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   5649篇
  免费   282篇
  2023年   49篇
  2020年   125篇
  2019年   129篇
  2018年   224篇
  2017年   217篇
  2016年   247篇
  2015年   159篇
  2014年   155篇
  2013年   1605篇
  2012年   186篇
  2011年   213篇
  2010年   200篇
  2009年   163篇
  2008年   131篇
  2007年   125篇
  2006年   133篇
  2005年   85篇
  2004年   65篇
  2003年   69篇
  2002年   79篇
  2001年   79篇
  2000年   70篇
  1999年   84篇
  1998年   68篇
  1997年   46篇
  1996年   38篇
  1995年   52篇
  1994年   38篇
  1993年   52篇
  1992年   36篇
  1991年   46篇
  1990年   49篇
  1989年   46篇
  1988年   34篇
  1987年   47篇
  1986年   49篇
  1985年   48篇
  1984年   53篇
  1983年   48篇
  1982年   41篇
  1981年   47篇
  1980年   43篇
  1979年   40篇
  1978年   37篇
  1977年   36篇
  1975年   27篇
  1974年   28篇
  1973年   30篇
  1972年   30篇
  1970年   27篇
排序方式: 共有5931条查询结果,搜索用时 15 毫秒
101.
A multidisciplinary programme of research on Islamic pottery has been focused on questions of the dating, provenance and technology of Islamic pottery. One particular question has been the development of stonepaste, a material made primarily of crushed quartz with added frit-glass and clay. The combination of the different approaches of this study has revealed early foundations for the technology in ninth-century AD Iraq, apparently originating in the clay ceramic rather than the ‘Egyptian faience’ tradition. Subsequent and final practice developed in tenth- and eleventh-century AD Egypt. This technology becomes the primary body for all fine Islamic ceramics.  相似文献   
102.
The purpose of this paper is first, to present some evidence indicative of a rough daily periodicity in traffic counts at a cross-section of an urban road accompanied by a considerable amount of seemingly random additional variation; and second, to attempt an accounting through Fast Fourier Transform and power spectrum density functions of this additional variation beyond the rough daily cycle. Reasons behind the macroscopic variable's dynamic behavior are provided. Relatively extensive traffic counts make them especially suited for investigating various dynamic behaviors, including possibly nonperiodic (chaotic) patterns.  相似文献   
103.
104.
105.
106.
107.
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   
108.
Blue glass trade beads from well-dated late seventeenth- to early twentieth-century sites and collections have been analysed non-destructively by instrumental neutron activation analysis. The beads display enough variations in their elemental contents to allow us to characterize the different chemistries. The implication of these results is that similar chemical analyses of blue beads from undated archaeological sites may be used to help date the sites, since each bead chemistry has a specific earliest period.  相似文献   
109.
110.
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   
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