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241.
Maliheh Mousavi Virgine Béreau Carine Duhayon Jean-Pascal Sutter 《Comptes Rendus Chimie》2012,15(10):924-928
The preparation of the potassium salt of hexathiocyanate Re(IV) as a pure and crystalline solid is described. The crystal structure for [{K(H2O)2}2{Re(NCS)6}] (P21/c, a = 8.29132(8) Å, b = 15.0296(2) Å, c = 8.5249(1) Å, β = 90.885(1)°, V = 1062.21(2) Å3) revealed the formation of a 3-D coordination polymer based on K-S linkages. This organization leads to rather short intermolecular S···S contacts. The magnetic behavior for the compound is characterized by substantial antiferromagnetic interactions (with Curie-Weiss parameters C = 1.93 cm3mol−1 and θ = −171 K) that in turn lead to a weak ferromagnet with TC = 13 K. 相似文献
242.
Oxygenated volatile organic compounds (OVOCs) influence the oxidative properties of the atmosphere, and their transport from the ground may occur by scavenging by the HNO(3)-rich supercooled water droplets found in polluted convective air masses. With infrared spectroscopy, we have studied the interactions of four typical atmospheric OVOCs (acetone, hydroxyacetone, acetaldehyde and benzaldehyde) with model surfaces of water ice and of trihydrated nitric acid (NAT) ice. We show that these molecules weakly adsorb on water ice and NAT by hydrogen bonding. No chemical reaction occurs between the molecules and the NAT substrate, the OVOCs remaining intact when in contact with hydrated HNO(3) in atmospheric ice clouds. 相似文献
243.
Tiwari KN Monserrat JP Hequet A Ganem-Elbaz C Cresteil T Jaouen G Vessières A Hillard EA Jolivalt C 《Dalton transactions (Cambridge, England : 2003)》2012,41(21):6451-6457
Two series of ten chalcones and ten aurones, where ferrocene replaces the C ring and with diverse substituents on the A ring were synthesized. The compounds were tested against two antibiotic-sensitive bacterial strains, E. coli ATCC 25922 and S. aureus ATCC 25923, and two antibiotic-resistant strains, S. aureus SA-1199B and S. epidermidis IPF896. The unsubstituted compound and those with methoxy substitution showed an inhibitory effect on all bacterial strains at minimum inhibitory concentrations ranging between 2 and 32 mg L(-1). For four of these compounds, the effect was bactericidal, as opposed to bacteriostatic. The corresponding organic aurones did not show growth inhibition, underscoring the role of the ferrocene group. The methoxy-substituted aurones and the unsubstituted aurone also showed low micromolar (IC(50)) activity against MRC-5 non-tumoral lung cells and MDA-MB-231 breast cancer cells, suggesting non-specific toxicity. 相似文献
244.
Balaj OP Semrouni D Steinmetz V Nicol E Clavaguéra C Ohanessian G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(15):4583-4592
The intrinsic folding of peptides about a sodium ion has been investigated in detail by using infrared multiple photon dissociation (IRMPD) spectroscopy and a combination of theoretical methods. IRMPD spectroscopy was carried out on sodiated polyglycines G(n)-Na(+) (n=2-8), in both the fingerprint and N-H/O-H stretching regions. Interplay between experimental and computational approaches (classical and quantum) enables us to decipher most structural details. The most stable structures of the small peptides up to G(6)-Na(+) maximize metal-peptide interactions with all peptidic C=O groups bound to sodium. In addition, direct interactions between peptide termini are possible for G(6)-Na(+) and larger polyglycines. The increased flexibility of larger peptides leads to more complex folding and internal peptide structuration through γ or β turns. A structural transition is found to occur between G(6)-Na(+) and G(7)-Na(+), leading to a structure with sodium coordination that becomes tri-dimensional for the latter. This transition was confirmed by H/D exchange experiments on G(n)-Na(+) (n=3-8). The most favorable hydrogen-bonding pattern in G(8)-Na(+) involves direct interactions between the peptide termini and opens the way to salt-bridge formation; however, there is only good agreement between experimental and computational data over the entire spectral range for the charge solvation isomer. 相似文献
245.
The electronic structures, as well as spectroscopic and thermodynamic properties of the title Pu@M12 clusters, are considered at the density functional theory level. In both cases, a Pu2+ ion is encapsulated in an icosahedral, stanna- or plumbaspherene cage. As suggested before for M = Pb, both systems are reported to follow a 32-electron principle for the central atom. 相似文献
246.
Jean De Dieu Zabsonré Carine Lucas Adama Ouedraogo 《Nonlinear Analysis: Real World Applications》2013,14(2):1216-1224
In this paper, we consider a viscous bilayer shallow water model in one space dimension that represents two superposed immiscible fluids. For this model, we prove the existence of strong solutions in a periodic domain. The initial heights are required to be bounded above and below away from zero and we get the same bounds for every time. Our analysis is based on the construction of approximate systems which satisfy the BD entropy and on the method developed by A. Mellet and A. Vasseur to obtain the existence of global strong solutions for the one dimensional Navier–Stokes equations. 相似文献
247.
Besora M Maseras F McGrady JE Oulié P Dinh DH Duhayon C Etienne M 《Dalton transactions (Cambridge, England : 2003)》2006,(19):2362-2367
The synthesis and characterisation of the cyclobutyl complex Tp(Me2)NbCl(c-C4H7)(MeC[triple bond]CMe) completes the family of cycloalkyl complexes Tp(Me2)NbCl(c-C(n)H(2n-1)), n = 3-6. The properties of the cyclobutyl complex are qualitatively similar to those of its cyclopentyl and cyclohexyl analogues, and dramatically different from those of the cyclopropyl derivative. Most conspicuously, the cyclobutyl system has an alpha-C-H agostic interaction in the dominant isomer, with no evidence for the alpha-C-C agostic character found for the smaller ring. C-C agostic character therefore seems to be unique to the cyclopropyl complex, where the acute C-C-C angles destabilise the C-C bonding orbitals. 相似文献
248.
Aubry C Wilson AJ Jenkins PR Mahale S Chaudhuri B Maréchal JD Sutcliffe MJ 《Organic & biomolecular chemistry》2006,4(5):787-801
We present the design, synthesis, and biological activity of three classes of tryptamine derivatives, which are non-planar analogues of the toxic anti-cancer agent fascaplysin. We show these compounds to be selective inhibitors of CDK4 over CDK2, the most active compound has an IC50 for the inhibition of CDK4 of 6 microM. 相似文献
249.
Clavaguéra C Sansot E Calvo F Dognon JP 《The journal of physical chemistry. B》2006,110(26):12848-12851
Realistic molecular dynamics simulations of polyaminocarboxylate complexes of gadolinium (III) ion in water are performed, providing coordination numbers and average residence times in quantitative agreement with available experimental data. A theoretical analysis, based on fitting a fluctuating charges model on ab initio data, also indicates that charge transfer between the ion and the ligand is significant. 相似文献
250.
[Structure: see text] A polyionic gel-soaked Rh catalyst allows the formation of synthetically useful diphenylsilyl (DPS) enols under mild conditions. The reaction proceeds through dehydrogenative silylation of ketones, affording the kinetic silyl enol ether in good to excellent yields. The in situ formed DPS enols were directly involved, without purification, in one-pot aldol and Mannich condensations. 相似文献