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   155篇
  免费   1篇
化学   51篇
晶体学   2篇
力学   6篇
数学   34篇
物理学   63篇
  2015年   4篇
  2014年   1篇
  2013年   4篇
  2012年   10篇
  2011年   7篇
  2010年   7篇
  2009年   5篇
  2008年   8篇
  2007年   9篇
  2006年   12篇
  2005年   4篇
  2004年   6篇
  2003年   3篇
  2002年   4篇
  2001年   6篇
  2000年   6篇
  1999年   6篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   3篇
  1994年   6篇
  1993年   2篇
  1992年   7篇
  1991年   3篇
  1990年   3篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1982年   2篇
  1980年   1篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1973年   1篇
排序方式: 共有156条查询结果,搜索用时 15 毫秒
1.
2.
The reaction of [NBu4n]2Cu(mnt)2] with [Pt(CNMe)4][PF6]2 gives [Pt(mnt)(CNMe)2]·(NC)2C2S2CNMe, an X-ray study of which reveals co-stacking of neutral planar metal and organic molecules.  相似文献   
3.
4.
5.
6.
Razaghi  M.  Gandomkar  M.  Ahmadi  V.  Das  N. K.  Connelly  M. J. 《Optical and Quantum Electronics》2012,44(3-5):255-263
Optical and Quantum Electronics - In this paper, we analyse the picosecond wavelength conversion using semiconductor optical amplifier (SOA) with a novel technique. For an accurate and precise...  相似文献   
7.
The double spin asymmetry in the (-->)e(-->)p --> e(prime)pi(+)n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV(2). Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q(2) of the helicity asymmetry A1 for the F(15)(1680) resonance than expected from the analysis of the unpolarized data.  相似文献   
8.
9.
The effects of copolymerizing small amounts of an ionic moiety (0–7 mol %) into the backbone of a polycondensation polymer have been investigated by a combination of linear viscoelastic, steady-shear, and extensional testing. At a constant viscosity in dilute solution, both the zero-shear-rate viscosity and the maximum relaxation time in the melt increase monotonically with an increase in the ionic character. These effects are present after the data are normalized to remove the increase in the glass transition temperature Tg with increased ionic content. Large-strain, steady-shear flow experiments showed that the viscoelastic memory of the melt is affected by ionic content. An increase in ion content causes a decrease in the effect of strain on the memory function. This effect is not apparent in extensional flow experiments, which indicate that the ionic content does not affect the response if the tests are conducted at a constant temperature above Tg.  相似文献   
10.

Background  

There is great interest in appropriate phenotypes that serve as indicator of genetically transmitted frontal (dys)function, such as ADHD. Here we investigate the ability to deal with response conflict, and we ask to what extent performance variation on response interference tasks is caused by genetic variation. We tested a large sample of 12-year old monozygotic and dizygotic twins on two well-known and closely related response interference tasks; the color Stroop task and the Eriksen flanker task. Using structural equation modelling we assessed the heritability of several performance indices derived from those tasks.  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