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   223篇
  免费   15篇
  国内免费   3篇
化学   176篇
力学   8篇
数学   23篇
物理学   34篇
  2023年   2篇
  2022年   5篇
  2021年   10篇
  2020年   9篇
  2019年   9篇
  2018年   5篇
  2017年   6篇
  2016年   9篇
  2015年   8篇
  2014年   11篇
  2013年   14篇
  2012年   28篇
  2011年   18篇
  2010年   2篇
  2009年   16篇
  2008年   10篇
  2007年   11篇
  2006年   8篇
  2005年   9篇
  2004年   10篇
  2003年   5篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1999年   2篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1993年   1篇
  1992年   3篇
  1990年   1篇
  1986年   1篇
  1985年   2篇
  1983年   1篇
  1981年   1篇
  1979年   1篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1958年   4篇
排序方式: 共有241条查询结果,搜索用时 375 毫秒
21.
We will study circle actions on Cuntz–Krieger algebras trivially acting on its canonical maximal abelian \(C^*\)-subalgebras from the view points of continuous orbit equivalence of one-sided topological Markov shifts and flow equivalence of two-sided topological Markov shifts.  相似文献   
22.
23.
24.
The current-voltage characteristics of layered organic crystals theta-(BEDT-TTF)2MZn(SCN)4 (M = Cs, Rb) follow the power law with a large exponent (e.g., 8.4 at 0.29 K for M = Cs) over a wide range of currents in the low-temperature insulating state. The power-law characteristics are attributed to electric field-induced unbinding of electron-hole pairs that are thermally excited in the background of the two-dimensional charge order. The magnitude of crossover electric fields from Ohmic to the power-law characteristics indicates that the electron-electron Coulomb interaction is significantly long-ranged: The screening length is greater than 10 molecule sites.  相似文献   
25.
26.
27.
A stereoselective synthesis of scyphostatin hydrophilic moiety was accomplished. Substrate- and reagent-controlled dihydroxylation of tri- and monosubstituted alkenes afforded desired diols, respectively. Chemo- and stereoselective allylation of α-(methoxycarbonyl)cyclohexanone provided allylcyclohexanol. Oxidative cleavage of glycol and subsequent β-elimination of siloxycyclohexanone furnished the desired epoxycyclohexenone.  相似文献   
28.
Fujii  Kengo  Yasugi  Masaki  Maekawa  Satoshi  Yamamoto  Hirotsugu 《Optical Review》2022,29(3):250-260
Optical Review - This paper proposes a novel steganography method to show an aerial image that is formed with aerial imaging by retro-reflection by use of dual transparent balls made of acrylic...  相似文献   
29.
Utilization of biocatalysts with high accessibility and availability, which have recently been applied in the preparation of enantiomerically enriched starting materials and synthetic intermediates for natural product syntheses (mainly 2013–2017) are summarized in this review. The main contents are as follows: 1) recruitment of biocatalysts for the transformation of organic compounds; 2) special precautions for preparative-scale biocatalytic synthetic experiments; 3) asymmetric reduction of carbonyl substrates; 4) kinetic resolution of alcohol and carboxylate enantiomers; 5) desymmetrization of multifunctional alcohol and carboxylate substrates; and 6) recognition of remote and non-central chirality.  相似文献   
30.
An antioxidative liposome catalysis that mimics both superoxide dismutase (SOD) and peroxidase (POD) activities has been developed by using the liposomes modified with lipophilic Mn-(5,10,15,20-tetrakis[1-hexadecylpyridium-4-yl]-21H,23H-porphyrin) (Mn-HPyP). The SOD- and POD-like activities of the Mn-HPyP-modified liposome were first investigated by varying the type of phospholipid, such as 1,2-distearyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). Higher SOD-like activity was obtained in the case of DLPC and DMPC liposomes, in which the ligands were well-dispersed on the membrane in the liquid crystalline phase. The POD-like activity was maximal in the case of DMPC liposome, in which the Mn-HPyP complex was appropriately clustered on the membrane in the gel phase. On the basis of the above results, the co-induction of the SOD and POD activities to eliminate the superoxide and also hydrogen peroxide as a one-pot reaction was finally performed by using the Mn-HPyP-modified DMPC liposome, resulting in an increase in the efficiency of the elimination of both superoxide and hydrogen peroxide.  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