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   381篇
  免费   29篇
化学   301篇
晶体学   1篇
力学   4篇
数学   29篇
物理学   75篇
  2023年   5篇
  2022年   5篇
  2021年   6篇
  2020年   13篇
  2019年   5篇
  2018年   5篇
  2017年   4篇
  2016年   8篇
  2015年   15篇
  2014年   14篇
  2013年   29篇
  2012年   25篇
  2011年   18篇
  2010年   17篇
  2009年   19篇
  2008年   28篇
  2007年   21篇
  2006年   27篇
  2005年   17篇
  2004年   22篇
  2003年   26篇
  2002年   21篇
  2001年   6篇
  2000年   9篇
  1999年   8篇
  1998年   9篇
  1997年   4篇
  1996年   4篇
  1995年   5篇
  1994年   2篇
  1993年   4篇
  1992年   1篇
  1988年   1篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1943年   1篇
  1912年   1篇
排序方式: 共有410条查询结果,搜索用时 437 毫秒
21.
22.
A water‐soluble template‐assembled synthetic G‐quartet (TASQ) based on the use of a macrocyclodecapeptide scaffold was designed to display stable intramolecular folds alone in solution. The preformation of the guanine quartet, demonstrated by NMR and CD investigations, results in enhanced peroxidase‐type biocatalytic activities and improved quadruplex‐interacting properties. Comparison of its DNAzyme‐boosting properties with the ones of previously published TASQ revealed that, nowadays, it is the best DNAzyme‐boosting agent.  相似文献   
23.
In plane parallel arrangement and enhancement of NLO-activity are observed upon coordination of heteroditopic dipoles containing a phosphole ring on square-planar d8-palladium centre.  相似文献   
24.
A series of podands based on three hydrogen bonding 'arms' have been prepared and their affinities for simple inorganic anions measured.  相似文献   
25.
In this paper, we present the different theoretical line profiles, which can be used to describe a shape of molecular transitions in dilute gases: the Voigt, Galatry, Rautian and speed dependence models. We discuss their limitations and their advantages, and present for illustration different comparisons of model results with experimental data obtained with several diode laser spectrometers suitable for precise line shape measurements.  相似文献   
26.
Using a tunable diode-laser spectrometer, we have measured at room temperature the H2-broadening coefficients of for 36 lines belonging to QP and QR branches in the ν3 parallel band. The recorded lines with J values ranging from 1 to 15 and K from 0 to 9 (K?J) are located between 1196 and 1412 cm−1. The H2-broadening coefficients were determined by fitting each spectral line with Voigt, Rautian, and Galatry profiles. They were also calculated on the basis of a semiclassical model of interacting linear molecules performed by considering in addition to the weak electrostatic contributions the atom-atom Lennard-Jones potential. The theoretical results are in reasonable agreement with the experimental data, except for high J transitions where they are overestimated and for K approaching or equal to J with J?3 where they are underestimated. The latter discrepancy may be caused by the assumption to consider only ΔK=0 collision-induced transitions, associated with |ΔJ| transitions up to 4.  相似文献   
27.
Room temperature phosphorescence has been observed in a synthetically facile Pt(II) complex, Pt(dbbpy)(CtriplebondC-pyrene)(2) (dbbpy = 4,4'-di(tert-butyl)-2,2'-bipyridine; CtriplebondC-pyrene = 1-ethynylpyrene), in fluid solution. The static and time-resolved absorption and luminescence data are consistent with phosphorescence emerging from the appended CtriplebondC-pyrenyl units following excitation into the low energy dpi Pt --> pi* dbbpy metal-to-ligand charge transfer absorption bands.  相似文献   
28.
On the framework of coherence theory we discuss the averaged temporal intensity output provided by real-time optical Fourier transformers when the spectral line shape of the stationary source is considered. Some numerical examples are given and the deviations from perfectly monochromatic sources are pointed out.  相似文献   
29.
In this paper, we investigate the properties of porous structures anodically grown onto n-InP (100) in HCl. In situ electrochemical characterizations show the pore morphology strongly influences the properties of the InP surfaces. Both dc- and ac-electrochemical measurements reveal an enhancement of the capacitive current and a modification of the electronic distribution at the interface. Photocurrent spectra performed during the pore growth are also strongly modified. For low anodic charges, an increase of the photocurrent with a redshift of the absorption edge is measured. These evolutions can be respectively ascribed (i) to a reflection decrease due to a surface roughening and (ii) to the creation of surface states within the band gap. For higher anodic charges, the photocurrent drops with a narrowing of the spectrum. Using a model based on the “dead” layer, the porous layer is considered as an absorbent film that progressively attenuates the photocurrent of the bulk semiconductor.  相似文献   
30.
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