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81.
Infrared spectra of deuterated monofluoroacetylene, DCCF, have been recorded in the region between 320 and 850 cm?1 at an effective resolution ranging from 0.0024 to 0.0031 cm?1. In total, 6650 rotation vibration transitions were assigned to 37 bands involving the bending states with v4 + v5 and |l4+l5|, respectively, up to 3, allowing the characterisation of the ground state and of 18 vibrationally excited states. The vν5 bending fundamental has been studied for the first time. In addition, the difference band v3 ← v4 has been detected and analysed. All the assigned transitions have been fitted simultaneously by adopting a model Hamiltonian that takes into account the vibration and rotation l?type resonances. Rotational transitions in the ground and in bending excited states reported in the literature have been included in the global analysis. The set of 57 derived spectroscopic parameters reproduces 6130 infrared and 90 microwave and millimetre?wave transitions satisfactorily with root mean square values of 5.3 × 10?4 cm?1 and 77 kHz, respectively. 相似文献
82.
Tania Córdova-Sintjago Nancy Villa Lijuan Fang Raymond G. Booth 《Molecular physics》2014,112(3-4):398-407
The serotonin (5-hydroxytryptamine, 5-HT) 5-HT2 G protein-coupled receptor (GPCR) family consists of types 2A, 2B, and 2C that share ~75% transmembrane (TM) sequence identity. Agonists for 5-HT2C receptors are under development for psychoses; whereas, at 5-HT2A receptors, antipsychotic effects are associated with antagonists – in fact, 5-HT2A agonists can cause hallucinations and 5-HT2B agonists cause cardiotoxicity. It is known that 5-HT2A TM6 residues W6.48, F6.51, and F6.52 impact ligand binding and function; however, ligand interactions with these residues at the 5-HT2C receptor have not been reported. To predict and validate molecular determinants for 5-HT2C-specific activation, results from receptor homology modelling, ligand docking, and molecular dynamics simulation studies were compared with experimental results for ligand binding and function at wild type and W6.48A, F6.51A, and F6.52A point-mutated 5-HT2C receptors. 相似文献
83.
Wong JM Esfahani A Singh N Villa CR Mirrahimi A Jenkins DJ Kendall CW 《Journal of AOAC International》2012,95(1):24-30
Modulation of the gut microbiota is an area of growing interest, particularly for its link to improving and maintaining the systemic health of the host. It has been suggested to have potential to reduce risk factors associated with chronic diseases, such as elevated cholesterol levels in coronary heart disease (CHD). Diets of our evolutionary ancestors were largely based on plant foods, high in dietary fiber and fermentable substrate, and our gut microbiota has evolved against a background of such diets. Therapeutic diets that mimic plant-based diets from the early phases of human evolution may result in drug-like cholesterol reductions. In contrast, typical Western diets low in dietary fiber and fermentable substrate, and high in saturated and trans fatty acids, are likely contributors to the increased need for pharmacological agents for cholesterol reduction. The gut microbiota of those consuming a Western diet are likely underutilized and depleted of metabolic fuels, resulting in a less than optimal gut microbial profile. As a result, this diet is mismatched to our archaic gut microbiota and, therefore, to our genome, which has changed relatively little since humans first appeared. While the exact mechanism by which the gut microbiota may modulate cholesterol levels still remains uncertain, end products of bacterial fermentation, particularly the short chain fatty acids (i.e., propionate), have been suggested as potential candidates. While more research is required to clarify the potential link between gut microbiota and CHD risk reduction, consuming a therapeutic diet rich in plant foods, dietary fiber, and fermentable substrate would be a useful strategy for improving systemic health, possibly by altering the gut microbiota. 相似文献
84.
85.
David F. Ewing Christophe Len Grahame Mackenzie Gino Ronco Pierre Villa 《Tetrahedron: Asymmetry》2000,11(24)
1,2-O-Isopropylidene-α-
-xylofuranose has been used to protect one aldehyde group of o-phthalaldehyde. This chiral protecting group acts as a resolving agent and this leads to separable diastereoisomers when a new stereogenic centre is created by the conversion of the second aldehyde group to a benzyloxyhydroxyethyl chain. These separated diastereoisomers were cyclised to 1,3-dihydrobenzo[c]furans with retention of chiral integrity at the C3 site thus allowing further elaboration to enantiomerically pure nucleoside analogues. 相似文献
86.
Summary: The thermal polymerization of styrene is usually modeled by relying on a reaction scheme and a set of equations that were developed more than three decades ago by Hui and Hamielec. Many detailed models of styrene polymerization are available in the open literature and they are mostly based on the work of Hui and Hamielec, which nearly makes this the standard to follow in explaining the behavior of polystyrene reactors. The model of Hui and Hamielec does a very nice job of describing monomer conversion data but discrepancies are seen between observed and predicted values of number and weight average molecular weights, Mn and Mw. Discrepancies in number average molecular weight seem to be the result of random noise. Discrepancies in weight average molecular weight grow as the polymerization temperature decreases and some of the trends observed in the residuals over the entire temperature range cannot be attributed to random noise. Hui and Hamielec attributed the observed deficiencies to a standard deviation of ±10% in their GPC measurements. A new data set with an experimental error of 2% for average molecular weights is presented. The set contains measured values of Mn, Mw and Mz, so the polymerization scheme has been extended to include third order moments. The data set also includes the effect of ethylbenzene as a chain transfer agent. We present the results of comparing model predictions to our measurements and the adjustments made in the original set of kinetic parameters published by Hui and Hamielec. 相似文献
87.
Matteo Mori Giulia Cazzaniga Fiorella Meneghetti Stefania Villa Arianna Gelain 《Molecules (Basel, Switzerland)》2022,27(14)
SIRT5 is a member of the Sirtuin family, a class of deacetylating enzymes consisting of seven isoforms, involved in the regulation of several processes, including gene expression, metabolism, stress response, and aging. Considering that the anomalous activity of SIRT5 is linked to many pathological conditions, we present herein an overview of the most interesting modulators, with the aim of contributing to further development in this field. 相似文献
88.
Benigno Macías Isabel García María V. Villa Joaquín Borrs Alfonso Castieiras Francisca Sanz 《无机化学与普通化学杂志》2003,629(2):255-260
Sulfonamides obtained by reaction of 8‐aminoquinoline with benzenesulfonyl, toluene‐4‐sulfonyl and naphthalene‐2‐sulfonyl chlorides have been used to synthetize coordination compounds with ZnII with a ZnL2 composition. Determination of the crystal structures for the resulting complexes by X‐ray diffraction shows a distorted tetrahedral environment for the Zn2+ ions, sulfonamides acting as bidentate ligands through the nitrogen atoms from the sulfonamidate and quinoline groups. FT‐IR, 1H and 13C NMR and mass spectra of these compounds are also discussed. 相似文献
89.
The selective oxidation of alcohols and olefins is carried out commercially on complex systems based on Fe and Mo or Sb mixed
oxides. The role of active phases and of the dopant in the catalysts has been elucidated using several characterization techniques
and catalytic data.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
90.
The non-rigid group (NRG) for the wagging and torsion motions in methylamine is deduced in terms of rotation and inversion operations. The group is compared to that of LonguetHiggins for the same molecule expressed in terms of permutations and permutations-inversion. It is seen that the NRG is isomorphic to that of Longuet-Higgins and the C6
v symmetry point group. The character table is deduced, as well as the symmetry eigenvectors in terms of products of trigonometric functions. Selection rules for the infrared torsional-wagging transitions are given, and the band profiles of the spectrum discussed. 相似文献