全文获取类型
收费全文 | 263篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 11篇 |
大气科学 | 30篇 |
地球物理 | 40篇 |
地质学 | 137篇 |
海洋学 | 10篇 |
天文学 | 22篇 |
综合类 | 6篇 |
自然地理 | 12篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1969年 | 2篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1957年 | 3篇 |
1956年 | 4篇 |
1955年 | 2篇 |
1953年 | 2篇 |
1951年 | 3篇 |
1948年 | 5篇 |
1934年 | 1篇 |
1930年 | 1篇 |
1928年 | 2篇 |
1925年 | 1篇 |
1916年 | 1篇 |
1912年 | 1篇 |
排序方式: 共有268条查询结果,搜索用时 15 毫秒
91.
Alzheimer's disease (AD) is the most common form of dementia. Populations migrating from developing to industrialized countries seem to elicit a higher incidence and prevalence rate of AD, suggesting lifestyle and environmental factors to have a role in the pathophysiology of AD. One of its major neuropathological hallmarks is the deposition of Aβ peptides as amyloid plaques in the brain of AD patients. Aβ is proteolytically cleaved out of the larger amyloid precursor protein (APP). Cu and Mn are often found in drinking water and may have a neurotoxic potential. APP is involved in Cu homeostasis in mouse and man. In vitro observations and in vivo data obtained from APP mouse models provide strong evidence that APP overexpression enables intracellular Cu to be transported out of the cell. Disturbed metal‐ion homeostasis with elevated serum Cu levels occurs in Alzheimer and Down's patients and lowered levels in post‐mortem AD brain. We observed that bioavailable Cu has specific beneficial effects in an Alzheimer's disease mouse model. This should be regarded as a proof‐of‐concept for a prophylactic approach to overcome the observed CNS Cu deficiency in the brain of Alzheimer's disease patients. Manganism is a disorder with symptoms similar to that of Parkinson's disease. The precise mechanism how manganese can damage the nervous system is unknown. There is some evidence that iron and manganese may utilize similar transport systems. Epidemi ologic data strongly suggests that manganese enters the body primarily via inhalation and through the ingestion of manganese in drinking water. 相似文献
92.
In most of Europe, an increase in average annual surface temperature of 0·8 °C is observed, and a further increase is projected. Precipitation tends to increase in northern Europe and decrease in southern Europe, with variable trends in central Europe. The climate scenarios for Germany suggest an increase in precipitation in western Germany and a decrease in eastern Germany, and a shift of precipitation from summer to winter. When investigating the effects of climate change, impacts on water resources are among the main concerns. In this study, the first German‐wide impact assessment of water fluxes dynamics under climate change is presented in a spatially and temporally distributed manner using the state‐of‐the‐art regional climate model, Statistical Regional (STAR) model and the semi‐distributed process‐based eco‐hydrological model, soil and water integrated model (SWIM). All large river basins in Germany (lower Rhine, upper Danube, Elbe, Weser and Ems) are included. A special focus of the study was on data availability, homogeneity of data sets, related uncertainty propagation in the model results and scenario‐related uncertainty. After the model calibration and validation (efficiency from 0·6 to 0·9 in 80% of cases) the water flow components were simulated at the hydrotope level, and the spatial distributions were compared with those in the Hydrological Atlas of Germany. The actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions. The results for the second scenario period 2051–2060 show that water discharge in all six rivers would be 8–30% lower in summer and autumn compared with the reference period, and the strongest decline is expected for the Saale, Danube and Neckar. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). However, the uncertainty of impacts, especially in winter and for high water flows, remains high. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
93.
94.
Hermann J. Jakobs Stefan Tilmes Andre Heidegger Klaus Nester Gerhard Smiatek 《Journal of Atmospheric Chemistry》2002,42(1):23-40
Within the framework of the Tropospheric Research Programme (TFS) four working groups in Germany (University of Stuttgart, University of Cologne, Research Center Karlsruhe, German Weather Service) formed a network developing a model system for chemistry transport calculations on different scales. The network was optimized, based on each module and combined for the different interfaces in order to perform daily preoperational ozone forecasts and its precursors at the German Weather Service in summer 1999 (May through September). The setup of the model system, the interfaces and changes of each module are described. The results of the whole preoperational episode are displayed and discussed. Main efforts were done analyzing the model climate statistics and the verification of the predictions with an extensive data base of observations at stations in Germany. The results of this extensive verification demonstrate the relatively good performance of the entire forecast system. 相似文献
95.
Friedrich-Wilhelm Gerstengarbe Peter C. Werner Hermann Österle Olaf Burghoff 《Theoretical and Applied Climatology》2013,114(3-4):715-724
The development of winter storm- and summer thunderstorm-related loss events within the next decades in Germany was investigated with regard to change in frequency and intensity caused by climate changes. As a first step, observed meteorological data were connected with insurance data on a statistical basis. A regional climate model was then used to estimate future climate development. Using the statistical relations between meteorological and insurance data, the development of climate-driven damages was calculated. Results show that an increase of loss events can be expected within the next decades. These results show loss ratios shifting from higher return periods to smaller ones. In progressive decades, all these loss events become regionally more differentiated. 相似文献
96.
97.
Boehnhardt Hermann Barucci Antonella Delsanti Audrey De Bergh Catherine Doressoundiram Alain Romon Jennifer Dotto Elisabetta Tozzi Gianpaolo Lazzarin Monica Fornasier Sonia Peixinho Nuno Hainaut Olivier Davies John Rousselot Philippe Barrera Luis Birkle Kurt Meech Karen Ortiz JoseLuis Sekiguchi Tomohiko Watanabe Jun-ichi Thomas Nick West Richard 《Earth, Moon, and Planets》2003,92(1-4):145-156
BVRI photometry of 107 TNOs and Centaurs establishes the range of spectral gradients to be between –5 to 55%/100 nm (with one exception). A cluster of very red Cubewanos is firmly identified in orbits of low inclination and eccentricity beyond 40 AU from the Sun. Further correlations between surface colours and dynamical parameters (inclination and perihelion distance) are suggested for Cubewanos and scattered disk objects, but lack complete confidence for their reality. Plutinos and Centaurs do not show any clear correlation between surface colours and orbital parameters. We present in this paper 12 spectra obtained in the visible region and nine of them for which we obtained also near infrared spectra up to 2.4 microns. A few other objects have been observed, but the data are still under reduction and analysis. The principal reported results obtained are: (i) a wide range of visible slopes; (ii) evidence for surface variations on 2001 PT13; and (iii) possible detection of few percent of water ice (1999 TC36}, 2000 EB173, 1999 DE9, 2001 PT13, 2000 QC243, 1998 SG35). 相似文献
98.
99.
Coma Structures in Comet 73P/Schwassmann-Wachmann 3, Components B and C,Between January and May 2006
Jean-Baptiste Vincent Hermann Böhnhardt Ivano Bertini Luisa-Maria Lara Michael Küppers Rafael Rodrigo 《Earth, Moon, and Planets》2010,106(1):27-35
The Jupiter family comet 73P/Schwassmann-Wachmann 3 has been widely observed since 1995 after a nucleus break-up event produced
at least five components labeled 73P-A to E. During the 2006 appearance, two of them (B and C) showed very strong coma activity.
Our R-filter imaging of 73P-B & C from 21 January to 25 May 2006 revealed the presence of fan-like structures in the comae
of both components and evidence for further fragmentation events in component B. As of early April 2006, component C showed
two jets emanating from the nucleus, with one continuously visible. Through a simulation of the orbital geometry we infer
that the rotation axis of 73P-C has an inclination of 20° to the orbital plane and a longitude of 45° at perihelion. The coma
activity of component B was highly variable, displaying signatures of at least 3 fragmentation events. The coma was characterized
by the continuous presence of a jet roughly in sunward direction, starting from the beginning of May. The first fragmentation
event of component B may have happened between April 16 and April 26, leading to the presence of at least 6 fragments detected
in images of May 2. The second one happened on or shortly before May 8, the third one between May 18 and 24. For the rotation
axis of 73P-B we infer an inclination of 5°–15° to the orbital plane and a longitude of 20°–30° at perihelion. 相似文献
100.
A'Hearn Michael F. Boehnhardt Hermann Kidger Mark West Richard M. 《Earth, Moon, and Planets》1997,78(1-3):3-3
Earth, Moon, and Planets - 相似文献