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   178122篇
  免费   3053篇
  国内免费   1237篇
化学   93888篇
晶体学   2445篇
力学   7535篇
综合类   52篇
数学   20326篇
物理学   58166篇
  2021年   1465篇
  2020年   1742篇
  2019年   1865篇
  2018年   2226篇
  2017年   2287篇
  2016年   3599篇
  2015年   2243篇
  2014年   3543篇
  2013年   8287篇
  2012年   6561篇
  2011年   7706篇
  2010年   5513篇
  2009年   5503篇
  2008年   7113篇
  2007年   6977篇
  2006年   6562篇
  2005年   5943篇
  2004年   5385篇
  2003年   4789篇
  2002年   4672篇
  2001年   5399篇
  2000年   4035篇
  1999年   3120篇
  1998年   2624篇
  1997年   2458篇
  1996年   2153篇
  1995年   2186篇
  1994年   2164篇
  1993年   2030篇
  1992年   2302篇
  1991年   2242篇
  1990年   2188篇
  1989年   2089篇
  1988年   2105篇
  1987年   2096篇
  1986年   1996篇
  1985年   2613篇
  1984年   2652篇
  1983年   2323篇
  1982年   2464篇
  1981年   2265篇
  1980年   2242篇
  1979年   2400篇
  1978年   2441篇
  1977年   2383篇
  1976年   2429篇
  1975年   2352篇
  1974年   2316篇
  1973年   2485篇
  1972年   1602篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
1.
2.
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   
3.
Kinetics and Catalysis - The results of studies in the field of synthesis and characterization of layered double hydroxides (LDHs) obtained using solid-phase reactions are summarized. The effect of...  相似文献   
4.
Journal of Structural Chemistry - A new polymorph of the [ReCl3(MeCN)(PPh3)2] complex is synthesized and characterized by single crystal X-ray diffraction (XRD). Its recrystallization from the...  相似文献   
5.
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   
6.
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The...  相似文献   
7.

A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.

  相似文献   
8.
Mathematical Physics, Analysis and Geometry - In this paper, we develop the dressing method to study the modified Camassa-Holm equation with the help of reciprocal transformation and the associated...  相似文献   
9.
Optics and Spectroscopy - The current–voltage characteristics and photocurrent of “monolithic” diode optical pairs optically coupled by a substrate made of InAs common for them...  相似文献   
10.
Van’kov  A. B.  Kukushkin  I. V. 《JETP Letters》2021,113(2):102-114
JETP Letters - Extraordinary multiparticle effects in quantizing magnetic fields that are manifested in strongly interacting two-dimensional electron systems in MgZnO/ZnO heterostructures have been...  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