全文获取类型
收费全文 | 3850篇 |
免费 | 153篇 |
出版年
2020年 | 61篇 |
2019年 | 68篇 |
2018年 | 104篇 |
2017年 | 101篇 |
2016年 | 127篇 |
2015年 | 90篇 |
2014年 | 83篇 |
2013年 | 1182篇 |
2012年 | 94篇 |
2011年 | 102篇 |
2010年 | 97篇 |
2009年 | 89篇 |
2008年 | 96篇 |
2007年 | 81篇 |
2006年 | 67篇 |
2005年 | 63篇 |
2004年 | 55篇 |
2003年 | 40篇 |
2002年 | 56篇 |
2001年 | 59篇 |
2000年 | 32篇 |
1999年 | 52篇 |
1998年 | 24篇 |
1997年 | 34篇 |
1996年 | 27篇 |
1995年 | 23篇 |
1994年 | 39篇 |
1993年 | 33篇 |
1992年 | 35篇 |
1990年 | 32篇 |
1989年 | 29篇 |
1988年 | 32篇 |
1987年 | 33篇 |
1986年 | 32篇 |
1985年 | 36篇 |
1984年 | 52篇 |
1983年 | 55篇 |
1982年 | 48篇 |
1981年 | 39篇 |
1980年 | 34篇 |
1979年 | 42篇 |
1978年 | 42篇 |
1977年 | 32篇 |
1976年 | 32篇 |
1975年 | 35篇 |
1973年 | 28篇 |
1972年 | 35篇 |
1971年 | 21篇 |
1970年 | 32篇 |
1969年 | 21篇 |
排序方式: 共有4003条查询结果,搜索用时 15 毫秒
971.
H. Thomas Foster II 《Southeastern Archaeology》2017,36(1):1-13
Apalachicola was a Hitchitee community that was considered the capital of the Creek Nation during the seventeenth and eighteenth century in the Southeastern United States. The role of this community in the formation of the southeastern political and cultural geography is paramount because of their coalescence with emigrant Muscogee people. In this article, I synthesize 10 years of research at the site and clarify the population history of this community. The research demonstrates the formation of the Creek culture area in the material record. Pottery surface decoration becomes measurably homogenous and I interpret this pattern as a result of that cultural development. 相似文献
972.
Ingela Bergman Per H. Ramqvist 《Acta Borealia: A Nordic Journal of Circumpolar Societies》2017,34(2):134-158
Although the productive fishing grounds had long attracted the Crown and the Church to northern Sweden, it was not until the sixteenth century that the judicial and fiscal powers of the Swedish Crown were exercised in full. Records show that the regular fishing in interior lakes formed a prominent enterprise among coastal farmer communities. This paper examines the social and economic context of farmers engaged in interior fishing with respect to the internal organization of village communities, principles of private and collective ownership, land-use strategies and inter-community relations. There are no a-priori assumptions about the coastal population being “Swedish”. Instead of applying ethnonyms, the terms “farmer” and “coastal” are used throughout the paper. The main area of investigation includes the coastal area of northernmost Sweden and the western parts of Finnish Lapland. The study shows that interior lakes fitted into village resource areas, long sanctioned by usage, and that usufruct belonged to village members collectively. A large part of the fishing lakes are situated in interior Sámi territory. Fishermen were internalizing Sámi place names, implying close relations between the groups. Archeological investigations point to subsistence strategies including systemic interior lake fishing being established before AD 1200. The authors propose that coastal and interior communities should be perceived as two economic strategies representing indigenous and pre-colonial land-use schemes. 相似文献
973.
Chandra R. Bhat Subodh K. Dubey Mohammad Jobair Bin Alam Waleed H. Khushefati 《Journal of regional science》2015,55(5):801-841
This paper formulates a multiple discrete‐continuous probit (MDCP) land use model within a spatially explicit economic structural framework for land use change decisions. The spatial MDCP model is capable of predicting both the type and intensity of urban development patterns over large geographic areas, while also explicitly acknowledging geographic proximity‐based spatial dependencies in these patterns. At a methodological level, the paper focuses on specifying and estimating a spatial MDCP model that allows the dependent variable to exist in multiple discrete states with an intensity associated with each discrete state. The formulation also accommodates spatial dependencies, as well as spatial heterogeneity and heteroskedasticity, in the dependent variable, and should be applicable in a wide variety of fields where social and spatial dependencies between decision agents (or observation units) lead to spillover effects in multiple discrete‐continuous choices (or states). A simulation exercise is undertaken to evaluate the ability of the proposed maximum approximate composite marginal likelihood (MACML) approach to recover parameters from a cross‐sectional spatial MDCP model. The results show that the MACML approach does well in recovering parameters. An empirical demonstration of the approach is undertaken using the city of Austin parcel level land use data. 相似文献
974.
AbstractIn many countries, rural areas have shown a new spatial-economic dynamics that have meant a contrast with the traditional urban-rural dichotomy. In particular, the need to use economic-ecological sustainability as a guiding principle for new rural development is a prominent feature. But how will rural areas, sometimes suffering from lack of economic development, peripheral positions and relatively low social well-being be able to face new challenges? Can they be attractive, innovative and developed (“hot spots”) while maintaining their sustainability and continuity? This question was the background in conducting our research. Hence, this study aims to answer this question in three steps, namely (i) offering a contemporary overview, (ii) identifying the critical factors for and (iii) developing a set of sustainable development scenarios. In order to reach our aims, we applied the so-called pentagon model and used multi-criteria analysis, namely regime analysis. The data and information deployed in this study were obtained from field surveys conducted in 60 European and 17 Turkish rural areas. The results show that future choices are different among rural users and between European and Turkish villages. European users seem more consistent about their future and their will while the will of Turkish villages are still more concentrated on economic development rather than sustainable development itself. 相似文献
975.
The Influence of Soil Moisture,Temperature and Oxygen on the Oxic Decay of Organic Archaeological Deposits 下载免费PDF全文
The sensitivity of organic‐rich archaeological layers at Bryggen in Bergen, Norway, to changes in soil temperatures, water contents and oxygen concentrations is investigated. This is done by linking measurements of oxic decay at varying temperatures and water contents with on‐site monitoring data using a one‐pool decomposition model. The results show that the model can be used to elucidate the current in situ decay and to evaluate where and when the decay takes place. Future investigations need to include long‐term incubation experiments and decay studies at zero or very low oxygen contents in order to improve the robustness of predictions. 相似文献
976.
Phenol Formaldehyde Revisited—Novolac Resins for the Treatment of Degraded Archaeological Wood 下载免费PDF全文
Archaeological wood is usually severely degraded. The Norwegian Viking Age Oseberg find exemplifies problems arising due to past conservation treatments and the need for new types of preservatives. Phenol formaldehyde (PF) has been investigated as a consolidant for alum‐treated wood. X‐ray tomography has revealed that it is possible to obtain a porous structure inside the wood, ensuring ethical acceptability by allowing re‐treatment. In order to understand the curing mechanics, the kinetics of the initial condensation reaction were elucidated at room temperature. It was found that a second‐order reaction using both phenol and formaldehyde concentrations is the most probable mechanism. 相似文献
977.
978.
979.
H. Christoph Steinhardt 《亚洲研究评论》2015,39(1):119-137
AbstractIn recent years, popular protest in China has emerged from a state of near-invisibility. Drawing on a diachronic analysis of news media coverage, this paper traces how a number of major protest events gradually entered the Chinese media’s spotlight and came to be portrayed in an increasingly protester-sympathising fashion over the course of the Hu-Wen administration. It argues that these changes were triggered by structural transformations of the Chinese public sphere, but underlines that deliberate policy choices by the political leadership served as a crucial agent of change. Facing proliferating unrest and an increasingly unimpeded flow of information, the central authorities have gradually shifted propaganda policy from a suppressive to a more proactive approach. They have thereby created critical opportunities for Internet users and investigative journalists to push the envelope further towards protester-sympathising accounts. The development is significant as there are good reasons to surmise that increased media coverage has exacerbated the dynamics of popular contention. Theoretically, it deserves to be noted that non-inevitable choices by an authoritarian leadership have led to an outcome in which media coverage of citizens who challenge the state on the streets has become substantially more frequent and positive than before. 相似文献
980.
Tamer Topal Burcu Ertaş Deniz Neriman Şahin Güçhan 《International Journal of Architectural Heritage》2015,9(3):244-264
Mount Nemrut is a 2,206 m high mountain located in Adiyaman, Turkey. A number of monumental statues, a 50-m high tumulus, and a lion horoscope were constructed at the top of the mountain by King Antiochos I (69–36 bc) of the Commagene Kingdom. The site was included in the UNESCO World Heritage List in 1987 due to its unique character. However, the limestone statues located on both the east and the west terraces of the site are getting deteriorated. This study investigates the weathering of the limestone at Mount Nemrut based on field and laboratory studies. It is found that the dissolution occurs along microcracks developed in the limestone during geological time. It is more pronounced in the east terrace where freezing-thawing cycles are more than the west terrace. Furthermore, dissolution is more effective for the faces of the statues exposed to direct atmospheric contact. Due to harsh atmospheric conditions with dominant wetting-drying and freezing-thawing processes at the site, it is recommended that direct rain and snow contact with the statues should be minimized. 相似文献