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881.
A new approach is proposed for the environmental impact assessment of fresh waters. New indices and the cenological values of aquatic and semiaquatic bug (Hemiptera) species have been obtained through multivariate analysis based on the species list of 157 localities in Hungary. The 45 species involved in this study can be characterized by their preference for habitat types on a linear scale ranging from small, shallow waters to large, deep waters. The habitats themselves can be characterized by the added cenological values of the species found.  相似文献   
882.
A method is presented for the design of multi-pollutant air quality monitoring networks (AQMN). This technique leads to an optimal network, i.e. a network providing a maximum of information with a minimum of measurement devices. The spatial correlation analysis technique is used to compare the information given by the potential sites that may form the network. The concept of potential of violation is defined to take into account the number of times that the maximum emission values tolerated by law are exceeded. Both objectives are weighted automatically through an adjustable parameter, b, for which an estimation procedure has been developed in this study, depending on the purpose of the network. Several methods are described, allowing simultaneous consideration of different pollutants. As an illustration of these methods, a number of air quality monitoring networks is designed to perform an analysis of the environmental impact due to a hypothetical potash processing plant and two thermal power stations.  相似文献   
883.
Wastewater sludges are used in agriculture as soil amendment and fertilizer, with regard to their organic matter and nutrient content. However, availability of nitrogen and phosphorus from sludge-amended soils and their transfer in runoff may lead to eutrophication of downstream surface water. The aim of this study is to establish and compare the effect of two different sludges on these transfers: an anaerobically digested and thermically stabilised sludge (Seine-Aval treatment plant, sludge no. 1), and a limed sludge (Saint-Quentin treatment plant, sludge no. 2). Experiments were performed on 12 sloping micro-plots (1 m × 1 m) submitted to sludge spreading and controlled rainfall simulation. Runoff water was sampled and analysed for concentrations in nitrogen species and phosphorus. Results show that spreading of sludge no. 1 increased both ammonium nitrogen (mean of 1.1 mg L–1 N-NH4 vs. 0.2 mg L–1 N-NH4 for control micro-plots) and particulate phosphorus concentrations (mean of 2 mg L–1 P vs. 1.1 mg L–1 P for control micro-plots) in runoff water. On the other hand, sludge no. 2 did not induce any significant effect on nutrient concentrations in runoff. These results are related to chemical composition and physical treatment of sludges. This study underlines the existence of a short-term risk of nutrient mobilisation by runoff after sludge spreading on soil, and the need to check precisely the impact of this practice on water quality.  相似文献   
884.
In an attempt to identify Chironomus hemoglobins as biomarkers for environmental monitoring, alterations in the hemoglobins in Chironomus riparius Mg. (Diptera: Chironomidae) larvae, exposed to potassium dichromate and fenitrothion, were investigated under laboratory conditions. The hemoglobins were evaluated in terms of their total contents by a cyanomethemoglobin procedure, individual components by electrophoresis of isoelectric focusing, and their oxidation by multi wavelength rapid-scanning spectrophotometry. The total hemoglobin contents increased at the high level of fenitrothion exposure. No variations in the individual hemoglobin component levels were found, by exposure to either fenitrothion or potassium dichromate. Whereas, the absorption spectra of the hemoglobins showed decreases in the peaks corresponding to the oxyhemoglobins by exposure to both compounds, but more sensitively by the chromium, which probably reflects the increase of the autoxidation of the oxyhemoglobins to methemoglobins by these compounds. These results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemical exposure, and this biochemical parameter could be developed as a biomarker in environmental monitoring.  相似文献   
885.
Aljustrel mines were classified as having high environmental hazard due to their large tailings volume and high metal concentrations in waters and sediments.To assess acid mine drainage impacted systems whose environmental conditions change quickly,the use of biological indicators with short generation time such as diatoms is advantageous.This study combined geochemical and diatom data,whose results were highlighted in 3 groups:Group 1,with low p H(1.9–5.1)and high metal/metalloid(Al,As,Cd,Co,Cu,Fe,Mn,Ni,Pb,Zn;0.65–1032 mg/L)and SO_4(405–39124 mg/L)concentrations.An acidophilic species,Pinnularia aljustrelica,was perfectly adapted to the adverse conditions;in contrast,teratological forms of Eunotia exigua were found,showing that metal toxicity affected this species.The low availability of metals/metalloids in sediments of this group indicates that metals/metalloids of the exchangeable fractions had been solubilized,which in fact enables metal/metalloid diatom uptake and consequently the occurrence of teratologies;Group 2,with sites of near neutral p H(5.0–6.8)and intermediate metal/metalloid(0.002–6 mg/L)and SO_4(302–2179 mg/L)concentrations;this enabled the existence of typical species of uncontaminated streams(Brachysira neglectissima,Achnanthidium minutissimum);Group 3,with samples from unimpacted sites,showing low metal/metalloid(0–0.8 mg/L)and SO_4(10–315 mg/L)concentrations,high pH(7.0–8.4)and Cl contents(10–2119 mg/L)and the presence of brackish to marine species(Entomoneis paludosa).For similar conditions of acidity,differences in diversity,abundance and teratologies of diatoms can be explained by the levels of metals/metalloids.  相似文献   
886.
Prediction of future forest carbon (C) stocks as influenced by forest management and climate is a crucial issue in the search for strategies to mitigate and adapt to global change. It is hard to quantify the long-term effect of specific forest practices on C stocks due to the high number of processes affected by forest management. This work aims to quantify how forest management impacts C stocks in Mediterranean mountain forests based on 25 combinations of site index, tree species composition and thinning intensity in three different climate scenarios using the CO2Fix v.3.2 model Masera et al. (Ecol Modell 164:177–199, 2003). The study area is an ecotonal zone located in Central Spain, and the tree species are Scots pine (Pinus sylvestris L.) and Pyrenean oak (Quercus pyrenaica Willd.). Our results show a strong effect of tree species composition and a negligible effect of thinning intensity. Mixed stands have the highest total stand C stocks: 100 % and 15 % more than pure oak and pine stands respectively, and are here suggested as a feasible and effective mitigation option. Climate change induced a net C loss compared to control scenarios, when reduction in tree growth is taken into account. Mixed stands showed the lowest reduction in forest C stocks due to climate change, indicating that mixed stands are also a valid adaptation strategy. Thus converting from pure to mixed forests would enhance C sequestration under both current and future climate conditions.  相似文献   
887.
In this study, a hydrophobic synthetic zeolite, namely ZSM-5 is chosen as an adsorbent/catalyst for toluene removal. Experimental results showed that toluene adsorption onto ZSM-5 was favourable, following a Langmuir adsorption isotherm model. ZSM-5 zeolite was regenerated using gaseous ozone at low temperature. Adsorbed toluene was oxidised, releasing mainly CO2 and H2O. Traces of oxidation by-products such as acetic acid and acetaldehyde were formed and remained adsorbed after the oxidativate regeneration with ozone. After four successive cycles of adsorption/ozonation, the adsorption efficiency was not affected (92%–99%). These results showed that volatile organic compound (VOC) removal by adsorption onto ZSM-5 zeolite followed by ozone regeneration could be used as a promising hybrid process for the control of VOC emissions in terms of efficiency.  相似文献   
888.
Rabbits have been suggested as a zoonotic source of Hepatitis E virus. Phylogenetic analysis of HEV isolates from farmed, wild and pet rabbits in the Netherlands (23, 0, and 60 % respectively) showed them to be grouped amongst published rabbit HEV sequences and distinct from most human isolates. Dutch rabbits are unlikely to be a zoonotic source.  相似文献   
889.
The prevalence and genetical diversity of human Sapovirus were studied during an 18-month study in Ría do Burgo, an estuary nearby the city of A Coruña in Galicia (NW Spain). Sapovirus was detected using RT-qPCR procedure in 30 out of 80 mussel samples (37.5 %). Quantifications ranged from 2.2 × 103 to 2.1 × 105 RNA copies per gram of digestive tissue. Detection occurred mainly during the cold and rainy seasons of the period studied. Sequences obtained could be distributed into 5 genotypes being the most abundant GI.1 and GI.3. Results obtained indicate that the hydrodynamic characteristics of the harvesting area and the proximity of population density clearly influence the presence of the virus in shellfish.  相似文献   
890.
This paper explores and discusses the various meanings of the stewardship concept in the field of sustainability science. We highlight the increasing differences between alternative approaches to stewardship and propose a typology to enable scientists and practitioners to more precisely identify the basis and objectives of the concept of stewardship. We first present the two dimensions we used to map the diversity of stances concerning stewardship. Second, we analyse these positions in relation to the limits of the systemic approach, ideological manipulation, responsibility, and solidarity. In the final section we explain how the concept of ecological solidarity, a core principal in recent French law on biodiversity conservation and national park governance can contribute to the underpinning of a specific form of social-ecological stewardship.  相似文献   
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