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排序方式: 共有105条查询结果,搜索用时 31 毫秒
61.
E López-Árias A Aguilar-Lemarroy L Felipe Jave-Suárez G Morgan-Villela I Mariscal-Ramírez M Martínez-Velázquez AH Alvarez A Gutiérrez-Ortega R Hernández-Gutiérrez 《Electrophoresis》2012,33(14):2130-2137
Several studies have demonstrated that sera from patients with cancer contain antibodies that recognize a unique group of autologous antigens called tumor-associated antigens (TAA). In the current study, we employed an immunoproteomic approach, combining 2DE, Western blot, and MALDI-MS to identify TAA in the sera of patients diagnosed with infiltrating ductal or in situ carcinoma breast cancer. Sera obtained from 25 newly diagnosed patients with stage II breast cancer and 20 healthy volunteers was evaluated for the presence of novel TAA. Alpha 1-antitrypsin (A1AT) antibodies were detected in 24 of 25 patients with breast cancer (96%) and in 2 of 20 controls (10%). Sensitivity of detection of autoantibodies against A1AT in patients with breast cancer was 96%. Our preliminary results suggest that A1AT and autoantibodies against alpha 1 antitrypsin may be useful serum biomarkers for early-stage breast cancer screening and diagnosis. 相似文献
62.
63.
Ulrich Bismayer Dagmar Mathes Mois Aroyo Dirk Bosbach Andrew Putnis Gustaaf Van Tendeloo 《Phase Transitions》2013,86(3):243-270
Ferroelastic domain patterns in lead phosphate-type crystals depend on their chemical composition. The intersection of ferroelastic W domain walls with the (100) surface of lead phosphate-arsenate mixed crystals has been imaged using tapping mode atomic force microscopy. Dilution of the strain leads to characteristic surface deformations which deviate from those in pure lead phosphate. In highly twinned lead phosphate-arsenate X-ray diffraction was used to show renormalization effects and scattering phenomena stemming from the twin walls. Raman-active hard modes show wall-related profile changes and low-frequency tails. Symmetry mode analysis is used to describe the displacive modes characterizing the structural distortion in lead phosphate-arsenate for the sequence K m → P21/c. 相似文献
64.
Solvent isotope effects in the ethanolysis of sterically hindered arenesulfonyl chlorides ruled out a proton transfer in the rate‐determining step and agreed with a SN2 mechanism involving at least a second solvent molecule in the transition state (TS). The lack of a secondary kinetic isotope effect in the o‐alkyl groups allows us to disregard the possible contribution of σ–π hyperconjugation. The measured activation parameters are consistent with a SN2 mechanism involving the participation of solvent molecules in the TS, possibly forming a cyclic TS through a chain of solvent molecules. 相似文献
65.
A Kinetic Investigation of Regioselective Solvation of a Solvatochromic Dye in Aqueous Alcohols 下载免费PDF全文
Moisés Domínguez Vanderlei Gageiro Machado Leandro Guarezi Nandi Marcos Caroli Rezende Patricia Silva 《国际化学动力学杂志》2015,47(12):803-810
The kinetics of methylation of the solvatochromic dye 4‐[(2,4‐dinitrobenzyli‐dene)imino]‐2,6‐diphenylphenolate by dimethyl sulfate was investigated in three aqueous alcohols (1‐propanol, ethanol, and methanol), in the search of a sharp change in its reactivity in water‐rich media. The observed kinetic results paralleled previous observations of a sharp change in the solvatochromic behavior of the dye in the same media and was supported by a QM/MM simulation of the dye in two methanol–water mixtures, which rationalized the observed sharp change in the phenolate reactivity. 相似文献
66.
67.
Marcelo V. Migliorini Ricardo K. Donato Moisés A. Benvegnú Reinaldo S. Gonçalves Henri S. Schrekker 《Journal of Sol-Gel Science and Technology》2008,48(3):272-276
This article describes the preparation of xerogel silica’s by the sol–gel technique in the presence of the ionic liquids (ILs)
1-triethylene glycol monomethyl ether-3-methylimidazolium methanesulfonate 1 and 1-monoethylene glycol monomethyl ether-3-methylimidazolium methanesulfonate 2, using tetraethoxysilane as precursor. The addition of water to these ILs resulted in the formation of protonic acid. As
a consequence, the ILs functioned as morphology controller and acid pre-catalyst at the same time. Characterization of these
materials was performed by photography, scanning electron microscopy, thermogravimetric analysis and powder X-ray diffraction.
Compact lamellar monoliths with interlamellar distances of approximately 1.5 nm and flat surfaces were obtained with both
ILs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
68.
Mykyta Iazykov Moisés Canle J. Arturo Santaballa Ludmila Rublova 《Journal of Physical Organic Chemistry》2018,31(2)
We have studied the mechanism of solvolysis of arenesulfonyl chlorides by propan‐1‐ol and propan‐2‐ol at 303‐323 K. Kinetic profiles were appropriately fit by first‐order kinetics. Reactivity increases with electron‐donating substituents. Ortho‐alkyl substituted derivatives of arenesulfonyl chlorides show increased reactivity, but the origin of this “positive” ortho‐effect remains unclear. Likely, ortho‐methyl groups restrict rotation around the C‐S bond, facilitating the attack of the nucleophile. No relevant reactivity changes have been found with propan‐1‐ol and propan‐2‐ol in terms of nucleophile steric effect. The existence of isokinetic relationships for all substrates suggests a single mechanism for the series. Solvolysis reactions of all substrates in both alcohols show isokinetic temperatures (Tiso) close to the working temperature range, which is an evidence of the process being influenced by secondary reactivity factors, likely of steric nature in the TS. Solvation plays a relevant role in this reaction, modulating the reactivity. In some cases, the presence of t‐Bu instead of Me in para‐ position leads to changes in the first solvation shell, increasing the energy of the reaction (ca. 1 kJ·mol?1). The obtained results suggest the same kinetic mechanism of solvolysis of arenesulfonyl chlorides for propan‐1‐ol and propan‐2‐ol, as in MeOH and EtOH, where bimolecular nucleophilic substitution (SN2) takes place with nucleophilic solvent assistance of one alcohol molecule and the participation of the solvent network involving solvent molecules of the first solvation shell. 相似文献
69.
The ruthenium-catalyzed cycloisomerization of diynes containing one silyl alkyne and one propargyl alcohol yields 2-silyl-[6H]-pyrans instead of the expected unsaturated acylsilanes except when additional conjugation of a aromatic ring is present at the delta-position. Under certain conditions, a facile ruthenium-catalyzed isomerization of the product takes place as well. This regioselectivity of the cyclization can be controlled by the choice of solvent system. DFT calculations confirm the expected greater stability of the silyl-pyrans relative to the acylsilanes. 相似文献
70.
[chemical reaction: see text]. Bulky phosphite L6 and several sterically robust phosphoramidites are excellent ligands for promoting the Pd-catalyzed [3 + 2] intramolecular cycloaddition between alkylidenecyclopropanes and alkynes. The use of these ligands allows for low catalyst loadings and facilitates the otherwise sluggish cycloaddition of hept-6-ynylidenecyclopropane systems. 相似文献