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991.
Singh G Gupta SK Kumar R Sunderarajan M 《Environmental monitoring and assessment》2007,130(1-3):173-185
The present study describes the development of empirical models for the prediction of various trace metals i.e., Mn, Cu, Fe,
Zn and Pb found in the leachates generated from the ash ponds of various thermal power plants. The dispersion phenomenon of
these trace metals followed first order reaction rate kinetics. The empirical models for individual trace metals derived from
the lab scale models data correlate well with the real field data with regression coefficients varying from 0.93 to 0.98.
The predicted concentrations of the trace metals varied within ±3% of the observed values in the leachates generated from
the ash ponds of four thermal power plants with standard deviation varying from 0.001 to 0.032. The empirical models derived
from the study can be applied for prediction of trace metals in leachates generated from similar thermal power plants. 相似文献
992.
Meiyun Lin Taikan Oki Magnus Bengtsson Shinjiro Kanae Tracey Holloway David G. Streets 《Atmospheric environment (Oxford, England : 1994)》2008,42(24):5956-5967
Region-to-grid source–receptor (S/R) relationships are established for sulfur and reactive nitrogen deposition in East Asia, using the Eulerian-type Community Multiscale Air Quality (CMAQ) model with emission and meteorology data for 2001. We proposed a source region attribution methodology by analyzing the non-linear responses of the CMAQ model to emission changes. Sensitivity simulations were conducted where emissions of SO2, NOx, and primary particles from a source region were reduced by 25%. The difference between the base and sensitivity simulations was multiplied by a factor of four, and then defined as the contribution from that source region. The transboundary influence exhibits strong seasonal variation and generally peaks during the dry seasons. Long-range transport from eastern China contributes a significant percentage (>20%) of anthropogenic reactive nitrogen as well as sulfur deposition in East Asia. At the same time, northwestern China receives approximately 35% of its sulfur load and 45% of its nitrogen load from foreign emissions. Sulfur emissions from Miyakejima and other volcanoes contribute approximately 50% of the sulfur load in Japan in 2001. Sulfur inflows from regions outside the study domain, which is attributed by using boundary conditions derived from the MOZART global atmospheric chemistry model, are pronounced (10–40%) over most parts of Asia. Compared with previous studies using simple Lagrangian models, our results indicate higher influence from long-range transport. The estimated S/R relationships are believed to be more realistic since they include global influence as well as internal interactions among different parts of China. 相似文献
993.
我国自然灾害类应急预案评价方法研究(Ⅱ):责任矩阵评价 总被引:4,自引:2,他引:2
在突发事件应急过程中,由于分工不明、责任不清导致的部门间或者责任人之间的推诿扯皮等现象影响应急行动的高效有序开展,甚至会导致应急行动失败。因此,在应急预案中各应急部门(人员)责任分配是否适当是应急能否成功的关键。为解决该问题,笔者引入项目管理中的责任矩阵方法(Responsibility Matrix)。首先,根据应急的特点,定义直接责任(R)、支持(S)、建议(A)、约束(P)4种责任类型,确定了责任划分的原则;然后,总结出我国自然灾害类应急预案主要包含41种角色类型,并在该基础上建立了应急程序和应急人员间的责任矩阵及评价准则;进而采用上述方法分析一个实际的地震应急预案,对该应急预案的责任矩阵进行评价,最终确定其需要加强和完善的方面,为制定或修订应急预案提供参考。 相似文献
994.
针对突发事件未发生、发生前和发生中的3个不同阶段,把大型群众活动划分为日常、预警和应急3种管理状态。根据大型活动的组织机构和管理部门在策划、组织和运行过程中的安全管理责任和任务,设计了不同状态下活动承办者的安全责任矩阵。该研究对活动安全管理工作的落实和有效实施有重要的参考价值和指导意义。 相似文献
995.
Møhlenberg F Petersen S Petersen AH Gameiro C 《Environmental monitoring and assessment》2007,127(1-3):503-521
Nineteen years of monitoring data from the eutrophic Skive Fjord, Denmark were examined for linkages to external pressures
and drivers, including nutrient inputs, meteorology and stocks of blue mussels. Linkages were examined by: 1) time-series
analysis to document effects of nutrient reduction programs, 2) Pearson Rank correlations, 3) multivariate statistical analysis
(PLS) to identify water quality variables with high predictability and their linkages to pressures, and 4) regression analysis
to quantify relationships between pressures and water quality. Freshwater input, nitrogen load and phosphorus load showed
decreasing trends through the period 1984–2002. The load reductions were only partially translated into trends in water quality:
phosphorus decreased in most seasons, while total nitrogen decreased during winter and spring only. Phosphorus concentration
had the highest predictability (explained by seasonal temperature variation) followed by transparency, silicate, tot-N, chlorophyll-a,
primary productivity, phytoplankton diversity and phytoplankton turnover. The variation in pressures other than nutrient input
confounded the relations between loads and water quality. High biomass of mussels led to reduced chlorophyll-a and increased
transparency, while short-term variability in water column mixing led to changes in chlorophyll-a due to nutrient entrainment
and coupling to benthic mussels. 相似文献
996.
997.
An overview of systems analysis methods in delineating environmental quality indices 总被引:1,自引:0,他引:1
Environmental quality indices (EQIs) have been developed for a variety of purposes ranging from enforcement of environmental standards, to analysis of trends of environmental degradation or improvement, to scientific research. EQIs currently in use are not organized within an integrated framework and thus it has been difficult to analyze adequately complex, multidisciplinary, large-scale, global phenomena. In this paper we compare four different approaches to developing EQIs within a systems perspective. Our analysis suggests that: (1) non-linear regression models that represent an ecosystem's response to different impacts within a stress-response framework (method of response functions) are useful tools for analysis of environmental data; (2) non-equilibrium thermodynamics models based on the concept of exergy, which represents the free energy a system possesses in relation to its environment, provide a common basis for representing many aspects of ecosystem development and response to environmental impacts as a single measure; (3) diagram models based on the concept of emergy, which represents both environmental values and economic values with a single measure, provide a common basis for integrating economic development and environmental protection values into one index; and (4) complex systems simulation models based on general systems theory, which use the methodologies of systems analysis and simulation to identify, quantify, and interrelate EQIs within a dynamic systems context, provide explicit linkages between causes and effects (vertical integration) and identify cross-linkages among different environmental issues (horizontal integration). 相似文献
998.
Preisler Haiganoush K. Haase Sally M. Sackett Stephen S. 《Environmental and Ecological Statistics》2000,7(3):239-254
Prescribed fire is a management tool used by wildland resource management organizations in many ecosystems to reduce hazardous fuels and to achieve a host of other objectives. To study the effects of fire in naturally accumulating fuel conditions, the ambient soil temperature is monitored beneath prescribed burns. In this study we developed a stochastic model for temperature profiles (values at 15 minute intervals) recorded at four depths beneath the soil during a large prescribed burn study. The model was used to assess the temporal fit of the data to particular solutions of the heat equation. We used a random effects model to assess the effects of observed site characteristics on maximum temperatures and to estimate risks of temperatures exceeding critical levels in future similar prescribed fires. Contour plots of estimated risks of temperatures exceeding 60°C for a range of fuel levels and soil depths indicated high risks of occurrence, especially when the moisture levels are low. However, the natural variability among sites seems to be large, even after controlling fuel and moisture levels, resulting in large standard errors of predicted risks. 相似文献
999.
1000.
Sunil Kumar Sharma 《International Journal of Green Energy》2016,13(14):1490-1500
This study forecasts day-ahead wind speed at 15 minute intervals at the site of a wind turbine located in Maharashtra, India. Wind speed exhibits non-stationarity, seasonality and time-varying volatility clustering. Univariate linear and non-linear time series techniques namely MSARIMA, MSARIMA-GARCH and MSARIMA-EGARCH have been employed for forecasting wind speed using data span ranging from 3 days to 15 days. Study suggests that mean absolute percentage error (MAPE) values first decrease with the increase in data span, reaches its minima and then start increasing. All models provide superior forecasting performances with 5 days data span. It is further evident that ARIMA-GARCH model generates lowest MAPE with 5 days data span. All these models provide superior forecasts with respect to current industry practices. This study establishes that employing various linear and non-linear time series techniques for forecasting day-ahead wind speed can benefit the industry in terms of better operational management of wind turbines and better integration of wind energy into the power system, which have huge financial implications for wind power generators in India. 相似文献