全文获取类型
收费全文 | 378篇 |
免费 | 29篇 |
出版年
2023年 | 2篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 19篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 19篇 |
2015年 | 16篇 |
2014年 | 12篇 |
2013年 | 74篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 10篇 |
2009年 | 13篇 |
2008年 | 6篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1978年 | 4篇 |
1977年 | 9篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1972年 | 3篇 |
1969年 | 3篇 |
1958年 | 3篇 |
1947年 | 1篇 |
排序方式: 共有407条查询结果,搜索用时 15 毫秒
61.
H. Eckardt C. Chenery P. Booth J.A. Evans A. Lamb G. Müldner 《Journal of archaeological science》2009,36(12):2816-2825
Artefacts and burial rites in the late Roman cemetery at Lankhills School, Winchester, southern England, were used by Clarke (1979) to distinguish between local Romano-British individuals and migrants thought to be from the Danube region, a suggestion tested through isotope analysis by Evans et al. (2006a,b). This paper reports strontium (87Sr/86Sr) and oxygen (δ18O) isotope data for tooth enamel sampled from a further 40 individuals from more recent excavations on the same site. Results suggest that up to a quarter of the sampled Lankhills individuals were incomers, with several individuals possibly originating from the Hungarian Basin and the Southern Mediterranean. However, there was no clear link between isotopic signature and archaeological origin attribution, suggesting that in many cases burial practice was dictated by factors other than ‘ethnicity’, such as kinship, marriage or cultural and political preferences. 相似文献
62.
The recent articles by Vardi et al., “Tracing sickle blade levels of wear and discard patterns: a new sickle gloss quantification method” (Journal of Archaeological Science 37 (2010) 1716–1724), and Goodale et al., “Sickle blade life-history and the transition to agriculture: an early Neolithic case study from Southwest Asia” (Journal of Archaeological Science 37 (2010) 1192–1201), are two papers that seek to address interesting archaeological questions through the development of new approaches to measuring the duration of stone tool use. Here comment is made on the fashion in which research design and analytic procedures contribute to limit the capabilities of each of the techniques presented. Whilst the authors support the investigation of novel techniques, in order for the results of any use-wear analysis to be accepted as reliable the methods employed must be demonstrably sound. 相似文献
63.
Speybroeck N Paraje G Prasad A Goovaerts P Ebener S Evans DB 《Geographical analysis》2012,44(2):151-161
This article discusses options to allow comparative analysis of inequalities in the distribution of health workers (HWs) across and within countries using a single summary measure of the distribution. Income inequality generally is measured across individuals, but inequalities in the dispersion of HWs must use geographical areas or population groupings as units of analysis. The article first shows how this change of observational unit creates a resolution problem for various inequality indices and then tests how sensitive a simple ratio measure of the distribution of HWs is to changes in resolution. This ratio of inequality is illustrated first with the global distribution of HWs and then with its distributions within Indonesia. The resolution problem is not solved through this new approach, and indicators of inequalities of access to HWs or health services more generally appear not to be comparable across countries. Investigating geographical inequalities over time in one setting is possible but only if the units of analysis remain the same over time. 相似文献
64.
65.
66.
67.
Numerical simulations of multiphase CO2 behavior within faulted sandstone reservoirs examine the impact of fractures and faults on CO2 migration in potential subsurface injection systems. In southeastern Utah, some natural CO2 reservoirs are breached and CO2‐charged water flows to the surface along permeable damage zones adjacent to faults; in other sites, faulted sandstones form barriers to flow and large CO2‐filled reservoirs result. These end‐members serve as the guides for our modeling, both at sites where nature offers ‘successful’ storage and at sites where leakage has occurred. We consider two end‐member fault types: low‐permeability faults dominated by deformation‐band networks and high‐permeability faults dominated by fracture networks in damage zones adjacent to clay‐rich gouge. Equivalent permeability (k) values for the fault zones can range from <10?14 m2 for deformation‐band‐dominated faults to >10?12 m2 for fracture‐dominated faults regardless of the permeability of unfaulted sandstone. Water–CO2 fluid‐flow simulations model the injection of CO2 into high‐k sandstone (5 × 10?13 m2) with low‐k (5 × 10?17 m2) or high‐k (5 × 10?12 m2) fault zones that correspond to deformation‐band‐ or fracture‐dominated faults, respectively. After 500 days, CO2 rises to produce an inverted cone of free and dissolved CO2 that spreads laterally away from the injection well. Free CO2 fills no more than 41% of the pore space behind the advancing CO2 front, where dissolved CO2 is at or near geochemical saturation. The low‐k fault zone exerts the greatest impact on the shape of the advancing CO2 front and restricts the bulk of the dissolved and free CO2 to the region upstream of the fault barrier. In the high‐k aquifer, the high‐k fault zone exerts a small influence on the shape of the advancing CO2 front. We also model stacked reservoir seal pairs, and the fracture‐dominated fault acts as a vertical bypass, allowing upward movement of CO2 into overlying strata. High‐permeability fault zones are important pathways for CO2 to bypass unfaulted sandstone, which leads to reduce sequestration efficiency. Aquifer compartmentalization by low‐permeability fault barriers leads to improved storativity because the barriers restrict lateral CO2 migration and maximize the volume and pressure of CO2 that might be emplaced in each fault‐bound compartment. As much as a 3.5‐MPa pressure increase may develop in the injected reservoir in this model domain, which under certain conditions may lead to pressures close to the fracture pressure of the top seal. 相似文献
68.
EUROPE France; A Geographical Survey. By P. Pinchemel, translated by C. Trollope and A. J. Hunt. 454 pp. Illustrations, Tables, Bibliography. Bell, London, 1969. 100s. Italy. By George Kish. 8 × 5 1/4. 125 pp. 12 figures and index. Van Nostrand, New York, 1969. $1.lb95. AFRICA A Historical Geography of Ghana. By Kwamima B. Dickson. 15#lb5 × 23.lb5 cms. xiv + 379 pp., 58 maps and diagrams, 7 tables, appendices, bibliography, index. Cambridge U.P., London, 1969. 150s. The Soil Resources of Tropical Africa. Edited by R. P. Moss. 8 1/2 × 5 1/2. Cambridge University Press, 1968. £2. ASIA Afghanistan. By Ludolph Fischer. Geomedical Monograph Series No. 2, 12 × 8 1/2. Text (German and English), 16 plates and 10 maps. Springer‐Verlag, Berlin, Heidelberg and New York, 1968. DM48, $12.lb00. GEOLOGY AND GEOMORPHOLOGY Readings in the Earth Sciences, Vols. 1 and 2. 11 1/4 × 8 1/2 Published W. H. Freeman, San Francisco, 1969. 94s. each. Fife and Angus Geology. By A. R. MacGregor. 266 pp. Blackwood, Edinburgh and London, 1968. 21s. METEOROLOGY Essentials of Meteorology. By D. H. McIntosh and A. S. Thorn. 8 1/2 × 5 1/2. xv + 239 pp., numerous illustrations, answers to problems. Taylor and Francis, London. 20s. ECONOMIC GEOGRAPHY Industrial Britain: The North West. By David M. Smith. 10 × 6 1/4, 271 pp., 36 figures, 31 plates, bibliography and statistical appendix. David and Charles, Newton Abbot, 1969. 95s. Industrial Demand for Water: A study of South East England. By Judith Anne Rees. 8 1/2 × 5 1/2 L.S.E. Research Monographs 3, xiv + 194 pp., Weidenfeld and Nicolson, 1969, London. 65s. CARTOGRAPHY AND MAPS The Antonine Wall. Ordnance Survey 2 1/2 Inch Map. 1969. 11s. Maps and Air Photographs. By G. C. Dickinson. 10 × 17 1/2. xiv + 286 pp. Edward Arnold, London, 1969. 45s. Atlas Four. 10 1/2 × 8 1/2. 115pages, + index 60 pages. Collins/Longmans, 1969. 15s. EDUCATIONAL Learning Through the Environment. By Muriel F. S. Hopkins. 7 3/4 × 5 1/8. 151 pages, 26 figures. Longmans, London. 1969. 15s. Investigating Geography. By J. Philip Dodd. 9 3/4 × 7 1/4. 214 pp., 192 figures. Heinemann, London, 1969. 15s. The London Regional Geographies. Book 3: Asia. By Leonard Hadlow and Reginald Abbott. 8 1/2 × 5 1/2. 294 pp., 145 figs. U. of London Press, 1969. 18s. A Geography of Manufacturing. By H. R. Jarrett. 8 3/4 × 5 3/4. xvii + 349 pp. 67 illustrations. Macdonald &; Evans, 1969, London. 35s. The Mediterranean Lands. By J. Brannigan and H. R. Jarrett. The New Certificate Geography Series: Advanced Level. 9 × 5l. xiv + 620, 150 illustrations. Macdonald and Evans Ltd., 1969. 38s. 相似文献
69.
The elevation and age of surveyed shorelines in St Jonsfjorden, western Spitsbergen, provide a chronology for Late Weichselian deglaciation and a proxy for former ice thickness. Support is provided for previous reports of two sets of shorelines on NW Spitsbergen, the oldest (at 60 m in St Jonsfjorden) dating to a pre‐late Weichselian glaciation and the youngest documenting postglacial rebound. The remarkable survival of the older shorelines suggests that a large area of NW Spitsbergen was either covered by protective, cold‐based ice or was subject to only local glaciation during the late Weichselian even though glacier ice extended to the shelf edge in the Isfjorden Trough. A marine limit of 46 m at the mouth of St Jonsfjorden is compatible with the regional late Weichselian marine limit (LWML) dated to ~13 ka BP. A partial relative sea level curve and equidistant shoreline diagram are produced for St Jonsfjorden and used in conjunction with relative sea level curves based on data from previous studies to produce an isobase map for 9 ka BP. The curves indicate that western sites were subject to initial slow emergence followed by rapid emergence between 10 ka and 8.2 ka BP, trends characteristic of areas affected by a full glacial sea or at least subject to early break up of a thin or discontinuous glacier ice cover. A step in the 9 ka BP shoreline long profile over the western end of the peninsula separating Isfjorden and van Mijenfjorden suggests that Holocene neotectonics may have produced anomalously high rebound rates in that area. 相似文献
70.
Geoffrey N. Swinney 《Scottish Geographical Journal》2013,129(4):263-282
Following his participation in an expedition to the Weddell Sea (1892–1893), William Speirs Bruce determined to undertake further polar research and sought training and experience in such techniques and methodologies as might prove useful to him in securing opportunities to participate in future expeditions. During 1895–1896 he worked at the Ben Nevis Observatory gaining experience of meteorological research. The experience he gained in the design and operation of an observatory in a harsh environment he was later to apply when he established an observatory on Laurie Island, South Orkneys. This paper draws on a recently discovered archival source (Swinney (2001) to re‐examine Brace's involvement with the Ben Nevis Observatory. 相似文献