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161.
Ni in chrome pyrope garnets: a new geothermometer 总被引:1,自引:0,他引:1
W. L. Griffin D. R. Cousens C. G. Ryan S. H. Sie G. F. Suter 《Contributions to Mineralogy and Petrology》1989,103(2):199-202
Proton microprobe analyses of the minerals in garnet-peridotite xenoliths from kimberlites show that the partitioning of Ni between chrome pyrope garnet and olivine is strongly temperature(T)-dependent. The range of Ni contents in olivines is small relative to that in the analyzed garnets; a geothermometer therefore can be derived, based only on the Ni content of garnet. This allows estimation of T for single Cr-pyrope grains, such as the inclusions in diamonds, if these can be assumed to have equilibrated with olivine. 相似文献
162.
163.
O. Eugster Ch. Shen J. Beer M. Suter W. Wlfli W. Yi D. Wang 《Earth and Planetary Science Letters》1987,84(1)
A comprehensive study of the cosmic-ray exposure history of five ordinary chondrites from China was carried out using measurements of the noble gas isotopic abundances and10Be concentrations. The following average cosmic-ray exposure ages, based on cosmogenic21Ne and on81KrKr dating were obtained: Zhaodong (L4) — 15.7 ± 3.0 m.y., Nan Yang Pao (L6) — 48 ± 10.0 m.y., Guangrao (L6) — 16.8 ± 3.5 m.y., and Lunan (H6) — 26.7 ± 5.0 m.y. The H5 chondrite Zaoyang was exposed for only 0.90 ± 0.12 m.y. to galactic cosmic rays as calculated from the10Be activity and from the low amounts of cosmic-ray-produced noble gases. The Zhaodong chondrite contains large amounts of80Kr and82Kr produced by neutron capture of bromine. From the high slowing down density for neutrons we derive a preatmospheric mass of more than 1800 kg for this meteorite. 相似文献
164.
The number of studies on the actual and potential environmental consequences of contaminated ground water is growing. One means of studying these consequences is through an idealized flow and transport model, S-PATHS, which allows the hydrologist to determine the salient features of contaminant migration with a minimum of data. The transport of contaminants by ground water from many waste disposal sites can be geometrically idealized as flow between a line and a circle. The flow system adjacent to the disposal site can be represented as a contaminant line source, and a downgradient pumping well as a circular sink. To study waste disposal sites on a larger scale the model geometry is reversed and the disposal site is represented as a circular source, and a river or other convenient line of evaluation is represented as a line sink. This idealization allows S-PATHS to describe the flow and transport process directly by a single partial differential expression. S-PATHS considers transmissivity, effective porosity, sorption, source strength, source concentration, decay, potentiometric gradient, circle size, and distance to the line. Coding for the model is not lengthy and can be run on a large-capacity, hand-held calculator. 相似文献
165.
P Sharma B L K Somayajulu D Lal W Wolfli G Bonani Ch. Stoller M Suter J Beer 《Journal of Earth System Science》1983,92(1):1-4
Cosmogenic beryllium-10 activities have been measured in marine accumulations of up to ~6 m.y age by conventional beta counting technique and by accelerator mass spectrometry. The two sets of data at10Be levels of 109–1010 atoms/g agree within the absolute errors of the two methods. The detection limit for10Be by the accelerator mass spectrometry is about five orders of magnitude lower than that with the beta counting method. 相似文献
166.
167.
This paper addresses recent debates on the need for greater collaboration across the physical and human geography divide. We discuss some of the problems of producing work that can be considered genuinely interdisciplinary. The paper reflects on a project examining the use of sustainable drainage systems in Glasgow and how we unwittingly produced a piece of social science research looking at a physical science topic. We suggest that more than simply the need for 'trust' between researchers, the actual practice of working together in the field – and, indeed, having the opportunity to make mistakes and learn from them – is essential. In working together, academics have a better opportunity to understand each other's intellectual and epistemological framework and develop projects where researchers can move beyond their disciplinary boundaries and weave their expertise into a coherent research output. 相似文献
168.
Following the catastrophic “Great Sumatra–Andaman” earthquake- tsunami in the Indian Ocean on the 26th December 2004, questions
have been asked about the frequency and magnitude of tsunami within the region. We present a summary of the previously published
lists of Indian Ocean Tsunami (IOT) and the results of a preliminary search of archival materials held at the India Records
Office, at the British Library in London. We demonstrate that in some cases, normal tidal movements and floods associated
with tropical cyclones have been erroneously listed as tsunami. We summarise archival material for tsunami that occurred in
1945, 1941, 1881, 1819, 1762 and a little known tsunami in 1843. We present the results of modelling of the 2004, 1861 and
1833 tsunami generated by earthquakes off Sumatra and the 1945 Makran earthquake and tsunami, and examine how these results
help to explain some of the historical observations. The highly directional component to tsunami propagation illustrated by
the numerical models may explain why we are unable to locate archival records of the 1861 and 1833 tsunami at important locations
like Rangoon, Kolkata (formally Calcutta) and Chennai (formally Madras), despite reports that these events created large tsunami
that inundated western Sumatra. The numerical models identify other areas (particularly the central and southern Indian Ocean
islands) where the 1833 tsunami may have had a large enough effect to produce a historic record. We recommend further archival
research, coastal geological investigations of tsunami impacts and detailed modelling of tsunami propagation to better understand
the record and effects of tsunami in the Indian Ocean and to estimate their likelihood of occurring in the future. 相似文献
169.
O. Akoto B.Sc M.Phil. J. Adiyiah B.Sc 《International Journal of Environmental Science and Technology》2007,4(2):211-214
This study consisted of the determination of the trace metals and some physiochemical properties in drinking water samples from the Brong Ahafo region of the Republic of Ghana, where drinking water samples are not treated before it is consumed. The purpose was to ascertain the quality of water from these sources. Samples were taken from fifteen sampling points and analyzed for the following parameters Fe, Cu, Mn, Zn, Al, NO3 ?, NO2 ?, SO4 2, PO4 2?, and F? using the procedure outline in the palintest photometer method. The data showed the variation of the investigated parameters in samples as follows: pH 5.57-7.54, conductivity (EC) 35-1216 us/cm, turbidity 3.25-72.50 NTU,PO4 2?1 0.32-9.30 mg/L,F 0.32-1.05 mg/L,NO3 ? 0.09-0.99 mg/L,NO2 ? 0.006-0.114 mg/L, SO4 2? 3.33-8.02 mg/L, Cu 1.19-2.75 mg/L Fe 0.05-0.85mg/L, Zn 0.04-0.15 mg/L, Mn 0.003-0.011 mg/L and Al 0.05-0.15 mg/L. The concentrations of most of the investigated parameters in the drinking water samples from Brong Ahafo region were within the permissible limits of the World Health Organization drinking water quality guidelines. There were no correlations between metal concentrations in the drinking water samples. 相似文献
170.