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131.
E. A. Jarzembowski 《Cretaceous Research》1995,16(6)
The first fossil caddis cases from the Early Cretaceous (Wealden) of SE England are described and named Conchindusia rasnitsyni ichnosp. nov., Piscindusia sukachevae ichnogen. et isp. nov., ?Ostracindusia vyalovi ichnosp. nov. and Pelindusia percealleni ichnosp. nov. In addition, the necrotauliid caddisfly Paratrichopteridium purbeckianum (Handlirsch) comb. nov. from the earliest Cretaceous (Purbeck Group) of Dorset is redescribed. 相似文献
132.
南海南部地洼区新构造运动及其动力学机制 总被引:3,自引:2,他引:3
本文根据南海南部地洼区的岩石圈动力学环境,把本区新构造运动类型划分为拉张型、挤压型、平移剪切型和旋动型,并对其构造演化与动力学模式进行了初步分析。 相似文献
133.
The relationship between the monsoon rainfall throughout all India, northwest India and peninsular India as well as the onset dates of the monsoon and two indices of southern oscillation (SOI), namely Isla de Pascua minus Darwin (I-D) and Tahiti minus Darwin (T-D) pressure anomaly have been studied for different periods. The study indicates that the monsoon rainfall shows a strong and significant direct relationship with SOI for the concurrent, succeeding autumn and succeeding winter seasons. The magnitude of the direct correlation coefficient for the SOI using (I-D) is enhanced over all India and peninsular India if the above seasons happen to be associated with an easterly phase of the QBO (Quasi-Biennial Oscillation) at 50 mb. The result indicates that the strength of the monsoon plays an important role in the following southern oscillation events in the Pacific Ocean. The premonsoon tendency of the SOI anomaly spring minus winter SOI shows a significant positive correlation with monsoon rainfall over all India, northwest India and peninsular India. The absolute value of the positive correlation coefficient becomes highly enhanced over all India, northwest India as well as peninsular India if the 6-month period from December to March is associated with the westerly phase of the QBO. Hence, the premonsoon SOI tendency parameter can be a useful predictor of Indian monsoon rainfall especially if it happens to be associated with the westerly QBO. Significant negative association is also found between the anomaly of monsoon onset dates and SOI of the previous spring season, the absolute value being higher for SOI (T-D) than for SOI (I-D). The negative correlation coefficient becomes enhanced if the previous springs are associated with a westerly phase of the QBO. It shows that the previous spring SOI has some predictive value for the onset date of Indian monsoon, a positive SOI followed by an early onset of monsoon, andvice versa, especially if it is associated with a westerly phase of the QBO. 相似文献
134.
Salvi S. Quattrocchi F. Brunori C. A. Doumaz F. Angelone M. Billi A. Buongiorno F. Funiciello R. Guerra M. Mele G. Pizzino L. Salvini F. 《Natural Hazards》1999,20(2-3):255-278
A priority task for correct environmental planningis to evaluate Natural Hazards, especially inhighly populated areas. In particular, thoroughinvestigations based on different Earth Sciencetechniques must be addressed for the Seismic HazardAssessment (SHA) in tectonically active areas. Notonly the management but also the multidisciplinaryanalysis of all the SHA-related data sets is bestperformed using a Geographic Information System. In this paper we show how a research-oriented GIS isbuilt and used in a practical case. The GeochemicalGeographic Information System (G2IS) wasdeveloped and applied to the Gargano promontory(southern Italy) in the framework of an EC researchproject, the Geochemical Seismic Zonation (GSZ)Project. This multidisciplinary – multiscalingpowerful tool is described in its structure, updatingprocedures and manipulation techniques. Preliminaryresults are presented on the detection of geochemically active fault zones and theircorrelation with remote sensing data and otherevidences of seismogenic structures. 相似文献
135.
辽中南地区经济发展与资源环境关系 总被引:8,自引:4,他引:4
分析了辽中南地区资源环境对经济发展的作用和经济发展对资源环境的影响,阐明了区域经济发展与资源环境密不可分的关系,资源环境是经济发展的物质基础,经济发展为促进资源合理开发利用和环境保护创造条件。 相似文献
136.
南半球环流异常与我国夏季旱涝分布关系及其影响机制 总被引:6,自引:0,他引:6
利用1951—2000年NCEP/NCAR风场和高度场再分析资料及全国160站降水量资料, 采用奇异值分解、相关和合成分析方法, 研究6—8月南半球500 hPa高度、高低层纬向风距平差异常 (Δu850-Δu200) 与我国夏季旱涝分布的关系及其影响机制。结果表明:当500 hPa澳大利亚高压脊偏强及西南太平洋热带地区高低层纬向风距平差为负值时, 来自南半球冷空气活动偏弱, 有利于西北太平洋副热带高压位置偏南, 热带季风偏弱, 我国夏季雨带偏南。反之, 当澳大利亚高压脊偏弱及西南太平洋热带地区高低层纬向风距平差为正值时, 我国北方降水偏多。同时, 定义了澳大利亚冬季风指数, 指出澳大利亚冬季风强年和弱年影响我国夏季旱涝分布异常的水汽输送型式不同。 相似文献
137.
The gigantic fold-thrust fracture belt that ex-tends for 900 kmto the NWin the southern NorthChina plate strides across three provinces : Shaanxi ,Henan and Anhui .It is one of the most characteristicstructural deformations in the North China plate .Along this structural belt a series of i mportantcoalfields occur ( e . g. Pingdingshan, Queshan,Huainan) inthe southernmost edge of the North Chi-na coal-concentrating basin. Consequently ,this beltis not only of key value for research onthe… 相似文献
138.
Climatic change during the last 4000 years in the southern Tarim Basin,Xinjiang, northwest China 总被引:1,自引:0,他引:1
In this study, a ca. 4000 cal. yr ancient lacustrine (or wetland) sediment record at the southern margin of Tarim Basin is used to reconstruct the history of climate change. Six radiocarbon dates on organic matter were obtained. δ18O and δ13C of carbonate, pollen and sediment particle size were analysed for climate proxies. The proxies indicate that a drier climate prevailed in the area before ca. 1010 BC and during period 1010 BC–AD 500 climate then changed rapidly and continuously from dry to moist, but after about AD 500 climate generally shows dry condition. Several centennial‐scale climatic events were revealed, with the wettest spell during AD 450–550, and a relatively wetter interval between AD 930–1030. Pollen results show that regional climate may influence human agricultural activities. Spectral analysis of mean grain size (MGS) proxy reveals statistically pronounced cyclic signals, such as ca. 200 yr, ca. 120 yr, ca. 90 yr, ca. 45 yr and ca. 33 or 30 yr, which may be associated with solar activities, implying that solar variability plays an important role in the decadal‐ and centennial‐scale climate variations in the study area. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
139.
东昆仑南部晚新生代逆冲推覆构造系统 总被引:7,自引:1,他引:7
通过对东大滩—东温泉地区的路线地质观测与构造填图,在东昆仑南部发现晚新生代大型逆冲推覆构造系统。沿低角度逆冲断层,早二叠世大理岩和早三叠世砂板岩自北向南逆冲推覆于古新统—始新统风火山群紫红色砾岩和渐新世砖红色砂砾岩之上,形成大量不同规模的飞来峰;沿主逆冲断层发育厚层断层角砾岩与断层泥,局部形成碳酸盐质糜棱岩。东昆仑南部逆冲推覆构造的发育时代为渐新世晚期—中新世早期,主要形成、活动时期为26~13.5Ma;估算最小逆冲推覆距离为30~35km,最小逆冲推覆运动速率为2.4~2.8mm/a。东昆仑南部晚新生代逆冲推覆构造运动与现今山脉快速隆升存在着动力学成因联系。 相似文献
140.
藏南洛扎地区基性岩墙群锆石U-Pb定年、地球化学特征及构造意义 总被引:6,自引:1,他引:6
藏南洛扎地区广泛分布有近东西向产出的基性岩墙群,主要侵位于晚侏罗世—早白垩世及其以前的地层中,锆石U-Pb同位素定年获得成岩年龄138.0Ma±3.5Ma。基性岩墙可以划分为2种主要类型:一类低K(K2O=0.06%~0.54%),稀土元素总量和轻、重稀土元素分异程度低[∑REE=58.95×10-6~115.5×10-6,(La/Yb)N=0.23~2.94],亏损LILE;另一类富K(K2O=1.22%~1.67%),稀土元素总量和轻、重稀土元素分异程度较高[∑REE=199.97×10-6~381.47×10-6,(La/Yb)N=6.57~11.5],富集LILE而亏损HFSE。地球化学研究结果表明,基性岩墙为具大陆拉斑玄武岩特征的大陆板内岩浆侵入体,可能分别源于亏损的软流圈地幔和富集的岩石圈地幔。基性岩墙群是新特提斯洋晚期大规模扩张的产物,标志着喜马拉雅被动大陆边缘在晚侏罗世—早白垩世处于强烈的拉张、裂离和岩石圈伸展减薄、软流圈上涌的构造环境与动力学背景。 相似文献