全文获取类型
收费全文 | 88篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 10篇 |
地球物理 | 6篇 |
地质学 | 61篇 |
海洋学 | 3篇 |
天文学 | 1篇 |
自然地理 | 10篇 |
出版年
2014年 | 2篇 |
2013年 | 8篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 3篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有92条查询结果,搜索用时 375 毫秒
51.
Pressure, Temperature, and Structural Evolution of West-Central New Hampshire: Hot Thrusts over Cold Basement 总被引:2,自引:0,他引:2
KOHN MATTHEW J.; ORANGE DANIEL L.; SPEAR FRANK S.; RUMBLE DOUGLAS III; HARRISON T. MARK 《Journal of Petrology》1992,33(3):521-556
Pressure-temperature (P-T) paths have been calculated from pelitesand amphibolites of several major Acadian structures in west-centralNew Hampshire by using both inclusion thermobarometry and differentialthermodynamics (the Gibbs method). P-T paths calculated forrocks exposed in the Orfordville and Bronson Hill anticlinoriaare clockwise and show 12.5 kb of exhumationwith 30100 C of heating. Because this type of path ischaracteristic of the lower plate of overthrust terranes, theserocks are interpreted to be (para)autochthonous. P-T paths forrocks exposed in an intervening synclinorium (the Hardscrabblesynclinorium) show isothermal loading of 13 kb followedby possible isobaric cooling. This behavior is characteristicof rocks occupying a middle-plate structural position withina multiple thrust package, and so these rocks are interpretedto be allochthonous. The interpretation that the Hardscrabblerocks are allochthonous differs from previous models, but betterexplains the petrologic data and is consistent with the stratigraphicand structural data on which other models have been based. Correlation of the P-T paths with deformational events throughkinematic and textural analysis indicates that during nappestage deformation, the synclinorial rocks were transported westward,and that the anticlinorial and synclinorial rocks were buriedto depths of 2530 and 2025 km respectively. Theexhumation with heating recorded by the anticlinorial samplesoccurred during the dome stage of deformation, and differentiallyuplifted the anticlinorial rocks relative to the synclinorialrocks; this differential uplift may have been accommodated throughreactivation of early thrust faults with normal movement sense.P-T paths of the Hardscrabble synclinorium rocks are suggestiveof a relatively elevated initial geothermal gradient for theirpre-nappe source terrane, which is interpreted to have beenbetween the Kearsarge-Central Maine basin and the Bronson Hillparautochthon. 相似文献
52.
FRANK J. WOBBER 《Sedimentology》1967,9(4):265-317
Geologists increasingly concerned with detailed laboratory analyses at times overlook space-age techniques that promise the collection of valuable sedimentological data. Orbital remote sensing, and particularly space photography, can provide synoptic environmental data for geoscientists including those familiar with applying aerial photography to the analysis of sedimentary environments. Color space photographs obtained incident to the Gemini Program provide unique tools for analyzing sedimentary environments and processes and provide data that cannot be duplicated by conventional aerial photographic techniques. The principal advantages of orbital geoscience data collection include frequency of coverage leading to environmental analysis within the full spectrum of seasonal contrasts, and opportunities for environmental syntheses by synoptic observations. Gemini space photography is an available source of semi-quantitative data concerning changing environmental phenomena and mechanisms of sediment distribution. It also enables the survey and inventory of global sedimentary landforms. With the application of advanced sensors, increased system resolution, and repetitious photographic coverage, speedier and more reliable quantitative sedimentological analyses can be performed. 相似文献
53.
Classification and regression techniques are among the most used tools by chemometricians.Withclassification,the two classic methods are discriminant analysis and SIMCA.In this paper we discuss theconnection between these two methods and introduce two new ones of the same family:DASCO(discriminantanalysis with shrunken covariances)and RDA(regularized discriminant analysis).We demonstrate on bothsimulated and real data sets that their performance is superior to the old favorites.This is especially truein small-sample/high-dimension settings typical in chemistry. 相似文献
54.
A new, detailed tectonic model is presented for the Acadianorogenic belt of central New England (Vermont and New Hampshire)that accounts for a wide range of petrological and structuralobservations. Three belts are considered: the Eastern Vermont,Merrimack, and intervening Bronson Hill belts. Specific observationsin eastern Vermont that are accounted for in the model includethe following. PT paths are clockwise with maximum pressuresnear the Athens, Chester, and Strafford domes of 811kbar, but with maximum pressures decreasing to 35 kbarat the boundary with the Bronson Hill belt. Differential exhumationof the Vermont domes relative to the rocks in easternmost Vermontis required by the recorded differences in maximum pressure(56 kbar; 1520 km) and the present-day geographicalseparation (710 km). Specific observations in New Hampshirethat are explained include the following. PT paths inthe Merrimack belt are counter-clockwise with maximum pressuresof 45 kbar and are related to high regional heat flowand heat transfer by early Acadian plutons. PT pathsin the Bronson Hill belt are intimately associated with structuralposition. An early contact metamorphism is evidenced in theSkitchewaug and Fall Mountain nappes near contacts with theearly Acadian Bethlehem gneiss ( 相似文献
55.
KEITH E. BARBER FRANK M. CHAMBERS DARREL MADDY 《Boreas: An International Journal of Quaternary Research》2004,33(2):132-144
Plant macrofossil remains have been analysed from two raised peat bogs in northern Germany and Denmark. The quantified vegetation reconstructions of each profile were subjected to multivariate analyses to extract records of changing bog surface wetness (BSW), which are interpreted in these rain-fed bogs as being proxy climate signals. Age/depth models were constructed using radiocarbon dates and a number of drier and wetter phases were defined. The records both register cooler/wetter conditions around 2700, 1800 and 1400 cal. yr BP, and at the beginning of the Little Ice Age around AD 1250–1350. These rising bog water tables must have been reflected in poorer conditions for agriculture, and in particular near Dosenmoor where the profile records a catastrophic change to such conditions culminating at 2750–2600 cal. yr BP. 相似文献
56.
57.
A recent build-up of atmospheric CO2 over Europe. Part 1: observed signals and possible explanations
By MICHEL RAMONET PHILIPPE CIAIS TUULA AALTO CÉLINE AULAGNIER FRÉDÉRIC CHEVALLIER DOMENICO CIPRIANO THOMAS J. CONWAY LASZLO HASZPRA VICTOR KAZAN FRANK MEINHARDT JEAN-DANIEL PARIS MARTINA SCHMIDT PETER SIMMONDS IRÈNE XUEREF-RÉMY JAROSLAW N. NECKI 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):1-13
We analysed interannual and decadal changes in the atmospheric CO2 concentration gradient (ΔCO2 ) between Europe and the Atlantic Ocean over the period 1995–2007. Fourteen measurement stations are used, with Mace-Head being used to define background conditions. The variability of ΔCO2 reflects fossil fuel emissions and natural sinks activity over Europe, as well as atmospheric transport variability. The mean ΔCO2 increased by 1–2 ppm at Eastern European stations (∼30% growth), between 1990–1995 and 2000–2005. This built up of CO2 over the continent is predominantly a winter signal. If the observed increase of ΔCO2 is explained by changes in ecosystem fluxes, a loss of about 0.46 Pg C per year would be required during 2000–2005. Even if severe droughts have impacted Western Europe in 2003 and 2005, a sustained CO2 loss of that magnitude is unlikely to be true. We sought alternative explanations for the observed CO2 build-up into transport changes and into regional redistribution of fossil fuel CO2 emissions. Boundary layer heights becoming shallower can only explain 32% of the variance of the signal. Regional changes of emissions may explain up to 27% of the build-up. More insights are given in the Aulagnier et al. companion paper. 相似文献
58.
59.
WILLIAM DE GENST FRANK CANTERS WOLFGANG JACQUET SOPHIE VERMEERSCH 《International journal of geographical information science》2013,27(6):591-614
In this article a technique is presented to estimate the proportions of different map categories in a series of heterogeneous mapping units, using information on the degree of spatial correlation with other categorical data. The technique has been applied to decompose ecotope complexes in a categorical map of the biotic environment in Flanders, using secondary information on land cover and soil type. Because the conditional probability of an ecotope occurring given a certain soil type depends on the frequency with which the ecotope occurs in an area, determining the probability of occurrence of an ecotope from the conditional probabilities can lead to predictions that contradict prior knowledge about the composition of the different mapping units. A measure expressing the affinity of an ecotope for a soil type is proposed and is used as an alternative to conditional probability in the estimation procedure. The proposed method has been tested in a study area for which detailed field observations were collected, and proves to work well if reliable a priori knowledge about the composition of complex mapping units is available. 相似文献
60.
Environmental dynamics and luminescence chronology from the Orlovat loess–palaeosol sequence (Vojvodina,northern Serbia) 下载免费PDF全文