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781.
In this study, we examined the effect of four different organic wastes (OW)—composted sheep manure (CSM), spent coffee grounds (SCG), composted pine bark (CPB) and coir (CR)—on the potential groundwater pollution of propanil and isoxaben (herbicides), cadusafos (insecticide) and pencycuron (fungicide) under laboratory conditions. For this purpose, leaching studies were conducted using disturbed soil columns filled with a clay loam soil (Hipercalcic calcisol). The addition of organic matter (OM) drastically reduced the movement of the studied pesticides. The results obtained point to the interest in the use of agro-industrial and composted OW in reducing the groundwater pollution by pesticide drainage.  相似文献   
782.
Selection of reservoir location, the floodable basin forest handling, and the design of dam structures devoted to water supply (e.g. water outlets) constitute relevant features which strongly determine water quality and frequently demand management strategies to be adopted. Although these crucial aspects should be carefully examined during dam design before construction, currently the development of ad hoc limnological studies tailoring dam location and dam structures to the water quality characteristics expected in the future reservoir is not typical practice. In this study, we use numerical simulation to assist on the design of a new dam project in Spain with the aim of maximizing the quality of the water supplied by the future reservoir. First, we ran a well-known coupled hydrodynamic and biogeochemical dynamic numerical model (DYRESM–CAEDYM) to simulate the potential development of anoxic layers in the future reservoir. Then, we generated several scenarios corresponding to different potential hydraulic conditions and outlet configurations. Second, we built a simplified numerical model to simulate the development of the hypolimnetic oxygen content during the maturation stage after the first reservoir filling, taking into consideration the degradation of the terrestrial organic matter flooded and the adoption of different forest handling scenarios. Results are discussed in terms of reservoir design and water quality management. The combination of hypolimnetic withdrawal from two deep outlets and the removal of all the valuable terrestrial vegetal biomass before flooding resulted in the best water quality scenario.  相似文献   
783.
The objective of this study was to identify the organic compounds removed from the leachate when treated with Fenton–Adsorption by gas chromatography coupled to mass spectrometry (GC–MS) in order to identify toxic compounds that could be harmful for the environment or human health.The physicochemical characterization of the raw leachate was carried out before and after the Fenton–Adsorption process. The effluent from each stage of this process was characterized: pH, Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), Total Carbon (TC), Inorganic Carbon (IC), Total Solids (TS), Total Suspended Solids (TSS) and Color. The organic compounds were determined by GC–MS.The removal of COD and color reached over 99% in compliance with the Mexican Standard NOM-001-SEMARNAT-1996, which establishes the maximum permissible limits for contaminants present in wastewater discharges to water and national goods. The chromatographic analysis from the Fenton–Adsorption effluent proved that this treatment removed more than 98% of the organic compounds present in the initial sample. The mono (2-ethylhexyl) ester 1,2-benzenedicarboxylic acid persisted, although it is not considered as toxic compound by the NOM-052-SEMARNAT-2005. Therefore, the treated effluent can be safely disposed of into the environment.  相似文献   
784.
The metropolitan area of Rio de Janeiro is one of the twenty biggest urban agglomerations in the world, with 11 million inhabitants in the metropolitan area, and has a high population density, with 1700 hab. km?2. For this aerosol source apportionment study, the atmospheric aerosol sampling was performed at ten sites distributed in different locations of the metropolitan area from September/2003 to December/2005, with sampling during 24 h on a weekly basis. Stacked filter units (SFU) were used to collect fine and coarse aerosol particles with a flow rate of 17 L min?1. In both size fractions trace elements were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as well as water-soluble species by Ion-Chromatography (IC). Also gravimetric analysis and reflectance measurements provided aerosol mass and black carbon concentrations. Very good detection limits for up to 42 species were obtained. Mean annual PM10 mass concentration ranged from 20 to 37 μg m?3, values that are within the Brazilian air quality standards. Receptor models such as principal factor analysis, cluster analysis and absolute principal factor analysis were applied in order to identify and quantify the aerosol sources. For fine and coarse modes, circa of 100% of the measured mass was quantitatively apportioned to relatively few identified aerosol sources. A very similar and consistent source apportionment was obtained for both fine and coarse modes for all 10 sampling sites. Soil dust is an important component, accounting for 22–72% and for 25–48% of the coarse and fine mass respectively. On the other hand, anthropogenic sources as vehicle traffic and oil combustion represent a relatively high contribution (52–75%) of the fine aerosol mass. The joint use of ICP-MS and IC analysis of species in aerosols has proven to be reliable and feasible for the analysis of large amount of samples, and the coupling with receptor models provided an excellent method for quantitative aerosol source apportionment in large urban areas.  相似文献   
785.
Larval growth rate and settlement of the European flat oyster Ostrea edulis were experimentally studied as a function of the composition of dietary fatty acids. Diets differing in fatty acid composition were composed by mixtures of the microalgae Isochrysis galbana, Pavlova lutheri and Chaetoceros calcitrans. Fatty acid content in the tissue of the feeding larvae, analyzed by gas chromatography and mass spectrometry, reflected the composition in the diet. Larval growth rate was significantly correlated to the three omega-3 polyunsaturated fatty acids (PUFA) C18:3, C18:4 and C22:6, with minor differences for neutral and polar lipids. No relation between growth rate and the omega-3 PUFA C20:5 was detected, a PUFA often implied as essential for bivalves. It is suggested that naturally occurring variability in fatty acid composition may constrain larval growth. In settlement experiments in both still water and flume flow little substrate selectivity was found for some contrasting substrates. It is concluded that differences in dietary fatty acids may explain as much of settlement success as the variability of substrates. Received: 12 October 1998 / Accepted: 6 April 1999  相似文献   
786.
787.
Relative species abundances are the most frequently applied data type used for modern or paleolimnological diatom studies. In contrast, plant ecologists save time by commonly using ordinal scale data (class data), where the abundance of a species is estimated using dominance classes, instead of relative abundance data. This study compares the performance of models based on ordinal diatom species class data (class 1: sporadic (<0–1%) up to class 6: dominant (>60%)) with similar model types based on relative abundance data for different regional training sets and sediment cores. First, relative diatom abundances were converted into ordinal classes. Species response to total phosphorous (TP) was modelled using both types of data - relative abundance and ordinal class data. Secondly, TP was reconstructed for six sediment cores from North-East Germany, Switzerland, and Denmark using WA and WA-PLS based on both types of data. Thirdly, 20 lake sediment surface samples with known relative diatom abundances and known water TP concentrations were recounted using an ordinal data scale to create an independent test set. No significant differences were found between relative abundance and class data for (1) explained species variance, (2) reconstructed TP values, and (3) inferred TP values of the 20 recounted samples. This approach demonstrates that past TP concentrations may also be reliably reconstructed using class data instead of relative diatom abundances. Thus, by using class data lake managers may not only obtain more long-term records past water quality, but this approach is also quicker and therefore more cost effective. Moreover, the findings of this study may also advance the use of automatic diatom identification with digital image recognition, as we demonstrate that not every damaged diatom valve needs to be identified.  相似文献   
788.
Greenhouse gases (GHG) emissions from agricultural farming practice contribute significantly to European GHG inventories. For example, CO2 is emitted when grassland is converted to cropland or when peatlands are drained and cultivated. N2O emissions result from fertilization. Enabling farmers to reduce their GHG emissions requires sufficient information about its pressure–impact relations as well as incentives, such as regulations and funding, that support climate-friendly agricultural management. This paper discusses potentials to improve the supply of information on: farm-specific climate services or impacts, present policy incentives in Germany and England that support climate-friendly farm management and related adaptation requirements. Tools which have been developed for a farm environmental management software (to be added after review because of potential identification) are presented. These tools assess CO2 emissions from grassland conversion to cropland and peatland cultivation, as well as N2O emissions from nitrogen fertilization. As input data, the CO2 tool requires a classification of soil types according to soil organic carbon storage. The input data based on soil profile samples was compared with reference data from the literature. The N2O tool relies on farm data concerning fertilization. These tools were tested on three farms in order to determine their viability with respect to the availability of required data and the differentiation of results, which determines how well site-specific conservation measures can be identified. Assessing CO2 retention function of grassland conservation to cropland on the test farms leads to spatially differentiated results (~100 to ~900 potentially mitigated t CO2 ha?1). Assessed N2O emissions varied from 0.41 to 1.1 t CO2eq. ha?1 a?1. The proposed methods support policies that promote a more differentiated funding of climate conservation measures. Conservation measures and areas can be selected so that they will have the greatest mitigation effects. However, even though present policy instruments in Germany and England, such as Cross Compliance and agri-environmental measures, have the potential to reduce agricultural GHG, they do not appear to guide measures effectively or site-specifically. In order to close this gap, agri-environmental measures with the potential to support climate protection should be spatially optimized. Additionally, the wetland restoration measures which are most effective in reducing GHG emissions should be included in funding schemes.  相似文献   
789.
A knowledge transfer (KT) strategy was implemented by the IRSST, an occupational health and safety research institute established in Québec (Canada), to improve the prevention of psychological and musculoskeletal problems among 911 emergency call centre agents. An evaluability assessment was conducted in which each aspect of the KT approach was documented systematically to determine whether the strategy had the potential to be evaluated in terms of its impact on the targeted population. A review of the literature on KT in occupational health and safety and on the evaluation of such KT programmes, along with the development of a logic model based on documentary analysis and semi-structured interviews with key stakeholders, indicated that the KT strategy was likely to have had a positive impact in the 911 emergency call centre sector. Implications for future research are discussed.  相似文献   
790.
Geodiversity is considered as the natural range of geological, geomorphological, and soil features, including their assemblages, relationships, properties, interpretations, and systems. A method developed for the quantitative assessment of geodiversity was applied to Paraná, a Brazilian state with an area of about 200,000 km2. The method is based on the overlay of a grid over different maps at scales ranging from 1/500,000 to 1/650,000, with the final Geodiversity Index the sum of five partial indexes calculated on a 25 × 25 km grid. The partial indexes represent the main components of geodiversity, including geology (stratigraphy and lithology), geomorphology, paleontology, and soils. The fifth partial index covers mineral occurrences of geodiversity, such precious stones and metals, energy and industrial minerals, mineral waters, and springs. The Geodiversity Index takes the form of an isoline map that can be used as a tool in land-use planning, particularly in identifying priority areas for conservation, management, and use of natural resources at the state level.  相似文献   
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