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   3888篇
  免费   229篇
  国内免费   66篇
化学   2842篇
晶体学   48篇
力学   146篇
综合类   2篇
数学   442篇
物理学   703篇
  2024年   38篇
  2023年   68篇
  2022年   285篇
  2021年   361篇
  2020年   228篇
  2019年   196篇
  2018年   185篇
  2017年   143篇
  2016年   228篇
  2015年   164篇
  2014年   180篇
  2013年   291篇
  2012年   271篇
  2011年   294篇
  2010年   170篇
  2009年   137篇
  2008年   163篇
  2007年   147篇
  2006年   112篇
  2005年   101篇
  2004年   59篇
  2003年   55篇
  2002年   49篇
  2001年   20篇
  2000年   15篇
  1999年   10篇
  1998年   13篇
  1997年   13篇
  1996年   18篇
  1995年   12篇
  1994年   6篇
  1993年   11篇
  1992年   6篇
  1991年   7篇
  1990年   5篇
  1989年   9篇
  1988年   8篇
  1987年   10篇
  1986年   5篇
  1985年   5篇
  1984年   10篇
  1982年   8篇
  1981年   5篇
  1979年   5篇
  1978年   6篇
  1976年   10篇
  1975年   6篇
  1974年   4篇
  1973年   10篇
  1972年   6篇
排序方式: 共有4183条查询结果,搜索用时 15 毫秒
991.
Journal of Solid State Electrochemistry - Scientists are increasingly interested in improving electroactive technologies for supercapacitor applications, since energy storage devices have improved...  相似文献   
992.
Journal of Thermal Analysis and Calorimetry - Unsteady squeezed flow of hybrid nanofluid is investigated in this analysis. Comparison of hybrid nanofluid (using CNTs?+?CuO) and...  相似文献   
993.
Journal of Thermal Analysis and Calorimetry - In this paper, fabrication and characterization of Cu/PTB7-Th (35 mass%)/PC $$_{61}$$ BM (35 mass%)/graphene (30 mass%)/Ag...  相似文献   
994.
995.
Organic resin cross-linking ZIF-67/SiO2 superhydrophobic (SHPB) multilayer coating was successfully fabricated on metal substrate. The perfluoro-octyl-triethoxy silane (POTS) modified ZIF-67 and SiO2 coating was applied on primary coated polytetrafluoroethylene (PTFE) and epoxy resin (EP) via spray coating method. Here, we present that the robust superhydrophobicity can be realized by structuring surfaces at two different length scales, with a nanostructure design to provide water repellence and a microstructure design to provide durability. The as-fabricated multilayer coating displayed superior water-repellence (CA=167.4°), chemical robustness (pH=1–14) and mechanical durability undergoing 120th linear abrasion or 35th rotatory abrasion cycle. By applying different acidic and basic corrosive media and various weathering conditions, it can still maintain superior-hydrophobicity. To get a better insight of interaction between inhibitor molecules and metal surface, density functional theory (DFT) calculations were performed, showing lower energy gap and increased binding energy of ZPS/SiO2/PTFE/EP (ZPS=ZIF-67+POTS) multilayer coating compared to the ZIF-67/SiO2/PTFE/EP, thereby supporting the experimental findings. Additionally, such coatings may be useful for applications such as anti-corrosion, self-cleaning, and anti-icing multi-functionalities.  相似文献   
996.
Chen  Xiaolong  He  Yaowu  Ali  Muhammad Umair  He  Yu  Zhu  Yanan  Li  Aiyuan  Zhao  Changbin  Perepichka  Igor F.  Meng  Hong 《中国科学:化学(英文版)》2019,62(10):1360-1364
Herein, we propose a new strategy to develop air-stable n-type organic semiconductors with non-classical thiophene aromatic diimide derivatives by replacing aromatic naphthalene with a heteroaromatic isothianaphthene core. We designed and successfully synthesized the isothianaphthene core based diimide material, N,N′-bis(n-hexyl)isothianaphthene-2,3,6,7-tetracarboxylic acid diimide(BTDI-C6) as an n-type semiconductor. Compared to N,N′-bis(n-hexyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide(NDI-C6), BTDI-C6 possesses a deeper LUMO energy level of-4.21 eV, which is 0.32 eV lower than that of NDI-C6. Both molecular modelling and experimental results elucidated that organic thin film transistors(OTFTs)based on both of these materials exhibit comparable mobilities; however, the threshold voltage of BTDI-C6 based device(+7.5 V) is significantly lower than that of NDI-C6 based counterpart(+34V). Moreover, the low-lying LUMO energy level of BTDI-C6 ensures excellent air-stability which is further validated by the device performance. In addition, BTDI-C6 shows high luminescence while NDI-C6 is not luminescent at all in solution, which reveals the potential application of our newly synthesized material in n-type light-emitting transistors.  相似文献   
997.
Silicon (Si)-based anode materials with suitable engineered nanostructures generally have improved lithium storage capabilities, which provide great promise for the electrochemical performance in lithium-ion batteries (LIBs). Herein, a metal–organic framework (MOF)-derived unique core–shell Si/SiOx@NC structure has been synthesized by a facile magnesio-thermic reduction, in which the Si and SiOx matrix were encapsulated by nitrogen (N)-doped carbon. Importantly, the well-designed nanostructure has enough space to accommodate the volume change during the lithiation/delithiation process. The conductive porous N-doped carbon was optimized through direct carbonization and reduction of SiO2 into Si/SiOx simultaneously. Benefiting from the core–shell structure, the synthesized product exhibited enhanced electrochemical performance as an anode material in LIBs. Particularly, the Si/SiOx@NC-650 anode showed the best reversible capacities up to 724 and 702 mAh g−1 even after 100 cycles. The excellent cycling stability of Si/SiOx@NC-650 may be attributed to the core–shell structure as well as the synergistic effect between the Si/SiOx and MOF-derived N-doped carbon.  相似文献   
998.
Journal of Solid State Electrochemistry - Modified TiO2 nanocomposites have been recognized as attractive photocatalytic materials in solar energy conversion. The aim of this study is to enhance...  相似文献   
999.
Design, synthesis, and applications of metal–organic frameworks (MOFs) are among the most salient fields of research in modern inorganic and materials chemistry. As the structure and physical properties of MOFs are mostly dependent on the organic linkers or ligands, the choice of ligand system is of utmost importance in the design of MOFs. One such crucial organic linker/ligand is terpyridine (tpy), which can adopt various coordination modes to generate an enormous number of metal–organic frameworks. These frameworks generally carry physicochemical characteristics induced by the π-electron-rich (basically N-electron-rich moiety) terpyridines. In this minireview, the construction of 3D MOFs associated with symmetrical terpyridines is discussed. These ligands can be easily derivatized at the lateral phenyl (4′-phenyl) position and incorporate additional organic functionalities. These functionalities lead to some different binding modes and form higher dimensional (3D) frameworks. Therefore, these 3D MOFs can carry multiple features along with the characteristics of terpyridines. Some properties of these MOFs, like photophysical, chemical selectivity, photocatalytic degradation, proton conductivity, and magnetism, etc. have also been discussed and correlated with their frameworks.  相似文献   
1000.
Journal of Radioanalytical and Nuclear Chemistry - By using Durridge RAD7, onsite soil radon measurements were performed on 13 profiles and 65 points, across the known geological faults in district...  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