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   1487篇
  免费   42篇
  国内免费   3篇
化学   854篇
晶体学   8篇
力学   16篇
数学   200篇
物理学   454篇
  2023年   14篇
  2022年   10篇
  2021年   15篇
  2020年   26篇
  2019年   31篇
  2018年   23篇
  2017年   14篇
  2016年   33篇
  2015年   32篇
  2014年   27篇
  2013年   41篇
  2012年   70篇
  2011年   83篇
  2010年   61篇
  2009年   50篇
  2008年   55篇
  2007年   70篇
  2006年   60篇
  2005年   44篇
  2004年   49篇
  2003年   38篇
  2002年   38篇
  2001年   34篇
  2000年   39篇
  1999年   29篇
  1998年   15篇
  1997年   16篇
  1996年   24篇
  1995年   25篇
  1994年   33篇
  1993年   27篇
  1992年   16篇
  1991年   19篇
  1990年   17篇
  1989年   11篇
  1988年   14篇
  1987年   12篇
  1986年   14篇
  1985年   14篇
  1984年   13篇
  1981年   18篇
  1980年   11篇
  1979年   16篇
  1978年   17篇
  1977年   17篇
  1976年   11篇
  1975年   10篇
  1974年   19篇
  1973年   18篇
  1970年   9篇
排序方式: 共有1532条查询结果,搜索用时 15 毫秒
991.
992.
Measurements of transient magnetic fields (TF) were performed on swift heavy ions of56Fe and80Se, with Coulomb excitation of their first 2+ state as probe, traversing thin Fe layers with segmented and unsegmented structures. The 50 µm×50 µm squares of the segments were accomplished applying the techniques of photolithography and ion etching. The magnitude of the TF deduced clearly shows that by segmentation of the targets the ion beam induced attentuations can be eliminated. This finding has direct applications tog-factor measurements.  相似文献   
993.
The Landauer-Büttiker approach is used to describe electron transport along a chain of scatterers which allow elastic as well as inelastic processes. The inelastic scattering takes place via side branches coupling the chain to electron reservoirs which serve as a heat bath. For small inelastic coupling of the scatterers to the heat bath strong interference effects lead to spatial fluctuations of the charge density. The corresponding oscillations of the chemical potential are discussed in view of phase-sensitive experiments measuring the four-probe resistance.  相似文献   
994.
995.
996.
997.
998.
The phenolic coupling of halogen-containing ferulic acid and methyl ester derivatives was examined with particular reference to the synthesis of lignans of the aryltetralin and tetrahydrofuran classes. (±)-Isolariciresinol dimethyl ether (18) and (±)-veraguensin (27) have been synthesized.  相似文献   
999.
Frequency map of the spiral ganglion in the cat   总被引:1,自引:0,他引:1  
A frequency map of the cat spiral ganglion has been determined on the basis of reconstructed cochleas in which individual spiral ganglion cells were labeled with horseradish peroxidase following determination of their characteristic frequency; the cochleas were the same as those used by Liberman and Oliver [J. Comp. Neurol. 223, 163-176 (1984)]. By matching this map to one previously described for the organ of Corti [M. C. Liberman, J. Acoust. Soc. Am. 72, 1441-1449 (1982)], an estimate of the afferent innervation density of the inner hair cells was derived. Counts of myelinated nerve fibers at the habenula perforata and inner hair cells were also performed and yielded similar results in all but the most basal 10%-15% of the cochlea. Between 0.1 and 20 kHz there is a gradual monotonic increase as a function of frequency in the number of spiral ganglion cells terminating on each inner hair cell, from about eight ganglion cells per inner hair cell to about 30 ganglion cells per inner hair cell. Above 20 kHz, it seems there is a decrease to about ten ganglion cells per inner hair cell. The greatest innervation density is at approximately the region of the basilar membrane with the greatest density of inner hair cells per millimeter.  相似文献   
1000.
Some balanced complete block designs   总被引:1,自引:0,他引:1  
Letq=6t±1, ν=2q+2. The (ν/3) tri ples on ν marks may be partitioned intoq sets, each forming a BIBD of parameters (ν,3,2). Related results, some of them known, are also discussed briefly.  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