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41.
42.
Lucija Juki Simon Re
nik Jurij Svete Branko Stanovnik Simona Goli Grdadolnik 《Journal of heterocyclic chemistry》2001,38(4):859-868
Alkyl (Z)‐2‐[(E)‐2‐ethoxycarbonyl‐2‐(2‐pyridinyl)ethenyl]amino‐3‐dimethylaminopropenoates 7 and 8 were prepared from ethyl 2‐pyridinylacetate (1) in two steps. Substitution of the dimethylamino group with alkyl‐, aryl‐, or heteroarylamines afforded the corresponding β‐alkyl‐ 22–24 , β‐aryl‐ 25–35 , and β‐herteroaryl‐amino‐α,β‐didehydro‐α‐amino acid 36 and 37 derivatives, intermediates for further preparation of various heterocyclic systems. The orientation around both double bonds were determined by various nmr techniques. 相似文献
43.
Barbara Modec Jurij V. Bren
i
Ljubo Goli
《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):780-782
The Mo atoms in the title compounds, i.e. triethylammonium cis‐tetrachlorobis(4‐ethylpyridine‐N)molybdate(III), cis‐(C6H16N)[MoCl4(C7H9N)2], and trans‐tetrachlorobis(4‐ethylpyridine‐N)molybdenum(IV), trans‐[MoCl4(C7H9N)2], are six‐coordinate with octahedral geometry. The Mo atom in the latter complex lies on a site with crystallographic 2/m symmetry. 相似文献
44.
The interparticle forces for a 3-body system in scalar QFT with nonlinear mediating fields are shown to be confining. 相似文献
45.
Like-charged surfaces are able to attract each other if they are embedded in an electrolyte solution of multivalent rodlike ions, even if the rods are long. To reproduce this ability the Poisson-Boltzmann model has recently been extended so as to account for the rodlike structure of the mobile ions. Our model properly accounts for intraionic correlations but still neglects correlations between different rodlike ions. For sufficiently long rods, the model shows excellent agreement with Monte Carlo simulations and exhibits two minima - a depletion and a bridging minimum - in the interaction free energy. In the present work, we generalize the Poisson-Boltzmann model to systems with polydisperse rod lengths and arbitrary charge distributions along the rods, including the presence of salt. On the level of the linearized Debye-Hu?ckel model we derive a general criterion for whether an electrolyte with given distribution of rodlike ions is able to mediate attraction between like-charged surfaces. We numerically analyze two special cases, namely the influence of salt on symmetric and asymmetric mixtures of monodisperse rodlike ions. The symmetric mixture is characterized by the presence of both negatively and positively charged (but otherwise identical) rodlike ions. For the asymmetric mixture, the system contains rodlike ions of only one type. We demonstrate that the addition of salt retains the depletion minimum but tends to eliminate the bridging minimum. 相似文献
46.
A Simple Synthesis of Polyfunctionalized 4‐Aminopyrazolidin‐3‐ones as ‘Aza‐deoxa’ Analogs of D‐Cycloserine 下载免费PDF全文
Ana Novak Matej Štefanič Uroš Grošelj Martina Hrast Marta Kasunič Stanislav Gobec Branko Stanovnik Jurij Svete 《Helvetica chimica acta》2014,97(2):245-267
A simple five‐step synthesis of fully substituted (4RS,5RS)‐4‐aminopyrazolidin‐3‐ones as analogs of D ‐cycloserine was developed. It comprises a two‐step preparation of 5‐substituted (4RS,5RS)‐4‐(benzyloxycarbonylamino)pyrazolidin‐3‐ones, reductive alkylation at N(1), alkylation of the amidic N(2) with alkyl halides, and simultaneous hydrogenolytic deprotection/reductive alkylation of the primary NH2 group. The synthesis enables an easy stepwise functionalization of the pyrazolidin‐3‐one core with only two types of common reagents, aldehydes (or ketones) and alkyl halides. The structures of products were elucidated by NMR spectroscopy and X‐ray diffraction. 相似文献
47.
Dr. Bojan Šarac Prof. Dr. Marija Bešter‐Rogač Prof. Dr. Jurij Lah 《Chemphyschem》2014,15(9):1827-1833
Differential scanning calorimetry (DSC), the most important technique for studying the thermodynamics of structural transitions of biological macromolecules, is seldom used in quantitative thermodynamic studies of surfactant micellization/demicellization. The reason for this could be ascribed to an insufficient understanding of the temperature dependence of the heat capacity of surfactant solutions (DSC data) in terms of thermodynamics, which leads to problems with the design of experiments and interpretation of the output signals. We address these issues by careful design of DSC experiments performed with solutions of ionic and nonionic surfactants at various surfactant concentrations, and individual and global mass‐action model analysis of the obtained DSC data. Our approach leads to reliable thermodynamic parameters of micellization for all types of surfactants, comparable with those obtained by using isothermal titration calorimetry (ITC). In summary, we demonstrate that DSC can be successfully used as an independent method to obtain temperature‐dependent thermodynamic parameters for micellization. 相似文献
48.
Uroš Grošelj Črtomir Podlipnik Jure Bezenšek Jurij Svete Branko Stanovnik Dieter Seebach 《Helvetica chimica acta》2013,96(10):1815-1821
Replacement of the cis‐Me group by CH2F in the imidazolidinone organocatalyst specified in the title (so‐called McMillan generation‐I catalyst) leads to reversal of the product configuration in the title reaction. The topicity reversal in the nucleophilic addition step must arise either from cis‐addition with respect to the benzylic substituent of an (E)‐iminium ion intermediate or from trans‐addition to the corresponding (Z)‐iminium ion. Mechanistic investigations have not provided evidence for either one of these two possibilities, so far. 相似文献
49.
Uroš Grošelj Amalija Golobič Damijan Knez Martina Hrast Stanislav Gobec Sebastijan Ričko Jurij Svete 《Molecular diversity》2016,20(3):667-676
The synthesis of two novel (+)-isocampholenic acid-derived amines has been realized starting from commercially available (1S)-(+)-10-camphorsulfonic acid. The novel amines as well as (+)-isocampholenic acid have been used as building blocks in the construction of a library of amides using various aliphatic, aromatic, and amino acid-derived coupling partners using BPC and CDI as activating agents. Amide derivatives have been assayed against several enzymes that hold potential for the development of new drugs to battle bacterial infections and Alzheimer’s disease. Compounds 20c and 20e showed promising selective sub-micromolar inhibition of human butyrylcholinesterase \((h\hbox {BChE})\) (\(\hbox {IC}_{50}\) values \(0.80\,\pm 0.05\) and \(0.25\,\pm 0.02\,{\upmu }\hbox {M}\), respectively). 相似文献
50.
Malavasic C Brulc B Cebasek P Dahmann G Heine N Bevk D Groselj U Meden A Stanovnik B Svete J 《Journal of combinatorial chemistry》2007,9(2):219-229
Solution-phase combinatorial synthesis of (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxamides was studied. First, di-tert-butyl (2S,4S)-4-amino-5-oxopyrrolidine-1,2-dicarboxylate hydrochloride was prepared as the key intermediate in five steps from (S)-pyroglutamic acid. Acylation of the amino group followed by acidolytic deprotection gave (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxylic acids, which were then coupled with amines to furnish a library of (2S,4S)-4-acylamino-5-oxopyrrolidine-2-carboxamides. Four coupling reagents, BPC, EEDQ, TBTU, and PFTU, were tested for the amidation reactions in the final step. Amidations with EEDQ and TBTU led to the desired carboxamides. On the other hand, BPC and PFTU were not suited, since diketopiperazines were sometimes obtained instead of the desired carboxamides. 相似文献