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   116039篇
  免费   9250篇
  国内免费   7525篇
化学   68715篇
晶体学   1469篇
力学   6770篇
综合类   622篇
数学   14253篇
物理学   40985篇
  2023年   1024篇
  2022年   1622篇
  2021年   2384篇
  2020年   3073篇
  2019年   3235篇
  2018年   3506篇
  2017年   3443篇
  2016年   4336篇
  2015年   3270篇
  2014年   4594篇
  2013年   6300篇
  2012年   6798篇
  2011年   7257篇
  2010年   5619篇
  2009年   5627篇
  2008年   5921篇
  2007年   5462篇
  2006年   5026篇
  2005年   4409篇
  2004年   3881篇
  2003年   3297篇
  2002年   3274篇
  2001年   3040篇
  2000年   2367篇
  1999年   1930篇
  1998年   1787篇
  1997年   1598篇
  1996年   1506篇
  1995年   1297篇
  1994年   1356篇
  1993年   1237篇
  1992年   1146篇
  1991年   1232篇
  1990年   1206篇
  1989年   1098篇
  1988年   976篇
  1987年   972篇
  1986年   913篇
  1985年   940篇
  1984年   934篇
  1983年   839篇
  1982年   821篇
  1979年   803篇
  1978年   810篇
  1977年   807篇
  1976年   923篇
  1975年   819篇
  1974年   841篇
  1973年   845篇
  1972年   751篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
61.
Russian Physics Journal - The temperature dependences of the linear dielectric permittivity ε′ and the third harmonic coefficient γ3ω for nanocomposites obtained by embedding a...  相似文献   
62.
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   
63.
Lin  Yu  Wu  Yeyu  Tan  Xuecai  Wu  Jiawen  Huang  Kejing  Mi  Yan  Ou  Panpan  Wei  Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin...  相似文献   
64.
Hexagonal boron nitride (BN) platelets, also known as white graphite, are often used to improve the thermal conductivities of polymeric matrices. Due to the poor interfacial compatibility between BN platelets and polymeric matrices, in this study, polyrhodanine (PRd) was used to modify BN platelets and prepared functionalized BN-PRd platelets, thereby enhancing the interfacial interaction between the thermal conductive filler and polymeric matrix. Then, BN-PRd platelets were dispersed into the nitrile butadiene rubber (NBR) matrix to yield high thermally conductive composites. The presence of N? C═S groups in PRd allowed the combination of PRd and NBR chains containing stable covalent bonds via vulcanization reaction. The thermal conductivity of the as-prepared 30 vol% BN-PRd/NBR composite reached 0.40 W/mK, representing an increment of 135% over pure NBR (0.17 W/mK). In addition, the largest tensile strength of NBR composite containing 30 vol% BN-PRd platelets was 880% times of pure NBR. The 30 vol% BN-PRd/NBR composite also displayed a relatively high dielectric constant (9.35 at 100 Hz) and a low dielectric loss tangent value (0.07 at 100 Hz), indicating their usefulness as dielectric flexible materials of microelectronics. In sum, the simplicity and good efficiency of formation of covalent bonds between boron nitride and rubber chains look very promising for large-scale industrial production of high thermally conductive composites.  相似文献   
65.
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed....  相似文献   
66.
The artificially accurate design of nonmetal electrocatalysts’ active site has been a huge challenge because no pure active species with the specific structure could be strictly controlled by traditional synthetic methods. Species with a multiconfiguration in the catalyst hinder identification of the active site and the subsequent comprehension of the reaction mechanism. We have developed a novel electro-assisted molecular assembly strategy to obtain a pure pentagon ring on perfect graphene avoiding other reconstructed structures. More importantly, the active atom was confirmed by the subtle passivation process as the topmost carbon atom. Recognition of the carbon-defect electrocatalysis reaction mechanism was first downsized to the single-atom scale from the experimental perspective. It is expected that this innovative electro-assisted molecular assembly strategy could be extensively applied in the active structure-controlled synthesis of nonmetal electrocatalysts and verification of the exact active atom.  相似文献   
67.
Bo  Luo  Gao  Wei  Yu  Yuguo  Chen  Xiaojun 《Nonlinear dynamics》2022,110(1):281-311
Nonlinear Dynamics - The perovskite solar cell (PSC) is one of the most promising photovoltaic candidates along with the highly increasing demand for green electricity. One of the main concerns...  相似文献   
68.
Russian Journal of General Chemistry - Aminophosphabetaines, i.e., isobutyl {[alkyl(dimethyl)ammonio]methyl}phosphonates with higher alkyl substituents at the nitrogen atom, were obtained by a...  相似文献   
69.
Recently,the negative differential thermal resistance effect was discovered in a homojunction made of a negative thermal expansion material,which is very promising for realizing macroscopic thermal transistors.Similar to the Monte Carlo phonon simulation to deal with grain boundaries,we introduce positive temperature-dependent interface thermal resistance in the modified Lorentz gas model and find negative differential thermal resistance effect.In the homojunction,we reproduce a pair of equivalent negative differential thermal resistance effects in different temperature gradient directions.In the heterojunction,we realize the unidirectional negative differential thermal resistance effect,and it is accompanied by the super thermal rectification effect.Using this new way to achieve high-performance thermal devices is a new direction,and will provide extensive reference and guidance for designing thermal devices.  相似文献   
70.
Physics of Atomic Nuclei - Hadron form factors are calculated using the Lorentz-contracted wave functions, determined in the arbitrary dynamical scheme with the instantaneous interaction. It is...  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