全文获取类型
收费全文 | 7461篇 |
免费 | 255篇 |
出版年
2020年 | 94篇 |
2019年 | 110篇 |
2018年 | 159篇 |
2017年 | 175篇 |
2016年 | 196篇 |
2015年 | 153篇 |
2014年 | 144篇 |
2013年 | 2012篇 |
2012年 | 212篇 |
2011年 | 227篇 |
2010年 | 200篇 |
2009年 | 212篇 |
2008年 | 245篇 |
2007年 | 173篇 |
2006年 | 137篇 |
2005年 | 108篇 |
2004年 | 104篇 |
2003年 | 80篇 |
2002年 | 87篇 |
2001年 | 141篇 |
2000年 | 102篇 |
1999年 | 104篇 |
1998年 | 73篇 |
1997年 | 67篇 |
1996年 | 81篇 |
1995年 | 71篇 |
1994年 | 70篇 |
1993年 | 82篇 |
1992年 | 71篇 |
1991年 | 67篇 |
1990年 | 56篇 |
1989年 | 70篇 |
1988年 | 68篇 |
1987年 | 83篇 |
1986年 | 64篇 |
1985年 | 83篇 |
1984年 | 83篇 |
1983年 | 119篇 |
1982年 | 85篇 |
1981年 | 88篇 |
1980年 | 96篇 |
1979年 | 72篇 |
1978年 | 85篇 |
1977年 | 95篇 |
1976年 | 88篇 |
1975年 | 69篇 |
1974年 | 56篇 |
1973年 | 55篇 |
1972年 | 54篇 |
1971年 | 61篇 |
排序方式: 共有7716条查询结果,搜索用时 407 毫秒
991.
This study presents the application of multi-element soil analyses (X-ray fluorescence spectroscopy and inductively coupled plasma optical emission spectroscopy of 1 M HCl extracts) to grid samples from 3 archaeological house plans embedded in sandy clays, clays and sands to assess effects of site lithology on geochemical signatures of human occupation. 相似文献
992.
Yuichi Nakazawa Lawrence G. Straus Manuel R. González-Morales David Cuenca Solana Jorge Caro Saiz 《Journal of archaeological science》2009
Stone boiling is one of the principal cooking methods used by hunter-gatherer societies. The present paper proposes behavioral and organizational inferences as to how stone boiling was incorporated into hunter-gatherer subsistence practices through an examination of a shallow-basin hearth in an Early Magdalenian level (c. 15,500 14C B.P.) of El Mirón Cave, Cantabria (northern Spain). Exploratory analysis of spatial patterns of archaeological remains (bones, lithic artifacts, and fire-cracked rocks) and use-life analysis of fire-cracked rocks demonstrate that the hearth was used and maintained during visits of humans who preyed mainly on ibex and red deer near the site. The relative accessibility of these ungulates and cost-induced technology of stone boiling suggest the implication that stone boiling was employed to maximize the energy and nutrition obtained from carcasses of these game taxa under the circumstance of resource intensification. 相似文献
993.
Brian S. Robinson George L. Jacobson Martin G. Yates Arthur E. Spiess Ellen R. Cowie 《Journal of archaeological science》2009,36(10):2184-2191
A paucity of archaeological remains of Atlantic salmon in Northeast North America has been cited as evidence that the species may have been present in the region only during and after the Little Ice Age (ca. 1450–1850 AD), one of coldest periods of the Holocene. However, significant problems of preservation, recovery and identification remain. Here, improved methods of identification use vertebra structure to distinguish salmon from trout, and strontium/calcium ratios to differentiate sea-run from landlocked salmon. In addition to the Little Ice Age, Atlantic salmon is identified in tightly dated contexts at 7000–6500 and 3500–3000 calendar years BP, during climate periods that were comparatively warm and wet. 相似文献
994.
Soil multi-element analysis is now a routine technique employed to help answer questions about space use and function in and around archaeological sites. The pattern of enhancement of certain elements, including P, Pb, Ca, Zn, and Cu, has been shown by numerous studies to correlate closely with the archaeological and historical record. Interpretation of these soil signatures, however, has generally been more problematic. One approach to the problem has been the use of ethnographic or “known” sites to guide interpretation, but how confidently can results from one site be extrapolated to another? This study of abandoned farms tests the site specificity of soil multi-element signatures of past space use through the use of discriminant models. Data analysis suggests that one to one comparisons of similar sites are much less accurate (38% accuracy) than comparisons based on a wider range of sites (59.3% accuracy), even when the latter have contrasting geology. The results highlight the importance of individual anthropogenic practices during occupation and abandonment in the development of diagnostic soil geochemical signatures. 相似文献
995.
996.
997.
This study employs the Institutional Analysis and Development framework across three collaborative watershed partnerships with differing membership profiles (government centered, citizen centered, or mixed) to determine how rules at varying levels of action (operational rules, collective-choice rules, and constitutional rules) affect the formation and implementation of rules-in-use at different levels. Examining trends across group types at varying levels of action helps illuminate how the operational rules produced by different types of partnerships result in outputs that impact watershed management. Results show that the source of rules and their impact on subsequent levels of action vary by group type, with federal and state policies playing a larger role in government-centered and mixed-membership groups than in citizen-centered groups. 相似文献
998.
999.
Among peace researchers and practitioners, it is generally accepted that efforts to prevent violence can be instrumental in its mitigation. So, it was distressing to read the research findings of Meier, Bond, and Bond (2007) that mitigation was positively related to organized raids in the Horn of Africa where there is pastoralist–pastoralist and pastoralist–agriculturalist violence. This article seeks to build on their research. It uses a ‘de-trending’ approach for time-series analysis that is commonly used in economics and financial studies. It reports an opposite statistically significant finding. When the data used by Meier et al. are de-trended, violence associated with organized raids is negatively correlated with mitigation. This negative correlation is similar when data on mitigation and organized raids are de-trended with time as a predictor, on the one hand, and with seasonality over time as a predictor, on the other. Implications regarding the temporal dimension of peace research and practice are presented. 相似文献
1000.
Marisa Lazzari Lucas Pereyra DomingorenaMaria Cristina Scattolin Leslie CecilMichael D. Glascock Robert J. Speakman 《Journal of archaeological science》2009
This article presents the results of ongoing instrumental neutron activation analyses (INAA) conducted on archaeological artifacts from the Formative period of northwestern Argentina (NWA). These studies are part of a wider archaeological project that seeks to understand the structure of the social landscape of the period by examining domestic and burial evidence from a wide range of villages across the area known as the southern Calchaquí valleys. Elemental data is discussed in the light of its potential contribution to reassess past social interaction strategies in the region. 相似文献