全文获取类型
收费全文 | 96篇 |
免费 | 2篇 |
国内免费 | 5篇 |
专业分类
化学 | 68篇 |
晶体学 | 1篇 |
数学 | 15篇 |
物理学 | 19篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 12篇 |
2012年 | 3篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1996年 | 7篇 |
1994年 | 2篇 |
1982年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有103条查询结果,搜索用时 46 毫秒
61.
Ramona Enea Ana-Maria Resmeriţă Laura Petraru Cristian Grigoraş Dan Scutaru Cristofor I. Simionescu Nicolae Hurduc 《Central European Journal of Chemistry》2007,5(4):981-995
This paper presents the syntheses, characterization and photochromic behavior of some new azo-polysiloxanes modified with
uracil, cytosine or nitro-phenolic groups. Taking into consideration the possibility of generating H-bonds or donor/acceptor
interactions, this class of materials present a potential applicability in the immobilization of biomolecules and their nano-manipulations.
Also, such compounds are capable of producing a fluid phase, with directional flowing capacity. For all these polymers, the
molecular modeling simulations have shown disordered structures, which would generate amorphous phases, a very important aspect
for molecules’ nano-manipulation. The photochromic behavior in the presence of UV irradiation was also evaluated.
相似文献
62.
Oana Cătălina Mocioiu Maria Zaharescu Irina Atkinson Ana-Maria Mocioiu Petru Budrugeac 《Journal of Thermal Analysis and Calorimetry》2014,117(1):131-139
The crystallization process of some glasses in the ternary Na2O–SiO2–PbO system with good chemical stability that can be used for waste inertization was studied using X-ray diffraction (XRD), infrared spectroscopy (FT-IR), differential thermal analysis (DTA) and scanning electron microscopy. The parent glasses were characterized by XRD and FT-IR, and their vitreous state was determined. DTA measurements evidenced glass transition (T g) and crystallization temperatures (T c). The thermal treatments were conducted at vitreous transition temperature (400 °C) and at highest effect of crystallization (650 °C). XRD evidenced the lead and sodium silicate crystalline phases in samples treated at 650 °C for 12 h. Micrometer crystallites dispersed in the glass matrices have affected the transparence of glasses and made them opaque after treatment at 650 °C. The influence of oxide quantities in compositions on the crystallization tendency was revealed. A PbO higher content than that of SiO2 as well as lower Na2O content decreased the tendency of crystallization. 相似文献
63.
POPESCU Ana-Maria 《高等学校化学研究》2014,(5):800-805
This study deals with SnO2-based ceramic anodes doped with Sb203 and CuO, aiming at contributing new data regarding their electrochemical behavior in cryolite melts. The performances of the anodes were evaluated by anodic polarization, cyclic voltammetry, and current efficiency and corrosion measurements. The investigation proves that the anodic process of SnO2-based inert anodes occurs at a low overvoltage and the oxygen discharge takes place in one step with an exchange of two electrons. The current efficiency and corrosion were proved to be dependent on the electrolysis parameters and composition of electrolysis bath. For a long term electrolysis, the dissolution of the anode in the cryolite-alumina melt produced small aluminium contamination(ca. 0.2%, mass fraction). 相似文献
64.
The influence of the evaporation of a little amount of the target material on the air breakdown is sometimes mainly due to an initial change in density. The estimations are in agreement with the performed experiments on Li, K, Sr targets with CO2-TEA laser. 相似文献
65.
Vladimir?Iancu Mihai?Razvan?Mitroi Ana-Maria?Lepadatu Ionel?Stavarache Magdalena?Lidia?CiureaEmail author 《Journal of nanoparticle research》2011,13(4):1605-1612
The quantum efficiency of the absorption on quantum confinement levels is investigated. This is achieved by modeling the electron
confinement in a spherical quantum dot (QD). The confinement levels are calculated using both infinite and finite rectangular
quantum wells. The spectral internal quantum efficiency is evaluated within both the models, by computing Einstein’s coefficients
for the transitions between confinement levels. The size of QDs (1–3 nm radius) leads to negligible many body effects. The
nature of the QD material and of the matrix embedding is taken into account in the finite rectangular quantum well approximation
and introduces only a small correction. The temperature dependence of the efficiency is also taken into account. A numerical
application is performed for a silicon QD of 2.5 nm radius, embedded in amorphous silica. It is proved that the absorption
threshold shifts toward the far infrared limit and that the spectral internal quantum efficiency reaches 4–5% at the threshold. 相似文献
66.
Prosenjak C Banu AM Gellan AD Düren T 《Dalton transactions (Cambridge, England : 2003)》2012,41(14):3974-3984
Thermal desorption spectra of a number of metal-organic frameworks were studied using grand canonical Monte Carlo simulation. Our simulation results are in qualitative agreement with experimental results but also show that great care must be taken when choosing the force field to describe the hydrogen/framework interaction. As the simulations additionally yield the positions and potential energies of the adsorbed molecules it is straightforward to assign the peaks and features in the thermal desorption spectra to specific adsorption sites. We show that the location of the peaks is directly related to the hydrogen-framework interaction which is a complex function of the chemical and topological environment of the pore space, the pore size and the presence of specific interaction sites such as open metal sites. Finally, we demonstrate that an IRMOF-8 sample used to obtain an experimental thermal desorption spectrum must have indeed been catenated as previously suspected. Overall, molecular simulation is a useful tool to complement the interpretation of experimental thermal desorption spectra. 相似文献
67.
Speranta Avram Ana Maria Udrea Diana Camelia Nuta Carmen Limban Adrian Cosmin Balea Miron Teodor Caproiu Florea Dumitrascu Ctlin Buiu Alexandra Teodora Bordei 《Molecules (Basel, Switzerland)》2021,26(14)
(1) Background: The research aims to find new treatments for neurodegenerative diseases, in particular, Alzheimer’s disease. (2) Methods: This article presents a bioinformatics and pathology study of new Schiff bases, (EZ)-N′-benzylidene-(2RS)-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide derivatives, and aims to evaluate the drug-like, pharmacokinetic, pharmacodynamic and pharmacogenomic properties, as well as to predict the binding to therapeutic targets by applying bioinformatics, cheminformatics and computational pharmacological methods. (3) Results: We obtained these Schiff bases by condensing (2RS)-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide with aromatic aldehydes, using the advantages of microwave irradiation. The newly synthesized compounds were characterized spectrally, using FT-IR and NMR spectroscopy, which confirmed their structure. Using bioinformatics tools, we noticed that all new compounds are drug-likeness features and may be proposed as potentially neuropsychiatric drugs (4) Conclusions: Using bioinformatics tools, we determined that the new compound 1e had a high potential to be used as a good candidate in neurodegenerative disorders treatment. 相似文献
68.
Teodor Adrian Enache Ana-Maria Chiorcea-Paquim Orlando Fatibello-Filho Ana Maria Oliveira-Brett 《Electrochemistry communications》2009,11(7):1342-1345
The hydroxyl radicals electrochemically generated in situ on a boron-doped diamond (BDD) electrode have been investigated for the first time in different electrolyte media, over the whole pH range between 1 and 11. A more extensive characterisation of BDD electrochemical properties is very important to understand the reactivity of organic compounds towards electrochemical oxidation on the BDD electrode, which is related to their interaction with adsorbed hydroxyl radicals due to water oxidation on the electrode surface. An oxidation peak corresponding to the transfer of one electron and one proton was observed in pH <9 electrolytes, associated with the water discharge process and electrochemical generation of hydroxyl radicals, which can interact and enhance the electro-oxidation of organic compounds. In pH >9 electrolytes the electrochemical generation of hydroxyl radicals was not observed; ammonia buffer electrolyte gave a pH-independent peak corresponding to the ammonia oxidation reaction. Additionally, for most pH values studied, a few small peaks associated with the electrochemical interaction between non-diamond carbon species on the doped diamond electrode surface and the electrolyte were also seen, which suggests that the doped diamond is relatively unreactive, but not completely inert, and the electrogenerated hydroxyl radicals play a role as mediator in the oxidation of organics. 相似文献
69.
Absorption and steady state fluorescence study of interaction between eosin and bovine serum albumin 总被引:2,自引:0,他引:2
Birla L Cristian AM Hillebrand M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(3):551-556
The interaction between eosin and bovine serum albumin in buffer solution, at pH 7.4 has been studied by means of absorption and emission spectroscopy. Applying the Scatchard model to the absorbance data a non-linear plot was obtained, reflecting a complex process. In the fluorescence spectra, two distinct effects were observed. Upon increasing the protein-dye ratio to about 0.60, the intensity of eosin emission band (544 nm) decreases to approximately 30% of its initial value. During this quenching, a small red shift is noticed. The data were rationalized in terms of two classes of binding sites. At higher protein concentrations, a new band localized at 556 nm appears, which could be assigned to a new fluorescent species. This second process corresponds to a 1:1 binding. 相似文献
70.
The surface of alumina supported catalysts containing 10 wt.% metal (Fe and/or Ni) has been spectroscopically investigated by CO adsorption. The stretching vibration range characteristic for CO bonded to metallic species shows very large absorptions, indicating a high surface heterogeneity. A certain FeNi stoichiometry seems to impose the reduction extent and the catalytic properties. 相似文献