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281.
Chlorpyrifos is an anticholinesterase organophosphate insecticide widely used in Argentina in the production of food derived from animal, fruit and horticultural origin and is reported as a residue within these products. Local reference values for acetyl and butyrylcholinesterase were determined in Aberdeen Angus bovine and cross bred cattle (n = 25), a requirement to be able to evaluate toxicity of commercial organophosphate and carbamate formulations. The activity of cholinesterase enzymes presented an overall mean of 2,183.00 ± 485.6 IU L?1 for erythrocyte acetylcholinesterase and 203.1 ± 42.06 IU L?1 for plasma butyrylcholinesterase, which are used as reference values for meat steers within a system of intensive production in a semi-arid region. The toxic potential of chlorpyrifos in steers of the same breeds (n = 12) was assessed applying chlorpyrifos 15.00% Tipertox® in a single therapeutic dose of 7.50 mg kg?1 by topical route. Prior to application and then on day 1 and day 21 post-application, both blood cholinesterases, serum chlorpyrifos concentration by ultra-high resolution liquid chromatography with mass detector, analysis of blood counts, total proteins, liver enzymes, urea and creatinine were evaluated. The mean plasma concentration of chlorpyrifos was 27.90 ug L?1 at 24 h. The findings indicate that the therapeutic treatment of castrated male bovines treated with chlorpyrifos, applied by pour-on according to the manufacturer's instructions, does not cause changes in the variables evaluated.  相似文献   
282.
A transformation to sustainability calls for radical and systemic societal shifts. Yet what this entails in practice and who the agents of this radical transformation are require further elaboration. This article recenters the role of environmental justice movements in transformations, arguing that the systemic, multi-dimensional and intersectional approach inherent in EJ activism is uniquely placed to contribute to the realization of equitable sustainable futures. Based on a perspective of conflict as productive, and a “conflict transformation” approach that can address the root issues of ecological conflicts and promote the emergence of alternatives, we lay out a conceptual framework for understanding transformations through a power analysis that aims to confront and subvert hegemonic power relations; that is, multi-dimensional and intersectional; balancing ecological concerns with social, economic, cultural and democratic spheres; and is multi-scalar, and mindful of impacts across place and space. Such a framework can help analyze and recognize the contribution of grassroots EJ movements to societal transformations to sustainability and support and aid radical transformation processes. While transitions literature tends to focus on artifacts and technologies, we suggest that a resistance-centred perspective focuses on the creation of new subjectivities, power relations, values and institutions. This recenters the agency of those who are engaged in the creation and recuperation of ecological and new ways of being in the world in the needed transformation.  相似文献   
283.
The reutilisation of MSWI natural weathered bottom ash (WBA) in many applications such as road and underground constructions, embankments or as an aggregate replacement is a common practice in many developed countries. Its potential environmental risk has regularly been evaluated from the point of view of the leaching of heavy metals and metalloids. Nevertheless, the influence over steel rebar when reinforced concrete is exposed to the contact with WBA has been poorly assessed before. In this study, it has been possible to evaluate in terms of days the probability of corrosion in a common case of WBA reutilisation, which is in contact with reinforced concrete formulated with conventional Portland cement. The corrosion monitoring indicates that the probability of corrosion of steel rebar is higher than 90 % with a corrosion rate (CI) estimated to be 11.6 µm year?1. The aggressive conditions imposed by WBA suppose an important withdrawal if the application of reutilisation involves contact with steel rebar.  相似文献   
284.
Inorganic urban solid waste (IUSW) is a serious problem in developing countries, and IUSW in the street that does not have adequate final disposal is responsible for serious environmental effects. The aim of this work was to determine the dynamics of the generation of IUSW in the streets of two neighborhoods of different socioeconomic strata in Mexico City during 5 weeks in 2006. The amount of IUSW was recorded every day from 9:00 to 12:00 h, separated, classified, and registered. It was found that plastic (50%) and paper (44.5%) wastes were found most frequently, whereas, textiles (0.4%) and glass (0.5%) wastes were present less frequently in all samples. The IUSWs without commercial brands were more abundant. Branded plastic wrappers of PepsiCo and Bimbo, as well as polyethylene terephthalate (PET) containers of Coca Cola, registered the highest values, while Gatorade, Barrilitos, and Peñafiel registered the lowest. The neighborhood with a higher income and more vegetation on sidewalks or in jardinières, which are used to hide solid waste, had more IUSW than the neighborhood with lower income, where IUSW was thrown out directly into the street. The knowledge of the real generation and composition of IUSW will contribute to the prevention of its negative environmental and social impacts, as well as guarantee the efficiency of its sustainable management.  相似文献   
285.
傅里叶变换红外光谱法测定废水中的酚   总被引:1,自引:1,他引:0  
以三氯化碳萃取模拟含酚废水,再采用傅里叶变换红外光谱法(FTIR)测定废水中的酚含量。结果表明:废水中酚质量浓度大于100.0mg/L时,含酚废水与三氯化碳体积比为1:1,萃取效果最好,酚质量浓度测定的相对误差小于2%,检出限为11.95mg/L;废水中酚质量浓度为10.0~50.0mg/L时,含酚废水与三氯化碳体积比为10:1,萃取效果最好,酚质量浓度测定的相对误差小于5%,检出限为1.19mg/L。FTIR法的相对标准偏差平均为0.354%,加标回收率为101.7%~103.2%。采用FTIR法测定含酚工业废水中的酚质量浓度与GB7491-87《水质挥发酚的测定蒸馏后溴化容量法》测定结果非常接近。  相似文献   
286.
Interannual, seasonal, daily and altitudinal patterns of tropospheric ozone mixing ratios, as well as ozone phytotoxicity and the relationship with NOx precursors and meteorological variables were monitored in the Central Catalan Pyrenees (Meranges valley and Forest of Guils) over a period of 5 years (2004–2008). Biweekly measurements using Radiello passive samplers were taken along two altitudinal transects comprised of thirteen stations ranging from 1040 to 2300 m a.s.l. Visual symptoms of ozone damage in Bel-W3 tobacco cultivars were evaluated biweekly for the first three years (2004–2006). High ozone mixing ratios, always above forest and vegetation protection AOT40 thresholds, were monitored every year. In the last 14 years, the AOT40 (Apr–Sept.) has increased significantly by 1047 μg m?3 h per year. Annual means of ozone mixing ratios ranged between 38 and 67 ppbv (38 and 74 ppbv during the warm period) at the highest site (2300 m) and increased at a rate of 5.1 ppbv year?1. The ozone mixing ratios were also on average 35–38% greater during the warm period and had a characteristic daily pattern with minimum values in the early morning, a rise during the morning and a decline overnight, that was less marked the higher the altitude. Whereas ozone mixing ratios increased significantly with altitude from 35 ppbv at 1040 m–56 ppbv at 2300 m (on average for 2004–2007 period), NO2 mixing ratios decreased with altitude from 5.5 ppbv at 1040 m–1 ppbv at 2300 m. The analysis of meteorological variables and NOx values suggests that the ozone mainly originated from urban areas and was transported to high-mountain sites, remaining aloft in absence of NO. Ozone damage rates increased with altitude in response to increasing O3 mixing ratios and a possible increase in O3 uptake due to more favorable microclimatic conditions found at higher altitude, which confirms Bel-W3 as a suitable biomonitor for ozone concentrations during summer time. Compared to the valley-bottom site the annual means of ozone mixing ratios are 37% larger in the higher sites. Thus the AOT40 for the forest and vegetation protection threshold is greatly exceeded at higher sites. This could have substantial effects on plant life at high altitudes in the Pyrenees.  相似文献   
287.
The aim of this work was to improve the quality of aqueous effluents coming from the Gasification Unit in an Integrated Gasification Combined Cycle (IGCC) Thermoelectric Power Station, with the purpose of fulfilling the future more demanding normative. To this end, an integral wastewater treatment including coagulation, flocculation, neutralization, photocatalytic oxidation, and ion-exchange has been studied. A final scheme has been proposed to remove pollutants. All the parameters of the treated wastewater are below pouring specifications. In the first stage, the wastewater was treated with CaCl2 (optimal dose=11 g CaCl2/g F-) as coagulant and a commercial anionic polyelectrolyte (optimal dose=0.02 g/g F-) as flocculant to remove fluoride ions (99%) and suspended solids (92%). The water was then neutralized, improving the degree of transmission of ultraviolet light, allowing the faster photo-degradation of pollutants. The photochemical study included different systems (H2O2, UV/H2O2, Fenton, Fenton-like, UV/Fenton, UV/Fenton-like and UV/H2O2/O2). In the Fenton-like system, the influence of two parameters (initial concentration of H2O2 and amount of Cu(II)) on the degradation of cyanide and formate (taken as the reference of the process) was studied. Experimental results were fit using neural networks (NNs). Results showed that the photocatalytic process was effective for total cyanide destruction after 60 min, while 180 min was needed to remove 80% of formates. However, a more simple system with UV/H2O2/O2 yields similar results and is preferred for industrial application due to fewer complications. Finally, an ion-exchange process with Amberlite IRA-420 was proposed to remove the excess of chlorides added as a consequence of the initial coagulation process.  相似文献   
288.
Saline wetlands in the Monegros Desert, NE Spain, are situated in an agricultural landscape which is undergoing significant changes. Agricultural intensification in recent decades and current installation of new irrigation systems threaten these valuable habitats, set to be included in the Natura2000 network. Their preservation and successful management depend on the information available regarding the transformation of surrounding areas. When soil and vegetation maps at adequate scale are not available, remote sensing is an alternative means to obtain needed data. We have used SAR data, taking advantage of the soil surface characteristics perceived in SAR images. The objective of this work is to explore the capability of multitemporal SAR data to characterize the land covers of these wetlands and their environment. We have developed specific contextual classifications which take into account the statistical properties of the radar distribution. Moreover, we tested the contribution of radar in Landsat classification.  相似文献   
289.
One of the basic assumptions of the travel cost method for recreational demand analysis is that the travel cost is always incurred for a single purpose recreational trip. Several studies have skirted around the issue with simplifying assumptions and dropping observations considered as nonconventional holiday-makers or as nontraditional visitors from the sample. The effect of such simplifications on the benefit estimates remains conjectural. Given the remoteness of notable recreational parks, multi-destination or multi-purpose trips are not uncommon. This article examines the consequences of allocating travel costs to a recreational site when some trips were taken for purposes other than recreation and/or included visits to other recreational sites. Using a multi-purpose weighting approach on data from Gros Morne National Park, Canada, we conclude that a proper correction for multi-destination or multi-purpose trip is more of what is needed to avoid potential biases in the estimated effects of the price (travel-cost) variable and of the income variable in the trip generation equation.  相似文献   
290.
Recognition and understanding of landscape dynamics as a historical legacy of disturbances are necessary for sustainable management of forest ecosystems. This study analyzed spatial and temporal changes in land use and land cover patterns in a typical mountain watershed in the Gumushane district along the Northeastern part of Turkey. The area is investigated by comparing LANDSAT images from 1987 to 2000 and evaluated the temporal changes of spatial structure of forest conditions through spatial analysis of forest cover type maps from 1971 and 1987 using GIS and FRAGSTATS™. The results show a general decreasing trend in area of natural land cover types including broadleaf and conifer forests as well as coppice between 1971 and 1987 (0.54%, respectively). In contrast, between 1987 and 2000 this natural land cover types show increasing trend (1.6%). In parallel with forest dynamics, the area of managed land including lowland and upland agricultural areas, rangelands and grasslands increased during the first period and decreased during second period. In terms of spatial configuration, Gümüşhane forests aren’t generally fragmented by intensive forest utilization in the latter periods. This is partially due to out-migration of rural population in Gümüşhane. Nevertheless, land use pattern significantly changed over time depending on a few factors such as unregulated management actions, social pressure and demographic movements. The study revealed that demographic movements have a major effect on landscape dynamics.  相似文献   
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