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231.
Isolated Trichoderma atroviride from Cu-polluted river sediment at the Serdang Industrial Area was studied under in vitro conditions to understand the mechanisms that allowed the fungi to thrive in the Cu-polluted freshwater ecosystem. From this study, adsorption was recognized as the main mechanism of Cu tolerance with 50–85% adsorption during the in vitro experiment. The uptake capacity of the isolate in liquid medium ranged from 0.8 to 11.2 mg g?1 in the potato dextrose broth medium with increasing Cu concentrations from 25 to 300 mg L?1. It was found that 2.7–5.0% of Cu was lost due to washing. The high percentage of Cu adsorption and the high uptake capacity of Cu by T. atroviride suggest that it is a potential bioremediator of Cu. However, further studies are needed to confirm its practical use as a bioremediating agent for Cu under field conditions. 相似文献
232.
Mercury and arsenic pollution has been recognized as a potential environmental and public health problem for over 40 years. The major source of exposure to mercury for humans is the ingestion of fish. This study was conducted with the aim of determining the levels of mercury and arsenic in the muscles of four fish species caught in the Beheshtabad River and comparing the results with the maximum tolerance levels for mercury and arsenic. The samples of 90 fish were used for the determination of both the metals by graphite furnace atomic absorption spectrometry. The results showed that the concentrations ranged from 1.5 to 3.8 µg kg?1 for mercury and from 35 to 70 µg kg?1 for arsenic, with means of 2.7 ± 0.5 and 57 ± 12 µg kg?1, respectively. Both mean levels were lower than the threshold limits acceptable by WHO standards. 相似文献
233.
The production of neem oil coated urea (NOCU), a technology developed by the Indian Agricultural Research Institute, has been grown to over 2.0 million tons per year. The estimation of neem oil content in NOCU is important due to its significance in ensuring agronomic efficiency. Therefore, this study was taken up to develop a simple method for the determination of neem oil in NOCU. The procedure involves extraction of neem oil from NOCU; saponification of extracted oil; oxidation of released glycerol to formaldehyde, and subsequent conversion of formaldehyde to a dihydrolutidine derivative. Its concentration was determined spectrophotometrically. The recoveries of neem oil from NOCU with oil load of 500 and 1000?ppm were 87.6?±?3.0% and 90.0?±?4.8% respectively with direct method; and improved to 92.6?±?4.0% and 96.7?±?3.8% after including the in situ purification. A simple method based on the Hantzsch reaction was developed for the determination of neem oil in NOCU. This method is superior to earlier methods in terms of sensitivity, simplicity, and time required. 相似文献
234.
In this work, a new procedure for the enrichment of the trace amount of Cu2+, Ni2+, Co2+, Pb2+, Fe2+, and Zn2+ ions based on the utilization of multiwalled carbon nanotubes (MWCNT) modified with 2-(2-hydroxy-5-nitrophenyl)-4,5-diphenyl imidazole as chelating agent prior to their determination by flame atomic absorption spectrometry has been described. The influence of effective parameters including pH, amount of ligand and MWCNT, composition of eluent, and coexisting ions on recoveries of understudy metal ions was examined. At the optimum pH of 5.0, all metal ions were quantitatively sorbed onto the proposed solid phase and completely desorbed with 8?mL of 5.0?mol?L?1 HNO3. The detection limit of Cu2+, Co2+, Ni2+, Pb2+, Fe2+, and Zn2+ ions was 1.7, 2.4, 2.3, 2.9, 2.8, and 1.4?µg?L?1, while the preconcentration factor was 63 for Cu2+ and 94 for the other metal ions and relative standard deviations between 1.8 less than 3.0%. The proposed procedure was applied for the analysis of various samples. 相似文献
235.
AbstractA rapid and selective technique for extraction, preconcentration and determination of trace amounts of cobalt in water and pharmaceutical samples by air-assisted liquid–liquid microextraction combined with flame atomic absorption spectrometry is proposed. 1-Nitroso-2-naphthol is used as a complexing agent and 1-octanol as an extraction solvent. Parameters relevant for analytical effectivity, i.e. pH of sample solution, concentration of complexing agent, volume of extraction solvent, and number of extraction cycles are optimized using a Box–Behnken design. At optimum conditions, a dynamic linear range of 5–600?µg L?1 is obtained, with a limit of detection of 1.2?µg L?1. The method is used for determination of Co(II) in environmental water and pharmaceutical samples. 相似文献
236.
An anayltical procedure based on a sequential extraction scheme is applied to samples of suspended particulates from an urban area of Barcelona. This area presents high levels of air pollution owing to automotive emissions and industrial activity. The procedure allows the partitioning of particulate trace metals into four fractions: soluble and exchangeable, bound to carbonates and iron‐manganese oxides, bound to organic matter and residual. In this work, the chemical associations of Fe, Pb, Cu, Mn, Cr and Cd have been investigated. In the analysed samples, only the cadmium is predominantly in the first fraction whereas the other metals are largely associated to carbonates and Fe‐Mn oxides. 相似文献
237.
238.
Mauro Mecozzi Demetria Cardarilli Eva Pietrantonio Marina Amici 《Chemistry and Ecology》2013,29(4):239-254
In this paper a method for the study of the qualitative similarity of extractable humic substance (EHS) in marine sediments based on the realisation of UV spectral library of EHS is described. the spectral library was built including the digitised spectra of humic substance extracted from several marine sediments (46 samples) and two samples of standard materials (lignin sulphonate and humic substance) in a Statistica data file. the data matrix was elaborated by means of different multivariate statistic techniques such as Cluster Analysis (CA), Principal Components Analysis (PCA) and the univariate technique Spectral Correlation Analysis (SCA). This approach allows us to show the contribution of different organic compounds (aromatic, lipid and acid) to the composition of EHS and moreover it evidences also the structural characteristics of EHS in terms of similarities in the qualitative composition of samples such as presence of terrestrial and/or vegetal contributions. the UV library is an objective tool to study the qualitative composition of EHS and it represents a complementary approach to the most common methods based on the application of spectroscopic (IR, 13CNMR), potentiometric and chromatographic techniques. 相似文献
239.
M. Hafidi G. Ait Baddi V. Gilard P. Ramos K. Alimi J. C. Revel 《Chemistry and Ecology》2013,29(4):313-324
Elemental analysis, fluorescence spectroscopy and differential scanning calorimetry (DSC) were applied to the study of fulvic acids isolated from different stages during olive mill waste composting. The fulvic extracted acids are characterized by a high nitrogen content and O/C ratio values that may result from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by fluorescence spectroscopy in the synchronous-scan mode by the decrease of shoulder intensities at intermediate wavelengths indicating the increase of polycondensation and conjugation of unsaturated structures and the greater uniformity of fluorophores. Fluorescence spectra in the emission, excitation and synchronous modes became simpler with compost maturation. This was confirmed by DSC results which proved the high degree of polycondensation of aromatic nuclei of fulvic acid molecules during olive mill waste composting. 相似文献
240.