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121.
Currently, energy consumption for cooking in rural households of India is mostly based on fuelwood used in traditional stoves. This paper presents results of a study carried out in a forest fringe area of India on cooking energy use. The concept of calculating levelized cost as cost per unit of useful energy is applied on source–device combinations of cooking and validated in Bargaon Community Development Block of Sundergarh District in Odisha, India. About 92 % of the households in the study area use fuelwood as the only energy source for cooking; the total use of fuelwood for only cooking, in the Block is nearly 1.8 times the total sustainable wood supply showing an urgent need for promoting alternative cooking energy options. This paper also presents an assessment of different cooking options in terms of cost per unit of useful cooking energy. LPG, biogas and gasifier stoves are found to be far too expensive for the local people. Briquette-fired improved stoves appear to be a promising cooking energy option in the study area. Government support and intervention are recommended for promoting this option.  相似文献   
122.
This study investigated methods for identifying daily incidence rates for bird species. It focused on relationships between incidence rates, site and season. We used sightings of 23 common resident species routinely reported every month from January 2004 to December 2007 at seven wetland locations in the Thale Noi non-hunting area of southern Thailand. Our findings revealed that the log-linear model gives a quite satisfactory fit, so it appears a suitable type of model for bird abundance. On taking logarithms of the incidence rates though, the zero counts must be replaced by an appropriate constant. Our model suggests that Cattle Egret (Bubulcus ibis) was found at the Thale Noi non-hunting area with the highest incidence rate. In contrast, we found a low mean of model outputs for Lesser Whistling-Duck (Dendrocygna javanica) relative to the mean in the data, and this species was not observed on at least 25 % or 3 days per year. These data had a low number of zeros and a large number of various species. Therefore, we recognize a remark on “what is being counted” that it is important to reasonably explain the species abundance in terms of statistical and ecological approaches.  相似文献   
123.
This paper examines consumer attitudes and behavior on the use of plastic and cloth bags in Eski?ehir, Turkey. To this end, a structural equation model is proposed. Environmental consciousness regarding the use of plastic bags, social pressure, support for the banning of plastic bags, the intention to use cloth bags and behavior to reduce plastic bag use are employed as latent variables in the model. The intention to use cloth bags and the behavior to reduce the use of plastic bags are defined as endogenous latent variables in the structural model. In the conclusion of the study, it is identified that consumers who are environmentally conscious and feel under social pressure, tend to reduce the use of plastic bags and switch to using cloth bags.  相似文献   
124.
This paper discusses the economic potential in terms of income changes that may result from conversion to low-external-input agriculture (LEIA) organic farming in a Kenya’s catchment area. A spreadsheet model applying the gross margin and net present value analysis was developed to estimate economic returns to labour and land of alternative smallholder cropping systems in the East Mau Catchment. The income and costs over a 10-year horizon associated with current cropping practices of a typical farm household cultivating 1.12 hectares of maize–bean intercrop, Irish potato, carrots, tomatoes, cabbages and kales mix were characterized based on field work conducted in 2008–2010. An “average” smallholder LEIA organic farm was simulated based on the conventional one, and its income discounted. A comparison was then made of the two farm types. Results indicate annual net present value returns to cropped land average Ksh 21,878/ha ($ 267/ha) and Kshs 22,561/ha (€ 275/ha) in 2010 values for conventional and prototype LEIA organic farming systems, respectively. Net returns are particularly sensitive to crop yields and price and cost of fertilizers and seeds. Further efforts should be made to provide an economic analysis of other LEIA organic farming practices such as composting, double digging and agroforestry in terms of additional labour costs resultant. The model can be extended to build more scenarios on the role of price premiums. Additionally, further research should be done to exploit the socio-demographic factors affecting the adoption of low-external-input systems.  相似文献   
125.
Sustainability indicators are well recognized for their potential to assess and monitor sustainable development of agricultural systems. A large number of indicators are proposed in various sustainability assessment frameworks, which raises concerns regarding the validity of approaches, usefulness and trust in such frameworks. Selecting indicators requires transparent and well-defined procedures to ensure the relevance and validity of sustainability assessments. The objective of this study, therefore, was to determine whether experts agree on which criteria are most important in the selection of indicators and indicator sets for robust sustainability assessments. Two groups of experts (Temperate Agriculture Research Network and New Zealand Sustainability Dashboard) were asked to rank the relative importance of eleven criteria for selecting individual indicators and of nine criteria for balancing a collective set of indicators. Both ranking surveys reveal a startling lack of consensus amongst experts about how best to measure agricultural sustainability and call for a radical rethink about how complementary approaches to sustainability assessments are used alongside each other to ensure a plurality of views and maximum collaboration and trust amongst stakeholders. To improve the transparency, relevance and robustness of sustainable assessments, the context of the sustainability assessment, including prioritizations of selection criteria for indicator selection, must be accounted for. A collaborative design process will enhance the acceptance of diverse values and prioritizations embedded in sustainability assessments. The process by which indicators and sustainability frameworks are established may be a much more important determinant of their success than the final shape of the assessment tools. Such an emphasis on process would make assessments more transparent, transformative and enduring.  相似文献   
126.
Does status matter in community-based forest management? If so, are the high-status households more benefited than the low-status households? What drives status differences, if any, in the appropriation of forest resources? To address these questions, we draw on a theory of status and resource use that defines one’s status as one’s relative position in a group on the basis of power, prestige, honor and deference. Following this perspective, we surveyed the heads of 341 forest-based rural households in India from 2009 to 2010. We find that collective actions themselves are status-driven and the high-status households are more interested and involved in status-maintaining collective actions such as decision-making and implementation, while the low-status households perform general tasks like forest patrol. Moreover, the high-status households derive benefits from local forest significantly more than the low-status households. Further, decomposition analysis shows that a household’s prestige and honor measured by its access to social resources, problem faced and useful contacts explain about 56 % of the status gap in forest benefits, while socioeconomic characteristics explain only 16 % of the gap. Thus, due emphasis on household status from a broader socioeconomic perspective is required to reduce inequality in participation and the distribution of forest benefits in co-management.  相似文献   
127.
This study assessed metals in irrigation water, soil and potato crops impacted by mining discharges, as well as potential human health risk in the high desert near the historic mining center of Potosí, Bolivia. Metal concentrations were compared with international concentration limit guidelines. In addition, an ingested average daily dose and minimum risk level were used to determine the hazard quotient from potato consumption for adults and children. Irrigation water maximum concentrations of Cd, Pb and Zn in mining-impacted sites were elevated 20- to 1100-fold above international concentration limit guidelines. Agricultural soils contained total metal concentrations of As, Cd, Pb and Zn that exceeded concentration limits in agricultural soil guidelines by 22-, 9-, 3- and 12-fold, respectively. Potato tubers in mining-impacted sites had maximum concentrations of As, Cd, Pb and Zn that exceeded concentration limits in commercially sold vegetables by 9-, 10-, 16- and fourfold, respectively. Using conservative assumptions, hazard quotients (HQ) for potatoes alone were elevated for As, Cd and Pb among children (range 1.1–71.8), in nearly all of the mining-impacted areas; and for As and Cd among adults (range 1.2–34.2) in nearly all of the mining-impacted areas. Only one mining-impacted area had a Pb adult HQ for potatoes above 1 for adults. Toxic trace elements in a major regional dietary staple may be a greater concern than previously appreciated. Considering the multitude of other metal exposure routes in this region, it is likely that total HQ values for these metals may be substantially higher than our estimates.  相似文献   
128.
The spatial distribution of the C/N ratios and variations in δ13C and δ15N of suspended particulate matter were used to characterise their source in Asia’s largest brackish water lagoon, Chilika, India. In addition, the significance of re-mineralised nutrients in the primary productivity of the shallow lagoon was also determined through quantification of the subsurface nitrogen uptake conditions at two relatively stable locations in the lagoon. The results indicated that the influence of terrestrial organic matter was the maximum in the northern sector and was relatively limited at the central and southern part of the lagoon. In situ 15N uptake experiments (daytime) under biogeochemically stable conditions revealed that the N uptake by phytoplankton ranged between 0.24 and 1.01?mM?m?3?h?1 during pre-monsoon and post-monsoon seasons. New production and regenerated production in the shallow lagoon was also estimated by calculating f-ratios (ratio of nitrate assimilation by phytoplankton to total nitrogenous nutrient assimilation, have been estimated), which varied from 0.52 in the post-monsoon to 0.38 in the pre-monsoon. Lowering of the f-ratio from post- to pre-monsoon indicated a dominance of mineralisation over the new production.  相似文献   
129.
A typical two-phase debris flow exhibits a high and steep flow head consisting of rolling boulders and cobbles with intermittent or fluctuating velocity. The relative motion between the solid phase and the liquid phase is obvious. The motion of a two-phase debris flow depends not only on the rheological properties of the flow, but also on the energy transmission between the solid and liquid phases. Several models have been developed to study two-phase debris flows. An essential shortcoming of most of these models is the omission of the interaction between the two phases and identification of the different roles of the different materials in two-phase debris flows. The tracer particles were used for the velocity of solid phase and the velocity of liquid phase was calculated by the water velocity on the surface of the debris flow in the experiments. This paper analyzed the intermittent feature of two-phase debris flows based on videos of debris flows in the field and flume experiments. The experiments showed that the height of the head of the two-phase debris flow increased gradually in the initiation stage and reached equilibrium at a certain distance from the start of the debris flow. The height growth and the velocity of the flow head showed fluctuating characteristics. Model equations were established and the analyses proved that the average velocity of the two-phase debris flow head was proportional to the flood discharge and inversely proportional to the volume of the debris flow head.  相似文献   
130.
The scaling problem associated with the modeling of turbidity currents has been recognized but is yet to be explored systematically. This paper presents an analysis of the dimensionless governing equations of turbidity currents to investigate the scale effect. Three types of flow conditions are considered: (i) conservative density current; (ii) purely depositional turbidity current; and (iii) mixed erosional/depositional turbidity current. Two controlling dimensionless numbers, the Froude number and the Reynolds number, appear in the non-dimensional governing equations. When densimetric Froude similarity is satisfied, the analysis shows that the results would be scale-invariant for conservative density current under the rough turbulent condition. In the case of purely depositional flows, truly scale-invariant results cannot be obtained, as the Reynolds-mediated scale effects appear in the bottom boundary conditions of the flow velocity and sediment fall velocity. However, the scale effect would be relatively modest. The Reynolds effect becomes more significant for erosional or mixed erosional/depositional turbidity currents as Reynolds-mediated scale effects also appear in the sediment entrainment relation. Numerical simulations have been conducted at three different scales by considering densimetric Froude scaling alone as well as combined densimetric Froude and Reynolds similarity. Simulation results confirm that although the scaling of densimetric Froude number alone can produce scale-invariable results for conservative density currents, variations occur in the case of turbidity currents. The results become scale invariant when densimetric Froude and Reynolds similarities are satisfied simultaneously.  相似文献   
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