首页 | 官方网站   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   51077篇
  免费   9015篇
  国内免费   6193篇
数理化   66285篇
  2024年   115篇
  2023年   1049篇
  2022年   1259篇
  2021年   1704篇
  2020年   2103篇
  2019年   2041篇
  2018年   1796篇
  2017年   1678篇
  2016年   2447篇
  2015年   2463篇
  2014年   2928篇
  2013年   3727篇
  2012年   4552篇
  2011年   4733篇
  2010年   3221篇
  2009年   3278篇
  2008年   3514篇
  2007年   3102篇
  2006年   2936篇
  2005年   2316篇
  2004年   1844篇
  2003年   1491篇
  2002年   1375篇
  2001年   1125篇
  2000年   1092篇
  1999年   1059篇
  1998年   911篇
  1997年   866篇
  1996年   844篇
  1995年   762篇
  1994年   645篇
  1993年   542篇
  1992年   517篇
  1991年   403篇
  1990年   360篇
  1989年   278篇
  1988年   246篇
  1987年   204篇
  1986年   180篇
  1985年   181篇
  1984年   119篇
  1983年   89篇
  1982年   66篇
  1981年   44篇
  1980年   22篇
  1979年   18篇
  1977年   6篇
  1975年   5篇
  1965年   4篇
  1957年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Research on Chemical Intermediates - Owing to the simultaneous utilization of photogenerated electrons and holes, coupling light-driven hydrogen (H2) evolution reaction (HER) and biomass-derived...  相似文献   
2.
Refractory wounds have always been an important issue to healthcare systems, whose healing process is always delayed by multiple factors, including bacterial infections, chronic inflammation, and excessive exudates, etc. Employing multifunctional wound dressings is recognized as an effective strategy to deal with refractory wounds, which has yielded promising outcomes in recent years. Among these advanced wound dressings, fibrous dressings have gained growing attention due to their unique merits. Such wound dressings have demonstrated great potential in delivering theranostic agents, such as antibacterial agents, anti-inflammatory drugs, growth factors, and diagnostic probes, etc., for the purposes of accelerating wound healing. This paper reviews the development of multifunctional fibrous dressings and their applications in treating refractory wounds. The construction approaches of novel fibrous dressing with capabilities of antibacterial, anti-inflammation, exudate management and diagnosis were also introduced. Furthermore, the existing problems and challenges are also discussed briefly.  相似文献   
3.
Xu  Feixiang  Luo  Jiangchen  Jiang  Liqun  Zhao  Zengli 《Cellulose (London, England)》2022,29(3):1463-1472
Cellulose - In this research, the production of levoglucosan (LG) and levoglucosenone (LGO) was improved from acid-impregnated cellulose via fast pyrolysis. Thermogravimetric and kinetic analysis...  相似文献   
4.
Three nonfused ring electron acceptors (NFREAs) TTC6,TT-C8T and TT-TC8 were purposefully designed and synthesized.The molecular geometry can be adjusted by the steric hindrance of lateral substituents.According to the DFT calculations,from TTC6 to TT-C8T and TT-TC8,planarity of the molecular backbone is gradually improved,accompanying with the enhancing of intramolecular charge transfer effect.As for TT-TC8,the two phenyl substituents are almost perpendicular to the molecular backbone,which endues the acceptor with good solubility and suppresses it to form over-aggregation.Multidirectional regular molecular orientation and closer molecular stacking are formed in TT-TC8 film.As a result,TT-TC8 based devices afford the highest PCE of 13.13%,which is much higher than that of TTC6 (4.41%) and TT-C8T (10.42%) and among the highest PCE values based on NFREAs.  相似文献   
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.
7.
International Journal of Theoretical Physics - This paper mainly studied the observer design of Lipschitz stochastic discrete system. For the first time, generalized Lipschitz conditions are...  相似文献   
8.
Wang  Xuebin  Xu  Can  Zheng  Zhigang 《Nonlinear dynamics》2021,103(3):2721-2732
Nonlinear Dynamics - The classical Kuramoto model serves as a useful tool for studying synchronization transitions in coupled oscillators that is limited to the sinusoidal and pairwise...  相似文献   
9.
Li  Y.  Shi  W. H.  Dong  L. M.  Xu  S. X.  Huang  H. J.  Yin  J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,...  相似文献   
10.
Photoelectrochemical (PEC) cytosensors, a combination of the PEC process and the living-cell assay, have emerged as a powerful tool in the analytical and biological science. This mini review provides a brief introduction of this arena and summaries the key steps about the development of PEC cytosensors with representative examples, followed by future prospects based on our own opinions.  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-23

京公网安备 11010802026262号