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421.
422.
基于东北航线的中欧贸易研究 总被引:1,自引:0,他引:1
东北航线因其战略地位重要而日益受到世界各国的关注.本文计算出中欧港口航运经济成本及中欧国家贸易互补指数,基于东北航线构建随机前沿贸易引力模型,探究中国对欧洲18国进出口贸易的影响因素,结果发现:①以12000 TEU运输量为对比,中欧港口基于东北航线的航运经济成本约为传统航线的1.58~2.80倍.②2000-2018... 相似文献
423.
阐述了水价确定与调水工程良性运行的关系,通过对不同水价制定方法的经济学分析,论述了长期边际成本定价对调水资源优化配置的有效性,提出了南水北调工程水价制定原则:以长期边际成本定价思想为指导,实现容量水价与计量水价相结合,以动态调整和价格歧视为辅助措施的水价机制;适当提升南水北调水价,确保受水区水价和水源结构的平稳过渡。 相似文献
424.
我国矿产资源有偿使用制度体系的改革思考 总被引:2,自引:0,他引:2
我国现有的矿业税费制度体系,特别是矿产资源有偿使用收费制度体系无论在制度理论、收费项目设置、收取依据、收取标准和收益分配等方面均存在诸多问题.本文主要就矿产资源有偿使用收费制度体系中的制度因子——矿业权价款的经济内涵做了较为深入的探讨,在此基础上提出了我国矿业权税费制度体系改进的基本方案. 相似文献
425.
Daniel Buor 《GeoJournal》2002,56(2):145-157
The research primarily aims at testing a model, adapted from existing models, on the influence of distance on the use of health services in the Kumasi metropolis, an expanding urban centre in Ghana. Primary data, collected between August 2000 and February 2001, were used for the study. The data were analysed using a multiple regression model and compound bar graphs. A sample of 250, drawn through systematic random and stratified procedures, was used for the cross-sectional retrospective survey. Data were collected through formal interview schedules, after preliminary observational survey. The survey has established three principal findings. First, distance shows a strong inverse relationship with the utilisation of health services in the metropolis. Second, travel time and transport cost, variables that are related to distance, exhibit a weak negative and positive associations respectively with the use of health services. Third, the vulnerable groups of women, the aged, the sickly, the illiterate and the poor are not affected by distance decay in the utilisation of health services. Finally, independent variables that are statistically significant in influencing utilisation, alongside distance, are education, service cost, quality of service and health status. Recommendations for locational modelling of health services at the deprived periphery, an introduction of an insurance scheme to facilitate health care use, and recommendations for further research have been made. 相似文献
426.
面对勘探任务,做到生产有保障、成本有优势、项目管理有水平是每个生产企业的发展目标。本文结合从事勘探劳务生产的倬方岩土公司对钻探生产能力的建设,从钻探队伍建设、成本降低、管理水平提高等方面所做的一些工作和探索进行一些分析和论述。 相似文献
427.
Alexandre B. Gonçalves 《International journal of geographical information science》2013,27(7):983-996
The computation of least-cost paths over a cost surface is a well-known and widely used capability of raster geographic information systems (GISs). It consists in finding the path with the lowest accumulated cost between two locations in a raster model of a cost surface, which results in a string-like, thin and long sequence of cells. In this article, a new extension of raster-based least-cost path modelling is proposed. The new modelling approach allows the computation of paths or corridors with a fixed width, larger than one cell. These swaths are called wide paths and may be useful in circumstances where the detail level of the raster cost surfaces is higher than the width of the desired path or corridor. The wide path model presented in the article is independent of the choice of least-cost algorithms, because the transformation from regular to wide paths is applied to the construction of nodes and edges of an induced graph. The article gives the foundations and discusses the particularities of such paths, regardless of the imposed width, and explores the difference from the usual least-cost path model. Test cases were included, one hypothetical and the other with real data. The results are coherent and indicative of the applicability of wide paths. 相似文献
428.
Geotechnical and Geological Engineering - 相似文献
429.
Marek Kacewicz 《Mathematical Geology》1991,23(1):111-118
This paper presents an approach to solve the kriging problem, defined in terms of projections, by using Gram-Schmidt orthogonalization. The Gram-Schmidt orthogonalization allows us to find an optimal approximationY* in then-dimensional subspaceH
n
of any vectorY element of a Hilbert spaceH. This approach requiresO(n
3) multiplication operations to obtain an orthogonal basis, andO(n
2) multiplications needed to calculate kriging solution for a given point. 相似文献
430.
In this paper, an economic model was constructed to determine the optimal wolf population and distribution across the Northern Rocky Mountains. Both ecological and economic concepts were incorporated in an implicitly spatial social welfare maximization problem. This interdisciplinary model relies on multiple data sources, including current wolf population and distribution information, opportunity cost to local landowners, and contingent valuation studies to determine willingness-to-pay for wolves. Economic models tend to externalize ecological concerns and ecological models often omit the complex human dimensions of conservation policy. Accordingly, this model can serve as a guide for integrating best practices from both fields. The model presented here is sufficiently general to apply to wolves in other ecosystems and to other highly interacting species such as beavers and bison. The Northern Rocky Mountain wolf was used as an example of how this economic model works, but this model can be applied far more broadly. 相似文献