全文获取类型
收费全文 | 157篇 |
免费 | 0篇 |
国内免费 | 8篇 |
专业分类
测绘学 | 20篇 |
大气科学 | 8篇 |
地球物理 | 47篇 |
地质学 | 61篇 |
海洋学 | 7篇 |
天文学 | 19篇 |
自然地理 | 3篇 |
出版年
2022年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 1篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 11篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有165条查询结果,搜索用时 15 毫秒
71.
G. Klee A. Bunger G. Meyer F. Rummel B. Shen 《Rock Mechanics and Rock Engineering》2011,44(5):531-540
The development of Hot-Dry Rock (HDR) geothermal energy in Australia with drillings to some kilometres depth yields an impetus
for deep stress logging. For the Olympic Dam HDR-project, borehole Blanche-1 was drilled to almost 2 km depth and provided
the possibility to estimate the in situ stresses within the granitic borehole section by the analysis of borehole breakouts
and core discing, as well as by hydraulic fracturing combined with acoustic borehole televiewer logging for fracture orientation
determination. Although the stress magnitudes derived by the different methods deviate significantly, they clearly indicate
for the depth range between 800 and 1,740 m a compressional stress regime of S
v ≤ S
h < S
H and a consistent East–West orientation of maximum horizontal compression in agreement with existing stress data for Australia.
The minor horizontal stress S
h derived from the hydraulic fracturing closure pressure values is about equal to the overburden stress and may be regarded
as most reliable. 相似文献
72.
Fabiano R. L. Faulstich Reiner Neumann Jacques Pironon Aurelien Randi 《Geostandards and Geoanalytical Research》2013,37(4):393-402
In this study, we detail procedures to synthesise inclusions of fluids of known composition under diagenetic conditions – low temperatures (50–180 °C) and pressures (2–25 MPa) – hosted by quartz. Pre‐existing microcavities in polished quartz chips were used, decrepitated and rinsed before being healed in an autoclave. Each synthesis required around 4 weeks. A range of biphase liquid–vapour inclusions in the H2O–CH4–NaCl system, similar to natural ones, were synthesised in quartz, varying the content of all three components. The quartz chips were checked before and after synthesis by optical microscopy, microthermometry and Raman spectroscopy. The method was used to build a series of calibration curves relating methane‐to‐water count ratios to the methane content of aqueous fluid inclusions. Good correlation was obtained between Raman band area ratios and the expected CH4 solubilities from equations of state. The chosen procedure's main advantages, compared with other published methods, are as follows: quicker healing of the microfractures at lower temperatures, larger inclusions, simple quartz sample preparation, control of fluid inclusion composition and the use of commercial reactors. Such reference material inclusions allow the calibration of Raman microspectrometers with the objective of PTX reconstruction of palaeofluid migration in petroleum reservoirs. 相似文献
73.
Global height system unification with GOCE: a simulation study on the indirect bias term in the GBVP approach 总被引:4,自引:2,他引:2
One of the main objectives of ESA’s Gravity Field and Steady-State Ocean Circulation mission GOCE (Gravity field and steady-state ocean circulation mission, 1999) is to allow global unification of height systems by directly providing potential differences between benchmarks in different height datum zones. In other words, GOCE provides a globally consistent and unbiased geoid. If this information is combined with ellipsoidal (derived from geodetic space techniques) and physical heights (derived from leveling/gravimetry) at the same benchmarks, datum offsets between the datum zones can be determined and all zones unified. The expected accuracy of GOCE is around 2–3 cm up to spherical harmonic degree n max ≈ 200. The omission error above this degree amounts to about 30 cm which cannot be neglected. Therefore, terrestrial residual gravity anomalies are necessary to evaluate the medium and short wavelengths of the geoid, i.e. one has to solve the Geodetic Boundary Value Problem (GBVP). The theory of height unification by the GBVP approach is well developed, see e.g. Colombo (A World Vertical Network. Report 296, Department of Geodetic Science and Surveying, 1980) or Rummel and Teunissen (Bull Geod 62:477–498, 1988). Thereby, it must be considered that terrestrial gravity anomalies referring to different datum zones are biased due to the respective datum offsets. Consequently, the height reference surface of a specific datum zone deviates from the unbiased geoid not only due to its own datum offset (direct bias term) but is also indirectly affected by the integration of biased gravity anomalies. The latter effect is called the indirect bias term and it considerably complicates the adjustment model for global height unification. If no satellite based gravity model is employed, this error amounts to about the same size as the datum offsets, i.e. 1–2 m globally. We show that this value decreases if a satellite-only gravity model is used. Specifically for GOCE with n max ≈ 200, the error can be expected not to exceed the level of 1 cm, allowing the effect to be neglected in practical height unification. The results are supported by recent findings by Gatti et al. (J Geod, 2012). 相似文献
74.
Tectonic evolution of the South Tianshan orogen and adjacent regions,NW China: geochemical and age constraints of granitoid rocks 总被引:36,自引:0,他引:36
Jun Gao Lingli Long Reiner Klemd Qing Qian Dunyi Liu Xianming Xiong Wen Su Wei Liu Yitian Wang Fuqun Yang 《International Journal of Earth Sciences》2009,98(6):1221-1238
Geochemical and geochronological evidence was obtained from granitoids of the South Tianshan orogen and adjacent regions,
which consist of three individual tectonic domains, the Kazakhstan–Yili plate, the Central Tianshan Terrane and the Tarim
plate from north to south. The Central Tianshan Terrane is structurally bounded by the Early Paleozoic ‘Nikolaev Line–North
Nalati Fault’ and Late Paleozoic ‘Atbashy–Inyl’chek–South Nalati–Qawabulak Fault’ zones against the Kazakhstan–Yili and Tarim
plates, respectively. The meta-aluminous to weakly peraluminous granitic rocks, which are exposed along the Kekesu River and
the Bikai River across the Central Tianshan Terrane, have a tholeiitic, calc-alkaline or high-potassium calc-alkaline composition
(I-type). Geochemical trace element characteristics and the Y versus Rb–Nb or Y versus Nb discrimination diagrams favor a
continental arc setting for these granitoid rocks. SHRIMP U–Pb and LA-ICP-MS U–Pb zircon age data indicate that the magmatism
started at about 480 Ma, continued from 460 to 330 Ma and ended at about 275 Ma. The earlier magmatism (>470 Ma) is considered
to be the result of a simultaneous southward and northward subduction of the Terskey Ocean beneath the northern margin of
the Tarim plate and the Kazakhstan–Yili plate, respectively. The later magmatism (460–330 Ma) is related to the northward
subduction of the South Tianshan Ocean beneath the southern margin of the Kazakhstan–Yili–Central Tianshan plate. The dataset
presented here in conjunction with previously published data support a Late Paleozoic tectonic evolution of the South Tianshan
orogen, not a Triassic one, as recently suggested by SHRIMP U–Pb zircon dating for eclogites. 相似文献
75.
76.
A local density approximation (LDA) method is developed for reconstructing the trajectories of type III radio bursts through the interplanetary medium. The method uses the measured source directions and the measured frequency drift rates of the type III burst to determine the locations of the radio source in the interplanetary medium at consecutive frequency levels. The technique is used to reconstruct the trajectory of an actual type III burst and the results are compared to the trajectory obtained from the global density law method. The LDA method represents an improvement in that it utilizes more observed data on the type III burst and that it takes full account of the local density variations at the source locations. 相似文献
77.
Primary fluids entrapped at blueschist to eclogite transition: evidence from the Tianshan meta-subduction complex in northwestern China 总被引:5,自引:1,他引:5
Orthopyroxene and olivine exposed along the rim of a harzburgite xenolith from La Palma (Canary Islands) show polycrystalline selvages and diffusion zones that result from contact with mafic, alkaline, silica-undersaturated melts during at least 10-100 years before eruption. The zoned selvages consist of a fine-grained reaction rim towards the xenolith and a coarser grained, cumulate-like layer towards the melt contact. The diffusion zones are characterized by decreasing magnesium number from about 89-91 in the xenolith interior to 79-85 at the rims, and clearly result from Fe-Mg exchange with surrounding mafic melt. The width of the diffusion zones is 80-200 µm in orthopyroxene and 1,020-1,730 µm in olivine. Orthopyroxene also shows decreasing Al2O3 and Cr2O3 and increasing MnO and TiO2 towards the reaction rims. Textural relations and comparisons with dissolution experiments suggest that orthopyroxene dissolution by silica-undersaturated melt essentially ceased after days to weeks of melt contact, possibly because of decreasing temperature and formation of the reaction rims. The short dissolution phase was followed by prolonged growth of diffusion zones through cation exchange between xenolith minerals and melt across the reaction rims, and by the growth of cumulus crystals. The observations indicate that orthopyroxene xenocrysts and harzburgite xenoliths can survive in mafic, silica-undersaturated, subliquidus magmas at 1,050-1,200 °C and 200-800 MPa for tens of years. Modeling and comparison of the diffusion zones indicate that the average Fe-Mg interdiffusion coefficient DFeMg in orthopyroxene is 2 log units lower than that in olivine; at 1,130 °C and QFM-buffered oxygen fugacity, DFeMgopx = 3 ×10 - 19 m2 s- 1D_{FeMg}^{opx} = 3 \times 10^{ - 19} \,{\rm m}^2 \,{\rm s}^{{\rm - 1}} . The new data overlap well with recently published data for DFeMg in diopside, and indicate that DFeMg opxD_{FeMg\,}^{opx} (as predicted by previous authors) may be extrapolated to higher temperatures and oxygen fugacities. It is suggested that DFeMg opx D_{FeMg\,}^{opx} and DFeMg in Mn-poor ferromagnesian garnet are similar within 0.5 log units at temperatures between 1,050 and 1,200 °C. 相似文献
78.
A general scheme is given for the solution in a least-squares sense of the geodetic boundary value problem in a spherical,
constant-radius approximation, both uniquely and overdetermined, for a large class of observations. The only conditions are
that the relation of the observations to the disturbing potential is such that a diagonalization in the spectrum can be found
and that the error-covariance function of the observations is isotropic and homogeneous. Most types of observations used in
physical geodesy can be adjusted to fit into this approach. Examples are gravity anomalies, deflections of the vertical and
the second derivatives of the gravity potential.
Received: 3 November 1999 / Accepted: 25 September 2000 相似文献
79.
80.
Certain geodetic problems such as the downward continuation of gravity information from satellite or aerial altitudes to the
surface of the earth or the inverse Stokes problem are improperly posed in the sense that the best approximate solution does
not continuously depend on the given observations. In order to obtain a stable solution a technique of regularization is discussed
which can be shown to be identical to the method of least squares collocation. The characteristic features of regularization
are analysed transferring the problem through a singular value decomposition into the spectral domain which allows an easy
interpretation as a special method of filtering.
In practical applications the stability depends not only on the observational errors including the computer round-off but
in the same way on the number of observations and their distribution. The regularized solution should achieve a proper trade-off
between sufficient smoothness and highest possible resolution with a limit defined through the internal accuracy of the computer. 相似文献