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71.
河南栾川南泥湖和上房沟花岗岩体与钼多金属成矿作用密切相关。本文用电子探针测试方法,分析了南泥湖岩体和上房沟岩体中黑云母的成分特征。结果表明,2个岩体中黑云母均具有高硅、富镁、低铝和贫铁的特征,属镁质黑云母。2个岩体的结晶温度分别为730~830℃和750~860℃,氧逸度(logfO2)分别为-8.5~-7.0和-8.0~-6.5,结晶压力和深度分别为72~120MPa、54~127MPa和2.62~4.37km、1.97~4.63km,有利于南泥湖-三道庄和上房沟超大型钼矿床的形成,地球化学特征显示2个岩体均属壳幔混源的Ⅰ型花岗岩,属深源中浅成花岗岩。 相似文献
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Pedoja Kevin 《中国科学D辑(英文版)》2005,48(11):1900-1912
The importance of calcimicrobes and microbialite in carbonate platform and reefal environments has been stressed in recent literature. Burne and Moore[1] introduced the term microbialite to describe the clotted, laminated and undifferentiated fabrics formed by mi-crobial communities. Microbialites are organosedi-mentary deposits that have accreted as a result of ben-thic (prokaryotic or eukaryotic) communities, trapping and binding detrital sediment[1]. Microbial organisms and microbialite are… 相似文献
74.
Biogenic carbonates spawned from microbial activities are common occurrences in soils. Here, we investigate the carbonate biomineralization mediated by the bacterium Bacillus megaterium, a dominant strain separated from a loess profile in China. Upon completing bacterial cultivation, the ensuring products are centrifuged, and the resultant supernatant and the concentrated bacterial sludge as well as the un-separated culture are added separately into a Ca-CO3 containing solution for crystallization experiments. Results of XRD and SEM analysis indicate that calcite is the dominant mineral phase formed when the bacteria are present. When the supernatant alone is used, however, a significant portion of vaterite is also precipitated. Experimental results further reveal that the bacteria have a strong tendency to colonize the center area of the calcite {1 0 4} faces. Observed crystal morphology suggests that the bacterial colony may promote the growth normal to each individual {1 0 4} face of calcite when the cell concentration is high, but may retard it or even cause dissolution of the immediate substrate surfaces when the concentration is low. SEM images taken at earlier stages of the crystallization experiments demonstrate the nucleation of calcite on the bacterial cell walls but do not show obvious morphological changes on the nanometer- to submicron-sized nuclei. δ13C measurements unveil that the crystals grown in the presence of bacteria are further enriched in the heavy carbon isotope, implying that the bacterial metabolism may not be the carbon sources for the mineralization. Based upon these findings, we propose a mechanism for the B. megaterium mediated calcite mineralization and conclude that the whole process involves epi- and inter-cellular growth in the local microenvironments whose conditions may be controlled by cell sequestration and proton pumping during bacterial respiration. 相似文献
75.
隔振问题是绝对重力仪研制中的关键技术难题之一。在自主研制"小型mGal级绝对重力仪"过程中发现,除了需要克服地面振动的影响之外,系统自振的影响也不容忽视,最大能达到mGal量级。通过对研制样机实验观测结果的分析,研究了系统自振产生的原因以及对系统偏差与观测内符合精度的影响模式,并给出了改进方案,以消除"系统自振"的影响,提高研制仪器的观测精度。 相似文献
76.
基于时间序列法的北京市需水量预报(英文) 总被引:2,自引:0,他引:2
It is essential to establish the water resources exploitation and utilization planning,which is mainly based on recognizing and forecasting the water consumed structure rationally and scientifically.During the past 30 years(1980-2009),mean annual precipitation and total water resource of Beijing have decreased by 6.89% and 31.37% compared with those perennial values,respectively,while total water consumption during the same period reached pinnacle historically.Accordingly,it is of great significance for the harmony between socio-economic development and environmental development.Based on analyzing total water consumption,agricultural,industrial,domestic and environmental water consumption,and evolution of water consumed structure,further driving forces of evolution of total water consumption and water consumed structure are revealed systematically.Prediction and discussion are achieved for evolution of total water consumption,water consumed structure,and supply-demand situation of water resource in the near future of Beijing using Time Series Forecasting Method.The purpose of the endeavor of this paper is to provide scientific basis for the harmonious development between socio-economy and water resources,for the establishment of rational strategic planning of water resources,and for the social sustainable development of Beijing with scientific bases. 相似文献
77.
在极化SAR影像极化特征的基础上,引入影像的纹理信息,利用带核函数的SSVM算法对极化SAR影像进行分类研究。该方法首先利用精致LEE滤波器对极化SAR影像进行去噪处理;然后采用小波变换对去噪后的总功率影像Span进行纹理特征提取;最后将纹理信息和极化信息结合,并采用SSVM方法对极化SAR影像进行分类。利用NASA/JPL AIRSAR获取的L波段SanFrancisco海湾和荷兰中部Flevoland地区的影像对该方法进行验证,结果表明,SSVM算法可有效地用于极化SAR影像分类,且分类精度和分类效率都优于SVM算法。同时纹理信息的引入使SSVM算法的分类精度得到了进一步提高。 相似文献
78.
基于ASTER遥感影像的西昆仑岩性信息提取方法研究 总被引:1,自引:0,他引:1
基于西昆仑西段布伦口地区各岩性段内岩石样品的矿物组成及其光谱特征分析,提取代表各岩性单元的岩性端元波谱曲线;对研究区内ASTER可见光(VNIR)和短波红外(SWIR)数据进行匹配滤波处理,成功提取了研究区内9种重要的岩性单元(包括古元古界布仑阔勒群的黑云石英岩、黑云斜长片麻岩、黑云石英片岩和黑云角闪斜长片麻岩,志留系温泉沟群的绿泥石绢云母板岩、黑色千枚岩和绢云母石英片岩,以及石英闪长岩和英云闪长岩)。经已知地质资料和野外查证资料分析证明,用上述方法提取岩性信息的结果可靠,能为岩性填图及矿床勘查工作提供参考。 相似文献
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