首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4326篇
  免费   176篇
  2020年   64篇
  2019年   85篇
  2018年   108篇
  2017年   116篇
  2016年   116篇
  2015年   103篇
  2014年   102篇
  2013年   1081篇
  2012年   139篇
  2011年   128篇
  2010年   113篇
  2009年   139篇
  2008年   166篇
  2007年   120篇
  2006年   92篇
  2005年   59篇
  2004年   69篇
  2003年   59篇
  2002年   59篇
  2001年   94篇
  2000年   63篇
  1999年   61篇
  1998年   45篇
  1997年   32篇
  1996年   50篇
  1995年   50篇
  1994年   39篇
  1993年   46篇
  1992年   30篇
  1991年   35篇
  1990年   30篇
  1989年   40篇
  1988年   38篇
  1987年   42篇
  1986年   40篇
  1985年   43篇
  1984年   52篇
  1983年   60篇
  1982年   46篇
  1981年   42篇
  1980年   51篇
  1979年   37篇
  1978年   49篇
  1977年   43篇
  1976年   54篇
  1975年   27篇
  1974年   27篇
  1973年   30篇
  1972年   30篇
  1971年   30篇
排序方式: 共有4502条查询结果,搜索用时 15 毫秒
101.
Nestorian Crosses from Jabal Berri   总被引:1,自引:1,他引:0  
Two small crosses, one of bronze and the other of mother-of-pearl, from the surface of a site near Jabal Berri in northeastern Saudi Arabia are presented. They are attributed to the Nestorian community of Bet Qatraye which is known from literary sources to have flourished during the Sasanian period.  相似文献   
102.
103.
An important line of research concerning historical fertility patterns in currently developed countries of Europe has concluded that, prior to the fertility transition, marital fertility was essentially constant over time, and deliberate fertility control was virtually unknown. It has been argued that variations over time in overall fertility were largely the consequence of variations in nuptiality. Other researchers have challenged these views and present evidence for the existence of a significant minority of fertility controllers in pretransition populations. In this article, we find support for this second view and argue that (1) there was significant, non-random variation in marital fertility over time, prior to the transition; (2) in many cases, this variation in marital fertility was large relative to contemporaneous variations in nuptiality; and (3) in a substantial minority of the cases, the variation over time in pretransition marital fertility was so large that it is suggestive of deliberate fertility control. Thus, our findings question the view of fertility transition as an innovation in deliberate marital fertility control. While most of our evidence is based on data from England and Wales, we find corroboration of our key results in other European data.  相似文献   
104.
105.
106.
Accelerator mass spectrometry radiocarbon ages have been taken for a test suite of small samples of material removed from some of the ‘beeswax’art figures found in rock shelters in northern Australia. The results indicate that we can reliably date this unique form of rock art with no noticeable damage. We had not expected to find figures of any great antiquity, and so we were surprised to find that the ages obtained spanned the time period from the recent past to about 4000 BP.  相似文献   
107.
108.
ABSTRACT. Data for 28 metropolitan areas over a 15-year period are used to determine the impacts of government spending, taxes, and public infrastructure on total employment and disaggregated employment. After carefully controlling for the government budget constraint we find that taxes are negatively related to total employment and education spending is positively related to total employment. Nevertheless, we find that it is difficult for metropolitan areas to influence the composition of their employment with government tax and expenditure policies. Moreover, at current levels of public infrastructure, marginal changes in infrastructure have no strong effect on employment.  相似文献   
109.
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号