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871.
以农安幅1:20万综合水文地质图空间数据库的建立为例,介绍了利用GIS建立空间数据库的全过程。讨论了建库过程中的主要操作步骤、方法和一些值得注意的问题。着重讨论在图形数据采集及建立空间属性数据库时,如何保证图形的数学精度,如何使拓扑结构合理,以及如何使属性联接正确。 相似文献
872.
人工横波地震是工程物探的一种新技术,但由于理论上存在一些误区,在工程实践中给地质解释带来一定困难。正确理解和计算横波波速是解决这个问题的首要任务,利用多次叠加时动校正的速度能量团计算横波速度比较可靠,该技术的应用已成功地解决了一些疑难复杂地质问题。准确的横波波速计算可使横波勘探得到更好地推广和应用,为工程设计和建设提供可靠的地质资料。 相似文献
873.
通过六合区采矿权拍卖的试点,探索矿业权市场的运行规律和特点,说明矿业权市场建设对促进矿产资源的可持续利用的重要性。结合南京实际,提出了采矿权储备、采矿权市场机构建设等方面的建议。 相似文献
874.
The Shengli I Point Bar on the Yellow River Delta: Three-Dimensional Structures and Their Evolution 总被引:3,自引:0,他引:3
ZHONG Jianhu SHEN Xiaohu NI Jinren WANG Guanmin WEN Zhifeng WANG Xibin WANG Haiqiao LI Li WU Kongyou LI Yong HONG MeiEarth Resource Information College Petroleum University of Chin Dongyin Shandong Earth Science Department Zhejiang University Hangzhou Zhejiang Center for Environment Science Peking University Beijing 《《地质学报》英文版》2002,76(4):463-477
Point bars are well developed on the Yellow River delta, among which the Shengli I point bar is the most typical. The point bar, being about 4 km in length and several tens to more than 100 meters in width, is located on the south side of the Shengli Bridge in Kenli County, Dongying, Shandong. It is a typical fine-grained point bar with silt, which is predominant, some clay and minor plant debris and clay boulders. The Shengli I point bar has complicated 3-D structures. Firstly, in a plane view, it comprises mainly eight sedimentary units, bar edge, bar ridge, bar platform, bar plain, bar channel, bar gully, bar pond and bar bay, developing side by side and superimposed one by one in a complex way. Secondly, its vertical structures are very complex due to the partial superimposition of the 8 sedimentary units. Besides hydatogenesis, very intensive wind erosion, eolian, ice and meltwater actions are also visible on the Shengli I point bar. The complex form is made even more complicated because of the abo 相似文献
875.
After the establishment of the global stratotype section and point (GSSP) of the Permian-Triassic boundary (PTB), the definition of the accessory section and point (ASP) of the terrestrial Permian-Triassic boundary (TPTB) is now on the agenda. However, all good TPTB sections so far known have the following shortcoming:(1) the exact TPTB horizon is difficult to define paleontologically with high-resolution, and (2) accurate correlation between marine and terrestrial PTBs in hard to attain. In order to enhance the understanding of the nature of the global life crisis in both the marine and terrestrial environments across the Paleozoic-Mesozoic transition, these shortcomings need to be addressed. In western Guizhou and eastern Yunnan, Southwest China, some fossiliferous PTB sections which include marine, paralic and terrestrial are well-developed, allowing bed-to-bed correlation of the PTB sequences. Fortunately, the marine PTB sequence in this area is almost the same as found at the Meishan Section, where the GSSP of the PTB is located, which may provide a reliable auxiliary marker for high-resolution demarcation of the TPTB. These features fund in estern Guizhou and eastern Yunnan make this area a good place to study the ASP of the TPTB, so we propose to study the ASP of the TPTB in this area. 相似文献
876.
点状、线状和面状地图符号数学定义的研究 总被引:5,自引:2,他引:5
根据集合论和拓扑学的有关理论,导出了点状地图符号、线状地图符号和面状地图符号的数字定义。阐述了图形和背景的相互依存关系以及它们在传输地理信息中的整体功能。 相似文献
877.
以1954年北京坐标为起算对GPS基线网平差的影响 总被引:1,自引:0,他引:1
本文分析了以1954年北京坐标为起算对GPS基线网平差的影响,并结合实例,得出了一些结论。 相似文献
878.
峨眉宝光研究之一——宝光机理的综合研究 总被引:1,自引:1,他引:1
王鹏飞 《南京气象学院学报》2002,25(2):180-185
通过对宝光形成思路的追索,否定“冰晶云不可能出现宝光”的看法,综合考虑了不同条件下出现的宝光应遵循不同的形成机理。指出水云和冰晶云都能出现宝光,而冰晶云上宝光的伴生光象不是主虹,而是对日晕。 相似文献
879.
880.
Rock magnetic measurements of Nihewan sediments from Xujiayao section demonstrate that magnetite, hematite and maghemite are
dominant remanent magnetization carriers. Monitoring the variations of magnetic susceptibility (MS) and saturating isothermal
remanent magnetization (SIRM) at low temperature are the attractive ways of detecting the presence of magnetite, maghemitization
and superparamagnetic grain sizes. Low-temperature MS investigations suggest that susceptibility enhancement for Xujiayao
samples is mainly due to the remarkable presence of SD/MD magnetite to some degree though some magnetite grains have been
partially oxidized at some depths. It is tentatively concluded that both SD/MD magnetite and hematite are of detrital origin
and carry a characteristic remanent magnetization (ChRM), whereas maghemite can be attributed to be chemical origin, overprinting
a reversed polarity component of Matuyama age. 相似文献