全文获取类型
收费全文 | 5500篇 |
免费 | 430篇 |
出版年
2021年 | 28篇 |
2020年 | 53篇 |
2019年 | 184篇 |
2018年 | 163篇 |
2017年 | 171篇 |
2016年 | 224篇 |
2015年 | 167篇 |
2014年 | 159篇 |
2013年 | 1531篇 |
2012年 | 215篇 |
2011年 | 202篇 |
2010年 | 211篇 |
2009年 | 185篇 |
2008年 | 150篇 |
2007年 | 174篇 |
2006年 | 140篇 |
2005年 | 75篇 |
2004年 | 84篇 |
2003年 | 79篇 |
2002年 | 78篇 |
2001年 | 88篇 |
2000年 | 78篇 |
1999年 | 64篇 |
1998年 | 75篇 |
1997年 | 65篇 |
1996年 | 69篇 |
1995年 | 58篇 |
1994年 | 58篇 |
1993年 | 47篇 |
1992年 | 45篇 |
1991年 | 39篇 |
1990年 | 25篇 |
1989年 | 43篇 |
1988年 | 38篇 |
1987年 | 52篇 |
1986年 | 39篇 |
1985年 | 44篇 |
1984年 | 51篇 |
1983年 | 44篇 |
1982年 | 35篇 |
1981年 | 42篇 |
1980年 | 55篇 |
1979年 | 47篇 |
1978年 | 28篇 |
1977年 | 56篇 |
1976年 | 36篇 |
1975年 | 38篇 |
1974年 | 25篇 |
1972年 | 25篇 |
1969年 | 23篇 |
排序方式: 共有5930条查询结果,搜索用时 18 毫秒
1.
Evidence from several disciplines supports the proposition that following the Wisconsinan and an initial but brief moist phase of the Holocene, there was a gradual drying trend in the mid-continent Prairie Peninsula that peaked about 7000 years ago, a pattern that was not reversed until about 4000 years ago. Except for minor perturbations, conditions during the past four millennia have essentially been similar to those of the present. Studies in palynology and geomorphology have shown that the climatic regimes of the early/mid Post-glacial had a marked influence on both the biota and landscape erosional patterns, especially along the margins of the Prairie Peninsula. Measurable changes in the landscape and attendant biota show a time-transgressive pattern of drought related phenomena recorded palaeo-ecologically from west to east.Few studies of archaeological sites in the Prairie Peninsula have examined the evidence in and around the sites themselves for data reflecting local environmental dynamics. In fact, earlier models proposed for explaining the evolution of food-procuring systems in eastern North America virtually ignored potential changes in the natural environment. This paper examines data from two archaeological sites along the prairie-forest border in Missouri that contain long cultural sequences. Evidence is presented that pronounced changes in the natural environment occurred and that these biophysical variables are indeed critical for understanding the evolution of food-procuring societies in the American Midwest. 相似文献
2.
3.
4.
5.
6.
7.
8.
Anna Lora‐Wainwright 《Anthropology today》2012,28(4):8-13
China has officially become a predominantly urban country, with over 50% of the population now registered as urban residents. Its urbanization process has been described as the most managed in human history. The Chinese government manages the building of new cities, regulates the housing of displaced people and controls squatters. As an historically poorer area, the west of China has been the target of ongoing efforts at infrastructural development. Describing urbanization as managed however masks the conflicts and contradictions involved in a process which is far from smooth. Although villagers are usually seen to be largely the powerless victims of these initiatives, it is clear that many try to take advantage of the situation, while others are unable to do so. Based on recent fieldwork and eight years of visits to one village undergoing urbanization, this article looks at the complex dynamics involved and at the moral battleground which they lay bare. 相似文献
9.
10.