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Roger M. Jacobi James Rose Alison MacLeod Thomas F.G. Higham 《Quaternary Science Reviews》2009,28(25-26):2551-2556
Woolly rhinoceros bones, from a number of sites in Britain, have been AMS radiocarbon dated following ultrafiltration pre-treatment. These determinations give a coherent set of ages between >50 and c. 35 cal ka BP. The youngest (35,864–34,765 cal BP) come from the area around Bishopbriggs in western central Scotland and are derived from glaciofluvial sand and gravel overlain by till, both deposited during the Last Glacial Maximum (LGM) glaciation. A previous radiocarbon date from the site suggested that woolly rhinoceros lived c. 27 14C ka BP and the region was ice-free at the time. This date has had significant influence on the timing of extinction of woolly rhinoceros and the onset of glaciation over Britain during the LGM. The new dates revise this earlier determination and confirm that woolly rhinoceros became extinct in Britain after c. 35 cal ka BP, that central Scotland was ice-free at this time, and glaciation extended across this region sometime after 35 cal ka BP. 相似文献
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Analytical Procedures for the Measurement of Boron Isotope Compositions by Ion Microprobe in Meteorites and Mantle Rocks 总被引:3,自引:1,他引:3
Marc Chaussidon François Robert Denis Mangin Pascal Hanon Estelle F. Rose 《Geostandards and Geoanalytical Research》1997,21(1):7-17
An analytical procedure has been developed to measure in situ the 11 B/10 B ratio in terrestrial basaltic rocks and meteoritic chondrules having B concentration of less than 1 μg g?1 using a small radius ims3f ion microprobe. The central difficulties for these measurements are (i) the removal of the trace amount of B contamination introduced in the sample during polishing, (ii) the precise calibration of instrumental mass fractionation of B isotopes and (iii) the low count rates of 10 B and 11 B. Contamination experiments conducted with isotopically labelled B enriched in 10 B showed that ultrasonic cleaning in bi-distilled water (< 1 ng g?1 B) and pre-sputtering of the analysed area decrease B contamination to the level of 0.01 μg g?1. Analyses of isotope standards spanning a range of 11 B/10 B between 3.93 and 4.20 showed that instrumental mass fractionation was constant within? during one session of analyses. Repeated analyses of a standard glass showed a reproducibility of instrumental mass fractionation between February 1991 and October 1996 of 1.3. Taking into account all sources of error, boron isotope measurements are accurate to within 5 for meteoritic samples having B contents in the range 0.1 to 1 μg g?1. A slightly better accuracy of 1.5 can be achieved for basaltic glasses which can be sputtered with very intense primary beams. 相似文献
89.
W. I. Rose Jr. S. Bonis R. E. Stoiber M. Keller T. Bickford 《Bulletin of Volcanology》1973,37(3):338-364
The 1971 eruptions of Cerro Negro volcano in Nicaragua and Fuego volcano in Guatemala produced ash blankets with minimum volumes of 7 × 107 m3 and 6 × 107 m3, respectively. Seven new chemical analyses show that ash produced by both eruptions was basaltic and similar to previously — erupted lavas of both volcanoes. Both ash blankets were sampled areally and stratigraphically before they were affected by rain. Chemical analyses of soluble materials leached from these ashes show that near the end of both eruptions the concentrations of soluble materials increased by about an order of magnitude. These changes are believed to reflect changes in the composition of eruptive gases. 相似文献
90.
Osamu Nagafuchi Neil L. Rose Akira Hoshika Kenichi Satake 《Journal of Paleolimnology》2009,42(3):359-371
Fly-ash particles comprising spheroidal carbonaceous particles (SCP) and inorganic ash spheres (IAS), produced from industrial
fossil-fuel combustion, are found in lake sediments throughout the world where they provide an historical record of atmospheric
pollutant deposition. These particles have been widely used to assess the temporal and spatial distribution of industrial
atmospheric pollution in both freshwater and terrestrial environments in Europe and the USA. However, there have been very
few palaeolimnological fly-ash studies undertaken in Japan and none in Japanese mountain lakes. Here, we present the historical
SCP and IAS records from a radiometrically dated sediment core taken from Lake Akagi-konuma (36°31′ 54″N, 139°11′ 32″E; elevation
1,470 m) located 100 km north-west of Tokyo. Meteorological data and back trajectory analyses confirm potential sources both
within Japan and further afield in China and South Korea. SCP contamination began in the 1950s and increased rapidly to a
peak in the mid-1980s. It is thought this represents contamination of Japanese origin, principally oil-fired power stations
within 150 km of the lake. The profile of IAS, almost solely coal-derived, shows a rapid increase in the 1970s, in contrast
to the record of coal consumption in Japan. The IAS record is therefore thought to reflect long-range transport from coal
combustion sources in eastern China which started to expand in the 1970s. This raises concerns over the potential impact on
Japanese mountain areas from recent rapid increases in, and predicted acceleration of, emissions from this industrial process.
The scale of SCP contamination recorded in Lake Akagi-konuma is equivalent to moderately impacted mountain lakes in Europe,
but is at the upper end of the range for remote lakes in the western United States. 相似文献