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   175884篇
  免费   17388篇
  国内免费   12306篇
化学   94417篇
晶体学   1841篇
力学   12114篇
综合类   683篇
数学   43730篇
物理学   52793篇
  2024年   227篇
  2023年   2062篇
  2022年   2350篇
  2021年   3496篇
  2020年   4210篇
  2019年   3975篇
  2018年   13155篇
  2017年   12690篇
  2016年   10511篇
  2015年   5584篇
  2014年   6223篇
  2013年   8037篇
  2012年   12919篇
  2011年   19600篇
  2010年   12094篇
  2009年   12109篇
  2008年   13068篇
  2007年   14410篇
  2006年   5932篇
  2005年   6031篇
  2004年   5196篇
  2003年   4901篇
  2002年   3686篇
  2001年   2514篇
  2000年   2294篇
  1999年   2255篇
  1998年   1966篇
  1997年   1744篇
  1996年   1723篇
  1995年   1505篇
  1994年   1329篇
  1993年   1120篇
  1992年   982篇
  1991年   857篇
  1990年   712篇
  1989年   570篇
  1988年   439篇
  1987年   397篇
  1986年   392篇
  1985年   317篇
  1984年   230篇
  1983年   194篇
  1982年   166篇
  1981年   118篇
  1980年   107篇
  1979年   69篇
  1978年   57篇
  1973年   42篇
  1914年   45篇
  1909年   41篇
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
1.
Yang  T. L.  Kao  C. L.  Kuo  C. E.  Yeh  H. C.  Li  W. J.  Li  H. T.  Chen  C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the...  相似文献   
2.
Zhang  Hongchi  Liu  Rui  Li  Hui  Yang  Yang  Zhou  Feng 《Chemistry of Natural Compounds》2022,58(3):541-544
Chemistry of Natural Compounds -  相似文献   
3.
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   
4.
Zhang  Bing  Yang  Jie-qin  Liu  Ying  Hu  Bin  Yang  Yang  Zhao  Li  Lu  Qiang 《Cellulose (London, England)》2022,29(12):6565-6578
Cellulose - Heating is essential in various biomass pre-treatments and thermal conversion processes. It is of practical significance to study the characteristics of cellulose-lignin and...  相似文献   
5.
From the implementation point of view, the printable magnetic Janus colloidal photonic crystals (CPCs) microspheres are highly desirable. Herein, we developed a dispensing-printing strategy for magnetic Janus CPCs display via a microfluidics-automatic printing system. Monodisperse core/shell colloidal particles and magnetic Fe3O4 nanoparticles precursor serve as inks. Based on the equilibrium of three-phase interfacial tensions, Janus structure is successfully formed, followed by UV irradiation and self-assembly of colloid particle to generate magnetic Janus CPCs microspheres. Notably, this method shows distinct superiority with highly uniform Janus CPCs structure, where the TMPTA/Fe3O4 hemisphere is in the bottom side while CPCs hemisphere is in the top side. Thus, by using Janus CPCs microspheres with two different structural colors as pixel points, a pattern with red flower and green leaf is achieved. Moreover, 1D linear Janus CPCs pattern encapsulated by hydrogel is also fabricated. Both the color and the shape can be changed under the traction of magnets, showing great potentials in flexible smart displays. We believe this work not only offers a new feasible pathway to construct magnetic Janus CPCs patterns by a dispensing-printable fashion, but also provides new opportunities for flexible and smart displays.  相似文献   
6.
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   
7.
8.
9.
10.
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   
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