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91.
Selective pyrolytic deprotection of 2‐ethyl and 2‐cyanoethyl‐4‐arylidenimino‐1,2,4‐triazol‐3(2H)‐ones and their 3(2H)‐thiones was studied by flash vacuum pyrolysis. This study is useful in regioselective synthesis of 2‐ and 4‐substituted 1,2,4‐triazoles of potential biological applications. The kinetic results and product analysis lend support to a reaction pathway involving a six‐membered transition state. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:50–55, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10086 相似文献
92.
Takeshi Yamazaki Dr. Hicham Fenniri Prof. Dr. Andriy Kovalenko Prof. Dr. 《Chemphyschem》2010,11(2):361-367
We reveal how water solvent determines the self‐assembly pathway and stability of organic rosette nanotubes (RNTs) and show their possible functions, using three‐dimensional molecular theory of solvation (a.k.a. 3D‐RISM). Structural water molecules penetrate the pockets on the RNT outer surface, form a wetting monolayer in the RNT channel and bridge RNT rosettes. We predict that the inner water shell might stabilize rare gas atoms inside the RNT channel, and envision molecular devices with RNT channels transporting water or holding guest molecules for targeted delivery. 相似文献
93.
Fabio Mazzotti Hicham Benabdelkamel Leonardo Di Donna Constantinos M. Athanassopoulos Anna Napoli Giovanni Sindona 《Journal of mass spectrometry : JMS》2012,47(7):932-939
5‐Dimethylamino‐1‐sulfonyl naphthalene (DNS, commonly referred as dansyl) is a functionality, bearing well‐established properties in directing the fragmentation, by mass spectrometry (MS), of the corresponding ionized sulfonylated derivatives. This property is shared also by its labeled analogs. The use of d0/d6 DNS derivatives is now exploited in the application of the well‐established isotope dilution mass spectrometric approach in the assay of complex mixtures. A new method for the quantitation of amino acids (AAs) in beverages is therefore presented, which relies on liquid chromatographic separation of their N‐dansylated derivatives followed by comparative electrospray tandem MS/MS of the d0/d6 isobaric mixtures. Labeled and unlabeled DNS derivatives of the selected AAs are readily available by microwave‐assisted synthetic protocols. The novelty of the method is represented by the use of heavy and light DNS‐isotopologue providing suitable reporter groups. Multiple‐reaction monitoring has been applied in the assay of AAs in wine, pineapple juice and bergamot juice with good‐to‐excellent results as proved by both relative standard deviation, lower than 15%, and by the accuracy values in the range 90–110%. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
94.
Abdallah Chahadih Hicham El Hamzaoui Rémy Bernard Laurence Bois Franc Beclin Odile Cristini Bruno Capoen Mohamed Bouazaoui 《Journal of nanoparticle research》2011,13(12):6507-6515
Direct space-selective growth of PbS nanoparticles, embedded inside a transparent porous sol–gel derived silica matrix, has
been achieved using continuous laser irradiation. Before the irradiation, the porous silica host has been soaked in a PbS
precursor solution. The effect of the concentration of PbS precursors and of the incident laser power on the mean particle
size was studied. Absorption spectroscopy, X-ray diffraction analysis, and TEM measurements were used to identify the PbS
crystallites inside the xerogel and to estimate the average particle size. It has been shown that PbS crystallite sizes range
between 3 and 13 nm depending on the PbS precursors concentration. 相似文献
95.
Frontispiece: Surface Functionalization of g‐C3N4: Molecular‐Level Design of Noble‐Metal‐Free Hydrogen Evolution Photocatalysts
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96.
Substitutional self-assembly of nonanedithiol from a hexanethiol self-assembled monolayer and the effects of use of ethanol and n-hexane as solvents were investigated. It was found that presence of original solvents in the HT SAM allowed easy replacement, while dried SAMs were more resilient to substitution and much longer times are necessary for substitution to occur. In general substitution in ethanol leads to production of a disordered dithiol SAM, with existence of extra molecules bonded to the SAM. Well ordered substituted SAMs were obtained with degassed n-hexane solutions and in absence of ambient light. 相似文献
97.
Surface Functionalization of g‐C3N4: Molecular‐Level Design of Noble‐Metal‐Free Hydrogen Evolution Photocatalysts
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Dr. Yin Chen Dr. Bin Lin Dr. Weili Yu Prof. Yong Yang Shahid M. Bashir Dr. Hong Wang Prof. Kazuhiro Takanabe Prof. Hicham Idriss Prof. Jean‐Marie Basset 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10290-10295
A stable noble‐metal‐free hydrogen evolution photocatalyst based on graphite carbon nitride (g‐C3N4) was developed by a molecular‐level design strategy. Surface functionalization was successfully conducted to introduce a single nickel active site onto the surface of the semiconducting g‐C3N4. This catalyst family (with less than 0.1 wt % of Ni) has been found to produce hydrogen with a rate near to the value obtained by using 3 wt % platinum as co‐catalyst. This new catalyst also exhibits very good stability under hydrogen evolution conditions, without any evidence of deactivation after 24 h. 相似文献
98.
Pasquali L Terzi F Seeber R Nannarone S Datta D Dablemont C Hamoudi H Canepa M Esaulov VA 《Langmuir : the ACS journal of surfaces and colloids》2011,27(8):4713-4720
We report a study of the self-assembly of 1,4-benzenedimethanethiol monolayers on gold formed in n-hexane solution held at 60 °C for 30 min and in dark conditions. The valence band characteristics, the thickness of the layer, and the orientation of the molecules were analyzed at a synchrotron using high resolution photoelectron spectroscopy and near edge X-ray adsorption spectroscopy. These measurements unambiguously attest the formation of a single layer with molecules arranged in the upright position and presenting a free -SH group at the outer interface. Near edge X-ray absorption fine structure (NEXAFS) measurements suggest that the molecular axis is oriented at 24° with respect to the surface normal. In addition, valence band features could be successfully associated to specific molecular orbital contributions thanks to the comparison with theoretically calculated density of states projected on the different molecular units. 相似文献
99.
MANSOURI Said MAJDOUBI Hicham HADDAJI Younesse TAMRAOUI Youssef EL ACHABY Mounir MANOUN Bouchaib ABOURRICHE Abdelkrim HANNACHE Hassan OUMAM Mina 《高等学校化学研究》2020,36(6):1339-1347
This paper discusses the elaboration of adsorbents from oil shale. The experimental designs a response surface methodology(RSM), which has been applied to optimize the significant preparation factors, such as temperature, time, and the activating agent percentage. The results obtained from central composite design(CCD) revealed that the interaction between the factors was significant for the maximum quantity of adsorption(response). Planned results have shown that a maximum quantity of adsorption for methylene blue is 65 mg/g, which could be achieved with a temperature of 275℃ over 2 h and a percentage of the activating agent of 45%. The predicted values agreed with the experimental finding, with a determination coefficient(R2) of 0.96. The model has been validated by experiments after conditions optimization. The new material(RHO) was characterized by cation exchange capacity, zero charge pH, surface functions, X-ray fluorescence, specific surface area, and electron microscopy analysis. Phenol adsorption was determined using Langmuir, Freundlich and Temkin, which were used to describe the adsorption isotherms. The adsorption capacity of the material was about 263 mg/g, and the kinetic studies showed rapid adsorption. 相似文献
100.
This work reports a comprehensive electroanalytical study of carbon nanohorns (CNHs) in electrochemical applications. Compared to other types of carbons, the bare CNHs electrode exhibited higher peak current densities and lowest anodic peak‐to‐cathodic peak separation of less than 50 mV for the [Fe(CN)4?]6/[Fe(CN)3?]6 redox couple. Furthermore, CNHs exhibited excellent electrocatalyst supporting properties for porous Pt film towards methanol oxidation reaction reaching a peak current density of 127 mA cm?2 or peak current mass activity 184 mA mgPt?1. Regarding oxygen reduction reaction, an onset potential as positive as 0. 77 V vs. Ag/AgCl was achieved with CNHs/porous Pt film. 相似文献