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91.
How effective was the Kyoto protocol? International Environmental Agreements (IEA) have been on the rise over the past four decades; however, thus far their effectiveness is controversial. In view of the conflicting results found in the related literature, this paper addresses its effectiveness by utilizing for the first time the generalized synthetic control method (GSCM) to compare the emissions of the industrialized countries with a “No- Kyoto” counterfactual scenario that represents the expected emissions in the absence of the protocol. This method facilitates a robust comparison between treated and control countries as done by Almer and Winkler (2017) and account for the multiple treated units as done by Grunewald and Martinez-Zarzoso (2016), so as to capture the collective nature of the protocol. Results show that the protocol was successful in reducing the emissions of the ratifying countries approximately by 7% below the emissions expected under a “No-Kyoto” scenario, confirming the importance of accounting for the collective nature of the agreement. 相似文献
92.
Revisiting Kappa to account for change in the accuracy assessment of land-use change models 总被引:7,自引:0,他引:7
Land-use change models are typically calibrated to reproduce known historic changes. Calibration results can then be assessed by comparing two datasets: the simulated land-use map and the actual land-use map at the same time. A common method for this is the Kappa statistic, which expresses the agreement between two categorical datasets corrected for the expected agreement. This expected agreement is based on a stochastic model of random allocation given the distribution of class sizes. However, when a model starts from an initial land-use map and makes changes to it, that stochastic model does not pose a meaningful reference level. This paper introduces KSimulation, a statistic that is identical in form to the Kappa statistic but instead applies a more appropriate stochastic model of random allocation of class transitions relative to the initial map. The new method is illustrated on a simple example and then the results of the Kappa statistic and KSimulation are compared using the results of a land-use model. It is found that only KSimulation truly tests models in their capacity to explain land-use changes over time, and unlike Kappa it does not inflate results for simulations where little change takes place over time. 相似文献
93.
Environmental conditions act above and below ground, and regulate carbon fluxes and evapotranspiration. The productivity of boreal forest ecosystems is strongly governed by low temperature and moisture conditions, but the understanding of various feedbacks between vegetation and environmental conditions is still unclear. In order to quantify the seasonal responses of vegetation to environmental factors, the seasonality of carbon and heat fluxes and the corresponding responses for temperature and moisture in air and soil were simulated by merging a process-based model (CoupModel) with detailed measurements representing various components of a forest ecosystem in Hyytiälä, southern Finland. The uncertainties in parameters, model assumptions, and measurements were identified by generalized likelihood uncertainty estimation (GLUE). Seasonal and diurnal courses of sensible and latent heat fluxes and net ecosystem exchange (NEE) of CO2 were successfully simulated for two contrasting years. Moreover, systematic increases in efficiency of photosynthesis, water uptake, and decomposition occurred from spring to summer, demonstrating the strong coupling between processes. Evapotranspiration and NEE flux both showed a strong response to soil temperature conditions via different direct and indirect ecosystem mechanisms. The rate of photosynthesis was strongly correlated with the corresponding water uptake response and the light use efficiency. With the present data and model assumptions, it was not possible to precisely distinguish the various regulating ecosystem mechanisms. Our approach proved robust for modeling the seasonal course of carbon fluxes and evapotranspiration by combining different independent measurements. It will be highly interesting to continue using long-term series data and to make additional tests of optional stomatal conductance models in order to improve our understanding of the boreal forest ecosystem in response to climate variability and environmental conditions. 相似文献
94.
按照《辐射环境保护管理导则—电磁辐射环境影响评价方法与标准》(HJ/T10.3—1996)的有关规定,GSM移动通信基站电场强度的管理目标值为5.4 V/m,功率密度的管理目标值为8μW/cm2。在根据麦克斯韦电磁场理论确定远场区范围,结合基站天线运行的基本参数,以及在对垂直波瓣图进行拟合的基础上,通过《辐射环境保护管理导则——电磁辐射监测仪器和方法》(HJ/T 10.2-1996)中的微波远场轴向功率密度计算公式计算GSM移动通信基站对周围环境的辐射水平进行预测。预测结果表明,基站周围的电磁辐射水平与天线的发射功率、公众活动区域与天线的高度差以及天线的主瓣方向关系密切。实际应用中可以通过减小发射功率,增加天线与公众活动区域的高度差以及调整天线的主瓣方向等措施来降低其对周围环境的影响,并通过制定有效的监测、管理计划和加强公众沟通,及时消除可能的电磁污染。 相似文献
95.
Stefan Van Dongen 《Environmental and Ecological Statistics》2006,13(2):213-228
Plant–herbivore interactions are complex and affect herbivore fitness components and life history traits in many different
ways. In this paper, we present results from an experiment studying the effects of leaf quality on pupal survival and duration
of pupation (as measured by time-to-emergence) in the winter moth. Because only surviving pupae are at risk of emerging, analysis
of time-to-emergence should exclude the dead pupae. However, due to right censoring, the survival status could not be determined
for each individual. This failure to determine the group of moths at risk of emerging a priori motivated the development of
a joint model of both survival probability and time-to-emergence. We formulate the model in a Bayesian framework and apply
Monte Carlo Markov Chain (MCMC) to obtain posterior distributions. Time-to-emergence is modeled by a Cox Proportional Hazards
(CPH) model where only the surviving pupae are at risk of emergence. Probability of pupal survival was modeled by a Generalized
Linear Mixed Model (GLMM). The censored individuals were included in the analysis as a missing value in the GLMM. The GLMM
then generated prior distributions of survival probabilties—and thus of the probability of being at risk of emergence—for
these 19 individuals, conditional on the model parameters. The CPH model was formulated as a count process and the binary
frailty was incorporated as a zero-inflated Poisson model. Zeros in this model represent the non-survivors. Leaf quality did
not appear to influence time-to-emergence. Pupal survival was affected in a complex and unexpected way showing opposite effects
in males and females. We also explored the robustness of our model against increased levels of censoring. While the degree
of censoring was low in our study (< 1%), we artificially increased it to 67%. Although further study is required to study
the generality of these results in a theoretical framework, our explorations suggest that the newly proposed technique may
be widely applicable in a variety of situations where the identification of the at risk population cannot be done in a straightforward
way.
Received: January 2005 / Revised: June 2005 相似文献
96.
In spatial planning and environmental management, maps are found very helpful in many situations, but in other situations they may also deepen conflicts or be ignored. This paper addresses the question what explains such phenomena, with particular emphasis on, and reference to, collaborative policymaking settings in the Netherlands. We have elaborated the concept of 'frames' and 'framing' to structure and analyze the function of maps in the context of deliberative policymaking. With help of discourse analysis, a method adopted from the policy sciences, we have observed ongoing multi-actor processes and focused on discussions around maps in several case studies. From the observations of both the maps themselves and the discussions and actions with the maps, we have interpreted the meaning and frames represented 'in' the map images, as well as the various perspectives of actors 'on' the collaborative use of the map. We have conceptualized three fundamentally different perspectives or frames on the function of maps in the decision-making process. The cross-frame debate over maps is illustrated with the recollection of one particular map-making example. We conclude that the conflicts observed in a number of case studies can be adequately explained with help of the three identified frames, and provide some recommendations for the profession of mapping. 相似文献
97.
Nicola J. van Wilgen Núria Roura-Pascual David M. Richardson 《Environmental management》2009,44(3):590-607
Assessing climatic suitability provides a good preliminary estimate of the invasive potential of a species to inform risk
assessment. We examined two approaches for bioclimatic modeling for 67 reptile and amphibian species introduced to California
and Florida. First, we modeled the worldwide distribution of the biomes found in the introduced range to highlight similar
areas worldwide from which invaders might arise. Second, we modeled potentially suitable environments for species based on
climatic factors in their native ranges, using three sources of distribution data. Performance of the three datasets and both
approaches were compared for each species. Climate match was positively correlated with species establishment success (maximum
predicted suitability in the introduced range was more strongly correlated with establishment success than mean suitability).
Data assembled from the Global Amphibian Assessment through NatureServe provided the most accurate models for amphibians,
while ecoregion data compiled by the World Wide Fund for Nature yielded models which described reptile climatic suitability
better than available point-locality data. We present three methods of assigning a climate-match score for use in risk assessment
using both the mean and maximum climatic suitabilities. Managers may choose to use different methods depending on the stringency
of the assessment and the available data, facilitating higher resolution and accuracy for herpetofaunal risk assessment. Climate-matching
has inherent limitations and other factors pertaining to ecological interactions and life-history traits must also be considered
for thorough risk assessment.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
98.
Western European landscapes have drastically changed since the 1950s, with agricultural intensifications and the spread of
urban settlements considered the most important drivers of this land-use/land-cover change. Losses of habitat for fauna and
flora have been a direct consequence of this development. In the present study, we relate butterfly occurrence to land-use/land-cover
changes over five decades between 1951 and 2000. The study area covers the entire Swiss territory. The 10 explanatory variables
originate from agricultural statistics and censuses. Both state as well as rate was used as explanatory variables. Species
distribution data were obtained from natural history collections. We selected eight butterfly species: four species occur
on wetlands and four occur on dry grasslands. We used cluster analysis to track land-use/land-cover changes and to group communes
based on similar trajectories of change. Generalized linear models were applied to identify factors that were significantly
correlated with the persistence or disappearance of butterfly species. Results showed that decreasing agricultural areas and
densities of farms with more than 10 ha of cultivated land are significantly related with wetland species decline, and increasing
densities of livestock seem to have favored disappearance of dry grassland species. Moreover, we show that species declines
are not only dependent on land-use/land-cover states but also on the rates of change; that is, the higher the transformation rate from small to large farms, the higher the loss of dry grassland species.
We suggest that more attention should be paid to the rates of landscape change as feasible drivers of species change and derive
some management suggestions. 相似文献
99.
100.
提出基于GSM的可移动危险源处警系统总体方案,在技术实施中考虑现有的可行性通讯资源和低成本实现,采用GSM网络短信息通信,利用带有移动通讯装置和PC机的主站设备来实现。利用GSMAT指令控制收发短信息,并应用数据库对短信息进行管理。对可移动危险源体系、预警方法以及相关关键技术进行较为深入的分析和研究,并在VB环境下编程实现可移动危险源处警系统的基本功能以及通信控件的查询工作方式和事件驱动方式的过程。该研究成果对可移动危险源跟踪、定位、监控,降低可移动危险源的爆炸、泄漏,避免造成重大事故具有一定的实用价值。 相似文献