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   531729篇
  免费   6106篇
  国内免费   1920篇
化学   281928篇
晶体学   6506篇
力学   24930篇
综合类   22篇
数学   62481篇
物理学   163888篇
  2020年   4426篇
  2019年   5221篇
  2018年   6541篇
  2017年   6492篇
  2016年   9770篇
  2015年   6160篇
  2014年   9569篇
  2013年   24498篇
  2012年   18607篇
  2011年   22764篇
  2010年   15828篇
  2009年   16040篇
  2008年   20832篇
  2007年   20803篇
  2006年   19180篇
  2005年   17497篇
  2004年   15954篇
  2003年   14024篇
  2002年   12929篇
  2001年   15220篇
  2000年   11319篇
  1999年   8545篇
  1998年   7012篇
  1997年   7169篇
  1996年   6733篇
  1995年   6507篇
  1994年   6343篇
  1993年   6260篇
  1992年   6912篇
  1991年   7061篇
  1990年   6620篇
  1989年   6632篇
  1988年   6616篇
  1987年   6483篇
  1986年   6149篇
  1985年   8564篇
  1984年   8706篇
  1983年   7169篇
  1982年   7543篇
  1981年   7338篇
  1980年   7009篇
  1979年   7386篇
  1978年   7575篇
  1977年   7610篇
  1976年   7778篇
  1975年   7187篇
  1974年   7206篇
  1973年   7533篇
  1972年   5034篇
  1971年   4104篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
101.
102.
Svetlakova  A. V.  Mendez  M. Sanchez  Tuchin  E. S.  Khodan  A. N.  Traore  M.  Azouani  R.  Kanaev  A.  Tuchin  V. V. 《Optics and Spectroscopy》2021,129(8):846-850
Optics and Spectroscopy - We study the photocatalytic activity of nanocomposites based on θ-phase alumina (Al2O3) with different TiO2 concentrations for heterogeneous photocatalysis and...  相似文献   
103.
Baskakov  A. G.  Krishtal  I. A.  Uskova  N. B. 《Differential Equations》2021,57(10):1273-1278
Differential Equations - We present spectrum localization theorems for Dirac operators and operators with involution in a class of function spaces introduced in [Contemp. Math., 2018, vol. 706, pp....  相似文献   
104.
Crystallography Reports - The electrical conductivity of natural samples of exogenous silicides has been studied. In the temperature range of 515?700 K, the conductivity increases from 1.1...  相似文献   
105.
Acta Mathematica Hungarica - This paper is devoted to the studying of the weak Orlicz–Lorentz space $$\Lambda_X^{\varphi, \infty}(w)$$ , which can be regarded as an extension of weak Orlicz...  相似文献   
106.
In the pursuit to enlarge the library of polyimide materials for energy applications, new polyimide/MWCNTs composite films have been developed by MWCNTs-assisted polycondensation reaction of a hydroxyl and triphenylmethane-containing diamine with benzophenone tetracarboxylic dianhydride targeting to highlight their electrical storage capability as flexible electrodes in micro-supercapacitors (mSCs). The Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance, UV–vis, fluorescence, and Raman spectroscopies were used to demonstrate the evolution of interfacial interactions between MWCNTs and the precursors (diamine monomer and intermediate polyamidic acid) and polyimide matrix that proved to be the origin of MWCNTs homogeneous dispersion. Thus, composite films incorporating 1, 3, 5, and 10 w.t.% MWCNTs were obtained and thoroughly investigated with regard to their morphology, mechanical behavior, thermal stability, and electrical conductivity. The electrochemical performance of these composites was first analyzed in a classical three-electrode cell by cyclic voltammetry and galvanostatic charge-discharge in both aqueous and organic electrolyte systems. By far, the best electrical storage capacity was obtained with the composite polyimide film containing 10% MWCNTs that was further used as both active material and current collector in a flexible symmetric mSC realized by a straightforward and low-cost procedure. In the attempt to better exploit the advantages of this composite film, it was layered with a graphite-containing paint and tested as an electrode in a flexible mSC, which provided satisfactory results. To our knowledge, this is the first report on the electrical charge storage capability of a polyimide/MWCNTs free-standing film as a flexible electrode in mSCs, which do not require time- and resource-consuming processing steps.  相似文献   
107.
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   
108.
Knyazev  Yu. V.  Kazak  N. V.  Gavrichkov  V. A.  Polukeev  S. I.  Ovchinnikov  S. G. 《JETP Letters》2022,116(8):567-573
JETP Letters - Changes in the magnetic properties of FeBO3 single crystals in the course of spin crossover occurring with increasing pressure up to 63 GPa are studied both experimentally and...  相似文献   
109.
Nikolaev  N. N. 《JETP Letters》2022,115(11):639-643
JETP Letters - A new approach to search for axions in the storage ring experiments, applicable at a short coherence time of the in-plane polarization as is the case for protons is discussed. The...  相似文献   
110.
Makarov  G. N. 《JETP Letters》2022,115(11):660-666
JETP Letters - Using the spectroscopic data on the 235UF6 and 238UF6 molecules and on the lasing frequencies of CF4 and para-H2 lasers and recent results, a method has been proposed to increase the...  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