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   673篇
  免费   27篇
  2023年   4篇
  2020年   13篇
  2019年   13篇
  2018年   18篇
  2017年   19篇
  2016年   23篇
  2015年   16篇
  2014年   16篇
  2013年   260篇
  2012年   18篇
  2011年   17篇
  2010年   12篇
  2009年   18篇
  2008年   14篇
  2007年   3篇
  2006年   6篇
  2005年   3篇
  2004年   9篇
  2003年   8篇
  2002年   9篇
  2001年   8篇
  2000年   7篇
  1999年   11篇
  1998年   7篇
  1997年   4篇
  1996年   3篇
  1995年   13篇
  1994年   8篇
  1993年   8篇
  1992年   4篇
  1990年   5篇
  1987年   3篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   7篇
  1982年   8篇
  1981年   10篇
  1980年   5篇
  1979年   7篇
  1978年   6篇
  1977年   7篇
  1976年   5篇
  1975年   5篇
  1973年   5篇
  1972年   6篇
  1967年   5篇
  1966年   6篇
  1951年   2篇
  1948年   3篇
排序方式: 共有700条查询结果,搜索用时 15 毫秒
81.
82.
83.
The Arabian Peninsula occupies a critical position at the intersect of several major Old World landmasses. Inland aridity and a major coastal perimeter have long made maritime activities critical to Arabia’s cultural trajectory. A wealth of recent studies, not previously synthesised, suggest not only that the peninsular littoral offered a rich resource base for thousands of years of human occupation in the region, but also that Arabia witnessed some of the world’s earliest seafaring and maritime exchange activities, and played a role in Bronze Age maritime trade that has often been underestimated. Maritime activities were closely linked to developments in agriculture, which not only fuelled trade and exchange, but were also impacted on by the dispersal of domesticates along early maritime corridors. While regional specialisation has to some degree prevented consideration of the maritime prehistory of the peninsula as a whole, it is clear that there are interesting parallels, as well as important differences, between cultural trajectories in different parts of the peninsula.  相似文献   
84.
85.
86.
Through use of methodology common in sedimentary geology, we apply U–Pb ages of detrital zircons to source nonlocal temper sand in an ancient ceramic assemblage recovered from Roviana Lagoon of the New Georgia Group in the Solomon Islands. Most potsherds from the Roviana Lagoon contain local volcanic sand as temper, but a small number of sherds contain anomalous granitic temper sand that does not appear to be local. To determine the origin of the anomalous temper, ages of zircons from the anomalous Roviana sherds are compared with ages of zircons in materials from Lizard Island off the Queensland coast and in sand from Muyuw Island in the Solomon Sea where generically similar granitic sands occur. U–Pb analyses of grains from the Roviana sherds yield Middle Miocene ages, while analyses of grains from Lizard Island granitic bedrock, sand, and local potsherds yield much older Permian-Triassic ages, disproving any possibility that the Roviana sherds were derived from Lizard Island, but suggesting local production of the Lizard Island sherds. Ages of grains in a sand sample from Muyuw Island are nearly identical to the ages of grains in the Roviana sherds. All grains in the Muyuw sand are Middle Miocene in age, overlapping closely with the Roviana age population. This strong similarity in detrital zircon signals indicates that the Roviana temper was likely derived from Muyuw Island sands. Our test case for the use of U–Pb ages of detrital zircons in sourcing temper sands is of only regional significance, and not of intrinsic global interest. The methodology, however, should find wide applicability for sourcing temper sands in many parts of the world, for it provides more specific data for the origins of tempers than either petrographic or chemical analysis.  相似文献   
87.
This paper summarises the current development in the southern Ionian Islands (Kefallinia and Zakynthos) prehistory and places it within the context of seafaring. Archaeological data from the southern Ionian Islands show human habitation since Middle Palaeolithic going back to 110 ka BP yet bathymetry, sea-level changes and the Late Quaternary geology, show that Kefallinia and Zakynthos were insular at that time. Hence, human presence in these islands indicates inter island-mainland seafaring. Seafaring most likely started some time between 110 and 35 ka BP and the seafarers were the Neanderthals. Seafaring was encouraged by the coastal configuration, which offered the right conditions for developing seafaring skills according to the “voyaging nurseries” and “autocatalysis” concepts.  相似文献   
88.
Seventy-five intact Mimbres and Jornada pottery sherds from the American Southwest were analyzed by portable XRF and instrumental neutron activation analysis (INAA). Examination of the data demonstrates that INAA and portable XRF results for elements common to both analyses can be used to construct similar compositional groups. When individual compositional groups are compared to one another, it is apparent that unambiguous separation of compositional groups is challenging by portable XRF given (1) the limited number of key discriminating elements that can be measured relative to INAA, and (2) the relative analytical precision and accuracy of portable XRF for measurements of intact heterogeneous ceramics. We conclude that sourcing intact ceramics by portable XRF is challenging and that bulk analytical measurements, such as INAA, remain a better approach for sourcing archaeological pottery.  相似文献   
89.
ABSTRACT We analyze the impact of fiscal decentralization on U.S. county population, employment, and real income growth. Our findings suggest that government organization matters for local economic growth, but that the impacts vary by government unit and by economic indicator. We find that single‐purpose governments per square mile have a positive impact on metropolitan population and employment growth, but no significant impact on nonmetropolitan counties. In contrast, the fragmentation of general‐purpose governments per capita has a negative impact on employment and population growth in nonmetropolitan counties. Our results suggest that local government decentralization matters differently for metropolitan and nonmetropolitan counties.  相似文献   
90.
ABSTRACT This research analyzes manufacturing growth and decline across metropolitan and nonmetropolitan regions during the 1972–2002 period. We decompose real value added growth across local labor market areas in the lower 48 U.S. states into contributions from labor, capital, and total factor productivity. We then estimate a model describing the long‐run growth of labor, capital, and productivity and find that increased productivity increases the growth of labor and capital, as well as a positive correlation between labor and capital stock growth. We also find evidence that human capital investment and agglomeration economies encourage productivity growth, while unionization discourages it.  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