全文获取类型
收费全文 | 1489篇 |
免费 | 89篇 |
专业分类
1578篇 |
出版年
2024年 | 8篇 |
2023年 | 40篇 |
2022年 | 16篇 |
2021年 | 18篇 |
2020年 | 62篇 |
2019年 | 77篇 |
2018年 | 88篇 |
2017年 | 83篇 |
2016年 | 74篇 |
2015年 | 57篇 |
2014年 | 58篇 |
2013年 | 198篇 |
2012年 | 115篇 |
2011年 | 85篇 |
2010年 | 83篇 |
2009年 | 73篇 |
2008年 | 80篇 |
2007年 | 75篇 |
2006年 | 60篇 |
2005年 | 32篇 |
2004年 | 18篇 |
2003年 | 27篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 17篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1978年 | 3篇 |
排序方式: 共有1578条查询结果,搜索用时 15 毫秒
1.
J.M.P. Cabral M.A. Gouveia A.M. Alarcão J. Alarcao 《Journal of archaeological science》1983,10(1):61-70
The concentrations of two major elements and thirteen trace elements in 73 selected sherds of fine grey ware from the Iron Age and Roman period, excavated at Conimbriga, Santa Olaia and Tavarede, Portugal, were determined by instrumental neutron activation analysis. These concentrations were used to calculate distance matrices which were then subjected to cluster analysis employing SAHN and k-means methods, as well as to principal components analysis, to group the sherds according to the overall similarity of their compositional characteristics. The results showed that equivalent groupings appeared regardless of the taxonomic method used. Two major clusters were recognized corresponding to two different sites, namely Conimbriga and Santa Olaia, suggesting that the ceramics from these sites were made locally. No significant differences in compositional patterns were observed between iron age and roman sherds from Conimbriga. 相似文献
2.
Svante Pbo 《Journal of archaeological science》1985,12(6):411-417
The presence of DNA has been demonstrated in the cell nuclei of an ancient Egyptian mummy fragment. When extracted, this DNA proved to be degraded to a considerable extent and chemically modified. However, the preservation of nucleic acids in this specimen suggests that applying recombinant DNA techniques to the study of ancient mummified tissues might prove to be a fruitful future area of research. 相似文献
3.
乡村振兴要求走乡村内生性发展道路,客观认知乡村发展能力的时空分异格局和交互关系对乡村振兴战略实施具有重要意义。本文从农业产业发展、农村基础建设和农民社会生活三个维度构建测度指标体系,并引入面板向量自回归模型识别影响乡村发展能力的敏感因素,以此测度乡村发展能力指数,进而采用探索性时空数据分析方法揭示乡村发展能力的时空交互特征。结果表明:(1)我国中部地区多维乡村发展能力提升,但呈明显的空间异质性,不同维度间差异化显著;(2)中部地区多维乡村发展能力局域空间格局呈现较强的动态性并整体表现出较强的空间依赖关系;(3)邻接地级市多维乡村发展能力的时空交互网络以正向关联为主,局部空间呈差异化的竞合态势。 相似文献
4.
Veronica Puente Pablo Martín Botta Paula Mariela Desimone Cinthia Paula Ramos José Manuel Porto Lopez 《Archaeometry》2023,65(1):64-83
The results obtained from the multi-analytic compositional characterization of ceramic pastes and paints of the Santa María style, from the El Bolsón valley (Belén Department, Catamarca Province, Argentina), are presented here. This pottery style had a wide regional distribution in Northwestern Argentina between ca. 1000 and1600 ce and is characterized by its complex iconography painted in black, cream and red. The analyses show that the containers correspond to the technical tradition of using grog temper and suggest that its manufacture involved a double firing process. This reveals a new practice for the time. 相似文献
5.
Matthew Quick Tanya Christidis Toyib Olaniyan Nick Newstead Lauren Pinault 《The Canadian geographer》2023,67(3):352-365
Cooling centres provide respite, safety, and social support during extreme heat events for populations that do not have the resources to own or operate in-home air conditioning. The objective of this study was to measure the spatial accessibility of cooling centres and analyze the associations between cooling centre access and marginalization in Montreal, Toronto, and Vancouver, Canada. The potential spatial accessibility of cooling centres within a 15-minute walk was measured at the dissemination area scale using the two-step floating catchment area method. A two-stage modelling approach was used to analyze the associations between cooling centre access and marginalization. Approximately 62%, 58%, and 54% of the populations in Montreal, Toronto, and Vancouver had access to at least one cooling centre. In Montreal and Vancouver, high marginalization areas were more likely to have cooling centre access than low marginalization areas. Of the areas with cooling centre access, smaller access scores were observed in areas with high residential instability. Approximately one-fifth of the areas in each city had no cooling centre access and high marginalization, and may be considered for future cooling centres or programs that improve accessibility to existing centres. 相似文献
6.
本文采用因子生态分析方法剖析多伦多都市区的居住空间结构。主成分分析表明,家庭构成、年龄构成、职业构成是形成城市居住分异的主要因素。聚类分析表明,家庭构成和年龄构成的分异呈同心园格局,职业构成的分异呈扇形格局。形成这种居住分异格局的机制包括动力机制、管理机制和行为机制三个方面。 相似文献
7.
8.
Dario Musolino 《Journal of Cultural Geography》2018,35(2):251-273
ABSTRACTGeographers interested in how entrepreneurs perceive locational environments have studied their mental maps in several European countries, within the theoretical framework provided by behavioral approach. Such studies have typically employed quantitative techniques, but qualitative studies are relatively new to this line of research. In this article, I examine the mental maps of entrepreneurs in Italy by using a mixture of qualitative and quantitative methods. I present and discuss the qualitative outcomes of this research, focusing in particular on the explanatory location factors and the key influences on the mental maps of entrepreneurs. What emerges is the realization that entrepreneurs are far from being fully rational economic actors, who exploit optimally all information and who are driven only by objective considerations. Rather, their views are also affected by subjective factors, individual’s own insights, commonplaces, stereotypes, and prejudices, particularly with reference to the southern regions of Italy (Mezzogiorno), and of other peripheral areas. 相似文献
9.
10.
Alongside the institutionally constructed European identity, research shows that insights into citizens’ sense of belonging are valuable as well in assessing questions of identity. The tendency to conflate European identity with EU identity has spurred debates about the components that underlie European identification. The online subsidiarity adopted by the EU through e-platforms has allowed for a new form of citizenship where e-citizens (de)legitimate the issues under debate. This article examines the contents of European and national identities in the e-debaters’ comments posted on the Debating Europe platform. Drawing on narrative and discursive approaches, we propose a framework to operationalize the (de)legitimation and identification categories used by e-debaters within their discursive construction of European identity. The qualitative empirical research shows three main (de)legitimation clusters: the “EU as a loss,” “inclusive gain,” and “exclusive gain.” We discuss these findings within the broader context of Europeanization, identity multiplicity, and the conditions of the EU enlargement policy. 相似文献