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41.
42.
Amarande Murisier Marie Andrie Szabolcs Fekete Matthew Lauber Valentina D'Atri Katharina Iwan Davy Guillarme 《Journal of separation science》2022,45(12):1997-2007
The present study describes the possibilities offered by an innovative bioinert size exclusion chromatography column for size variant characterization of complex monoclonal antibody products. This size exclusion chromatography column includes a novel column hardware surface. The column was prepared from metallic hardware components that were treated to have prototype hydrophilically modified hybrid organic–inorganic silica surfaces called hybrid surface technology. This provides a significant reduction in nondesired hydrophobic and electrostatic interactions that can occur between column and analyte when performing size exclusion chromatography analysis with volatile mobile phase. Compared to a reference stainless-steel column packed with the same batch of packing material, peak tailing, band broadening, and above all recovery of high molecular weight species were distinctly improved for all types of monoclonal antibody products. Based on our observations, we found that 50 mM ammonium acetate in water was a suitable mobile phase offering good compromise in terms of liquid chromatography performance and mass spectrometry sensitivity. In addition, method repeatability (intra- and interday relative standard deviations) on elution times and high molecular weight species peak areas were found to be excellent. By using this innovative size exclusion chromatography material, the low and high molecular weight species contained in various stressed and nonstressed monoclonal antibody products were successfully characterized with mass spectrometry detection. 相似文献
43.
44.
Salyi S Kritikos M Akermark B Sun L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(2):557-560
A dinuclear 2Fe2S mimic 6 of the active site of the Fe-only hydrogenases has been synthesized. Complex 6 contains a free amino group which enables linkage to a protein backbone or to a redox active species for the study of electron transfer processes in proteins or in supramolecular systems. The structures of the complex 6 and its Boc-protected precursor 5 could be verified by X-ray crystallography. 相似文献
45.
László Nyulászi Dénes Szieberth Gábor I. Csonka József Reffy Joachim Heinicke Tamás Veszpremi 《Structural chemistry》1995,6(1):1-7
He(I) and He(II) photoelectron spectra of phenylphosphine and phenylarsine have been investigated and assigned. The rotational barrier of the phosphino group has been investigated at the MP2/6-31G(d,p)//MP2/6-31G(d,p) and HF/6-31G(d,p)//HF/6-31G(d,p) levels of theory, and that of the arsino group at the HF/6-31G(d,p)//6-31G(d,p) levels of theory. The rotational barrier of the two molecules is nearly the same. The energy difference between the two possible conformers of the molecules is low (1.5 kJ/mol at the MP2/6-31G(d,p) level of theory), allowing nearly free rotation about the P-C bond. The photoelectron spectrum cannot be interpreted by considering the most stable rotamer, but all possible conformers should be taken into account. The present interpretation is consistent with the smalln
p
- interaction concluded from other investigations. The rotational barrier ofo-phosphinophenol is significantly larger than for phenylphosphine, and the photoelectron spectrum of this compound can be interpreted by considering a single conformer, and no appreciable interaction between the -system of the ring and the phosphorus lone pair. 相似文献
46.
The effect of the inclusion of the exact exchange into self-interaction corrected generalized gradient approximation density
functional theory (GGA-DFT) for the simplest hydrogen abstraction reaction, H + H2 → H3 → H2 + H, is presented using a triple-zeta augmented 6-311++G(d,3pd) basis set. The introduction of the self-interaction correction has a considerably larger effect on molecular geometry and
vibrational frequencies than the inclusion of the exact exchange. We investigate the influence of the self-interaction error
on the shape of the potential energy surface around the transition state of the hydrogen abstraction reaction. The decomposition
of the self-interaction error into correlation and exchange parts shows that the exchange self-interaction error is the main
component of the energy barrier error. The best agreements with the experimental barrier height were achieved by self-interaction
corrected B3LYP, B-LYP and B3PW functionals with errors of 1.5, 2.9 and 3.0 kcal/mol, respectively.
Received: 13 August 1997 / Accepted: 14 November 1997 相似文献
47.
J zsef Kaizer R bert Csonka G bor Speier 《Journal of molecular catalysis. A, Chemical》2002,180(1-2):91-96
The oxidation reaction of 2-aminophenol (OAP) to 2-aminophenoxazin-3-one (APX) initiated by 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) has been investigated in methanol at ambient temperature. The oxidation of OAP was followed by electronic spectroscopy and the rate constants were determined according to the rate law −d[OAP]/dt=kobs[OAP][TEMPO]. The rate constant, activation enthalpy and entropy at 298 K are as follows: kobs (dm3 mol−1 s−1)=(1.49±0.02)×10−4, Ea=18±5 kJ mol−1, ΔH‡=15±4 kJ mol−1, ΔS‡=−82±17 J mol−1 K−1. The results of oxidation of OAP show that the formation of 2-aminophenoxyl radical is the key step in the activation process of the substrate. 相似文献
48.
P. Csonka 《Archive of Applied Mechanics (Ingenieur Archiv)》1935,6(5):373-382
Ohne Zusammenfassung 相似文献
49.
50.
Simple inorganic reactions in gels, such as NaOH + CuCl(2), NaOH + AgNO(3), and CuCl(2) + K(3)[Fe(CN)(6)], can yield to various precipitation patterns. The first compound penetrates in a hydrogel by diffusion, and reacts with the second compound homogenized in the gel. The precipitate patterns formed in these reactions have got two kinds of bordering surfaces. Recent experimental results suggested that one of these surfaces has an ion-selective (semipermeable) character: It restrains the diffusion of the reacting ion contained by the reactant that diffuses into the gel. In this paper, we built the above experimental observation into a reaction-diffusion cellular-automata model of the pattern formation. Computer simulations showed that the model is able to reproduce the basic building elements of the patterns. 相似文献