全文获取类型
| 收费全文 | 2363篇 |
| 免费 | 92篇 |
| 国内免费 | 27篇 |
专业分类
| 测绘学 | 41篇 |
| 大气科学 | 194篇 |
| 地球物理 | 567篇 |
| 地质学 | 958篇 |
| 海洋学 | 216篇 |
| 天文学 | 287篇 |
| 综合类 | 3篇 |
| 自然地理 | 216篇 |
出版年
| 2022年 | 6篇 |
| 2021年 | 33篇 |
| 2020年 | 38篇 |
| 2019年 | 59篇 |
| 2018年 | 79篇 |
| 2017年 | 41篇 |
| 2016年 | 71篇 |
| 2015年 | 59篇 |
| 2014年 | 63篇 |
| 2013年 | 128篇 |
| 2012年 | 87篇 |
| 2011年 | 100篇 |
| 2010年 | 93篇 |
| 2009年 | 112篇 |
| 2008年 | 106篇 |
| 2007年 | 101篇 |
| 2006年 | 104篇 |
| 2005年 | 84篇 |
| 2004年 | 89篇 |
| 2003年 | 92篇 |
| 2002年 | 84篇 |
| 2001年 | 47篇 |
| 2000年 | 58篇 |
| 1999年 | 38篇 |
| 1998年 | 40篇 |
| 1997年 | 33篇 |
| 1996年 | 30篇 |
| 1995年 | 28篇 |
| 1994年 | 30篇 |
| 1993年 | 32篇 |
| 1992年 | 33篇 |
| 1991年 | 19篇 |
| 1990年 | 26篇 |
| 1989年 | 32篇 |
| 1988年 | 27篇 |
| 1987年 | 34篇 |
| 1986年 | 28篇 |
| 1985年 | 29篇 |
| 1984年 | 35篇 |
| 1983年 | 32篇 |
| 1982年 | 29篇 |
| 1981年 | 27篇 |
| 1980年 | 36篇 |
| 1979年 | 20篇 |
| 1978年 | 16篇 |
| 1977年 | 21篇 |
| 1976年 | 11篇 |
| 1975年 | 13篇 |
| 1974年 | 12篇 |
| 1973年 | 15篇 |
排序方式： 共有2482条查询结果，搜索用时 46 毫秒
181.
In a pseudodynamic test, errors in restoring-force feedback are introduced into numerical computations. Some of these errors can excite the higher-frequency response of the specimen. In this paper, the use of viscous and numerical dampings to eliminate spurious higher-frequency effects is studied. Since the tangent stiffness of a non-linear specimen cannot be measured accurately, initial-stiffness-dependent viscous damping is considered. In addition, an explicit integration algorithm with desired numerical damping properties is proposed and examined. The analytical and numerical studies presented indicate that viscous-damping properties can be substantially changed by non-linear deformations. For this reason, the use of numerical damping appears to be more advantageous. 相似文献
182.
Stephen Ayrton 《International Journal of Earth Sciences》1987,76(1):81-88
It is stressed that a thorough investigation of the subtle and still poorly understood relationships between orogeny, magmatism and associated sediments is warranted. Certain types of sediments appear to be commonly linked to specific magmatic contexts. This is especially true for the oceanic crust, but it may be equally valid for bimodal continental magmatism with the development of granite. Grand scale regression with the formation of continental detrital deposits could represent the response to mantle upwelling and/or plume activity.
Zusammenfassung Zwischen Orogenese, Magmatismus und zugehörigen Sedimenten existiert ein enger Zusammenhang, der meist wenig verstanden ist und dringend eingehender Studien bedarf. Gewisse Sediment-Typen sind meist an einen ganz spezifischen, magmatischen Kontext gebunden. Dies ist insbesondere der Fall für die ozeanische Kruste, könnte aber auch für den bimodalen, kontinentalen magmatischen Zyklus mit der Bildung von Granit zutreffen. Die gro\räumigen Regressionen und die damit verbundene Entstehung von kontinentalen, detritischen Ablagerungen könnte die Antwort auf vertikale Mantel-Konvektion oder Plume-Aktivität sein.
Résumé Il est important de mieux comprendre les relations subtiles existant entre orogenèse, magmatisme et sédiments associés. Certains types de sédiments sont systématiquement apparentés à un contexte magmatique spécifique. Ceci est particulièrement évident pour la croûte océanique, mais pourrait Être également valable dans le cadre du magmatisme continental bimodal avec développement de granite. Les régressions à grande échelle avec formation de sédiments détritiques continentaux pourraient représenter la conséquence d'une activité accrue et/ou de mouvements convectifs du manteau.
, , , . . . . , , . , plume activity.相似文献
183.
Geoffrey D. Price Stephen C. Parker Maurice Leslie 《Physics and Chemistry of Minerals》1987,15(2):181-190
We use an approach based upon the Born model of solids, in which potential functions represent the interactions between atoms in a structure, to calculate the phonon dispersion of forsterite and the lattice dynamical behaviour of the beta-phase and spinel polymorphs of Mg2SiO4. The potential used (THB1) was derived largely empirically using data from simple binary oxides, and has previously been successfully used to model the infrared and Raman behaviour of forsterite. It includes ‘bond bending’ terms, that model the directionality of the Si-O bond, in addition to the pair-wise additive Coulombic and short range terms. The phonon dispersion relationships of the Mg2SiO4 polymorphs predicted by THB1 were used to calculate the heat capacities, entropies, thermal expansion coefficients and Gruneisen parameters of these phases. The predicted heat capacities and entropies are in outstandingly good agreement with those determined experimentally. The predicted thermodynamic data of these phases were used to construct a phase diagram for this system, which has Clausius-Clapeyron slopes in very close agreement with those found by experiment, but which has predicted transformation pressures that show less close agreement with those inferred from experiment. The overall success, however, that we have in predicting the lattice dynamical and thermodynamic properties of the Mg2SiO4 polymorphs shows that our potential THB1 represents a significant step towards finding the elusive quantitative link between the microscopic or atomistic behaviour of minerals and their macroscopic properties. 相似文献
184.
185.
186.
187.
188.
189.
Stephen G. Warren 《Climatic change》1982,4(4):329-340
The growth and decay of ice sheets are driven by forces affecting the seasonal cycles of snowfall and snowmelt. The external forces are likely to be variations in the earth's orbit which cause differences in the solar radiation received. Radiational control of snowmelt is modulated by the seasonal cycles of snow albedo and cloud cover. The effects of orbital changes can be magnified by feedbacks involving atmospheric CO2 content, ocean temperatures and desert areas. Climate modeling of the causes of the Pleistocene ice ages involves modeling the interactions of all components of the climate system; snow, sea ice, glacier ice, the ocean, the atmosphere, and the solid earth. Such modeling is also necessary for interpreting oxygen isotope records from ice and ocean as paleoclimatic evidence. 相似文献
190.