全文获取类型
收费全文 | 62篇 |
免费 | 0篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 3篇 |
地球物理 | 10篇 |
地质学 | 14篇 |
海洋学 | 9篇 |
天文学 | 17篇 |
自然地理 | 8篇 |
出版年
2021年 | 1篇 |
2016年 | 1篇 |
2013年 | 4篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2000年 | 1篇 |
1998年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1971年 | 4篇 |
1967年 | 1篇 |
排序方式: 共有62条查询结果,搜索用时 390 毫秒
51.
Gürtleret al. (1981) argue that SiO could not be the material responsible for the interstellar 10 micron feature as had been proposed by Duleyet al. (1979). While Millar (1982) has quite successfully refuted the arguments of Gürtleret al. (1981), we present here some additional considerations which indicate that the model of Duleyet al. (1979) requires appreciable modification to be consistent with recent experimental results. 相似文献
52.
Laboratory investigations of CN radical formation by photodissociation of parent molecules have suggested the possibility of observing emission lines in cometary spectra from newly formed CN radicals. These laboratory studies have shown that high initial internal excitation of CN is the rule with excitation of rotational levels N up to 70. In the collisionless environment of the cometary atmosphere this initial excitation would yield a corresponding distribution for the lowest vibrational level of the ground X2Σ+ state. Our calculations show that it is feasible with present observational techniques to detect photochemically excited lines with N ~ 30 in the 0-0 band of the violet system. 相似文献
53.
Calculations have been made to determine the effects of atmospheric drag and gravity on impact ejecta trajectories on Venus, Mars, and the Earth. The equations of motion were numerically integrated for a broad range of body sizes, initial velocities, and initial elevation angles. A dimensionless parameter was found from approximate analytic solutions which correlated the ejecta range, final impact angle, and final impact velocity for all three planets. 相似文献
54.
Monalisa Mallick Suryendu Dutta Paul F. Greenwood Norbert Bertram 《Journal of the Geological Society of India》2009,74(1):16-22
The molecular structure of an Eocene fossil resin (Vastan, Cambay basin, Western India) has been investigated with complimentary
spectroscopic techniques. The FTIR spectrum shows strong aliphatic CH
x
(3000–2800 and 1460–1450 cm−1) and CH3 (1377 cm−1) absorptions and less intense aromatic C=C (1560–1610 cm−1) absorptions. The major products from analytical pyrolysis are cadalene based bicyclic sesquiterpenoids including some bicadinenes
and bicadinanes. The polycadinane products confirm the fossil material as an Angiosperm dammar resin, associated with inputs
of tropical rain forests supported by past climates. 相似文献
55.
Hermann Rügner Marc Schwientek Barbara Beckingham Bertram Kuch Peter Grathwohl 《Environmental Earth Sciences》2013,69(2):373-380
Transport of hydrophobic organic pollutants in rivers is mainly coupled to transport of suspended particles. Turbidity measurements are often used to assess the amount of suspended solids in water. In this study, a monitoring campaign is presented where the total concentration of polycyclic aromatic hydrocarbons (PAHs), the amount of total suspended solids (TSS), and turbidity was measured in water samples from five neighboring catchments in southwest Germany. Linear correlations of turbidity and TSS were obtained which were in close agreement to the literature data. From linear regressions of turbidity versus total PAH concentrations in water, mean concentrations of PAH on suspended particles could be calculated and these varied by catchment. These values furthermore comprise a robust measure of the average sediment quality in a given catchment. Since in the catchments investigated in this study, PAH concentrations on suspended particles were stable over a large turbidity range (1–114 Nephelometric Turbidity Units), turbidity could be used as a proxy for total PAHs and likely other highly hydrophobic organic pollutants in river water if the associated correlations are established. Based on that, online monitoring of turbidity (e.g., by optical backscattering sensors) seems very promising to determine annual pollutant fluxes. 相似文献
56.
Catchments as reactors: a comprehensive approach for water fluxes and solute turnover 总被引:1,自引:1,他引:0
Peter Grathwohl Hermann Rügner Thomas Wöhling Karsten Osenbrück Marc Schwientek Sebastian Gayler Ute Wollschläger Benny Selle Marion Pause Jens-Olaf Delfs Matthias Grzeschik Ulrich Weller Martin Ivanov Olaf A. Cirpka Ulrich Maier Bertram Kuch Wolfgang Nowak Volker Wulfmeyer Kirsten Warrach-Sagi Thilo Streck Sabine Attinger Lars Bilke Peter Dietrich Jan H. Fleckenstein Thomas Kalbacher Olaf Kolditz Karsten Rink Luis Samaniego Hans-Jörg Vogel Ulrike Werban Georg Teutsch 《Environmental Earth Sciences》2013,69(2):317-333
Sustainable water quality management requires a profound understanding of water fluxes (precipitation, run-off, recharge, etc.) and solute turnover such as retention, reaction, transformation, etc. at the catchment or landscape scale. The Water and Earth System Science competence cluster (WESS, http://www.wess.info/) aims at a holistic analysis of the water cycle coupled to reactive solute transport, including soil–plant–atmosphere and groundwater–surface water interactions. To facilitate exploring the impact of land-use and climate changes on water cycling and water quality, special emphasis is placed on feedbacks between the atmosphere, the land surface, and the subsurface. A major challenge lies in bridging the scales in monitoring and modeling of surface/subsurface versus atmospheric processes. The field work follows the approach of contrasting catchments, i.e. neighboring watersheds with different land use or similar watersheds with different climate. This paper introduces the featured catchments and explains methodologies of WESS by selected examples. 相似文献
57.
Bertram Boehrer 《地球物理与天体物理流体动力学》2013,107(1-2):105-126
Abstract Convection experiments in a rotating long cavity were conducted to investigate the changes introduced by Coriolis-force to the well understood convection in the (nonrotating) long cavity. In the far convective regime, the results indicated that large-scale features of the convection were dominated by geostrophically balanced confined primary currents. Close to the transition regime, where the intruding currents gain a thickness close to the vertical dimension of the tank, secondary features became predominant. In the transition regime, these secondary features were not present and the simple picture of two cavity filling counter currents with laterally tilted isotherms could be confirmed. 相似文献
58.
Donn S. Gorsline 《Geo-Marine Letters》1984,4(3-4):133-138
Fine-grained sediments comprise about 70% of all sediments and sedimentary rocks. In the past decade, research on these deposits has increasingly looked at processes and process-responses. While much of the earlier work was devoted to large-scale stratigraphic and petrologic studies, the present active frontiers appear to be in microstratigraphy, properties of grain aggregates and bulk characteristics, and the origins of these aggregates. Clays have historically been well studied, but silts are relatively poorly understood. Much of the geologic record must be reexamined. 相似文献
59.
Ulrich's radiating, compressible, spherical thermal model of turbulent convection in a superadiabatic atmosphere is examined analytically. Since the governing ordinary differential equations form an autonomous system, for which the characteristics are obtained by asymptotic approximations, the possible solutions can be exhaustively classified on the basis of their evolution in time. Results show that there are two types of thermal with finite lifetimes, and that these occur, in an atmosphere of fixed background turbulence and structure, only when the initial size and velocity of the thermal are restricted to specified regions of the (size, velocity) plane. Comparison of the analytical solution for the characteristics to a stable numerical solution indicates excellent agreement. This analytical solution should allow detailed structure calculations for superadiabatic layers at a computational cost comparable to present mixing-length calculations. 相似文献
60.
U. C. Bertram Volker Heine I. L. Jones Geoffrey D. Price 《Physics and Chemistry of Minerals》1990,17(4):326-333
Computer simulation is used to investigate the effect of Al/Si disordering over the tetrahedral sites on the lattice energy and the lattice constants of the mineral sillimanite Al2SiO5. A methodology for an atomistic assessment of the energy of the reaction 2(Si-O-Al)→(Si-O-Si)+(Al-O-Al) and its various contributions is established. This ordering energy is 0.97 eV for nearest neighbour sites in the ab-plane and 0.56 eV for those separated in the c-direction. The large difference is due to a greater constraint on the atomic relaxation in the ab-plane and shows the structural dependence of the ordering energy. Its magnitude appears to be determined by a complicated balance between Coulomb and short-range repulsive energy involving strain over many bonds, both in the ordered and disordered structures. There is also a significant interaction between second neighbour sites whereas the contribution of more distant neighbours is negligible. The lattice energies of most of the 154 configurations studied show a linear behaviour as a function of short-range order, specified by the number of Al-Al pairs. The ordering temperature Tc, estimated on the basis of a statistical mechanical model of disordering, and the calculated ordering energies are in semi-quantitative agreement with experimental values. 相似文献