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91.
《Geoforum》2017
The Internet and the representation of space therein are almost omnipresent in society and everyday life. Peer-produced geographic data is gaining a particular importance through increasingly available digital tools and techniques that shape the perception of space in the internet, such as flickr, OpenStreetMap or Wikipedia. However, few studies focused on how space is represented, and by whom it is described. We hypothesize that the alleged opening up of geographic information and the assumed benefits for every individual and society through the occurrence of ‘easy-to-use-mapping-tools’ was premature. To explore these assumptions, a comparative study of the flickr worldmap was undertaken and roughly 6.8 million metadatasets of geocoded photos in France, and roughly 50,000 metadatasets in Afghanistan were downloaded and the metadata was analyzed. Our results indicate that photos geocoded in France show a large diversity of motives, while photos geocoded in Afghanistan are mostly limited to content containing warfare when they are up loaded in English. The content of the photo and therefore the representation of space strongly depend on who uploaded the photo, particularly in Afghanistan. We can show that the representation of space on the internet, for the case of flickr, is strongly dominated by perceptions of Western societies and individuals. We therefore confirm our hypothesis that the supposed opening up of geographic information systems through ‘easy-to-use-mapping-tools’ and their democratization thereof was premature. Moreover, we highlight the importance of understanding who contributes online content to be able to evaluate peer-produced data, its value, and its possible applications to avoid reproducing biases. 相似文献
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93.
PEI Xiandeng KONG Lingwang ZHU Yuanhong HUANG Hao 《地球空间信息科学学报》2005,8(4):306-310
IntroductionIn color reproduction and communication, met-amer exists inherently when the conventionalcondition matching used. Therefore , the colordifference introduced makes the accuracy of colorrepresentation be lowered.In order to eli minatemetamer CIE developed the scheme so-calledspectra matching in Publication 15 .2 and speci-fied that using band-pass filters with 5 nminter-val to sample and then reconstruct the originalcolor signal ,thus the color difference will disap-pear[1].Spectra… 相似文献
94.
SHAZongyao BIANFuling 《地球空间信息科学学报》2005,8(1):57-63
This paper introduces some definitions and defines a set of calculating indexes to facilitate the research, and then presents an algorithm to complete the spatial clustering result comparison between different clustering themes. The research shows that some valuable spatial correlation patterns can be further found from the clustering result comparison with multi-themes, based on traditional spatial clustering as the first step. Those patterns can tell us what relations those themes have, and thus will help us have a deeper understanding of the studied spatial entities. An example is also given to demonstrate the principle and process of the method. 相似文献
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JAY LEE 《International journal of geographical information science》2013,27(3):267-285
Abstract Triangulated irregular networks (TINs) are increasingly popular for their efficiency in data storage and their ability to accommodate irregularly spaced elevation points for many applications of geographical information systems. This paper reviews and evaluates various methods for extracting TINs from dense digital elevation models (DEMs) on a sample DEM. Both structural and statistical comparisons show that the methods perform with different rates of success in different settings. Users of DEM to TIN conversion methods should be aware of the strengths and weaknesses of the methods in addition to their own purposes before conducting the conversion. 相似文献
98.
D. Sheeren S. Mustière J.‐D. Zucker 《International journal of geographical information science》2013,27(8):961-992
When different spatial databases are combined, an important issue is the identification of inconsistencies between data. Quite often, representations of the same geographical entities in databases are different and reflect different points of view. In order to fully take advantage of these differences when object instances are associated, a key issue is to determine whether the differences are normal, i.e. explained by the database specifications, or if they are due to erroneous or outdated data in one database. In this paper, we propose a knowledge‐based approach to partially automate the consistency assessment between multiple representations of data. The inconsistency detection is viewed as a knowledge‐acquisition problem, the source of knowledge being the data. The consistency assessment is carried out by applying a proposed method called MECO. This method is itself parameterized by some domain knowledge obtained from a second method called MACO. MACO supports two approaches (direct or indirect) to perform the knowledge acquisition using data‐mining techniques. In particular, a supervised learning approach is defined to automate the knowledge acquisition so as to drastically reduce the human‐domain expert's work. Thanks to this approach, the knowledge‐acquisition process is sped up and less expert‐dependent. Training examples are obtained automatically upon completion of the spatial data matching. Knowledge extraction from data following this bottom‐up approach is particularly useful, since the database specifications are generally complex, difficult to analyse, and manually encoded. Such a data‐driven process also sheds some light on the gap between textual specifications and those actually used to produce the data. The methodology is illustrated and experimentally validated by comparing geometrical representations and attribute values of different vector spatial databases. The advantages and limits of such partially automatic approaches are discussed, and some future works are suggested. 相似文献
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100.
Zhilin Li 《International journal of geographical information science》2013,27(5):855-880
Spatial data can be represented at different scales, and this leads to the issue of multi-scale spatial representation. Multi-scale spatial representation has been widely applied to online mapping products (e.g., Google Maps and Yahoo Maps). However, in most current products, multi-scale representation can only be achieved through a series of maps at fixed scales, resulting in a discontinuity (i.e., with jumps) in the transformation between scales and a mismatch between the available scales and users' desired scales. Therefore, it is very desirable to achieve smoothly continuous multi-scale spatial representations. This article describes an integrated approach to build a hierarchical structure of a road network for continuous multi-scale representation purposes, especially continuous selective omission of roads in a network. In this hierarchical structure, the linear and areal hierarchies are constructed, respectively, using two existing approaches for the linear and areal patterns in a road network. Continuous multi-scale representation of a road network can be achieved by searching in these hierarchies. This approach is validated by applying it to two study areas, and the results are evaluated by both quantitative analysis with two measures (i.e., similarity and average connectivity) and visual inspection. Experimental results show that this integrated approach performs better than existing approaches, especially in terms of preservation of connectivity and patterns of a road network. With this approach, efficient and continuous multi-scale selective omission of road networks becomes feasible. 相似文献