全文获取类型
收费全文 | 11479篇 |
免费 | 382篇 |
出版年
2020年 | 133篇 |
2019年 | 202篇 |
2018年 | 485篇 |
2017年 | 461篇 |
2016年 | 549篇 |
2015年 | 223篇 |
2014年 | 204篇 |
2013年 | 2824篇 |
2012年 | 272篇 |
2011年 | 444篇 |
2010年 | 434篇 |
2009年 | 284篇 |
2008年 | 295篇 |
2007年 | 321篇 |
2006年 | 184篇 |
2005年 | 156篇 |
2004年 | 149篇 |
2003年 | 130篇 |
2002年 | 140篇 |
2001年 | 144篇 |
2000年 | 150篇 |
1999年 | 191篇 |
1998年 | 127篇 |
1997年 | 84篇 |
1996年 | 96篇 |
1995年 | 101篇 |
1994年 | 98篇 |
1993年 | 114篇 |
1992年 | 105篇 |
1991年 | 91篇 |
1990年 | 86篇 |
1989年 | 90篇 |
1988年 | 96篇 |
1987年 | 105篇 |
1986年 | 99篇 |
1985年 | 136篇 |
1984年 | 135篇 |
1983年 | 138篇 |
1982年 | 111篇 |
1981年 | 120篇 |
1980年 | 128篇 |
1979年 | 112篇 |
1978年 | 108篇 |
1977年 | 129篇 |
1976年 | 111篇 |
1975年 | 105篇 |
1974年 | 88篇 |
1973年 | 90篇 |
1972年 | 70篇 |
1971年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Ronald J. Krumm 《Journal of regional science》1987,27(1):119-128
ABSTRACT. The intertemporal structure of regional nominal-wage differentials by race is estimated using panel data from 1973 through 1978. This allows for a more complete analysis of the time pattern of changes in wage differentials, which is not possible from cross-sectional studies. The findings indicate that, in addition to the presence of substantial locational differentials, there was a systematic change in the differentials over time. 相似文献
122.
ABSTRACT This paper develops a model of regional financial markets which can encompass different degrees of spatial financial integration. The behavior of the system is analyzed under alternative assumptions about the time frame of analysis and the extent of the flexibility of interest rates. It is argued that links may exist between regional real and financial sectors even in the short run and that such links must, through the regional balance of payments, exist in the long run, even where there is perfect financial spatial integration. It is observed that these relationships have generally been ignored by regional economic model builders. 相似文献
123.
124.
James Anquandah 《African Archaeological Review》1987,5(1):171-180
An Iron Age complex which flourished around the fifteenth to the seventeenth century AD is currently under investigation in Komaland, northern Ghana. The complex is known chiefly from its numerous burial sites characterized by stone circles and earth mound superstructures, and containing human and animal burials, domestic pottery, milling stones, metal implements and cast figures, together with ubiquitous and distinctive terracotta sculptures. This paper discusses the findings from the first season's excavation and their significance in West African archaeology.
Résumé Des recherches actuellement en cours portent sur un complexe de l'Age du Fer, qui a prospéré entre le 15e et le 17e siècle après J.C., en Komaland, au nord du Ghana. Le complexe est connu surtout par ses nombreux sépultures caractérisées par des cercles de pierres, avec comme superstructures des tumulus de terre où se trouvent des inhumations de humains et d'animaux, de la céramique domestique, des molettes, des outils en métal, et des figures coulées, avec des sculptures en terre cuite ubiquistes et distinctives. Cet article présente des résultats de la première saison de fouilles, et discute de leur signification dans l'archéologie de l'Afrique Occidentale.相似文献
125.
126.
127.
128.
J. A. J. Gowlett 《Journal of World Prehistory》1987,1(2):127-170
Accelerator mass spectrometry (AMS) allows radiocarbon dating to be carried out by direct counting of14C atoms, rather than the conventional counting of radioactive disintegrations. The result is that samples up to 1000 times smaller can be handled. The approach was tested in principle by 1977 and for archaeological operation by 1983. More than 2000 samples per year are now being dated worldwide. The machines can now operate to about ± 80 years or better. Dates older than 40,000 years have not yet been achieved, but the ability to use small samples has already had considerable impact on dating the period 10,000–30,000 years ago. Bone is an ideal material for the new technique, since amino acids can normally be isolated and purified from gram-size samples. Studies of the origins of domestication are aided by the dating of individual grains and seeds. Because small samples can be mobile in the soil, careful sample selection strategies and procedures are required. The full impact of the technique can be assessed only through the rapid and comprehensive publication of archaeological results. 相似文献
129.
130.