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741.
742.
The criteria for classification and labelling of substances as “dangerous for the environment” agreed upon within the European Union (EU) were applied to two sets of existing chemicals. One set (sample A) consisted of 41 randomly selected compounds listed in the European Inventory of Existing Chemical Substances (EINECS). The other set (sample B) comprised 115 substances listed in Annex I of Directive 67/548/EEC which were classified by the EU Working Group on Classification and Labelling of Existing Chemicals. The aquatic toxicity (fish mortality,Daphnia immobilisation, algal growth inhibition), ready biodegradability and n-octanol/water partition coefficient were measured for sample A by one and the same laboratory. For sample B, the available ecotoxicological data originated from many different sources and therefore was rather heterogeneous. In both samples, algal toxicity was the most sensitive effect parameter for most substances. Furthermore, it was found that, classification based on a single aquatic test result differs in many cases from classification based on a complete data set, although a correlation exists between the biological end-points of the aquatic toxicity test systems.  相似文献   
743.
Trace metals in wastewater effluents   总被引:2,自引:0,他引:2  
  相似文献   
744.
ABSTRACT: The feasibility of simulating monthly runoff for southeast Michigan, which comprises four major river basins, was evaluated with the Streamflow Synthesis and Reservoir Regulation watershed model. The evaluation covered a 13-year period (1961–73), which encompassed a complete runoff cycle. Results indicate it is feasible to simulate monthly runoff volumes on a regional scale with a single equivalent watershed by using daily precipitation and temperature data. Simulation of regional flows appears particularly attractive for the Great Lakes basin, since the basin consists of many relatively small watersheds. This method also appears promising for development of monthly runoff forecasts by employing average monthly meteorological data distributed on a daily basis. Tests of six-month runoff forecasts show relatively small deterioration with time and offer considerable improvement over climatology.  相似文献   
745.
746.
The article summarizes outcomes of a biomass study conducted in a young speckled alder plantation on a cold mountain site. At this location, the previously existing old forest was clear felled because of damage from air pollution, and present-day surface humus is in need of restoration. The intention of this study was to quantify the biomass and nutrients accumulated by alders and their components and assess whether the initial fertilization resulted in increased biomass production and nutrient accumulation in the biomass. Besides the control, two fertilized treatments were installed. In the surface treatment (SUT), the amendment was applied as a base dressing in small circles around trees. In the planting-hole treatment (PHT), the amendment was incorporated into soil inside the planting holes. Five growth seasons after planting and fertilization, six alders from each treatment were harvested including roots. Their biomass was quantified and analyzed for macroelements. The greatest pool of dry mass (DM) was branches in the control and stem wood in the fertilized treatments. The greatest pools of macroelements were leaves and branches. The most pronounced effects of fertilization were recorded in the DM and consequently in the absolute quantities of nutrients. The DM of an average tree in the control, SUT, and PHT was 85, 226, and 231 g, respectively. The absolute contents of nutrients per tree in the fertilized treatments showed the following increases, as compared with the control: (N) 2.5–2.6 times; (P) 1.6–2.4 times; (K) 1.8–2.1 times; and (Mg) 1.8–2.0 times, respectively. Speckled alder responded positively to fertilization.  相似文献   
747.
The local scale dispersion tensor, Dd, is a controlling parameter for the dilution of concentrations in a solute plume that is displaced by groundwater flow in a heterogeneous aquifer. In this paper, we estimate the local scale dispersion from time series or breakthrough curves, BTCs, of Br concentrations that were measured at several points in a fluvial aquifer during a natural gradient tracer test at Krauthausen. Locally measured BTCs were characterized by equivalent convection dispersion parameters: equivalent velocity, v(eq)(x) and expected equivalent dispersivity, [lambda(eq)(x)]. A Lagrangian framework was used to approximately predict these equivalent parameters in terms of the spatial covariance of log(e) transformed conductivity and the local scale dispersion coefficient. The approximate Lagrangian theory illustrates that [lambda(eq)(x)] increases with increasing travel distance and is much larger than the local scale dispersivity, lambda(d). A sensitivity analysis indicates that [lambda(eq)(x)] is predominantly determined by the transverse component of the local scale dispersion and by the correlation scale of the hydraulic conductivity in the transverse to flow direction whereas it is relatively insensitive to the longitudinal component of the local scale dispersion. By comparing predicted [lambda(eq)(x)] for a range of Dd values with [lambda(eq)(x)] obtained from locally measured BTCs, the transverse component of Dd, DdT, was estimated. The estimated transverse local scale dispersivity, lambda(dT) = DdT/U1 (U1 = mean advection velocity) is in the order of 10(1)-10(2) mm, which is relatively large but realistic for the fluvial gravel sediments at Krauthausen.  相似文献   
748.
This paper examines the effects of wildlife tourism‐based payments for ecosystem services (PES) on poverty, wealth inequality and the livelihoods of herders in the Maasai Mara Ecosystem in south‐western Kenya. It uses the case of Olare Orok Conservancy PES programme in which pastoral landowners have agreed to voluntary resettlement and exclusion of livestock grazing from their sub‐divided lands. These lands are set aside for wildlife tourism, in return for direct monetary payments by a coalition of five commercial tourism operators. Results show that, on the positive side, PES is the most equitable income source that promotes income diversification and buffers households from the livestock income declines during periods of severe drought, such as in 2008‐2009. Without accounting for the opportunity costs, the magnitude of the PES cash transfer to households is, on average, sufficient to close the poverty gap. The co‐benefits of PES implementation include the creation of employment opportunities in the conservancy and provision of social services. There is however a need to mitigate the negative effects of PES, including the widening inequality in income between PES and non‐PES households and the leakages resulting from the displacement of settlements and livestock to currently un‐subdivided pastoral commons.  相似文献   
749.
Residue materials generated in the metallurgical industry have gained an increasing importance, both from the points of view of energy and material supply. A joint process integration model for the integrated steel plant system is developed and used in this paper. It takes into account both residue materials and energy recirculation for the system. The potential for increased recirculation and the effect on the system from an environmental point of view is presented, and implementations and practical experiences are discussed. The model developed can serve as a benchmark for different steelmaking operations and constitute a basis for the continuous work involved in material, energy, environment or economic analyses for the steel production system.  相似文献   
750.
It is crucial for a steel making production system to operate at the lowest possible production cost, while satisfying stability and reliability conditions. To plan future production strategies, it is therefore important to be able to model the system behaviour when internal and external parameters are changed. In this study the sensitivity and stability of an optimised solution, of an integrated steel plant, have been investigated. The solution’s sensitivity has been analysed taking both internal process changes and external price variations into account, through applying both simulation and optimisation. The analysis also includes both costs and environmental issues such as carbon dioxide and sulphur emissions. Based on the methodology suggested, it is possible to determine the stability of the system solution, including both economic and environmental performance.  相似文献   
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