (0–10, 10–20, and 20–30 cm) from Lake Ac?göl is described to present the current contamination levels and grift structure of detrital and evaporate mineral patterns of these sediments in this extreme saline environment. The spatial and vertical concentrations of major oxides were not uniform in the each subsurface interval. However, similar spatial distribution patterns were observed for some major element couples, due mainly to the detrital and evaporate origin of these elements. A sequential extraction procedure including five distinct steps was also performed to determine the different bonds of trace elements in the <?60-μ particulate size of recent sediments. Eleven trace elements (Ni, Fe, Cd, Pb, Cu, Zn, As, Co, Cr, Al and Mn) in nine surface and subsurface sediment samples were analyzed with chemical partitioning procedures to determine the trace element percentage loads in these different sequential extraction phases. The obtained accuracy values via comparison of the bulk trace metal loads with the total loads of five extraction steps were satisfying for the Ni, Fe, Cd, Zn, and Co. While, bulk analysis results of the Cu, Ni, and V elements have good correlation with total organic matter, organic fraction of sequential extraction characterized by Cu, As, Cd, and Pb. Shallow Lake Ac?göl sediment is characteristic with two different redox layer a) oxic upper level sediments, where trace metals are mobilized, b) reduced subsurface level, where the trace metals are precipitated.  相似文献   
177.
This study was carried out to determine the accumulation levels of heavy metals (Zn, Cd, Pb, Cu, Fe, Cr) in seston to three different freshwater resources poured into the Iskenderun Bay. Seasonal averages of physico-chemical parameters measured at stations, Arsuz Stream, Payas Stream, and Ceyhan River, are classified as Class III—contaminated water according to the temperature parameter in the summer. Payas Stream has been determined to be Class III—polluted water according to pH parameters during the summer season. Ceyhan River was found to be Class III—contaminated water according to the dissolved oxygen parameter in the autumn season. Heavy metal accumulation levels in the seston were determined Fe?>?Cr?>?Zn?>?Cu?>?Pb?>?Cd in Arsuz Stream, Fe?>?Zn?>?Pb?>?Cr?>?Cu?>?Cd in Payas Stream, and Fe?>?Zn?>?Cr?>?Cu?>?Pb?>?Cd in Ceyhan River. The results in this study showed that high accumulation levels in seston were determined for Fe while low accumulation levels for Cd.  相似文献   
178.
Bioavailability and degradation of phenanthrene in compost amended soils   总被引:1,自引:0,他引:1  
Bioavailability in soil of organic xenobiotics such as phenanthrene is limited by mechanisms of diffusion of the xenobiotics within soil micropores and organic matter. The agricultural utilization of compost may reduce the risk connected to organic xenobiotic contamination by means of: (i) a reduction of the bioavailable fraction through an increased adsorption and (ii) an enhanced degradation of the remaining bioavailable fraction through an inoculum of degrading microorganisms. Aim of this work is to test this hypothesis by assessing the effects of compost amendment on the bioavailability and degradation of phenanthrene in soil. Experiments were carried out in both sterilized and non-sterilized conditions, and chemical and microbiological analyses were carried out in order to determine the extent of degradation and bioavailability and to monitor the evolution of the soil micro flora in time. Bioavailability was assessed in sterilized microcosms, in order to assess the physical effects of compost on aging processes without the influence of microbial degradation. Results showed that bioavailability is significantly reduced in soils amended with compost, although no differences were found at the 2 doses of compost studied. In non-sterilized soils the amount of phenanthrene degraded was always higher in the amended soils than in the non-amended one. Microbiological analyses confirmed the presence of a higher number of phenanthrene degraders in the amended soils and in samples of compost alone. These results suggest that compost induces the degradation in soils of easily degradable compounds such as phenanthrene, when the proper bacteria are in the compost; more resistant xenobiotics may instead be trapped by the compost organic matter, thus becoming less available.  相似文献   
179.
Climate change is becoming an ever important issue due to the possibility that it may result in extreme weather events such as floods or droughts. Consequently, precipitation forecasting has similarly gained in significance as it is a useful tool in meeting the increasing need for the efficient management of water resources as well as in preventing disasters before they happen. In the literature, there are various statistical and computational methods used for this purpose, including linear and nonlinear regression, kriging, time series models, neural networks, and multivariate adaptive regression splines (MARS). Among them, MARS stands out as the better performing precipitation modeling method. In this article, we used a recently developed method called robust conic mars (RCMARS), based on MARS (also on CMARS), to forecast precipitation owing to its ability to model complex uncertain data. In CMARS, which was developed as a powerful alternative to MARS, the model complexity is penalized in the form of Tikhonov regularization and studied as a conic quadratic programming. In RCMARS, on the other hand, CMARS is refined further by including the existence of uncertainty in the future scenarios and robustifying it with a robust optimization technique. To evaluate the performance of the RCMARS method, it was applied to build a precipitation model constructed as an early warning system for the continental Central Anatolia Region of Turkey, where drought has been a recurrent phenomenon for the last few decades. Furthermore, the performance of the RCMARS precipitation model was also compared to that of MARS and CMARS. The results indicated that RCMARS builds more accurate, precise, and stable precipitation models compared to those of MARS and CMARS. In addition to these advantageous features of the RCMARS precipitation model, it also provided a good fit to the data. As a result, we propose its use in precipitation forecasting for the region studied.  相似文献   
180.
The oil industry is a major source of contamination in Peru, and wastewater and sediments containing oil include harmful substances that may have acute and chronic effects. This study determined polycyclic aromatic hydrocarbon (PAH) concentrations by GC/MS, mutagenicity using TA98 and TA100 bacterial strains with and without metabolic activation in the Muta-ChromoPlate? test, and Microtox® 5-min EC50 values of Peruvian crude oil, and water and sediment pore water from the vicinity of San José de Saramuro on the Marañón River and Villa Trompeteros on the Corrientes River in Loreto, Peru. The highest total PAH concentration in both areas was found in water (Saramuro?=?210.15 μg/ml, Trompeteros?=?204.66 μg/ml). Total PAH concentrations in water from San José de Saramuro ranged from 9.90 to 210.15 μg/ml (mean?=?66.48 μg/ml), while sediment pore water concentrations ranged from 2.19 to 70.41 μg/ml (mean?=?24.33 μg/ml). All water samples tested from Saramuro and Trompeteros sites, and one out of four sediment pore water samples from Trompeteros, were found to be mutagenic (P?<?0.001). One sediment pore water sample in Saramuro was determined to have a measurable toxicity (Microtox EC50?=?335.1 mg/l), and in Trompeteros, the EC50 in water and sediment pore water ranged from 25.67 to 133.86 mg/l. Peruvian crude oil was mutagenic using the TA98 strain with metabolic activation, and the EC50 was 17.18 mg/l. The two areas sampled had very high PAH concentrations that were most likely associated with oil activities, but did not lead to acute toxic effects. However, since most of the samples were mutagenic, it is thought that there is a greater potential for chronic effects.  相似文献   
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