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991.
Alfonso Aragón-Salamanca Bo Milvang-Jensen George Hau Inger Jørgensen Jens Hjorth 《Astrophysics and Space Science》2002,281(1-2):339-342
We are carrying out a programme to measure the evolution of the stellar and dynamical masses and M/L ratios for a sizeable sample of morphologically-classified disk galaxies in rich galaxy clusters at 0.2 < z < 0.9. Using FORS2 at the VLT we are obtaining rotation curves for the cluster spirals so that their Tully-Fisher relation
can be studied as a function of redshift and compared with that of field spirals. We already have rotation curves for ∼ 10
cluster spirals at z = 0.83, and 25 field spirals at lower redshifts and we plan to increase this sample by one order of magnitude. We present
here the first results of our study, and discuss the implications of our data in the context of current ideas and models of
galaxy formation and evolution.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
992.
Erik Høg 《Astrophysics and Space Science》2002,280(1-2):139-142
The transit of exoplanets across a stellar disk will often occur in GAIA observations. A safe detection of the slight dimming
of the star can be made many hundred times, i.e. in cases where the star is sufficiently constant in intensity, and the photometry
is very precise. When combined with the simultaneous GAIA astrometry or ground-based radial velocities the scientific harvest
is orbit, mass and mass density for hundreds of exoplanets. We have typically considered Jupiter-size planets at Earth-like
distances from the stars.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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995.
Kurt H. Kjr Igor Demidov Michael Houmark-Nielsen Eiliv Larsen 《Global and Planetary Change》2001,31(1-4)
Recent studies in the Arkhangelsk region, northwest Russia, have identified at least three consecutive tills all associated with the last Valdaian (Weichselian) glaciation. The Scandinavian ice sheet deposited a Late Valdaian till (ca. 17 ka BP), whereas two tills were deposited in the Early–Middle Valdaian by the Barents/Kara Sea ice sheet (ca. 45–60 ka BP) and an older ice sheet with an eastern centre (ca. 74 ka BP). This article expands on previous stratigraphical work on the discrimination of regional till units by a combination of compositional characteristics and directional properties. Tills associated with the Scandinavian ice sheet were deposited by a glacier advancing from west or northwest, transporting predominantly material from the Fennoscandian shield and the White Sea area. The Barents/Kara Sea ice sheet moved from the north and northeast, whereas the oldest ice advance came from the east–southeast. Although, the two oldest tills both contain material with an eastern provenance, the Viryuga Till is dominated more by local carbonate-rich material. This study demonstrates that detailed investigation of till units facilitate the distinction of glacial events imperative for the reconstructing of the last glaciation in northern Russia. 相似文献
996.
Zhou Tengfei Zhou Yaoqi Søager Nina Holm Paul Martin Zhang Zhenkai Wang Jun Liang Zhao Mu Hongyu Cheng Yanjun Liu Feifei Wang Miao Zhang Yue Zhang Hui Gu Yangjian Dong Shihui Zhao Hanjie Li Manjie Chen Yang Liu Yanzi 《中国科学:地球科学(英文版)》2022,65(9):1751-1771
Science China Earth Sciences - The Lingshan Island scientific drill confirms that two episodes (Laiyang period and Qingshan period) of rifting developed in the central Sulu orogenic belt (SOB) in... 相似文献
997.
Kirsten Halsnæs Morten Andreas Dahl Larsen Per Skougaard Kaspersen 《Natural Hazards》2018,94(1):261-278
Least developed countries are generally regarded as particularly sensitive to climate change due to among other vulnerable locations and low adaptation capabilities. In the present study, we address climate change hazards in least developed countries by presenting a methodological framework, which is suitable for the estimation damage costs as a function of risk aversion, equality, income distribution and climate scenario using state-of-the-art climate model projections. As a case study, the methodology is applied to study severe storms in Cambodia based on two future climate scenarios and data on historical damages from storm events, which are used as a proxy in performing a sensitivity analysis on all input parameters. For the assumptions and parameter ranges used here, the study shows a high sensitivity to the income distribution (reflected by discount rates) and risk aversion and smaller effects from equality measures and extreme wind climate scenario. We emphasize that the assumptions on risk aversion reflecting consumption smoothing possibilities of low-income households clearly depicts that climate risks can be particularly high as a consequence of poverty and therefore recommend that context-specific vulnerabilities and equity concerns in climate risk studies should be included when making assessments for least developed countries. 相似文献
998.
Paolo Trinchero Jorge Molinero Hedieh Ebrahimi Ignasi Puigdomenech Björn Gylling Urban Svensson Dirk Bosbach Guido Deissmann 《Mathematical Geosciences》2018,50(5):549-567
Fractured crystalline rocks are under consideration by several countries as host formations for high-level nuclear waste repositories. The redox evolution in these host rock formations is an important issue for the stability and safety of these disposal sites. If, for example, during a glaciation/deglaciation event, oxygen-rich glacial meltwater penetrates to the depth of the planned repository, some of the engineered barriers would be adversely affected. Moreover, oxidizing conditions would increase the solubility and mobility of many radionuclides. Reactive transport simulations, which are typically used to assess the redox buffering capacity of these host rock formations, are computationally demanding, and thus, calculations for the evaluation of oxygen penetration are usually carried out over simplified geometries and the heterogeneity of the site, both physical (e.g., variability in the groundwater flow field and the kinematic porosity) and mineralogical (e.g., variability in the abundance of Fe(II)-bearing minerals), is usually represented in a simplified fashion. Here, it is shown how a recently developed numerical framework, combined with high performance computing technologies, allows the full geometrical, physical and mineralogical complexity of the site under study to be efficiently included in these types of reactive transport calculations. A synthetically generated realistic three-dimensional fractured medium is used to assess oxygen penetration patterns and their dependence on both the hydrogeological conditions and the availability of Fe(II)-bearing minerals. The results of the calculations point out the significant influence of both physical and mineralogical heterogeneity on the oxygen penetration patterns, thus highlighting the importance of a model parameterisation consistent with the site complexity. 相似文献
999.
Variations of southeast Vatnajökull ice cap (Iceland) 1650–1900 and reconstruction of the glacier surface geometry at the Little Ice Age maximum
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