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191.
Kent D. Trego 《Earth, Moon, and Planets》1991,52(1):93-94
A mild eruption process of a two layered deposit in the crust of Triton may be responsible for the origin of dark/light aureole areas on the satellite's surface. 相似文献
192.
Regional planning in Korea has seldom been influenced by the demands and pressures of interested groups or citizens. To remedy this and open up the planning process to citizen participation, the Korean government developed the Regional Development Regulations of 1981. This mechanism directs regional development planning and citizen participation in it.The experience of the Chungbook Regional Development Plan (1981–1982) is characteristic of the present process of citizen participation in planning in Korea. The methods of insuring citizen participation are fourfold: the citizen advisory committee, the survey of citizens' opinions, the study conference, and the public hearing. Nonetheless, both planners and citizens often assess the participatory elements as being unsatisfactory.Citizen participation in the planning process in Korea can be improved. Specific measures include the addition of a pre-plan phase to the current regional planning process. This phase would require widespread publicity informing citizens of the opportunity to participate in the planning process and improved mechanisms to elicit from citizens their views on the key issues of the regional plan before the decision making phase begins. Finally, the government needs to develop a long-term approach to improving citizen participation in the regional planning process. This should involve the development of training programs that advocate a bottom-up approach to planning based on grassroots citizen participation. 相似文献
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Kent D. Trego 《Earth, Moon, and Planets》1988,42(3):293-296
Large escarpments on the Uranian satellite Miranda are similar in structure to thrust faults on Mercury result of crustal contraction. The tectonic lineations may be considered evidence of a crustal contraction on Miranda result of differentiation of the satellite. 相似文献
196.
Thomas O. Reimer Kent C. Condie Gabriele Schneider Angelika Georgi 《Precambrian Research》1985,29(4):383-404
Pebbles of potassic granitoids and metamorphites constitute up to 5% of the basal conglomerate of the Moodies Group in a ratio of 2 : 1. The granitoid pebbles frequently show micrographic quartz–feldspar intergrowth, whereas the metamorphites—of a modal composition similar to that of the granitoids—are characterized by large quartz grains which could represent original quartz phenocrysts in felsic volcanic precursors.The granitoids show high K2O, Sr, K2O/Na2O, and K/Rb, small enrichment of light REE, large negative Eu-anomalies, and slightly depleted and fractionated heavy REE. Compared to the granitoids the metamorphites show higher Fe2O3, TiO2, and Cr concentrations, greater enrichment of light REE, and also large negative Eu-anomalies.There is little similarity between the Moodies pebbles and the majority of the rocks of the Ancient Gneiss Complex of Swaziland (AGC). There is only some similarity of the REE distribution patterns between the pebbles and the Mkhondo Metamorphic Suite, possibly an areally restricted phase of the AGC. The geochemical data, and especially the large negative Eu-anomalies suggest that the Moodies pebbles were derived from granites which represent residual magmas from which much plagioclase had been removed. The granites crystallized at depths of < 7 km from magmas with low H2O-pressures in a rather thick sialic crust. It appears possible that the pre-Moodies granitoids originated through partial melting of low-Al2O3 siliceous gneisses of the AGC. A chronologic connection of the formation of the granitoids with the late Onverwacht Group volcanicity is possible. 相似文献
197.
Kent Brooks 《Geology Today》2009,25(3):94-99
In Geology Today (2008, v.24, no.1,) I traced the history of geological research in northeast Greenland, research that has culminated in the new and impressive map of the region produced by the Geological Survey of Denmark and Greenland. But what did all this endeavour, spread over more than 150 years, and involving hundreds of geologists and costing perhaps hundreds of millions of dollars, achieve? Here I summarize the results: the understanding of the evolution of this region over billions of years. 相似文献
198.
Atlanta, Georgia (City of Atlanta, COA), is one of the most rapidly growing urban areas in the US. Beginning in 2003, the US Geological Survey established a long‐term water‐quantity/quality monitoring network for the COA. The results obtained during the first 2 years have provided insights into the requirements needed to determine the extent of urban impacts on water quality, especially in terms of estimating the annual fluxes of suspended sediment, trace/major elements, and nutrients. During 2004/2005, suspended sediment fluxes from the City of Atlanta (COA) amounted to about 150 000 t year?1; ≥ 94% of the transport occurred in conjunction with storm‐flow, which also accounted for ≥ 65% of the annual discharge. Typically, storm‐flow averaged ≤20% of the year. Normally, annual suspended sediment fluxes are determined by summing daily loads based on a single calculation step using mean‐daily discharge and a single rating curve‐derived suspended sediment concentration. Due to the small and ‘flashy’ nature of the COAs streams, this approach could produce underestimates ranging from 25% to 64%. Accurate estimates ( ± 15%) require calculation time‐steps as short as every 2–3 h. Based on annual median base‐flow/storm‐flow chemical concentrations, the annual fluxes of ≥ 75% of trace elements (e.g. Cu, Pb, Zn), major elements (e.g. Fe, Al), and total P occur in association with suspended sediment; in turn, ≥ 90% of the transport of these constituents occur in conjunction with storm‐flow. As such, base‐flow sediment‐associated and dissolved contributions represent relatively insignificant portions of the total annual load. An exception is total N, whose sediment‐associated fluxes range from 50% to 60%; even so, storm‐related transport typically exceeds 80%. Hence, in urban environments, non‐point‐sources appear to be the dominant contributors to the fluxes of these constituents. Published in 2007by John Wiley & Sons, Ltd. 相似文献
199.
200.
Delivery of Trace Metals (Al,Fe, Mn,V, Co,Ni, Cu,Cd, Ag,Pb) from the Trinity River Watershed Towards the Ocean 总被引:2,自引:0,他引:2
The Trinity River (Texas, USA) contains in its watershed 23 different reservoir lakes, the largest one being Lake Livingston
situated in the lower Trinity River watershed and two potentially polluting metroplexes, Dallas and Houston. In order to determine
fluxes of nutrients and trace metals to Galveston Bay, a survey that included 24 discreet samples collected over a year and
at various stages of discharge was carried out during 2000–2001. Geochemical (i.e., sorption by Fe oxyhydroxides), biological
(i.e., seasonal uptake by sinking algae in Lake Livingston), and hydrological (i.e., dilution effects by increasing flow rates)
controls were found to be mainly responsible for variations in dissolved trace metal concentrations rather than pollution
sources. The Trinity River loads of suspended sediments and pollutant trace metals entering Galveston Bay at Anahuac were
<20% of those reaching Lake Livingston, and only a few percent of the total upstream trace metal load is entering the Gulf
of Mexico. Thus, during the transit through the 23 man-made lakes and an estuary, >96% of the pollutant trace metal load is
lost to sediments. 相似文献