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991.
冬季风爆发前西伯利亚高压的演变 总被引:2,自引:0,他引:2
本文是一次个例的诊断分析,应用FGGE-Ⅲ_b资料分析了1979年11月12—17日的东亚寒潮过程,着重讨论冷空气爆发前,位于两伯利亚的冷堆的增强过程,运用准拉格朗日坐标系的热量方程和涡度方程诊断了500hPa冷中心的温度变化和地面冷高压上空涡度演变的物理过程,分析结果说明,冷堆的增强与高空槽后急流中心前方出口附近的侧向环流有密切关系,开始时500hPa冷中心就位于此侧向环流的上升支附近,绝热冷却是冷堆加强的主要因子,即动力因子是主要的,冷高压上空的涡度变化与相对的涡度平流关系密切,它也与高空急流的相对位置有关,在地面高压加强的后期,散度项和平流项对于温度变化的贡献相反,但它们的垂直分布都有利于下沉运动加剧.因此,在分析预报中要密切注意忽流的动态. 本文的分析结果将有助于进一步理解冷空气增强的物理机制,也为寒潮过程的分析预报提供一定的参考. 相似文献
992.
SEASONAL CHANGES OF SOIL MOISTURE INDUCED BY INCREASED CO2 AS SIMULATED BY THE ATMOSPHERIC GENERAL CIRCULATION AND MIXED LAYER OCEAN MODEL 下载免费PDF全文
The atmospheric general circulation model coupled to the mixed layer ocean model has been used to simulate thechanges of the global soil moisture.Comparing the simulated results with observations,it is shown that the model is ca-pable of doing sensitive experiments about the carbon dioxide change.The 2×CO_2/1×CO_2 comparison shows that there are the obvious changes of the soil moisture in the global forfour seasons.There are the wet soil moisture in the lower latitudes of both hemispheres and dry soil moisture in the mid-dle latitudes of both hemispheres for four seasons.The dry soil moisture in summer and wet in other seasons are foundin the northern higher latitudes.The analyses of the physical feedbacks responsible for the CO_2-induced changes of soil moisture show that the bud-gets of the surface water and heat are the important factors. 相似文献
993.
In this paper,the correlation of meteorological elements at an interval of 5-7 months,i.e.,the alternate-seasonal correlation,is thoroughly analyzed.The results show that the alternate-seasonal correlation is an important phenomenon in the long-range weather process,and it has a significant latitude effect and seasonal variations.Furthermore,the relation between this phenomenon and SST in the North Pacific is discussed. 相似文献
994.
By Using the P-σ five-layer primitive equation model,three sets of numerical experiments are performedwith normal zonal mean SST(the control case),the positive SST anomalies in the Kuroshio current andeast-of-Japan Ocean(the midlatitude western Pacific),and positive SST anomalies over both the midlatitudeand the equatorial western Pacific.The experimental results show that the positive SST anomalies over themidlatitude western Pacific have great influence on the Asian summer monsoon:the Indian monsoon is weak-ened and the East Asian monsoon is intensified.This happens just reverse to the effects of positive SSTanomalies over the equatorial westero Pacific on the Asian summer monsoon.Further,the influence mechanismof the SST anomalies over the midlatitude westcrn Pacific on the Asian summer monsoon is discussed. 相似文献
995.
V. Ramesh Babu J. S. Sastry V. V. Gopalakrishna D. V. Rama Raju 《Journal of Earth System Science》1991,100(1):55-68
The hydrographic structure in the east central Arabian Sea during premonsoon period undergoes significant temporal change
in the thermal field of upper 100 m, wherein temperature rises by about 0–5°C on an average from May to June. The major contribution
in increasing the surface layer temperature comes from surface heat exchange processes, while the horizontal advective process
tends to remove the heat from the upper layer. The geostrophic flow patterns are similar from May to June in the major part
of the study area while in the coastal areas off Goa a southerly current sets in June in response to coastal upwelling. 相似文献
996.
G. Salvadè K. Stocker J. Trösch F. Zamboni 《Aquatic Sciences - Research Across Boundaries》1992,54(3-4):187-204
The hydrodynamic processes in the Lake of Lugano (Lago di Lugano) have been the object of three major measuring campaigns. The first during summer 1979 in the North Basin, the second in the autumn of 1984 in the South Basin and the last in 1989 again in the North Basin. It is expected that analysis of the collected data in conjunction with theoretical concepts will yield conclusive findings on the driving forces and hydrodynamics of the lake. Numerical models have been applied to the lake and the results have been compared to the measurements. Some models calculate the periods and distributions of amplitude, as well as surface velocities and internal seiches. Other models calculate wind-induced water circulation. Evidence is given to the peculiarities of the North Basin and the difficulties related with the depth-width ratio and with its deep chemical stratification. 相似文献
997.
Many researchers use outputs from large-scale global circulation models of the atmosphere to assess hydrological and other impacts associated with climate change. However, these models cannot capture all climate variations since the physical processes are imperfectly understood and are poorly represented at smaller regional scales. This paper statistically compares model outputs from the global circulation model of the Geophysical Fluid Dynamics Laboratory to historical data for the United States' Laurentian Great Lakes and for the Emba and Ural River basins in the Commonwealth of Independent States (C.I.S.). We use maximum entropy spectral analysis to compare model and data time series, allowing us to both assess statistical predictabilities and to describe the time series in both time and frequency domains. This comparison initiates assessments of the model's representation of the real world and suggests areas of model improvement. 相似文献
998.
NUMERICAL EXPERIMENTS FOR THE IMPACT OF ANTARCTIC ICE COVER AND SEA SURFACE TEMPERATURE ON CLIMATE VARIABILITY* 下载免费PDF全文
By using a three-level atmospheric general circulation model(AGCM),we have completed several numerical experiments to study the impacts of sea surface temperature anomaly(SSTA) and antarctic ice cover anomaly(AICA) during 1981-1983 on climate variability.The results show that during the El Nino period of 1982-1983 the impact of SSTA overrides that of AICA.SSTA mainly affects equatorial zonal circulation and produces PNA wave train,and SE-NW wave train in East Asia to influence the weather of China.AICA produces west-east anomalous vortex streets in the middle latitudes of both hemispheres and affects the intensity of the polar vortex of Southern Hemisphere. 相似文献
999.
J. G. Zötl 《Environmental Geology》1997,29(3-4):176-187
Some years ago the thermal water wells of the spa Deutsch-Altenburg were considered the result of a local water circulation.
Extensive measurements of the water chemistry, trace elements, and environmental isotopes combined with drillings in the river
bed of the Danube resulted in the indication of a key position of the mineral thermal wells of Deutsch-Altenburg for the groundwater
circulation in the entire Vienna basin. The proof of this fact demanded the inclusion of the complicated geological position
of the basin into the argumentation.
The historical background of Bad Deutsch-Altenburg is the Roman municipium Carnuntum. During the reign of the Roman emperor
Marc Aurel (161-180 A.C.) Carnuntum became the largest Roman municipium northeast of Rome with about 50 000 inhabitants covering
the areas of present-day villages Petronell and Deutsch-Altenburg due to its strategic and trade position. The town was totally
destroyed during the era of "migration of nations." The land surface was farmland or meadows. The first document concerning
the thermal water of Deutsch-Altenburg is an expertise of the medical faculty of the University of Vienna (1548). During the
siege of Vienna by the Turkish army under Kara Mustafa (1683–84) Deutsch-Altenburg was again, destroyed. It was only at the
end of the 19th century that the modern installation of the spa began. The healing thermal water with the highest content
of sulfur in Austria made Deutsch-Altenburg one of the most well-known spas in the country. The archaeological excavation
of Carnuntum is the largest in Austria.
Received: 6 October 1995 · Accepted: 13 November 1995 相似文献
1000.
Very hot,very shallow hydrothermal dolomitization: An example from the Maritime Alps (north‐west Italy–south‐east France) 下载免费PDF全文
Luca Barale Carlo Bertok Namam Salih Talabani Anna d'Atri Luca Martire Fabrizio Piana Alain Préat 《Sedimentology》2016,63(7):2037-2065
In the Maritime Alps (north‐west Italy – south‐east France), the Middle Triassic–lowermost Cretaceous platform carbonates of the Provençal Domain locally show an intense dolomitization. Dolomitized bodies, irregularly shaped and variable in size from some metres to hundreds of metres, are associated with tabular bodies of dolomite‐cemented breccias, cutting the bedding at a high angle, and networks of dolomite veins. Field and petrographic observations indicate that dolomitization was a polyphase process, in which episodes of hydrofracturing and host‐rock dissolution, related to episodic expulsion of overpressured fluids through faults and fracture systems, were associated with phases of host‐rock dolomitization and void cementation. Fluid inclusion analysis indicates that dolomitizing fluids were relatively hot (170 to 260°C). The case study represents an outstanding example of a fossil hydrothermal system, which significantly contributes to the knowledge of such dolomitization systems in continental margin settings. The unusually favourable stratigraphic framework allows precise constraint of the timing of dolomitization (earliest Cretaceous) and, consequently, direct evaluation of the burial setting of dolomitization which, for the upper part of the dolomitized succession, was very shallow or even close to the surface. The described large‐scale hydrothermal system was probably related to deep‐rooted faults, and provides indirect evidence of a significant earliest Cretaceous fault activity in this part of the Alpine Tethys European palaeomargin. 相似文献