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脉状铅锌(铜、银)多金属热液矿床研究进展 总被引:1,自引:0,他引:1
目前在矿床学分类研究中对沉积岩容贱金属矿床的命名和分类尚未统一,其中一类赋矿围岩为沉积岩、矿体受构造(断层、褶皱等)控制呈脉状产出的、成矿金属为铅锌铜银多金属的矿床成为缺失环节,缺少系统的归纳总结。但该类矿床是造山作用的产物,对其进行归纳综合分析,有助于了解造山作用中的矿质迁移和沉淀过程。本文将该类矿床资料收集,对其成矿特征、控矿构造、成矿流体、矿质来源等进行分析总结。研究表明,此类矿床与造山作用或造山带有着紧密的联系。成矿物质表现为多源性,包括基底围岩、岩浆来源以及幔源贡献。成矿流体具有岩浆流体、变质流体、盆地卤水等多种来源,部分矿床的成矿流体受大气水影响。该类型矿床与MVT铅锌矿床有相似之处,但在成矿环境、控矿因素、金属来源以及成矿流体来源等方面有较大差异。 相似文献
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地籍测量过程中具有静态、可调平和转位的特点,在静基座条件下,捷联惯性测量系统(SIMS)粗对准的失准角与卡尔曼滤波精对准的失准角相当,但是解析粗对准的方位角误差较大。本文在建立SIMS静基座粗对准误差方程的基础上,对影响解析粗对准精度的误差因素进行分析,提出利用光纤陀螺寻北仪进行四位置转位寻北的方法来估算方位角的精度,以提高方位角的估计精度。仿真结果表明,该方法可以有效地提高对准精度,适合于静基座外界干扰小的捷联式惯性测量系统上,在一定程度上可以直接作为对准的结果用于地籍测量定位解算。 相似文献
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最佳小波包基的矿区植被及红边位置提取 总被引:1,自引:0,他引:1
小波包变换能同时对植被光谱信息的低频和高频分量进行分解,并能克服小波变换时间分辨率高而频率分辨率低的缺陷从而具有能够探测植被细微变化的优势。实验利用Hyperion高光谱影像对云南省普朗铜矿区植被像元的光谱进行最佳小波包基参量获取与植被信息识别,并在此基础上提出一种提取重金属污染下植被红边位置的最佳小波包基系数应用模型。研究结果表明基于最佳小波包基参量的植被信息识别及基于最佳小波包基系数的重金属污染探测具有可行性与一定优越性。 相似文献
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The Willyama Supergroup of the Broken Hill region in southern Australia consists of supracrustal sedimentary and magmatic rocks, formed between 1810 and 1600 Ma. A statistical analysis of nearly 2000 SHRIMP U–Pb zircon spot ages, compiled from published and unpublished sources, provides evidence for three distinct tectonostratigraphic successions and four magmatic events during this interval. Succession 1 includes Redan Geophysical Zone gneisses and the lower part of the Thackaringa Group (Cues Formation). These rocks were deposited after 1810 Ma and host granite sills of the first magmatic event (1710–1700 Ma). Succession 2 includes the upper Thackaringa Group (Himalaya Formation), the Broken Hill Group and the Sundown Group and was deposited between 1710 and 1660 Ma. These rocks all contain detrital zircons from the first magmatic event (1710–1700 Ma) and in some cases from the second magmatic event (1690–1680 Ma). The second magmatic event (1690–1680 Ma) was bimodal, resulted from crustal extension, and was coeval with deposition of the Broken Hill Group and deepening of the basin. With this event a mafic sill swarm focused in the Broken Hill Domain. Mafic sills lack any trace of inheritance, unlike the granitoids that commonly contain inherited zircons typical of the supracrustal sediments. Succession 3, the Paragon Group and equivalents were deposited after 1660 Ma, but before a regional metamorphic event at 1600 Ma. Metamorphism was closely followed by inversion of the succession into a fold‐and‐thrust belt, accompanied by a fourth late to post‐orogenic magmatic event (ca 1580 Ma) characterised by granite intrusion and regional acid volcanism (the local equivalents of the Gawler Range Volcanics in South Australia). 相似文献
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Hydrological processes of lowland watersheds of the southern USA are not well understood compared to a hilly landscape due to their unique topography, soil compositions, and climate. This study describes the seasonal relationships between rainfall patterns and runoff (sum of storm flow and base flow) using 13 years (1964–1976) of rainfall and stream flow data for a low‐gradient, third‐order forested watershed. It was hypothesized that runoff–rainfall ratios (R/P) are smaller during the dry periods (summer and fall) and greater during the wet periods (winter and spring). We found a large seasonal variability in event R/P potentially due to differences in forest evapotranspiration that affected seasonal soil moisture conditions. Linear regression analysis results revealed a significant relationship between rainfall and runoff for wet (r2 = 0·68; p < 0·01) and dry (r2 = 0·19; p = 0·02) periods. Rainfall‐runoff relationships based on a 5‐day antecedent precipitation index (API) showed significant (r2 = 0·39; p < 0·01) correspondence for wet but not (r2 = 0·02; p = 0·56) for dry conditions. The same was true for rainfall‐runoff relationships based on 30‐day API (r2 = 0·39; p < 0·01 for wet and r2 = 0·00; p = 0·79 for dry). Stepwise regression analyses suggested that runoff was controlled mainly by rainfall amount and initial soil moisture conditions as represented by the initial flow rate of a storm event. Mean event R/P were higher for the wet period (R/P = 0·33), and the wet antecedent soil moisture condition based on 5‐day (R/P = 0·25) and 30‐day (R/P = 0·26) prior API than those for the dry period conditions. This study suggests that soil water status, i.e. antecedent soil moisture and groundwater table level, is important besides the rainfall to seasonal runoff generation in the coastal plain region with shallow soil argillic horizons. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
117.
Thomas C. Winter Donald C. Buso Patricia C. Shattuck Phillip T. Harte Donald A. Vroblesky Daniel J. Goode 《水文研究》2008,22(1):21-32
The west watershed of Mirror Lake in the White Mountains of New Hampshire contains several terraces that are at different altitudes and have different geologic compositions. The lowest terrace (FSE) has 5 m of sand overlying 9 m of till. The two next successively higher terraces (FS2 and FS1) consist entirely of sand and have maximum thicknesses of about 7 m. A fourth, and highest, terrace (FS3) lies in the north‐west watershed directly adjacent to the west watershed. This highest terrace has 2 m of sand overlying 8 m of till. All terraces overlie fractured crystalline bedrock. Numerical models of hypothetical settings simulating ground‐water flow in a mountainside indicated that the presence of a terrace can cause local ground‐water flow cells to develop, and that the flow patterns differ based on the geologic composition of the terrace. For example, more ground water moves from the bedrock to the glacial deposits beneath terraces consisting completely of sand than beneath terraces that have sand underlain by till. Field data from Mirror Lake watersheds corroborate the numerical experiments. The geology of the terraces also affects how the stream draining the west watershed interacts with ground water. The stream turns part way down the mountainside and passes between the two sand terraces, essentially transecting the movement of ground water down the valley side. Transects of water‐table wells were installed across the stream's riparian zone above, between, and below the sand terraces. Head data from these wells indicated that the stream gains ground water on both sides above and below the sand terraces. However, where it flows between the sand terraces the stream gains ground water on its uphill side and loses water on its downhill side. Biogeochemical processes in the riparian zone of the flow‐through reach have resulted in anoxic ground water beneath the lower sand terrace. Results of this study indicate that it is useful to understand patterns of ground‐water flow in order to fully understand the flow and chemical characteristics of both ground water and surface water in mountainous terrain. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
118.
樊杰 《中国地理科学(英文版)》1994,4(1):43-54
ANANALYSISOFTHEPOLICY-MAKINGINREGULATINGTHEINDUSTRIALSTRUCTUREANDDISTRIBUTIONINTRADITIONALINDUSTRIALBASEINMIDDLELIAONINGPROVI... 相似文献
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