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61.
Adaptive management (AM) is a rigorous approach to implementing, monitoring, and evaluating actions, so as to learn and adjust those actions. Existing AM projects are at risk from climate change, and current AM guidance does not provide adequate methods to deal with this risk. Climate change adaptation (CCA) is an approach to plan and implement actions to reduce risks from climate variability and climate change, and to exploit beneficial opportunities. AM projects could be made more resilient to extreme climate events by applying the principles and procedures of CCA. To test this idea, we analyze the effects of extreme climatic events on five existing AM projects focused on ecosystem restoration and species recovery, in the Russian, Trinity, Okanagan, Platte, and Missouri River Basins. We examine these five case studies together to generate insights on how integrating CCA principles and practices into their design and implementation could improve their sustainability, despite significant technical and institutional challenges, particularly at larger scales. Although climate change brings substantial risks to AM projects, it may also provide opportunities, including creating new habitats, increasing the ability to quickly test flow‐habitat hypotheses, stimulating improvements in watershed management and water conservation, expanding the use of real‐time tools for flow management, and catalyzing creative application of CCA principles and procedures.  相似文献   
62.
This paper examines the emerging role of digital tools in a collaborative planning process for British Columbia's Bowen Island. The goal of this research was to evaluate the effectiveness of a 'digital workshop', combining the interactive CommunityViz tool with the immersive lab facilities at the Collaborative for Advanced Landscape Planning (CALP). In support of the larger community planning process, two 3-h workshops were held at CALP's Landscape Immersion Lab. To facilitate collaborative exploration, the interactive landscape visualisation and real-time data analysis capabilities of CommunityViz were employed to illustrate the possible outcomes of residential density policies for Bowen Island's Snug Cove community. The community planning workshops were structured to provide the 14 semi-expert participants with the opportunity to explore and discuss the contentious residential density components of the draft Snug Cove Village Plan. The abilities to dynamically explore the visualisations of the planning proposals, and to see real-time changes in indicator metrics were considered particularly informative, and appeared to increase participants' understanding of the plan. Written and verbal responses indicated, however, that there was insufficient time to examine and interact with the information during the workshop, suggesting a need to examine in greater depth how and when these tools might best be employed in collaborative settings. Current and future research relating to this project is discussed.  相似文献   
63.
Yang Y  Tan YM  Blount B  Murray C  Egan S  Bolger M  Clewell H 《Chemosphere》2012,88(8):1019-1027
Exposure to perchlorate is widespread in the United States and many studies have attempted to character the perchlorate exposure by estimating the average daily intakes of perchlorate. These approaches provided population-based estimates, but did not provide individual-level exposure estimates. Until recently, exposure activity database such as CSFII, TDS and NHANES become available and provide opportunities to evaluate the individual-level exposure to chemical using exposure surveillance dataset. In this study, we use perchlorate as an example to investigate the usefulness of urinary biomarker data for predicting exposures at the individual level. Specifically, two analyses were conducted: (1) using data from a controlled human study to examine the ability of a physiologically based pharmacokinetic (PBPK) model to predict perchlorate concentrations in single-spot and cumulative urine samples; and (2) using biomarker data from a population-based study and a PBPK model to demonstrate the challenges in linking urinary biomarker concentrations to intake doses for individuals. Results showed that the modeling approach was able to characterize the distribution of biomarker concentrations at the population level, but predicting the exposure-biomarker relationship for individuals was much more difficult. The type of information needed to reduce the uncertainty in estimating intake doses, for individuals, based on biomarker measurements is discussed.  相似文献   
64.
We used three non-linear bi-phasic models, bi-exponential (BEXP), first-order double exponential decay (FODED), and first-order two-compartment (FOTC), to fit the measured degradation data for six commonly used pesticides (atrazine, terbuthylazine, bromacil, diazinon, hexazinone and procymidone) in two New Zealand soils. Corresponding DT50 and DT90 values for each compound were numerically obtained and compared against those estimated by simple first-order kinetic (SFOK) model. All 3 non-linear models gave good fit of the measured data under both soil depths and were well supported by the values obtained for the respective statistical indices (RMSE, CRM and r 2). The FOTC model gave by far the best fit for most compounds, followed by the FODED and BEXP models. Overall, DT50 values derived by non-linear models for the six compounds in soils from both sites were lower than the values obtained by the SFOK model. Differences in the SFOK and the three non-linear models derived DT90were, however, an order of magnitude higher for some compounds, while for others differences were very small. Although all three non-linear models described most data by giving excellent fits, in a few instances > 5–10% asymptotes hindered the estimation of DT90 values. This work shows that when degradation deviates from first-order kinetic, application of non-linear decay models to describe the kinetics of degradation becomes important in order to derive the true end-points for pesticides in soil.  相似文献   
65.
Sustainability assessments are an increasingly common tool for measuring progress towards sustainable development. Despite their popularity, sustainability assessments and the indicators that compose them are said to have had little impact on the policy arena. In this paper we discuss four attributes that we contend will improve the use of sustainability assessments to guide decision making: non-compartmentalization, site specificity, built-in guidance for target setting, and ability to measure active sustainability. We present a novel assessment tool for wastewater treatment infrastructure that illustrates these attributes. The assessment is composed of two-dimensional indicators we call “burden to capacity” ratios, that reveal and quantify the local value of resources embodied in wastewater and treatment byproducts, and the tradeoffs between designing systems for disposal versus reuse. We apply the sustainability assessment framework to an existing treatment plant in Chengdu, China and discuss the results.  相似文献   
66.
In March 1995, a mass mortality of pilchard started to occur in South Australia. This spread very rapidly throughout the Australian pilchard's range, later reaching New Zealand. In November 1998, a similar mass mortality broke out in South Australia and also spread, at a slower rate, throughout the Australian range. The mortality appeared to be caused by a herpesvirus. The mortality spread as a classical epidemic front, but its speed of progress and the brief duration of mortalities at a given location are extreme. We apply simple epidemic modelling techniques, SIR and SEIR modelling, to examine the factors behind the spread of this mortality and the differences between the 1995 and 1998/9 epidemics. We discuss biological factors influencing the critical processes of long-distance (D) and local (beta) transmission of infection.  相似文献   
67.
ABSTRACT

A portion of a population is assumed to be at risk, with the mortality hazard varying with atmospheric conditions including total suspended particulates (TSP). This at-risk population is not observed and the hazard function is unknown; we wish to estimate these from mortality count and atmospheric variables. Consideration of population dynamics leads to a state-space representation, allowing the Kalman Filter (KF) to be used for estimation. A harvesting effect is thus implied; high mortality is followed by lower mortality until the population is replenished by new arrivals.

The model is applied to daily data for Philadelphia, PA, 1973-1990. The estimated hazard function rises with the level of TSP and at extremes of temperature and also reflects a positive interaction between TSP and temperature. The estimated at-risk population averages about 480 and varies seasonally. We find that lags of TSP are statistically significant, but the presence of negative coefficients suggests their role may be partially statistical rather than biological. In the population dynamics framework, the natural metric for health damage from air pollution is its impact on life expectancy. The range of hazard rates over the sample period is 0.07 to 0.085, corresponding to life expectancies of 14.3 and 11.8 days, respectively.  相似文献   
68.

Background  

Open-top chambers were used to study the impact of simultaneous exposure to atmospheric SO2 pollution and heavy metal contamination in soils on the metal contents and productivity of soybean plant.  相似文献   
69.
The hydrological conditions of the Lower Mekong Basin support a multitude of ecosystem services. Processes that influence water flow in the Mekong River will thus have implications for the tens of millions of people whose livelihoods depend on these services. This study presents an assessment of livelihood susceptibility to hydrological change in the Lower Mekong Basin. Using an index‐based approach, susceptibility scores were calculated for 2,703 households. Using those scores, we compared average household susceptibility across the basin, among countries and among eco‐zones. Due to their greater livelihood dependency on water‐related activities, mean household susceptibility was higher in Vietnam than in Cambodia, Laos, or Thailand. Households in Northern Laos also had high susceptibility, which was attributed to their low adaptive capacity. The findings suggest that policies aimed at reducing vulnerability to hydrological change in the Lower Mekong Basin should account for geographic context. Further, they highlight how policies may be able to strategically target the most susceptible households, but that poorly designed policies have the potential to exacerbate vulnerability. In the face of high uncertainty surrounding hydrological change in the Lower Mekong Basin, our assessment of susceptibility should help inform precautionary water management policies and provide baseline information needed for more comprehensive vulnerability assessments.  相似文献   
70.
The Opuha Dam was designed for water storage, hydropower, and to augment summer low flows. Following its commissioning in 1999, algal blooms (dominated first by Phormidium and later Didymosphenia geminata) downstream of the dam were attributed to the reduced frequency and magnitude of high-flow events. In this study, we used a 20-year monitoring dataset to quantify changes associated with the dam. We also studied the effectiveness of flushing flows to remove periphyton from the river bed. Following the completion of the dam, daily maximum flows downstream have exceeded 100 m3 s?1 only three times; two of these floods exceeded the pre-dam mean annual flood of 203 m3 s?1 (compared to 19 times >100 m3 s?1 and 6 times >203 m3 s?1 in the 8 years of record before the dam). Other changes downstream included increases in water temperature, bed armoring, frequency of algal blooms, and changes to the aquatic invertebrate community. Seven experimental flushing flows resulted in limited periphyton reductions. Flood wave attenuation, bed armoring, and a shortage of surface sand and gravel, likely limited the effectiveness of these moderate floods. Floods similar to pre-dam levels may be effective for control of periphyton downstream; however, flushing flows of that magnitude are not possible with the existing dam infrastructure. These results highlight the need for dams to be planned and built with the capacity to provide the natural range of flows for adaptive management, particularly high flows.  相似文献   
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