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61.
Incorporation of a Non‐Natural Arginine Analogue into a Cyclic Peptide Leads to Formation of Positively Charged Nanofibers Capable of Gene Transfection 下载免费PDF全文
Mao Li Martin Ehlers Stefanie Schlesiger Elio Zellermann Prof. Shirley K. Knauer Prof. Carsten Schmuck 《Angewandte Chemie (International ed. in English)》2016,55(2):598-601
Functionalization of the tetracationic cyclic peptide (Ka)4 with a single guanidiniocarbonyl pyrrole (GCP) moiety, a weakly basic but highly efficient arginine analogue, completely alters the self‐assembly properties of the peptide. In contrast to the nonfunctionalized peptide 2 , which does not self‐assemble, GCP‐containing peptide 1 forms cationic nanofibers of micrometer length. These aggregates are efficient gene transfection vectors. DNA binds to their cationic surface and is efficiently delivered into cells. 相似文献
62.
Anna Bertaso Elio Franco De Palo Vito Cirielli Franco Tagliaro 《Electrophoresis》2020,41(12):1039-1044
Forensic inquests, particularly, in assessing time since death currently recognize the importance of the analysis of vitreous humour (VH) biomarkers. Present research, studies, and validates the determination of lactate (La) in VH by CZE with indirect UV detection. The BGE (pH 8.9) consisted of Tris buffer (37 mM) containing 4-methoxybenzoic acid (4 mM) and alkyl-trimethyl-ammonium bromide (1.2 mM). Each VH specimen was diluted with a butyric acid solution (internal standard 0.057 mM) and La and butyrate were separated within 3–5 min (30 kV). The La LOQ and LOD were 4 and 2 mM, respectively. The calibration curve linearity ranged from 4 to 80 mM; intra- and interruns precisions were less than 10% for standard as well as for VH specimen, respectively. To investigate postmortem interval (PMI) and VH lactate level correlation, human VH specimens were collected during autopsy (n = 40) and stored at −20°C until assay. La levels ranged from 16 to 42 mM; PMI values ranged from 10 to 141 h. La (mM) and PMI (h) correlation was statistically significant (r2 = 0.527; p < 0.05). In conclusion, the present CZE analysis is efficacious to determine VH La as a biomarker for PMI investigation. 相似文献
63.
Benincori T Pilati T Rizzo S Sannicolò F Burk MJ de Ferra L Ullucci E Piccolo O 《The Journal of organic chemistry》2005,70(14):5436-5441
[reaction: see text] The 2,5-dimethyl-3,4-bis[(2R,5R)-2,5-dimethylphospholano]thiophene (UlluPHOS), a new thiophene-based analogue of (R,R)-1,2-bis(phospholano)benzene (Me-DuPHOS), was synthesized, geometrically and electronically characterized, and employed as ligand of Rh and Ru in some standard hydrogenation reactions of prostereogenic functionalized carbon-carbon and carbon-oxygen double bonds. The synthesis of UlluPHOS is much easier than that provided for Me-DuPHOS. UlluPHOS and Me-DuPHOS display very similar geometries, while the electronic availability of the former is higher than that exhibited by the latter. The Rh and Ru complexes of UlluPHOS produced excellent enantiomeric excesses (98.9-99.5%) in the hydrogenation of N-acetyl-alpha-enamino acids and reaction rates higher than those found when employing the analogous complexes of Me-DuPHOS. 相似文献
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65.
Paola Fisicaro Elio Giamello Gloria Berlier Carlo Lamberti 《Research on Chemical Intermediates》2003,29(7-9):805-816
The interaction of nitrogen monoxide with various types of iron-containing pentasilic zeolites has been investigated by EPR spectroscopy. The systems investigated were iron-silicalite, ion-exchanged ZSM-5 and a bare silicalite impregnated with iron ions at the external surface only. NO forms paramagnetic adducts on all these systems essentially reacting with Fe(II) species. Three distinct types of nytrosyl adducts have been identified all lacking the hyperfine structure. Two of them are in doublet (S=1/2) state while the third one, observed in ZSM-5 samples only and already reported in the literature, is a quadruplet (S=3/2). While all activated samples exhibit EPR spectra (due to Fe(III) ions) very similar one to each other, their reactivity towards NO is different in each case. This allows some advance in understanding the state of the activated samples which, due to the high importance of iron-containing pentasilic zeolites in heterogeneous catalysis, is the object of a active debate in the literature. 相似文献
66.
Mayra A. Marques Maicon Landim-Vieira Adolfo H. Moraes Bin Sun Jamie R. Johnston Karissa M. Dieseldorff Jones Elio A. Cino Michelle S. Parvatiyar Isela C. Valera Jerson L. Silva Vitold E. Galkin P. Bryant Chase Peter M. Kekenes-Huskey Guilherme A. P. de Oliveira Jose Renato Pinto 《Chemical science》2021,12(21):7308
Cardiac TnC (cTnC) is highly conserved among mammals, and genetic variants can result in disease by perturbing Ca2+-regulation of myocardial contraction. Here, we report the molecular basis of a human mutation in cTnC''s αD-helix (TNNC1-p.C84Y) that impacts conformational dynamics of the D/E central-linker and sampling of discrete states in the N-domain, favoring the “primed” state associated with Ca2+ binding. We demonstrate cTnC''s αD-helix normally functions as a central hub that controls minimally frustrated interactions, maintaining evolutionarily conserved rigidity of the N-domain. αD-helix perturbation remotely alters conformational dynamics of the N-domain, compromising its structural rigidity. Transgenic mice carrying this cTnC mutation exhibit altered dynamics of sarcomere function and hypertrophic cardiomyopathy. Together, our data suggest that disruption of evolutionary conserved molecular frustration networks by a myofilament protein mutation may ultimately compromise contractile performance and trigger hypertrophic cardiomyopathy.Cardiac TnC (cTnC) is highly conserved among mammals, and genetic variants can result in disease by perturbing Ca2+-regulation of myocardial contraction. 相似文献
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68.
The r.t. interaction of oxygen with finely-divided copper in Cu/ZnO catalysts has been studied by gas-solid microcalorimetry. The oxidation is accompanied by the presence of a pseudo-equilibrium pressure, which increases as the reaction proceeds. Surface and several subsurface layers are involved, but a metallic core is always left. The heat of reaction is the same for all samples and does not vary with the extent of reaction (ΔH=181 kJ mol (1/202)?1). The rate of reaction depends upon the pressure, and decreases dramatically to a point where oxidation stps and molecular oxygen is weakly chemisorbed. The overall process is interpreted by assuming that the rate-determining step is the surface dissociation of a molecular precursor onto Cu atoms. 相似文献
69.
Some cases of formation and stabilization of charge carriers (electron and holes) at the surface of solid oxides are discussed. Charge carriers can be simultaneously or independently stabilized at the surface metal oxides. In the former case, they usually derive from a process of charge separation in the solid triggered by above band gap irradiation. In the second case, the charge carrier isolation is the result of a chemical alteration of the stoichiometric equilibrium of the solid either by matter addition or by effect of chemical impurities (valence induction). Electron paramagnetic resonance (EPR) is highly suited to monitor the process of charge separation and to characterize electron or hole centers stabilized in the solid or at its surface. In this paper examples of trapped electron and/or trapped hole centers as detected by continuous-wave EPR at the surface of simple binary oxides are discussed with particular emphasis to the formation mechanism, the EPR parameters and the chemical reactivity. 相似文献
70.
Considering measurement uncertainty is mandatory in assessing conformance to legal or compositional limits, and specific guidelines
are available issued by ASME, ISO and Eurachem/CITAC. However, differences between ISO and EURACHEM/CITAC wordings could induce
some perplexities in the most careful readers. Possible problems arise from considering that, before performing a test, it
should be decided whether it is to be a test for conformity or a test for non-conformity. This choice could perhaps require
some renaming of acceptance/rejection zones as defined in the EURACHEM/CITAC Guide. A tentative solution is discussed in this
contribution. 相似文献