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   1717篇
  免费   34篇
  2022年   3篇
  2020年   8篇
  2019年   19篇
  2018年   282篇
  2017年   208篇
  2016年   253篇
  2015年   25篇
  2014年   15篇
  2013年   143篇
  2012年   48篇
  2011年   165篇
  2010年   188篇
  2009年   49篇
  2008年   73篇
  2007年   78篇
  2006年   9篇
  2005年   30篇
  2004年   15篇
  2003年   17篇
  2002年   5篇
  2001年   3篇
  2000年   4篇
  1999年   6篇
  1998年   5篇
  1997年   5篇
  1996年   4篇
  1995年   2篇
  1992年   4篇
  1991年   2篇
  1990年   5篇
  1989年   3篇
  1988年   2篇
  1987年   7篇
  1986年   3篇
  1985年   7篇
  1984年   4篇
  1983年   2篇
  1982年   4篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1977年   5篇
  1976年   4篇
  1975年   5篇
  1974年   2篇
  1973年   2篇
  1969年   2篇
  1967年   2篇
  1958年   2篇
  1955年   2篇
排序方式: 共有1751条查询结果,搜索用时 15 毫秒
11.
ABSTRACT. Data for 28 metropolitan areas over a 15-year period are used to determine the impacts of government spending, taxes, and public infrastructure on total employment and disaggregated employment. After carefully controlling for the government budget constraint we find that taxes are negatively related to total employment and education spending is positively related to total employment. Nevertheless, we find that it is difficult for metropolitan areas to influence the composition of their employment with government tax and expenditure policies. Moreover, at current levels of public infrastructure, marginal changes in infrastructure have no strong effect on employment.  相似文献   
12.
13.
14.
15.
16.
The years 1396–1399 were critical ones in terms of European and English politics alike and, concomitantly, in the course of the Great Schism of the West. England's attitude to the Schism at this time has hitherto been considered primarily from a presupposition of Richard II's own attitude and authority and as an aspect of European politics. An examination of the direct relationship between Richard II and both the Urbanist papacy and the English Church raises some doubts about the extent of his authority in ecclesiastical affairs both before and after his emphatic reassertion of his prerogative in 1397. Particular consideration is given to his personal view of his proper interest. A discussion of the effect of royal policy on the English Church, especially in respect of the episcopate, suggests that, both in practice and in theory, his influence, whilst strong, rested on co-operation as much as coercion, and the nature of the Anglo-papal concordat of November 1398 is reconsidered in this light. It is suggested that greater stress should be laid on the spiritual considerations which weighed with all parties at the time alongside those of a more familiar secular kind.  相似文献   
17.
Shell beads are well established in the archaeological record of sub-Saharan Africa and appear as early as 75,000 BP; however, most research has focused on ostrich eggshell (OES) and various marine mollusc species. Beads made from various land snails shells (LSS), frequently described as Achatina, also appear to be widespread. Yet tracking their appearance and distribution is difficult because LSS beads are often intentionally or unintentionally lumped with OES beads, there are no directly dated examples, and bead reporting in general is highly variable in the archaeological literature. Nevertheless, Achatina and other potential cases of LSS beads are present at over 80 archaeological sites in at least eight countries, spanning the early Holocene to recent past. Here, we collate published cases and report on several more. We also present a new case from Magubike Rockshelter in southern Tanzania with the first directly dated LSS beads, which we use to illustrate methods for identifying LSS as a raw material. Despite the long history of OES bead production on the continent and the abundance of land snails available throughout the Pleistocene, LSS beads appear only in the late Holocene and are almost exclusively found in Iron Age contexts. We consider possible explanations for the late adoption of land snails as a raw material for beadmaking within the larger context of environmental, economic, and social processes in Holocene Africa. By highlighting the existence of these artifacts, we hope to facilitate more in-depth research on the timing, production, and distribution of LSS beads in African prehistory.  相似文献   
18.
Professor James Kwesi Anquandah was Ghana’s first archaeologist. He was also the first Ghanaian to become head of the Archaeology Department at the University of Ghana, which was the first archaeology department in sub-Saharan Africa, established in 1951. Dedicating his life to Ghanaian archaeology, particularly during the difficult years in Ghana in the 1980s and early 1990s, Anquandah had a significant impact on the development of archaeology in Ghana. In addition to his research, advisory and curatorial work, Professor Anquandah was instrumental in the training of three generations of Ghanaian archaeologists. During the course of a professional career that spanned nearly six decades, Professor Anquandah made archaeology relevant and accessible to all Ghanaians.  相似文献   
19.
The period comprising the end of the Early Neolithic and the Middle Neolithic, dated broadly within the fifth millennium cal BC, corresponds to an interval that remains largely unknown in the extreme north-western tip of Africa. This situation contrasts with that of the Early Neolithic, a period characterised by the earliest evidence of the diffusion of a productive economy, cultivated plants and domestic animals. The paucity of data for these later phases can be explained in part by the lack of secure contexts and sequences based on radiocarbon datings of short-lived samples. The current study presents the results of the excavations of El-Khil Caves B and C that yield materials allowing re-evaluation of the chronology of a type of ceramic known as Ashakar ware. The study also identifies two traditions in the northern Moroccan Middle Neolithic. The first is heir to the so-called Impressa Mediterranean ware and rooted in the Cardial Neolithic, while the second is characterised by roulette cord impressions, red slip and tunnel lugs and probably rooted in the region of the Sahara, and has no technological precedents in the study area.  相似文献   
20.
The study presents the results of neutron activation analysis (NAA) of contemporary pottery from Tigray Regional State, northern highland Ethiopia. This is the first regional-scale study of ceramic composition of Tigray’s pottery and is part of an ethnoarchaeological study of the material and social contexts of pottery production and consumption in Tigray’s Eastern (Misraqawi), Central (Mehakelegnaw), and North-western (Semien Mi’irabawi) zones. The analysis identifies clear compositional groups with strong regional patterns, an encouraging result for the use of NAA to study Tigray’s ancient pottery trade. Significantly, the study further contributes to discussions of how mutually constituted social identities of potters and consumers affect compositional patterning in the distribution of pottery in market networks.  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