全文获取类型
收费全文 | 90篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 37篇 |
地球物理 | 11篇 |
地质学 | 33篇 |
天文学 | 7篇 |
综合类 | 1篇 |
自然地理 | 3篇 |
出版年
2019年 | 1篇 |
2017年 | 2篇 |
2015年 | 5篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1965年 | 2篇 |
1963年 | 1篇 |
1960年 | 1篇 |
1954年 | 1篇 |
1952年 | 1篇 |
1948年 | 1篇 |
1943年 | 2篇 |
1939年 | 1篇 |
1928年 | 1篇 |
1927年 | 2篇 |
1921年 | 1篇 |
1919年 | 1篇 |
1915年 | 1篇 |
1913年 | 2篇 |
1910年 | 1篇 |
排序方式: 共有93条查询结果,搜索用时 296 毫秒
31.
32.
J. Jacobeit H. Wanner J. Luterbacher C. Beck A. Philipp K. Sturm 《Climate Dynamics》2003,20(4):431-352
Based on monthly mean sea level pressure grids objectively reconstructed by Luterbacher et al. variations of dynamical modes of the atmospheric circulation for January and July are described by novel indices for running 31-year periods between 1659 and 1999. These indices reflect the continuous evolution of the atmospheric circulation not only with regard to frequency changes of major dynamical modes but also in terms of internal changes within each mode concerning both dynamic (vorticity, intensity) and climatic properties (Central European temperature and precipitation during occurrence of each mode, respectively). Results indicate the great importance of within-mode variations: the zonal circulation mode in January, varying in frequency with long-term cycles, primarily changed its dynamic and climatic properties (towards higher indices) during the transition from the Little Ice Age to modern conditions between 1800 and 1930. Within the Russian High mode of January a change in preference from easterly to westerly patterns above Central Europe occurred around 1850. For July, a striking frequency maximum of the westerly mode at the end of the eighteenth century coincided with a period of marked summer warmth in Central Europe due to negative/positive deviations in vorticity/temperature during occurrence of this mode. The long-term evolution in July indicates a general increase of anticyclonic conditions strengthening during the last 50 years towards a unique phenomenon within the last centuries. The strong increase in the winter-time westerly circulation during the last decades, however, does not appear extraordinary in view of the low-frequency variations of this mode. 相似文献
33.
P. M. Della-Marta J. Luterbacher H. von Weissenfluh E. Xoplaki M. Brunet H. Wanner 《Climate Dynamics》2007,29(2-3):251-275
We investigate the large-scale forcing and teleconnections between atmospheric circulation (sea level pressure, SLP), sea
surface temperatures (SSTs), precipitation and heat wave events over western Europe using a new dataset of 54 daily maximum
temperature time series. Forty four of these time series have been homogenised at the daily timescale to ensure that the presence
of inhomogeneities has been minimised. The daily data have been used to create a seasonal index of the number of heat waves.
Using canonical correlation analysis (CCA), heat waves over western Europe are shown to be related to anomalous high pressure
over Scandinavia and central western Europe. Other forcing factors such as Atlantic SSTs and European precipitation, the later
as a proxy for soil moisture, a known factor in strengthening land–atmosphere feedback processes, are also important. The
strength of the relationship between summer SLP anomalies and heat waves is improved (from 35%) to account for around 46%
of its variability when summer Atlantic and Mediterranean SSTs and summer European precipitation anomalies are included as
predictors. This indicates that these predictors are not completely collinear rather that they each have some contribution
to accounting for summer heat wave variability. However, the simplicity and scale of the statistical analysis masks this complex
interaction between variables. There is some useful predictive skill of summer heat waves using multiple lagged predictors.
A CCA using preceding winter North Atlantic SSTs and preceding January to May Mediterranean total precipitation results in
significant hindcast (1972–2003) Spearman rank correlation skill scores up to 0.55 with an average skill score over the domain
equal to 0.28 ± 0.28. In agreement with previous studies focused on mean summer temperature, there appears to be some predictability
of heat wave events on the decadal scale from the Atlantic Multidecadal Oscillation (AMO), although the long-term global mean
temperature is also well related to western European heat waves. Combining these results with the observed positive trends
in summer continental European SLP, North Atlantic SSTs and indications of a decline in European summer precipitation then
possibly these long-term changes are also related to increased heat wave occurrence and it is important that the physical
processes controlling these changes be more fully understood. 相似文献
34.
The Ekman boundary-layer model is extended analytically for a gradually varying eddy diffusivity K(z) ≥ 0, z ≥ 0. A solution for the Ekman layer is provided having similar structure to the constant-K case; that is, exponentially decaying sine functions for the two horizontal wind components. The analytical asymptotic solution compares well with its numerical counterpart for various K(z). The result can be useful in theoretical studies such as Ekman pumping, for efficient estimation of the Ekman layer profiles in various analyses with near-neutral stratifications, or for a rapid initialization of mesoscale models. 相似文献
35.
Rudolf BráZdil Christian Pfister Heinz Wanner Hans Von Storch JüRg Luterbacher 《Climatic change》2001,48(4):653-655
Volume Contents
Contents of Volume 48 相似文献36.
37.
J. Wanner 《International Journal of Earth Sciences》1943,33(7-8):499-506
Ohne Zusammenfassung 相似文献
38.
Xuexiang Gu Oskar Schulz Franz Vavtar Jianming Liu Minghua Zheng Shaohong Fu 《Ore Geology Reviews》2007,31(1-4):319
The Woxi W–Sb–Au deposit in Hunan, South China, is hosted by Proterozoic metasedimentary rocks, a turbiditic sequence of slightly metamorphosed (greenschist facies), gray-green and purplish red graywacke, siltstone, sandy slate, and slate. The mineralization occurs predominantly (> 70%) as stratabound/stratiform ore layers and subordinately as stringer stockworks. The former consists of rhythmically interbedded, banded to finely laminated stibnite, scheelite, quartz, pyrite and silty clays, whereas the latter occurs immediately beneath the stratabound ore layers and is characterized by numerous quartz + pyrite + gold + scheelite stringer veins or veinlets that are typically either subparallel or subvertical to the overlying stratabound ore layers. The deposit has been the subject of continued debate in regard to its genesis. Rare earth element geochemistry is used here to support a sedimentary exhalative (sedex) origin for the Woxi deposit. The REE signatures of the metasedimentary rocks and associated ores from the Woxi W–Sb–Au deposit remained unchanged during post-depositional processes and were mainly controlled by their provenance. The original ore-forming hydrothermal fluids, as demonstrated by fluid inclusions in quartz from the banded ores, are characterized by variable total REE concentrations (3.5 to 136 ppm), marked LREE enrichment (LaN/YbN = 28–248, ∑LREE/∑HREE = 16 to 34) and no significant Eu-anomalies (Eu/Eu = 0.83 to 1.18). They were most probably derived from evolved seawater that circulated in the clastic sediment pile and subsequently erupted on the seafloor. The bulk banded ores are enriched in HREE (LaN/YbN = 4.6–11.4, ∑LREE/∑HREE = 3 to 14) and slightly depleted in Eu (Eu/Eu = 0.63 to 1.14) relative to their parent fluids. This is interpreted as indicating the influence of seawater rather than a crystallographic control on REE content of the ores. Within a single ore layer, the degree of HREE enrichment tends to increase upward while the total REE concentrations decrease, reflecting greater influence and dilution of seawater. There is a broad similarity in chondrite-normalized REE patterns and the amount of REE fractionation of the banded ores in this study and exhalites from other sedex-type polymetallic ore deposits, suggesting a similar genesis for these deposits. This conclusion is in agreement with geologic evidence supporting a syngenetic (sedex) model for the Woxi deposit. 相似文献
39.
A 2D horizontal reactive transport model of a chromate-contaminated site near Rivera, Switzerland, was developed using the computer code CrunchFlow to evaluate site remediation strategies. Transport processes were defined according to the results of an existing hydrological model, and the definition of geochemical (reactive) processes is based on the results of a detailed mineralogical and geochemical site characterization leading to a comprehensive conceptual site model. Kinetics of naturally occurring Cr(VI) reduction by Fe(II) and natural solid organic matter is quantified by fitting measured Cr isotope ratios to a modeled 1D section along the best constrained flow line. The simulation of Cr isotope fractionation was also incorporated into the 2D model. Simulation of the measured present day Cr(VI) plume and δ53Cr value distribution was used for the 2D model calibration and corresponds to a situation where only monitored natural attenuation (MNA) is occurring. Other 2D model runs simulate alternate excavation scenarios. The simulations show that with an excavation of the top 2–4 m the groundwater Cr(VI) plume can be minimized, and that a deeper excavation depth only diminishes the plume if all the contaminants can be removed. A combination of an excavation of the top 2–4 m and monitoring of the ongoing natural Cr(VI) reduction is suggested as the most ecological and economical remediation strategy, even though a remaining time period with ongoing subsoil Cr(VI) contamination in the order of 1 ka is predicted. 相似文献
40.
The risk of groundwater contamination by chromate at a former chromite ore processing industrial site in Rivera (Switzerland) was assessed by determining subsoil Cr(VI) concentrations and tracking naturally occurring Cr(VI) reduction with Cr isotopes. Using a hot alkaline extraction procedure, a total Cr(VI) contamination of several 1000 kg was estimated. Jarosite, KFe3((SO4)x(CrO4)1−x)2(OH)6, and chromatite (CaCrO4) were identified as Cr(VI) bearing mineral phases using XRD, both limiting groundwater Cr(VI) concentrations. To track assumed Cr(VI) reduction at field scale δ53Cr values of contaminated subsoil samples in addition to groundwater δ53Cr data are used for the first time. The measurements showed a fractionation of groundwater δ53Cr values towards positive values and subsoil δ53Cr towards negative values confirming reduction of soluble Cr(VI) to insoluble Cr(III). Using a Rayleigh fractionation model, a current Cr(VI) reduction efficiency of approximately 31% along a 120 m long flow path was estimated at an average linear groundwater velocity of 3.3 m/d. Groundwater and subsoil δ53Cr values were compared with a site specific Rayleigh fractionation model proposing that subsoil δ53Cr values can possibly be used to track previous higher Cr(VI) reduction efficiency during the period of industrial activity. The findings strongly favor monitored natural attenuation to be part of the required site remediation measures. 相似文献