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21.
To efficiently and effectively monitor and mitigate air pollution in the urban environment, it is of paramount importance to integrate into a unified whole air pollutant concentration databases coming from different sources including the ground-based stations, mobile sensors, remote sensing, atmospheric-chemical-transport models and social media for the analysis and unraveling of the complex air pollution processes in space and time. This study constructs and implements for the first time a prototype of the fully integrated air pollution decision support system (APDSS) that put together in an integrated manner all relevant multi-scale, multi-type and multi-source data for decision-making on urban air pollution. The prototype contains the main system that handles the multi-source, multi-type and multi-scale databases, queries, visualization and data mining algorithms and the integrated modules that individually and holistically capitalize on the power of the ground-based stations, ground and aerial mobile sensors, satellite-borne remote-sensing technologies, atmospheric-chemical-transport models and social media. It renders a solid scientific foundation and system development methodology for the study of the spatiotemporal air pollution profiles crucial to the mitigation of urban air pollution. Real-life applications of the prototype are employed to illustrate the functionality of the APDSS.  相似文献   
22.
在系统分析总结国内外本领域的研究发展现状的基础上,以上海浦东新区城市生活垃圾卫生填埋处理为研究背景,首次提出LFGE效应系统分析方法的完整理论和应用体系,体系主要包括:LFGE效应的主控因素特征分析;在垃圾淋滤试验、有关土的工程性能试验和反映运移转化特征的土柱试验基础上的作用机制研究;具单元、组合、整体模拟及压实效应模拟功能的模拟计算研究;在不确定性条件存在下,随机模拟研究和以贝叶斯决策分析理论为基础的LFGE效应决策分析技术经济转换研究  相似文献   
23.
We evaluate the application of various statistical measures for the identification of optimal financial strategies in environmental projects that may be burdened by the consequences of low-probability, high-cost events. Our particular application lies in the area of transport and burial of hazardous and radioactive wastes but our approach applies to a wide range of problems where the utility structure is of the form of gains minus losses, and where limited and/or catastrophic failures may be encountered. We utilize four statistical measures, the expected value, variance, volatility and cumulative probability to compare the outcomes of limited and catastrophic spills. The maximum expected monetary value which is frequently used in the environmental and gas and oil industries as the sole criterion for the selection of optimum actions is seen to lead to erroneous decisions and fails to unambiguously differentiate the economic consequences of limited and catastrophic failures in a project. We demonstrate that unwarranted inclusion of catastrophic scenarios into the decision-making analysis can substantially alter the perspective of a project and guide a corporation away from an investment that could be profitable even under a limited liability case. We conclude by providing a decision-making procedure for cases where the probabilities associated with future events and/or the monetary returns are characterized not by sharp estimates but rather are represented by a range of values.  相似文献   
24.
地理信息系统支持下的山区遥感影像决策树分类   总被引:6,自引:2,他引:6  
山区遥感影像分类是遥感研究的一大难题。本文利用一种决策树生成算法(C 4.5算法)自动提取知识,基于知识建立决策树用于山区影像分类,并结合研究区土地利用类型与DEM空间统计关系的先验知识,在GIS空间分析的基础上进行影像分类的后处理。与传统的最大似然法分类结果相比,该方法极大地改善了山区地表覆被分类的精度,得到试验区较为可靠的遥感分类图像。  相似文献   
25.
A prototype multi-purpose index is proposed for use in the evaluation of practices for adaptation to climate variability and change. The Index of Usefulness of Practices for Adaptation (IUPA) allows the user to assign weights and scores to a set of user-defined evaluation criteria. Individual criterion scores are aggregated into a final index value. Both the final value and the individual parameter scores provide useful information for improved decision making in the context of climate change. An innovative aspect of IUPA is that guidance is given to the user through the inclusion of recommendations on evaluation criteria and criterion-specific weight factors. These have been defined by a panel of experts from the Latin-American and Caribbean Region (LAC). Application of the index is demonstrated for an existing adaptation practice from the Coquimbo Region, Chile. The IUPA tool is recommended for use in the evaluation of adaptation practices in their design, implementation and post-implementation phase. It is practical for a quick first assessment or when limited financial resources are available, making the tool especially useful for practitioners in the developing world. The index is flexible both from the perspective of its construction and use. Additional expert opinions can easily be included in the future versions of the tool.  相似文献   
26.
基于决策树的戈壁信息提取研究   总被引:2,自引:1,他引:1       下载免费PDF全文
 戈壁是我国西北干旱地区的一种主要地表景观类型。由于戈壁所处地带自然条件恶劣,人烟稀少不便于实地调查研究的开展,所以目前关于戈壁的研究资料非常少。本文以戈壁典型分布区内蒙古自治区额济纳旗为例,以Landsat TM遥感影像以及30 m DEM作为基本数据源,首先借助DEM数据,在GIS中,提取出非戈壁分布区,然后,在分析不同典型地物光谱特征基础上,建立基于知识的决策树信息提取模型,利用该模型实现了侵蚀型戈壁与堆积型戈壁信息的自动提取,戈壁信息提取总体精度达到91.57%,研究为使用遥感影像快速获取戈壁信息提供了技术支持。  相似文献   
27.
Image classification using multispectral sensors has shown good performance in detecting macrophytes at the species level. However, species level classification often does not utilize the texture information provided by high resolution images. This study investigated whether image texture provides useful vector(s) for the discrimination of monospecific stands of three floating macrophyte species in Quickbird imagery of the South Nation River. Semivariograms indicated that window sizes of 5 × 5 and 13 × 13 pixels were the most appropriate spatial scales for calculation of the grey level co-occurrence matrix and subsequent texture attributes from the multispectral and panchromatic bands. Of the 214 investigated vectors (13 Haralick texture attributes * 15 bands + 9 spectral bands + 10 transformations/indices), feature selection determined which combination of spectral and textural vectors had the greatest class separability based on the Mann–Whitney U-test and Jefferies–Matusita distance. While multispectral red and near infrared (NIR) performed satisfactorily, the addition of panchromatic-dissimilarity slightly improved class separability and the accuracy of a decision tree classifier (Kappa: red/NIR/panchromatic-dissimilarity – 93.2% versus red/NIR – 90.4%). Class separability improved by incorporating a second texture attribute, but resulted in a decrease in classification accuracy. The results suggest that incorporating image texture may be beneficial for separating stands with high spatial heterogeneity. However, the benefits may be limited and must be weighed against the increased complexity of the classifier.  相似文献   
28.
This paper introduces a risk-based decision process integrated into a drought early warning system (DEWS) for reservoir operation. It is to support policy making under uncertainty for drought management. Aspects of posterior risk, chances of option occurrences and the corresponding options to given chances, are provided to help decision makers to make better decisions. A new risk index is also defined to characterize decision makers’ attitudes toward risk. Decision makers can understand the inclination of attitude associated with any specific probability through accuracy assessment, and learn to adjust their attitudes in decision-making process. As a pioneering experiment, the Shihmen reservoir in northern Taiwan was tested. Over the simulation period (1964–2005), the expected overall accuracy approximated to 77%. The results show that the proposed approach is very practical and should find good use for reservoir operations.  相似文献   
29.
30.
In this study, a two-stage fuzzy chance-constrained programming (TFCCP) approach is developed for water resources management under dual uncertainties. The concept of distribution with fuzzy probability (DFP) is presented as an extended form for expressing uncertainties. It is expressed as dual uncertainties with both stochastic and fuzzy characteristics. As an improvement upon the conventional inexact linear programming for handling uncertainties in the objective function and constraints, TFCCP has advantages in uncertainty reflection and policy analysis, especially when the input parameters are provided as fuzzy sets, probability distributions and DFPs. TFCCP integrates the two-stage stochastic programming (TSP) and fuzzy chance-constrained programming within a general optimization framework. TFCCP incorporates the pre-regulated water resources management policies directly into its optimization process to analyze various policy scenarios; each scenario has different economic penalty when the promised amounts are not delivered. TFCCP is applied to a water resources management system with three users. Solutions from TFCCP provide desired water allocation patterns, which maximize both the system’s benefits and feasibility. The results indicate that reasonable solutions were generated for objective function values and decision variables, thus a number of decision alternatives can be generated under different levels of stream flows, α-cut levels and fuzzy dominance indices.  相似文献   
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