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991.
Didjour Albert Kambir Ahmont Claude Landry Kablan Thierry Acafou Yapi Sophie Vincenti Jacques Maury Nicolas Baldovini Pierre Tomi Mathieu Paoli Jean Brice Boti Flix Tomi 《Molecules (Basel, Switzerland)》2022,27(12)
The variability of chemical composition of the leaf essential oil (EO) from Neuropeltis acuminata, a climbing liana growing wild in Ivory Coast, was investigated for the first time. The in vitro anti-inflammatory activity was also evaluated. Thirty oil samples were isolated from leaves collected in three forests of the country and analyzed using a combination of Column Chromatography (CC), Gas Chromatography with Retention Indices (GC(FID)), Gas Chromatography-Mass Spectrometry (GC-MS), and 13Carbon-Nuclear Magnetic Resonance (13C-NMR). Fractionation by CC led to the first-time isolation from natural source of δ-cadinen-11-ol, whose structural elucidation by one dimension (1D) and 2D-NMR spectroscopy is reported here. Finally, 103 constituents accounting for 95.7 to 99.6% of the samples’ compositions were identified. As significant variations of the major constituents were observed, the 30 oil compositions were submitted to hierarchical cluster and principal components analyses. Five distinct groups were evidenced: Group I, dominated by (E)-β-caryophyllene, kessane, and δ-cadinene, while the main constituents of Group II were germacrene B, ledol, α-humulene, (E)-γ-bisabolen-12-ol, and γ-elemene. Group III exhibited guaiol, germacrene D, atractylone, (E)-γ-bisabolen-12-ol, δ-cadinene and bulnesol as main compounds. Group IV was dominated by (E)-nerolidol, guaiol, selina-4(15),7(11)-diene and bulnesol, whereas (E)-β-caryophyllene, α-humulene and α-muurolene were the prevalent compounds of Group V. As the harvest took place in the same dry season in the three forests, the observed chemical variability could be related to harvest sites, which includes climatic and pedologic factors, although genetic factors could not be excluded. The leaf oil sample S24 behaved as a high inhibitor of LipOXygenase (LOX) activity (half maximum Inhibitory Concentration, IC50: 0.059 ± 0.001 mg mL−1), suggesting an anti-inflammatory potential. 相似文献
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Changhee Han Laurie J. Burn Paul Vallelonga Soon Do Hur Claude F. Boutron Yeongcheol Han Sanghee Lee Ahhyung Lee Sungmin Hong 《Molecules (Basel, Switzerland)》2022,27(13)
A lead (Pb) isotopic record, covering the two oldest glacial–interglacial cycles (~572 to 801 kyr ago) characterized by lukewarm interglacials in the European Project for Ice Coring in Antarctica Dome C ice core, provides evidence for dust provenance in central East Antarctic ice prior to the Mid-Brunhes Event (MBE), ~430 kyr ago. Combined with published post-MBE data, distinct isotopic compositions, coupled with isotope mixing model results, suggest Patagonia/Tierra del Fuego (TdF) as the most important sources of dust during both pre-MBE and post-MBE cold and intermediate glacial periods. During interglacials, central-western Argentina emerges as a major contributor, resulting from reduced dust supply from Patagonia/TdF after the MBE, contrasting to the persistent dominance of dust from Patagonia/TdF before the MBE. The data also show a small fraction of volcanic Pb transferred from extra-Antarctic volcanoes during post-MBE interglacials, as opposed to abundant transfer prior to the MBE. These differences are most likely attributed to the enhanced wet removal efficiency with the hydrological cycle intensified over the Southern Ocean, associated with a poleward shift of the southern westerly winds (SWW) during warmer post-MBE interglacials, and vice versa during cooler pre-MBE ones. Our results highlight sensitive responses of the SWW and the associated atmospheric conditions to stepwise Antarctic warming. 相似文献
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Xavier Blanc Claude Le Bris Frdric Legoll 《应用数学学报(英文版)》2007,23(2):209-216
In order to describe a solid which deforms smoothly in some region,but non smoothly in someother region,many multiscale methods have been recently proposed that aim at coupling an atomistic model(discrete mechanics) with a macroscopic model (continuum mechanics).We provide here a theoretical basis forsuch a coupling in a one-dimensional setting,in the case of convex energy. 相似文献
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Yves Claude Guillaume Lydie Lethier Claire André 《Biomedical chromatography : BMC》2015,29(9):1338-1342
In a previous paper Guillaume's group demonstrated that magnesium (Mg2+ concentration range 0.00–2.60 mm ) increased the passive diffusion of statins and thus played a role in their potential toxicity. In order to confirm an increase in this passive diffusion by divalent salt cations, the role of calcium chloride (CaCl2) on the statin–immobilized artificial membrane (IAM) association was studied. It was demonstrated that calcium supplementation (Ca2+ concentration range 0.00–3.25 mm ) increases the statin passive diffusion. In addition, it was shown that the Ca2+ effect on the statin–IAM association is higher than that of Mg2+. These results show that Ca2+ enhances the passive diffusion of drugs into biological membranes and thus their potential toxicity. Also, addition of H2O2 to the medium showed a hyperbolic response for the statin passive diffusion and this effect was enhanced for the highest Ca2+ or Mg2+ concentrations in the medium. H2O2 is likely to interact with the polar head groups of the IAM through dipole–dipole interactions. The conformational changes in H2O2–IAM result in a higher degree of exposure of hydrophobic areas, thus explaining why the binding of pravastatin, which showed the lowest logP value, was less affected by H2O2. This result shows the significant contribution of H2O2 and thus the oxidative stress on the statin passive diffusion. Much of the sensitivity derives from the action of Ca2+ or Mg2+, in turn supported the idea that H2O2 may serve a Ca2+ or Mg2+ sensing function in statin passive diffusion Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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RogerL. Snowden Jean‐Claude Eichenberger Simon Linder Philippe Sonnay 《Helvetica chimica acta》2004,87(7):1711-1723
Treatment of the unsaturated allenic alcohols (E)‐ 7 , (Z)‐ 7, 10, 13 , and 19 with an excess of FSO3H in 2‐nitropropane at ?90° to ?30° afforded, in 68–85% yield, diastereoisomer mixtures of racemic tricyclic ethers 14a – d and 20a – d , respectively (Schemes 3 and 5), with high stereoselectivity (see Table and Scheme 6). These stereospecific transformations represent the first reported examples of an acid‐mediated polyene cyclization, in which an alkene is the initiating group and an allenic alcohol serves as the internal terminator. In close analogy to our earlier work, a nonsynchronous process is postulated, whereby the stereochemical course of cyclization is directed by the conformational structure of an intermediate cyclohexyl cation (see Schemes 3 and 6). In addition, the organoleptic properties of 14c and 20c , racemic didehydro and methyl didehydro analogues, respectively, of the known odorant Ambrox® ((?)‐ 4f ), are briefly discussed. 相似文献