全文获取类型
收费全文 | 395篇 |
免费 | 26篇 |
国内免费 | 3篇 |
学科分类
地球科学 | 424篇 |
出版年
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 19篇 |
2017年 | 16篇 |
2016年 | 26篇 |
2015年 | 11篇 |
2014年 | 21篇 |
2013年 | 18篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 33篇 |
2009年 | 29篇 |
2008年 | 23篇 |
2007年 | 23篇 |
2006年 | 14篇 |
2005年 | 16篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有424条查询结果,搜索用时 0 毫秒
101.
Christian Lehr Philipp Rauneker Marcus Fahle Tobias L. Hohenbrink Steven Böttcher Marco Natkhin Björn Thomas Ralf Dannowski Bernd Schwien Gunnar Lischeid 《水文研究》2017,31(3):750-752
Physical models are a well‐established tool in education to strengthen hydrological understanding. They facilitate the straightforward visualization of hydrological processes and allow the communication of hydrological concepts, research and questions of general interest to the public. In order to visualize the water cycle in a landscape of postglacial sediments, in particular the subsurface part, a physical model was constructed. In two videos, (1) a detailed construction manual and (2) visualization examples of hydrological concepts and processes are presented. With our contribution, we like to encourage professionals in the field of hydrology to share methods and tools of knowledge transfer and communication of hydrological concepts. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
102.
Ralf Greve 《Climatic change》2000,46(3):289-303
Numerical computations are performed with the three-dimensional polythermal ice-sheet model SICOPOLIS in order to investigate the possible impact of a greenhouse-gas-induced climate change on the Greenland ice sheet. The assumed increase of the mean annual air temperature above the ice covers a range from T = 1°C to 12°C, and several parameterizations for the snowfall and the surface melting are considered. The simulated shrinking of the ice sheet is a smooth function of the temperature rise, indications for the existence of critical thresholds of the climate input are not found. Within 1000 model years, the ice-volume decrease is limited to 10% of the present volume for T 3°C, whereas the most extreme scenario, T = 12°C, leads to an almost entire disintegration, which corresponds to a sea-level equivalent of 7 m. The different snowfall and melting parameterizations yield an uncertainty range of up to 20% of the present ice volume after 1000 model years. 相似文献
103.
Regional mean sea level changes in the German Bight are considered. Index time series derived from 15 tide gauge records are
analysed. Two different methods for constructing the index time series are used. The first method uses arithmetic means based
on all available data for each time step. The second method uses empirical orthogonal functions. Both methods produce rather
similar results for the time period 1924–2008. For this period, we estimate that regional mean sea level increased at rates
between 1.64 and 1.74 mm/year with a 90% confidence range of 0.28 mm/year in each case. Before 1924, only data from a few
tide gauges are available with the longest record in Cuxhaven ranging back till 1843. Data from these tide gauges, in particular
from Cuxhaven, thus receive increasingly more weight when earlier years are considered. It is therefore analysed to what extent
data from Cuxhaven are representative for the regional sea level changes in the German Bight. While this cannot be clarified
before 1924, it is found that this is not the case from 1924 onwards when changes in Cuxhaven can be compared to that derived
from a larger data set. Furthermore, decadal variability was found to be substantial with relatively high values towards the
end of the analysis period. However, these values are not unusual when compared to earlier periods. 相似文献
104.
Roberto P. Saglia Jan Snigula Robert Senger Ralf Bender 《Experimental Astronomy》2013,35(1-2):337-344
We describe the implementation of the PhotoZ code in the framework of the Astro-WISE package and as part of the Photometric Classification Server of the PanSTARRS pipeline. Both systems allow the automatic measurement of photometric redshifts for the millions of objects being observed in the PanSTARRS project or expected to be observed by future surveys like KIDS, DES or EUCLID. 相似文献
105.
Wave equation inversion of skeletalized geophysical data 总被引:2,自引:0,他引:2
106.
Remko Stuik Roland Bacon Ralf Conzelmann Bernard Delabre Enrico Fedrigo Norbert Hubin Miska Le Louarn Stefan Strbele 《New Astronomy Reviews》2006,49(10-12):618
MUSE, the Multi-Unit Spectroscopic Explorer, is an adaptive optics (AO)-assisted Integral Field Spectrograph, currently in the Preliminary Design Phase as a second generation instrument for the VLT. MUSE will feature two modes, each with an associated AO mode. The first mode is the wide field mode, mainly aiming at the study of high redshift galaxies. For this mode, the AO system has to deliver an improvement of at least a factor of two over the full 1′ × 1′ field of view. The second mode, the narrow field mode, aims at the high-resolution spectroscopy of nearby extended objects, for example, galaxies and globular clusters. For this mode, the AO system will have to deliver near-diffraction limited performance over a small field of view. In this paper, we discuss the trade-offs in the current design of GALACSI – the MUSE AO system – and illustrate with a number of simulations the expected performance in the wide- and narrow field modes. 相似文献
107.
Nondestructive spectroscopic and petrochemical investigations of Paleoarchean spherule layers from the ICDP drill core BARB5, Barberton Mountain Land,South Africa 下载免费PDF全文
Jörg Fritz Roald Tagle Luisa Ashworth Ralf Thomas Schmitt Axel Hofmann Béatrice Luais Phillip D. Harris Desirée Hoehnel Seda Özdemir Tanja Mohr‐Westheide Christian Koeberl 《Meteoritics & planetary science》2016,51(12):2441-2458
A Paleoarchean impact spherule‐bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro‐X‐ray fluorescence (μXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer‐scale, assisted in the localization and characterization of eight spherule‐bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The μXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni‐Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3‐rich and can be distinguished from the Al2O3‐poor marine sediments by distinct Al‐OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al‐OH‐rich spherule layers in Al2O3‐poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism. 相似文献
108.
Dust particles, like photons, carry information from remote sites in space and time. From knowledge of the dust particles' birthplace and their bulk properties, we can learn about the remote environment out of which the particles were formed. This approach is called “Dust Astronomy” which is carried out by means of a dust telescope on a Dust Observatory in space. Targets for a dust telescope are the local interstellar medium and nearby star forming regions, as well as comets and asteroids. Dust from interstellar and interplanetary sources is distinguished by accurately sensing their trajectories. Trajectory sensors may use the electric charge signals that are induced when charged grains fly through the detector. Modern in-situ dust impact detectors are capable of providing mass, speed, physical and chemical information of dust grains in space. A Dust Observatory mission is feasible with state-of-the-art technology. It will (1) provide the distinction between interstellar dust and interplanetary dust of cometary and asteroidal origin, (2) determine the elemental composition of impacting dust particles, and (3) monitor the fluxes of various dust components as a function of direction and particle masses. 相似文献
109.
110.