全文获取类型
收费全文 | 689篇 |
免费 | 22篇 |
专业分类
711篇 |
出版年
2024年 | 3篇 |
2023年 | 5篇 |
2021年 | 3篇 |
2020年 | 11篇 |
2019年 | 26篇 |
2018年 | 28篇 |
2017年 | 33篇 |
2016年 | 39篇 |
2015年 | 23篇 |
2014年 | 23篇 |
2013年 | 170篇 |
2012年 | 26篇 |
2011年 | 27篇 |
2010年 | 18篇 |
2009年 | 22篇 |
2008年 | 21篇 |
2007年 | 15篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 4篇 |
排序方式: 共有711条查询结果,搜索用时 0 毫秒
12.
13.
Stephen F. Poropat Jay P. Nair Caitlin E. Syme Philip D. Mannion Paul Upchurch Scott A. Hocknull 《Alcheringa: An Australasian Journal of Paleontology》2017,41(4):543-580
Poropat, S.F., Nair, J.P., Syme, C.E., Mannion, P.D., Upchurch, P., Hocknull, S.A., Cook, A.G., Tischler, T.R. &; Holland, T. XX.XXXX. 2017. Reappraisal of Austrosaurus mckillopi Longman, 1933 from the Allaru Mudstone of Queensland, Australia’s first named Cretaceous sauropod dinosaur. Alcheringa 41, 543–580. ISSN 0311-5518Austrosaurus mckillopi was the first Cretaceous sauropod reported from Australia, and the first Cretaceous dinosaur reported from Queensland (northeast Australia). This sauropod taxon was established on the basis of several fragmentary presacral vertebrae (QM F2316) derived from the uppermost Lower Cretaceous (upper Albian) Allaru Mudstone, at a locality situated 77 km west-northwest of Richmond, Queensland. Prior to its rediscovery in 2014, the type site was considered lost after failed attempts to relocate it in the 1970s. Excavations at the site in 2014 and 2015 led to the recovery of several partial dorsal ribs and fragments of presacral vertebrae, all of which clearly pertained to a single sauropod dinosaur. The discovery of new material of the type individual of Austrosaurus mckillopi, in tandem with a reassessment of the material collected in the 1930s, has facilitated the rearticulation of the specimen. The resultant vertebral series comprises six presacral vertebrae—the posteriormost cervical and five anteriormost dorsals—in association with five left dorsal ribs and one right one. The fragmentary nature of the type specimen has historically hindered assessments of the phylogenetic affinities of Austrosaurus, as has the fact that these evaluations were often based on a subset of the type material. The reappraisal of the type series of Austrosaurus presented herein, on the basis of both external morphology and internal morphology visualized through CT data, validates it as a diagnostic titanosauriform taxon, tentatively placed in Somphospondyli, and characterized by the possession of an accessory lateral pneumatic foramen on dorsal vertebra I (a feature that appears to be autapomorphic) and by the presence of a robust ventral mid-line ridge on the centra of dorsal vertebrae I and II. The interpretation of the anteriormost preserved vertebra in Austrosaurus as a posterior cervical has also prompted the re-evaluation of an isolated, partial, posterior cervical vertebra (QM F6142, the ‘Hughenden sauropod’) from the upper Albian Toolebuc Formation (which underlies the Allaru Mudstone). Although this vertebra preserves an apparent unique character of its own (a spinopostzygapophyseal lamina fossa), it is not able to be referred unequivocally to Austrosaurus and is retained as Titanosauriformes indet. Austrosaurus mckillopi is one of the oldest known sauropods from the Australian Cretaceous based on skeletal remains and potentially provides phylogenetic and/or palaeobiogeographic context for later taxa such as Wintonotitan wattsi, Diamantinasaurus matildae and Savannasaurus elliottorum.Stephen F. Poropat* [sporopat@swin. edu. au; stephenfporopat@gmail. com] Department of Chemistry and Biotechnology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Jay P. Nair [j. nair@uq. edu. au; jayraptor@gmail. com] School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; Caitlin E. Syme [caitlin. syme@uqconnect. edu. au] School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; Philip D. Mannion [philipdmannion@gmail. com] Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK; Paul Upchurch [p. upchurch@ucl. ac. uk] Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK; Scott A. Hocknull [scott. hocknull@qm. qld. gov. au] Geosciences, Queensland Museum, 122 Gerler Rd, Hendra, Queensland 4011, Australia; Alex G. Cook [alex. cook@y7mail. com] School of Earth Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; Travis R. Tischler [travisr. tischler@outlook. com] Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia; Timothy Holland [drtimothyholland@gmail. com] Kronosaurus Korner, 91 Goldring St, Richmond, Queensland 4822, Australia. *Also affiliated with: Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia. 相似文献
14.
Archaeological predictive modeling has been used successfully for over 20 years as a decision-making tool in cultural resources
management. Its appreciation in academic circles however has been mixed because of its perceived theoretical poverty. In this
paper, we discuss the issue of integrating current archaeological theoretical approaches and predictive modeling. We suggest
a methodology for doing so based on cognitive archaeology, middle range theory, and paleoeconomic modeling. We also discuss
the problems associated with testing predictive models. 相似文献
15.
Wook-Hyun Nahm Jin Kwan Kim Ju-Yong Kim Jaesoo Lim Jin Cheul Kim Kang-Min Yu 《Journal of archaeological science》2012
The Eurimji site in Jecheon City, Chungcheong Province holds major importance for Korean cultural heritage because it is assumed to be the oldest man-made reservoir for rice field irrigation in Korea. A multiproxy study provides the first scientific dating of the levee construction. The authors retrieved two sediment cores from the levee (core ER-1, 18.00 m long) and the reservoir bottom (core ER-3-1, 6.98 m long). Several plant fragment layers were observed between layers of dark gray clay–silt sediment in unit 2 of both cores. The spacing and thickness of these plant layers was relatively uniform (from 50 to 90 cm, and 5 to 6 cm, respectively). These features are interpreted to represent part of a man-made sedimentary sequence created using the consolidation-settlement drain method (tamped-earth or rammed-earth method) commonly used for dam or fortress construction in ancient times, as the features are not characteristic of natural river sedimentary processes. In this alternating sequence, bulk carbon from the sediment yielded AMS 14C dates of 2000–1400 14C yr BP, and the plant materials yielded dates of 1300–1200 14C yr BP. If workers at that time used two different materials such as available plant materials and clays for levee construction, the plant material is preferred for 14C age dating. This is because the origin of the carbon in the sediments is ambiguous, but the source of the plant materials has been confidently determined to be equivalent to the time of the levee construction. Therefore, the levee was constructed between 1200 and 1100 14C yr BP (AD 800–900), which is later than previously thought (i.e., AD 300 or AD 550). The results of our study also indicate that wetlands existed in the area before the construction of the Eurimji levee. 相似文献
16.
Jangsuk Kim 《Journal of Archaeological Method and Theory》2003,10(3):277-321
Although the forager–farmer interaction model successfully explains the gradual transmission of farming technology to foraging groups, it fails to explain rapid, abrupt transition to agricultural economies. This paper suggests that interaction between farmers and foragers often includes conflict and competition over land and that this conflict between different land-use strategies may lead to a rapid, discontinuous transition of subsistence economy. Comparing southern Scandinavian and central-western Korean cases, this paper suggests that the rapid transition to an agricultural economy in central-western Korea was a consequence of the appearance of territoriality of farmers in mobile, land-sharing context, resulting in a decrease in number of resource patches available to foragers. 相似文献
17.
18.
Philip Cooke 《European Planning Studies》2012,20(8):1415-1424
This short briefing paper addresses the next stage in the evolution of regional development policy. It is clear that the cluster idea has held sway in this field for some 20 years. By now, practitioners and academics are widely sceptical of policy capabilities to create let alone build clusters. Recessionary times make this more difficult. Moreover, where some recent success can be seen, it is associated with command economies such as China where normal market and democratic barriers to large public investments in such measures are absent. Nevertheless, clusters exist in many places and there is evidence, displayed in this paper, that in some regions they have mutated into multi-cluster platforms. Now, as regions seek to rebalance, platform policies are evolving and being implemented. This paper shows how this is in part a response to “Grand Challenges” and the emergence of “challenge-driven” innovation. 相似文献
19.
This paper summarizes results of a research project funded by the Overseas Development Administration of the UK Government. Its aims were to explore the nature and extent of foreign direct investment in Poland, and to assess the extent of integration of such investment with the indigenous economy. The research involved interviews with Polish government ministries, banks, development agencies, inward investors and indigenous firms. It concludes that there are numerous financial and technical obstacles to indigenous business development. The majority of inward investors aim to serve the Polish and other Central and Eastern European markets rather than simply selling cheaply produced products to the West. Moreover, most have already developed significant local sourcing from Polish suppliers. 相似文献
20.
Philip Freeman 《The Historian; a journal of history》2009,71(2):416-416