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   60725篇
  免费   6677篇
  国内免费   5418篇
化学   30903篇
晶体学   537篇
力学   2209篇
综合类   300篇
数学   5275篇
物理学   13509篇
综合类   20087篇
  2024年   171篇
  2023年   927篇
  2022年   1435篇
  2021年   1703篇
  2020年   1782篇
  2019年   1611篇
  2018年   1450篇
  2017年   1411篇
  2016年   2046篇
  2015年   2258篇
  2014年   2789篇
  2013年   3658篇
  2012年   4245篇
  2011年   4593篇
  2010年   3397篇
  2009年   3417篇
  2008年   3823篇
  2007年   3595篇
  2006年   3128篇
  2005年   2860篇
  2004年   2195篇
  2003年   1789篇
  2002年   1897篇
  2001年   1633篇
  2000年   1399篇
  1999年   1611篇
  1998年   1337篇
  1997年   1254篇
  1996年   1249篇
  1995年   1179篇
  1994年   1041篇
  1993年   920篇
  1992年   802篇
  1991年   717篇
  1990年   661篇
  1989年   540篇
  1988年   487篇
  1987年   349篇
  1986年   268篇
  1985年   245篇
  1984年   150篇
  1983年   92篇
  1982年   92篇
  1981年   76篇
  1980年   64篇
  1979年   67篇
  1978年   45篇
  1976年   48篇
  1975年   44篇
  1973年   50篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
Mathematical Programming - We provide a control-theoretic perspective on optimal tensor algorithms for minimizing a convex function in a finite-dimensional Euclidean space. Given a function...  相似文献   
3.
The coordination chemistry of f-block elements (lanthanide and actinide) in molten salts has become a resounding topic in view of its great importance to the research and development (R&D) of molten salt reactors and pyroprocessing. In this Review article, a general overview of the coordination chemistry of f-block elements in molten salts is provided including past achievements and recent advances. Particular emphases are placed on the oxidation state, speciation, and solution structure of f-block metal ions in molten salts, as well as their relationships with the salt composition. Furthermore, this review briefly discusses the spectroscopic and theoretical methods that complement each other in revealing the coordination properties.  相似文献   
4.
5.
Wang  Rong  Li  Xu  Zhou  Youshi  Cao  Shuxuan  Xu  Honghao  Han  Wenjuan  Zhang  Yuxia  Liu  Junhai 《Journal of Russian Laser Research》2022,43(4):476-481
Journal of Russian Laser Research - We demonstrate a passively-mode-locked Pr3+: LuLiF4 laser operated at the 604 nm orange wave-length, using monolayer graphene as a saturable absorber. The...  相似文献   
6.
与中国共产党的百年发展历程相伴的是国家科学技术的快速发展.广东省作为国家社会与经济发展的前沿阵地,其科学创新的发展经验能够代表国家在改革浪潮中的发展变化.尤其是改革开放伟大征程的开启以及粤港澳大湾区规划的提出,促进了广东省科技创新事业的快速发展.广东省目前已成为国际科技创新的重要发生地,甚至在一些科技创新领域领先全球.文章通过回顾改革开放40多年来广东省科技创新取得的伟大成就,从政策、人才培养与引进、制度创新与科创平台建设、企业发展等领域分析广东省科技创新发展的特征、优势以及独特的做法,以期为我国科技创新的发展提供借鉴.  相似文献   
7.
International Journal of Theoretical Physics - In this work, we give an analytical derivation of the reduced density matrix between two qubits in a cavity field, which is described by the quantum...  相似文献   
8.
Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air−water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar-thermal material di-cyan substituted 5,12-dibutylquinacridone (DCN−4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper. The DCN−4CQA@Paper combines desired chemical and physical properties, broadband light-absorbing, and shape-conforming abilities that render efficient photothermic vaporization. Notably, synergetic coupling of solar-steam and solar-electricity technologies by integrating DCN−4CQA@Paper and the thermoelectric devices is realized without trade-offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low-grade heat-to-electricity generation functions can provide potential opportunities for fresh water and electricity supply in off-grid or remote areas.  相似文献   
9.
Herein, we successfully construct the 3D biocompatible graphene through crosslinking 2D graphene nanosheet onto carbon fiber paper with poly(diallyldimethylammonium chloride) (PDDA) as anode of the alcohol biofuel cell. Compared with the bioanode without 3D graphene, the current density and output power of PDDA-graphene-ADH bioanode is increased by 23 % and 41 % at a high concentration of ethanol at pH 8.9, suggesting the stabilization role of graphene in enzyme loading. The study provides us a deep analysis on structures and performances of the bioanode incl. electrochemistry, X-ray photoelectron spectra, and atomic force microscopy images, which is significant to develop the new methods to construct 3D porous electrodes in energy conversion device.  相似文献   
10.
Secondary structures tend to be recognizable because they have repeating structural motifs, but mimicry of these does not have to follow such well-defined patterns. Bioinformatics studies to match side-chain orientations of a novel hydantoin triazole chemotype ( 1 ) to protein-protein interfaces revealed it tends to align well across parallel and antiparallel sheets, like rungs on a ladder. One set of these overlays was observed for the protein-protein interaction uPA⋅uPAR. Consequently, chemotype 1 was made with appropriate side-chains to mimic uPA at this interface. Biophysical assays indicate these compounds did in fact bind uPAR, and elicit cellular responses that affected invasion, migration, and wound healing.  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