全文获取类型
收费全文 | 8618篇 |
免费 | 323篇 |
出版年
2020年 | 116篇 |
2019年 | 163篇 |
2018年 | 172篇 |
2017年 | 212篇 |
2016年 | 289篇 |
2015年 | 183篇 |
2014年 | 170篇 |
2013年 | 2211篇 |
2012年 | 211篇 |
2011年 | 257篇 |
2010年 | 238篇 |
2009年 | 207篇 |
2008年 | 200篇 |
2007年 | 170篇 |
2006年 | 161篇 |
2005年 | 111篇 |
2004年 | 114篇 |
2003年 | 103篇 |
2002年 | 114篇 |
2001年 | 126篇 |
2000年 | 136篇 |
1999年 | 172篇 |
1998年 | 114篇 |
1997年 | 75篇 |
1996年 | 89篇 |
1995年 | 94篇 |
1994年 | 91篇 |
1993年 | 93篇 |
1992年 | 96篇 |
1991年 | 75篇 |
1990年 | 75篇 |
1989年 | 78篇 |
1988年 | 85篇 |
1987年 | 92篇 |
1986年 | 87篇 |
1985年 | 123篇 |
1984年 | 121篇 |
1983年 | 129篇 |
1982年 | 99篇 |
1981年 | 104篇 |
1980年 | 107篇 |
1979年 | 102篇 |
1978年 | 95篇 |
1977年 | 108篇 |
1976年 | 86篇 |
1975年 | 95篇 |
1974年 | 83篇 |
1973年 | 79篇 |
1972年 | 62篇 |
1971年 | 65篇 |
排序方式: 共有8941条查询结果,搜索用时 15 毫秒
111.
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
112.
113.
114.
115.
116.
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
117.
118.
119.
120.