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   1585篇
  免费   87篇
  国内免费   16篇
化学   1048篇
晶体学   7篇
力学   44篇
综合类   1篇
数学   282篇
物理学   306篇
  2023年   15篇
  2022年   10篇
  2021年   46篇
  2020年   60篇
  2019年   53篇
  2018年   30篇
  2017年   36篇
  2016年   71篇
  2015年   68篇
  2014年   55篇
  2013年   99篇
  2012年   78篇
  2011年   104篇
  2010年   48篇
  2009年   48篇
  2008年   71篇
  2007年   65篇
  2006年   67篇
  2005年   57篇
  2004年   68篇
  2003年   45篇
  2002年   32篇
  2001年   26篇
  2000年   17篇
  1998年   18篇
  1997年   16篇
  1996年   16篇
  1994年   15篇
  1993年   14篇
  1992年   19篇
  1991年   13篇
  1990年   9篇
  1989年   11篇
  1988年   16篇
  1986年   13篇
  1985年   14篇
  1984年   11篇
  1983年   9篇
  1982年   10篇
  1981年   18篇
  1980年   10篇
  1979年   11篇
  1978年   9篇
  1977年   18篇
  1976年   13篇
  1975年   13篇
  1974年   18篇
  1973年   17篇
  1972年   12篇
  1971年   11篇
排序方式: 共有1688条查询结果,搜索用时 890 毫秒
1.
The dependence of the strangeness saturation factor on the system size, centrality and energy is studied in relativistic heavy-ion collisions.  相似文献   
2.
A Geometric Characterization of Automatic Monoids   总被引:1,自引:0,他引:1  
  相似文献   
3.
4.
The systematics of hyperfine magnetic fields at sp impurities on the Z-sites in Co based Heusler alloys are investigated. New TDPAC measurements of Cd hyperfine fields are reported.  相似文献   
5.
In this paper, three new direct Mutually Orthogonal Latin Squares (MOLS) constructions are presented for 7 MOLS(24), 7 MOLS(75) and 8 MOLS(36); then using recursive methods, several new constructions for 7 and 8 MOLS are obtained. These reduce the largest value for which 7 MOLS are unknown from 780 to 570, and the largest odd value for which 8 MOLS are unknown from 1935 to 419. © 2003 Wiley Periodicals, Inc.  相似文献   
6.
7.
In the cuticle of live social hornets, such as Vespa orientalis (Hymenoptera, Vespinae), endogenous electric effects are encountered, i.e. voltages of 100–200 mV under illumination and currents amounting to several microamperes on its subjection to darkness—clearly a process of charging and discharging. Of the various wavelengths of sunlight, UV was found to be the most contributory to the active cuticular voltage generation. Throughout the warm season of the yearthe–the active period in colonies of social hornets and wasps—colony members exit from the dark nest during the daytime and fly to the field under the hot sun for various foraging purposes, ultimately returning to the nest. Thus, each hornet, be it queen, worker or drone, probably undergoes daily cyclical process of electric charge and discharge in the exterior part of their integument, cuticle, which lasts up to 30–40 min. Such photoelectric phenomenon was detected in both live, ether‐anaesthetized hornets and dead hornets, albeit in the latter the electric values recorded were lower. The present study addresses the possible impact of the phenomenon on vespan daily life and also compares it with a parallel occurrence in electric fish.  相似文献   
8.
Ultrasonic analysis of edible fats and oils   总被引:7,自引:0,他引:7  
Low intensity ultrasound is a powerful analytical technique for investigating the physico-chemical properties of many biological and non-biological materials. In this article its application for the characterization of edible fats and oils is assessed. Ultrasound can be used to determine the dynamic rheology and composition of oils, the oil content and droplet size of emulsions and the solid fat content of partially crystalline emulsions. It is capable of rapid and precise measurements, is non-destructive and non-invasive, can be used on-line or off-line and is relatively inexpensive. Ultrasonic techniques will therefore prove a useful addition to the existing analytical techniques used to characterize fats and oils.  相似文献   
9.
10.
The effect of the glass coating on the single domain wall potential in amorphous glass-coated Fe-based microwire has been studied by the switching field distribution technique. The thermoactivated mechanism model is used to describe the thermally activated switching through the complex energy barrier in amorphous FeSiB microwires. Glass removal leads to the increase of the probability of the thermally activated switching pointing to the decrease of the energy barrier.  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