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91.
Muhammad Ahsan Bashir Mohammad Al‐haj Ali Vasileios Kanellopoulos Jukka Seppälä Esa Kokko Sameer Vijay 《大分子反应工程》2013,7(5):193-204
The dependence of predictive capabilities of SL EOS on the pure characteristic parameters of monomers and polymers is investigated. A sensitivity analysis study is carried out to understand the effect of these parameters on the predictive capability of SL EOS for different α‐olefin/polyolefins systems. Among all pure component characteristic parameters, the monomer characteristic temperature (T*monomer) has the largest impact on SL EOS predictive capability; whereas the polymer characteristic density (ρ*polymer) is found to have the smallest impact.
92.
Askoxylakis V Zitzmann-Kolbe S Zoller F Altmann A Markert A Rana S Marr A Mier W Debus J Haberkorn U 《Molecules (Basel, Switzerland)》2011,16(2):1559-1578
The transfer of peptides identified through the phage display technology to clinical applications is difficult. Major drawbacks are the metabolic degradation and label instability. The aim of our work is the optimization of DUP-1, a peptide which was identified by phage display to specifically target human prostate carcinoma. To investigate the influence of chelate conjugation, DOTA was coupled to DUP-1 and labeling was performed with 111In. To improve serum stability cyclization of DUP-1 and targeted D-amino acid substitution were carried out. Alanine scanning was performed for identification of the binding site and based on the results peptide fragments were chemically synthesized. The properties of modified ligands were investigated in in vitro binding and competition assays. In vivo biodistribution studies were carried out in mice, carrying human prostate tumors subcutaneously. DOTA conjugation resulted in different cellular binding kinetics, rapid in vivo renal clearance and increased tumor-to-organ ratios. Cyclization and D-amino acid substitution increased the metabolic stability but led to binding affinity decrease. Fragment investigation indicated that the sequence NRAQDY might be significant for target-binding. Our results demonstrate challenges in optimizing peptides, identified through phage display libraries, and show that careful investigation of modified derivatives is necessary in order to improve their characteristics. 相似文献
93.
Polymer segmental dynamics and solvent thermal transitions in poly(ethyl acrylate)/p‐xylene mixtures
A. T. Stathopoulos A. Kyritsis F. J. Romero Colomer J. L. Gomez Ribelles N. Shinyashiki C. Christodoulides P. Pissis 《Journal of Polymer Science.Polymer Physics》2011,49(6):455-466
A poly(ethyl acrylate) polymer network was swollen with different concentrations of the nonpolar solvent p‐xylene, cpx, from xerogel until saturation (0 ≤ cpx ≤ 0.85). Differential scanning calorimetry (DSC) and thermally stimulated depolarization currents (TSDC) techniques were employed to study the polymer segmental dynamics and the solvent thermal transitions in homogeneous (cpx < 0.20) and partially crystallized (cpx ≥ 0.20) PEA/p‐xylene mixtures. Our DSC measurements indicate that p‐xylene undergoes cold crystallization for intermediate solvent concentrations, 0.20 ≤ cpx ≤ 0.30 while for higher cpx values crystallization takes place during cooling. The results show that for cpx ≤ 0.30 the Tg decreases with increasing cpx (plasticization effect) obeying the respective Fox equation. For the same cpx range we found that both the dielectric strength and the heat capacity increment of the segmental (α) relaxation process increase gradually with cpx whereas the distribution of relaxation times for the underlying molecular relaxations does not change. For cpx > 0.30 the partially crystallized mixtures exhibit a constant Tg corresponding to the gel phase of PEA with an amount of p‐xylene which is not able to crystallize under any conditions. The concentration of this noncrystallized p‐xylene, cUCpx, has been estimated to be between 0.12 and 0.15, independent of the total p‐xylene concentration in the mixtures. When a separate p‐xylene crystal phase is formed (for cpx > 0.30) the segmental dielectric strength and heat capacity increment decrease significantly exhibiting values significantly lower than those measured for the homogeneous gels. In addition, we found that the presence of p‐xylene crystals may induce marginal spatial heterogeneity of polymer (or p‐xylene) concentration within the gel phase affecting thus slightly the breath of the segmental relaxation of PEA. We attribute these results to restrictions of polymer segmental configurations due to constraints imposed by the p‐xylene crystals and/or to the immobilization of a part of the polymer chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
94.
Charalampopoulos VG Papaioannou JC Tsekouras AA Kakali G Karayianni HS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):279-287
The β-cyclodextrin (β-CD) polyiodide inclusion complex (β-CD)(2)·Co(0.5)·I(7)·21H(2)O has been synthesized, characterized and further investigated via FT-Raman spectroscopy in the temperature range of 30-120°C. The experimental results point to the coexistence of I(-)(7) units (I(2)·I(-)(3)·I(2)) that seem not to interact with the Co(2+) ions and I(-)(7) units that display such interactions. The former units exhibit a disorder-order transition of both their I(2) molecules above 60°C due to a symmetric charge-transfer interaction with the central I(-)(3) [I(2)←I(-)(3)→I(2)], whereas in the latter units only one of the two I(2) molecules becomes well-ordered above 30°C. The other I(2) molecule remains disordered presenting no charge-transfer phenomena. The Co(2+) ion induces a considerable asymmetry on the geometry of the I(-)(3) anion and a significant modification of its Lewis base character. Complementary dielectric measurements suggest no important involvement of H···I contacts in the observed modification of the I(-)(3) electron-transfer properties. 相似文献