首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   455篇
  免费   18篇
  2023年   4篇
  2021年   5篇
  2020年   8篇
  2019年   11篇
  2018年   21篇
  2017年   17篇
  2016年   22篇
  2015年   10篇
  2014年   12篇
  2013年   127篇
  2012年   16篇
  2011年   20篇
  2010年   16篇
  2009年   12篇
  2008年   13篇
  2007年   11篇
  2006年   14篇
  2005年   11篇
  2004年   7篇
  2003年   3篇
  2002年   13篇
  2001年   9篇
  2000年   8篇
  1999年   10篇
  1998年   2篇
  1997年   5篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1992年   5篇
  1990年   2篇
  1989年   3篇
  1988年   4篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1978年   3篇
  1976年   2篇
  1974年   2篇
  1973年   4篇
  1971年   2篇
  1970年   2篇
  1969年   3篇
  1968年   4篇
  1967年   3篇
  1964年   1篇
  1963年   1篇
  1956年   1篇
  1955年   1篇
排序方式: 共有473条查询结果,搜索用时 31 毫秒
61.
Integrating portable X-ray fluorescence (pXRF) instrumentation into archaeological investigations has generated as much interest as skepticism because several characteristics of the technique limit analytical accuracy and precision. This paper seeks to explore inter-instrument performance in order to assess the potential pXRF instrumentation has in examining the elemental composition of lithic raw materials. Two pXRF instruments, Delta and Omega models both manufactured by Olympus Innov-X Systems, were utilized to obtain the trace element signatures of five fine-grained volcanic sources and four obsidian sources in the Great Basin. We compared the two portable instruments to a wavelength-dispersive instrument extensively calibrated with geologic standards and to a commercial benchtop energy-dispersive system. Our results suggest that the relationships between the data produced by these different instruments are complex, and as we look to the future of pXRF use in archaeological analysis we argue that that the same strict protocols applied in laboratory-based XRF analyses, involving instrument calibration, evaluation of inter-instrument performance, and comparison to accepted geologic standards, need to be applied in pXRF analysis.  相似文献   
62.
This paper describes two approaches to the facial approximation of three individuals from the Wairau Bar burial site (New Zealand). Two individuals were approximated working in direct reference to the remains and incorporated manual drafting. The third individual, ‘Aunty’ (the respectful title given by the iwi Rangitane elders) was approximated from CT scans and using computer graphics. The computer graphic approach enabled a greater level of precision in the application of the research and recommendations that inform a facial approximation, and facilitated collaboration with appropriate expertise. The computer-graphic approach, however, also resulted in a more photographic facial appearance, which can imply a greater level of knowledge about hard/soft tissue relationships than is currently available.  相似文献   
63.
A key area in the analysis of urban structural evolution is identifying discontinuities. Effective analysis could improve long‐term forecasting and provide a better understanding of how to steer an urban system toward a desirable future state. We use a simple aggregate retail model to demonstrate an algorithm for identifying discontinuities in model parameter space. Explorations of retailing in both Greater London and South Yorkshire in the United Kingdom illustrate how understanding a system's potential for discontinuity can provide insights for both policy makers and retail businesses. The Harris and Wilson model, described in the section so‐named, is used as a simple archetype to illustrate the new framework. This model can be developed in a straightforward way to incorporate further refinement. In “ Executing the model and visualizing the results ,” we describe a single model run and in “ Investigating discontinuities ,” we explain our framework for detecting and analyzing discontinuities. “ Identifying discontinuities in the London retail system ” shows the results of applying this methodology to the Greater London retail system, and in “ Practical applications ,” we explore the policy applications for this technique as related to the decline of town centers in the South Yorkshire retail system. Some concluding comments are offered in “ Conclusions .”  相似文献   
64.
65.
Since 2005, a burgeoning wave of Chinese investments has set off a new ‘minerals boom’ in the Australian iron ore and coal mining sectors. While normally a welcome development, the state-owned and strategic nature of the investors has raised concerns in Australia about how these should be regulated. As a result, in February 2008 the Australian government declared an intention to more closely screen foreign direct investment (FDI) from state-owned sources, which both supporters and detractors alike have claimed is evidence of ‘resource nationalism’ in Australia's approach towards its trade and investment relationships with China. This article challenges this understanding through an examination of the characteristics of Chinese mining FDI, the dilemmas these present to the Australian government, and the relatively restrained nature of its response. Through this, Australia's FDI policy is explained as a defensive move against the potential for strategic behaviour by Chinese investors resulting from their state ownership, rather than any national program to subject minerals trade and investment to political control. On this basis, the article argues that Australian government policy instead evidences a ‘resource liberalism’ approach, which intends to ensure that the governance of Australia's minerals trade and investment with China remain market-based processes.  相似文献   
66.
67.
Commercial aerospace is a key sector in the Welsh economy, engaged in complex overlapping activities from aircraft manufacture (AM), through maintenance, repair and overhaul (MRO), to research, development and training (RDT). Defining and operationalizing a framework for analysis using both qualitative and quantitative data, this paper examines the actual and potential roles of the relationships in Wales between commercial aerospace firms, industry, government and institutional stakeholders, at both local and non-local levels. Concentrations of manufacturing in North Wales, and MRO in South Wales along with RDT operate as distinct constituent parts of aerospace clusters in neighbouring regions of England and beyond. The results, however, highlight links between the location of AM, MRO and RDT in Wales, emphasizing their (partially) geographically symbiotic relationships. Moreover, there are key inter-linkages that need consideration if the long-term health of Welsh aerospace is to be secured. Simultaneously, all three sub-sectors in Wales exhibit weaknesses which could render them vulnerable to greater external competition, particularly from developing countries. This emphasizes a need to alter the current governance arrangements and utilize different clustering characteristics that currently exist, with government, as a major sponsor of the industry, having a strong (but changing) role to play in encouraging these more balanced industry structures and decision-making processes.  相似文献   
68.
69.
Abstract

By focusing on the design and reception of successfully completed monuments, historians have overlooked the presence in nineteenth-century America of monuments that were left unfinished for decades, or even aborted altogether. This article recovers numerous such monuments, and shows how contemporaries seized on them not merely for their aesthetic value as homegrown ruins to be visited and sketched, but also for their rhetorical value as expressions of unfinished political and social struggles. In refashioning these incipient historical memorials as ironic anti-monuments to contemporary problems, diverse groups – radical workingmen and conservative Whigs, female activists and chauvinist newspapermen, patriotic Americans and critical Englishmen, proslavery southerners and abolitionist northerners – elaborated a broader discourse of unfinishedness. The fragments of these monuments could even figure the nation itself as a work-in-progress, contrary to current arguments about the construction of national identity through notions of organic wholeness. The article also questions scholars' assumption that monuments inevitably promote a culture of forgetting by projecting images of consensus and closure. In turning to the reception of monuments during their often-lengthy construction, we can perceive their more complex relationship to dominant ideologies and narratives of the nation-state.  相似文献   
70.
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   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号