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   461篇
  免费   5篇
  国内免费   3篇
化学   325篇
晶体学   6篇
力学   7篇
数学   34篇
物理学   97篇
  2023年   4篇
  2022年   3篇
  2021年   2篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2016年   4篇
  2015年   7篇
  2014年   13篇
  2013年   7篇
  2012年   23篇
  2011年   24篇
  2010年   13篇
  2009年   20篇
  2008年   27篇
  2007年   20篇
  2006年   21篇
  2005年   28篇
  2004年   17篇
  2003年   28篇
  2002年   16篇
  2001年   15篇
  2000年   9篇
  1999年   5篇
  1998年   9篇
  1997年   9篇
  1996年   10篇
  1995年   6篇
  1994年   3篇
  1993年   3篇
  1992年   8篇
  1991年   5篇
  1990年   5篇
  1989年   3篇
  1988年   6篇
  1987年   8篇
  1986年   9篇
  1985年   7篇
  1984年   7篇
  1983年   3篇
  1982年   10篇
  1981年   8篇
  1980年   3篇
  1979年   3篇
  1978年   5篇
  1977年   7篇
  1976年   3篇
  1974年   5篇
  1973年   4篇
  1968年   1篇
排序方式: 共有469条查询结果,搜索用时 15 毫秒
71.
Extraction of actinides like neptunium, plutonium and americium have been performed using polyphosphine polyoxides. Phosphorus compounds with (O)PCP(O) linkage exhibit very high liquid-liquid extraction properties. They demonstrate also quantitative and selective transport properties of some actinides by supported liquid membrane (SLM) technology.  相似文献   
72.
This paper overviews the present state of understanding on properties of the electrode material LiCoO2 as well as the impact of these properties on the electrode performance in lithium batteries. The properties that are important for applications, such as structure, non-stoichiometry, defect chemistry and related electrical properties are considered.  相似文献   
73.
The 29th domestic Chemical Society of Japan Symposium on Heteroatom Chemistry was held in Hiroshima during the period of December 12–14, 2002, under the management of Tetsuo Otsubo of Hiroshima University. About 250 chemists from various academic institutes and industries enjoyed four plenary lectures, 44 oral presentations, and 53 poster presentations. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:387–398, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10186  相似文献   
74.
75.
On leaving 4,4′‐dithiodimorpholine 6 powder undisturbed at room temperature over 10 years, it led to the formation of 4,4′‐tetrathiodimorpholine 7 . Reactions of 2′‐adamantylidene‐9‐benzonorbornenyidene 1 with 6, 7 , and 4,4′‐thiodimorpholine 8 and a Brønsted acid in CH2Cl2 at room temperature proceeded to afford the corresponding thiiranes, 2 and 3 . The order of reactivity of 4,4′‐oligothiodimorpholines combined with a Brønsted acid is 7 > 6 > 8 . The thiirane 3 was transformed to 1 and 2 under the reaction conditions. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:12–18, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20505  相似文献   
76.
Near-field photoluminescence (PL) imaging spectroscopy was used to investigate multi-exciton and charged-exciton states confined in a single GaAs interface fluctuation quantum dot. We determined the origin of peaks in the PL spectra by employing a wavefunction mapping technique. We observed distortion of the exciton wavefunction due to the electric field produced by an excess electron at a nearby confined state. Near-field wavefunction mapping was demonstrated to be a powerful tool for visualizing the local environment, which affects the emission properties of quantum dots.  相似文献   
77.
The anodic performances of Ni/CeO2–Sm2O3(Ni/SDC) modified by the addition of alkaline earth metal oxides (MgO, CaO, and SrO) were investigated for direct oxidation of CH4 in solid oxide fuel cells (SOFCs). Although the initial power density of cell with Ni/SDC anode modified by the addition of CaO was slightly lower than that of cell with Ni/SDC, the former anode exhibited an excellent stability compared to the latter one. Such a high stability of Ni–CaO/SDC anode may come from the inhibition of carbon deposition in addition to the retained ionic conductivity of anode.  相似文献   
78.
A reversed-phase ion-pair liquid chromatographic analysis combined with a solid-phase extraction clean-up method is used to assess the quantity of diphacinone residue found in invertebrates. Three invertebrate species are exposed to commercially available diphacinone-fortified bait used for rat control. The invertebrate samples are collected, frozen, and shipped to the laboratory. The samples are homogenized after cryogenic freezing. A portion of the homogenized samples are extracted with acidified chloroform-acetone, followed by cleanup with a silica solid-phase extraction column. Diphacinone is detected by UV absorption at 325 nm after separation by the chromatographic system. The method limit of detection (MLOD) for snail and slug samples averaged 0.055 and 0.066 mg/kg, respectively. Diphacinone residues in snail tissue ranges from 0.83 to 2.5 mg/kg for Oxychilus spp. The mean recoveries from snails at 0.20 and 2.0 are 97 +/- 21% and 84 +/- 6%. Diphacinone residues in slug tissue ranges from 1.3 to 4.0 mg/kg for Deroceras laeve and < MLOD to 1.8 mg/kg for Limax maximus, respectively. The mean recoveries from slugs at 0.20 and 2.0 mg/kg are 91% +/- 15% and 86% +/- 5%.  相似文献   
79.
Protons of N3, cis-bis(thiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)ruthenium(II), were in situ exchanged on N3-loaded TiO2 films with alkali-metal, tetrabutylammonium, and guanidinium cations. This simple strategy improved the open-circuit photovoltage (V(oc)) significantly, resulting in enhancement of the power conversion efficiency by 10-25%. Electrochemical impedance spectra revealed that the in situ proton exchange of the N3-loaded film suppressed charge recombination between injected electrons and I(3-) ions in the electrolyte, which, together with the negative shift of the conduction band edge for TiO2, may account for the remarkably increased V(oc) upon proton exchange of N3.  相似文献   
80.
Surface pressure (pi)-, surface potential (deltaV)-, and dipole moment (mu(perpendicular))-area (A) isotherms and morphological behavior were examined for monolayers of a newly designed 18-mer amphiphilic alpha-helical peptide (Hel 13-5), DPPC, and DPPC/egg-PC (1:1) and their combinations by the Wilhelmy method, ionizing electrode method, fluorescence microscopy (FM), and atomic force microscopy (AFM). The newly designed Hel 13-5 showed rapid adsorption into the air-liquid interface to form interfacial films such as a SP-B function. Regardless of the composition and constituents in their multicomponent system of DPPC/egg-PC, the collapse pressure (pi(c); approximately 42 mN m(-1)) was constant, implying that Hel 13-5 with the fluid composition of egg-PC is squeezed out of Hel 13-5/DPPC/egg-PC monolayers accompanying a two- to three-dimensional phase transformation. FM showed that adding a small amount of Hel 13-5 to DPPC induced a dispersed pattern of ordered domains with a "moth-eaten" appearance, whereas shrinkage of ordered domains in size occurred for the DPPC/egg-PC mixture with Hel 13-5. Furthermore, AFM indicated that (i) the intermediate phase was formed in pure Hel 13-5 systems between monolayer states and excluded nanoparticles, (ii) protrusions necessarily located on DPPC monolayers, and (iii) beyond the collapse pressure of Hel 13-5, Hel 13-5 was squeezed out of the system into the aqueous subphase. Furthermore, hysteresis curves of these systems nicely resemble those of the DPPC/SP-B and DPPC/SP-C mixtures reported before.  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