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   4291篇
  免费   511篇
  国内免费   895篇
化学   2669篇
晶体学   35篇
力学   609篇
综合类   76篇
数学   478篇
物理学   1830篇
  2024年   13篇
  2023年   13篇
  2022年   64篇
  2021年   42篇
  2020年   17篇
  2019年   21篇
  2018年   12篇
  2017年   14篇
  2016年   20篇
  2015年   16篇
  2014年   116篇
  2013年   33篇
  2012年   21篇
  2011年   24篇
  2010年   32篇
  2009年   24篇
  2008年   33篇
  2007年   51篇
  2006年   54篇
  2005年   45篇
  2004年   13篇
  2003年   335篇
  2002年   1416篇
  2001年   1207篇
  2000年   403篇
  1999年   322篇
  1998年   260篇
  1997年   67篇
  1996年   120篇
  1995年   171篇
  1994年   117篇
  1993年   153篇
  1992年   111篇
  1991年   96篇
  1990年   134篇
  1989年   105篇
  1985年   1篇
  1965年   1篇
排序方式: 共有5697条查询结果,搜索用时 758 毫秒
1.
The heterojunction interfacial modulation of FeP is an effective strategy to regulate the intrinsic activity and stability, which is a major challenge to promote the industrial application of FeP-based electrocatalysts. Herein, hollow Fe4C/FeP box with heterojunction interface and carbon armor is successfully synthesized, which can expose numerous active sites and protect catalyst from corrosion. Electrochemical measurements show that Fe4C/FeP exhibits excellent hydrogen ev...  相似文献   
2.
To conquer inherently low conductivity,volume swelling,and labile solid electrolyte interphase (SEI) films of Si anode in lithium ion battery (LIBs),it is widely accepted that appropriate structure design of Si-C hybrids performs effectively,especially for nanosize Si particles.Herein,inspired by the sturdy construction of high-rise buildings,a mansion-like 3D structured Si@SiO2/PBC/RGO (SSPBG) with separated rooms is developed based on 0D core-shell Si@SiO2,1D pyrolytic ba...  相似文献   
3.
A viologen-bearing Zn(Ⅱ) coordination polymer, [Zn(Bpybc)SO4]·H2O, has been successfully synthesized and structurally characterized. The title compound exhibits sunlight and UV-induced photochromism, thermoschromism, and amine-selective chemochromism.  相似文献   
4.
假设^13C是单粒子的2p态的结构,用Glauber多重散射理论研究了入射能量为1GeV的质子在^13C上的弹性散射,得到了与实验符合得很好的理论结果。这说明^13C可能存在着一个类晕的中子皮。  相似文献   
5.
6.
We investigate the nuclear shadowing effect on the K factor in the Drell-Yan process by introducing a Shadowing factor into the corresponding quantum chromodynamical αs order corrections.K factors for Au-Au collisions are calculated at the centre-of-mass system energies √s=60,130 and 200 GeV while the nuclear shadowing factor is taken into account.The numerical results indicate that the nuclear shadowing factor obviously raises the K value in the small x region,and for the same nucleon the K valus becomes smaller as the energy increases.The nuclear shadowing effect could be one reason for creating the non-constancy of the K factor.  相似文献   
7.
We have experimentally realized the Fredkin gate with only three transition pulses in a solution of alanine.It appears that no experimental realization of the Fredkin gate with fewer pulses has been reported yet.In addition,the simple structure of our scheme makes it easy to implement in experiments.  相似文献   
8.
In this paper,we study the generalized coupled Hirota-Satsuma KdV system by using the new generalized transformation in homogeneous balance method.As a result,many explicit exact solutions,which contain new solitary wave solutions,periodic wave solutions,and the combined formal solitary wave solutions,and periodic wave solutions ,are obtained.  相似文献   
9.
The breakthrough and stoichiometric SO2 adsorption efficiencies of a biomass supported Na2CO3 system (80 wt %Na2CO3/straw) have reached 48.9% and 80.6% respectively at a desulfurization temperature of 80℃.  相似文献   
10.
Acetophenone oxime and benzaldehyde oxime were converted to oxime ethers in the presence of alkyl halide or methyl sulfate and KOH in aqueous DMSO in 5 to 70 min. The yields of oxime ethers were 70-96%.  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