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   494361篇
  免费   6448篇
  国内免费   1374篇
化学   255975篇
晶体学   7647篇
力学   22406篇
综合类   9篇
数学   61813篇
物理学   154333篇
  2021年   4337篇
  2020年   4830篇
  2019年   5342篇
  2018年   7294篇
  2017年   7433篇
  2016年   10768篇
  2015年   6614篇
  2014年   10290篇
  2013年   23857篇
  2012年   19049篇
  2011年   22456篇
  2010年   16114篇
  2009年   15707篇
  2008年   20167篇
  2007年   20045篇
  2006年   18595篇
  2005年   16524篇
  2004年   15187篇
  2003年   13371篇
  2002年   13098篇
  2001年   14620篇
  2000年   10977篇
  1999年   8533篇
  1998年   7067篇
  1997年   6842篇
  1996年   6554篇
  1995年   5721篇
  1994年   5726篇
  1993年   5506篇
  1992年   6168篇
  1991年   6236篇
  1990年   5960篇
  1989年   5848篇
  1988年   5573篇
  1987年   5742篇
  1986年   5338篇
  1985年   6976篇
  1984年   7088篇
  1983年   5960篇
  1982年   6189篇
  1981年   5776篇
  1980年   5677篇
  1979年   6070篇
  1978年   6096篇
  1977年   5962篇
  1976年   6016篇
  1975年   5734篇
  1974年   5675篇
  1973年   5847篇
  1972年   3998篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
41.
Statistical Inference for Stochastic Processes - The problem of linear interpolation in the context of a multivariate time series having multiple (possibly non-consecutive) missing values is...  相似文献   
42.
Theoretical and Mathematical Physics - This paper is devoted to tetrahedron maps, which are set-theoretical solutions of the Zamolodchikov tetrahedron equation. We construct a family of tetrahedron...  相似文献   
43.
Crystallography Reports - Two LiInSe2 single crystals, grown under different conditions, have been studied. Characteristics of these crystals for neutron detection have been compared using...  相似文献   
44.
45.
Journal of Structural Chemistry - Structural parameters and relative Gibbs free energies are calculated by density functional theory methods for four tetrafluoro derivatives of zinc(II)...  相似文献   
46.
Crystallography Reports - Electron backscattered diffraction (EBSD) has been used to analyze structures of natural minerals and artificial compounds for almost three decades. In recent years, it is...  相似文献   
47.
48.
Foundations of Computational Mathematics - We present a finite element variational integrator for compressible flows. The numerical scheme is derived by discretizing, in a structure-preserving way,...  相似文献   
49.
A temperature control unit was implemented to vary the temperature of samples studied on a commercial Mobile Universal Surface Explorer nuclear magnetic resonance (MOUSE-NMR) apparatus. The device was miniaturized to fit the maximum MOUSE sampling depth (25 mm). It was constituted by a sample holder sandwiched between two heat exchangers placed below and above the sample. Air was chosen as the fluid to control the temperature at the bottom of the sample, at the interface between the NMR probe and the sample holder, in order to gain space. The upper surface of the sample was regulated by the circulation of water inside a second heat exchanger placed above the sample holder. The feasibility of using such a device was demonstrated first on pure water and then on several samples of bread dough with different water contents. For this, T1 relaxation times were measured at various temperatures and depths and were then compared with those acquired with a conventional compact closed-magnet spectrometer. Discussion of results was based on biochemical transformations in bread dough (starch gelatinization and gluten heat denaturation). It was demonstrated that, within a certain water level range, and because of the low magnetic field strength of the MOUSE, a linear relationship could be established between T1 relaxation times and the local temperature in the dough sample.  相似文献   
50.
Crystallography Reports - The orientation of grains and the special boundaries formed by them in multicrystalline silicon has been studied by electron backscattered diffraction. It is found that...  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