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361.
Valerio Loianno Kelly P. Bye Michele Galizia Pellegrino Musto 《Journal of polymer science. Part A, Polymer chemistry》2020,58(18):2547-2560
Despite substantial research efforts being devoted to design polymer membranes for organic solvent nanofiltration (OSN) exhibiting enhanced plasticization resistance, detailed studies of membrane structural stability in chemically challenging environments are rare. This study sets forth a multiscale method, which combines in situ FTIR measurements in the transmission mode with sorption and transport measurements, to investigate the molecular mechanism of polymer plasticization upon exposure to organic species. We recently reported that polybenzimidazole (PBI), a polymer that has been considered for OSN application, experiences severe plasticization upon exposure to methanol. FTIR measurements suggest that the mechanism of PBI plasticization relies on competitive hydrogen bonding. According to this mechanism, methanol molecules disrupt the hydrogen bonded network characteristic of dry PBI, by forming mutual polymer/penetrant hydrogen bonds, which enhances polymer chain mobility and favors polymer plasticization. The analysis of the isosteric heat of sorption supports the picture sketched above. The method developed in this study can be readily extended to many other systems of practical interest in membrane science, to shed fundamental light on the phenomenon of plasticization, whose molecular aspects are still largely unknown. Equally important, this study provides some useful guidelines to design OSN membrane materials. 相似文献
362.
Dose Valerio Mercuri Pietro Pal Ankan Stirpe Claudio 《Designs, Codes and Cryptography》2022,90(6):1347-1368
Designs, Codes and Cryptography - We illustrate a general technique to construct towers of fields producing high order elements in $$\mathbb {F}_{q^{2^n}}$$ , for odd q, and in $$\mathbb {F}_{2^{2... 相似文献
363.
p‐Toluate‐bridged dinuclear Cu(II) complexes in combination with tridentate chelating ligand: Crystal structure,density functional theory calculation,DNA/protein binding and catecholase activity
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The dinuclear Cu(II) complexes [Cu2(L1)2(mb)]?ClO4 ( 1 ) and [Cu2(L2)2(mb)]?ClO4 ( 2 ) (HL1 = 2‐[(2‐diethylaminoethylimino)methyl]phenol; HL2 = 2‐[1‐(2‐diethylaminoethylimino)propyl]phenol; mb = 4‐methylbenzoate) were synthesized and characterized using X‐ray crystal structure analysis and spectroscopic methods. Complexes 1 and 2 are dinuclear with distorted square pyramidal Cu (II) geometries, where Schiff base coordinates with tridentate (N,N,O) chelating mode and mb bridges two metal centres. Optimized structures and photophysical properties of ligands and complexes were calculated using density functional theory and time‐dependent density functional theory methods using B3LYP functional with 6‐31G (d,p) and LanL2MB basis sets. Interactions of the complexes with bovine serum albumin (BSA) and human serum albumin (HSA) were studied using UV–visible absorption and fluorescence spectroscopies and the calculated values of association constants (M?1) are 1.7 × 105 ( 1 –BSA), 5.7 × 105 ( 2 –BSA), 1.6 × 105 ( 1 –HSA) and 6.9 × 105 ( 2 –HSA). Interactions of the complexes with calf thymus DNA were also investigated and the binding affinities are 1.4 × 105 and 1.6 × 105 M?1 for 1 and 2 , respectively. Both complexes catalytically oxidize 3,5‐di‐tert‐butylcatechol to 3,5‐di‐tert‐butylbenzoquinone in the presence of molecular oxygen. 相似文献
364.
In Kaluza-Klein models, the compactification ofa high number of extra spatial dimensions generatesentropy in the observable four-dimensional universe. AKaluza–Klein cosmological model recently derived from the bosonic string theory in the limit ofan infinite number of extra dimensions is compared withthe available data from the observations of cosmicmicrowave background anisotropies. 相似文献
365.
Francesco Musiani Laura Rigobello Luisa Iommarini Valerio Carelli Mauro Degli Esposti Anna Maria Ghelli 《Molecules (Basel, Switzerland)》2022,27(4)
The finding that the most common mitochondrial DNA mutation m.11778G>A/MT-ND4 (p.R340H) associated with Leber’s hereditary optic neuropathy (LHON) induces rotenone resistance has produced a long-standing debate, because it contrasts structural evidence showing that the ND4 subunit is far away from the quinone-reaction site in complex I, where rotenone acts. However, recent cryo-electron microscopy data revealed that rotenone also binds to the ND4 subunit. We investigated the possible structural modifications induced by the LHON mutation and found that its amino acid replacement would disrupt a possible hydrogen bond between native R340 and Q139 in ND4, thereby destabilizing rotenone binding. Our analysis thus explains rotenone resistance in LHON patients as a biochemical signature of its pathogenic effect on complex I. 相似文献
366.
367.
Valerio Magnasco Arnaldo Rapallo Massimo Casanova 《International journal of quantum chemistry》1999,73(4):333-340
A new translation method for Slater‐type orbitals (STOs) is proposed involving exact translation of the regular solid harmonic part of the orbital followed by the series expansion of the residual spherical part in powers of the radial variable. The method is positively tested in the case of the overlap integral, showing good rate of convergence and great numerical stability under wide changes in the relevant molecular parameters. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 73: 333–340, 1999 相似文献
368.
Ivana Barravecchia Elisabetta Barresi Camilla Russo Francesca Scebba Chiara De Cesari Valerio Mignucci Davide De Luca Silvia Salerno Valeria La Pietra Mariateresa Giustiniano Sveva Pelliccia Diego Brancaccio Greta Donati Federico Da Settimo Sabrina Taliani Debora Angeloni Luciana Marinelli 《Molecules (Basel, Switzerland)》2021,26(24)
Molecule interacting with CasL 2 (MICAL2), a cytoskeleton dynamics regulator, are strongly expressed in several human cancer types, especially at the invasive front, in metastasizing cancer cells and in the neo-angiogenic vasculature. Although a plethora of data exist and stress a growing relevance of MICAL2 to human cancer, it is worth noting that only one small-molecule inhibitor, named CCG-1423 (1), is known to date. Herein, with the aim to develop novel MICAL2 inhibitors, starting from CCG-1423 (1), a small library of new compounds was synthetized and biologically evaluated on human dermal microvascular endothelial cells (HMEC-1) and on renal cell adenocarcinoma (786-O) cells. Among the novel compounds, 10 and 7 gave interesting results in terms of reduction in cell proliferation and/or motility, whereas no effects were observed in MICAL2-knocked down cells. Aside from the interesting biological activities, this work provides the first structure–activity relationships (SARs) of CCG-1423 (1), thus providing precious information for the discovery of new MICAL2 inhibitors. 相似文献
369.
370.
Ruel Valerio Robles De Grano Elena V. Vashchenko Madiha Nisar Herman H.-Y. Sung Valerii V. Vashchenko Ian D. Williams 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(5):490-499
The flavonoid Oroxylin A (6‐methoxychrysin or 5,7‐dihydroxy‐6‐methoxy‐2‐phenyl‐4H‐chromen‐4‐one, C16H12O5) and its regioisomers are of increasing interest for a variety of bioactive functions and their pharmaceutical formulation is of importance. Previous difficulties in the separation and misidentification of Oroxylin A from its regioisomers Wogonin (8‐methoxychrysin or 5,7‐dihydroxy‐8‐methoxy‐2‐phenyl‐4H‐chromen‐4‐one) and Negletein (5,6‐dihydroxy‐7‐methoxyflavone or 5,6‐dihydroxy‐7‐methoxy‐2‐phenyl‐4H‐chromen‐4‐one) render its full structural and powder X‐ray characterization highly desirable. The low‐temperature (100 K) crystal structures of Oroxylin A, Negletein and Wogonin sesquihydrate are reported for the first time. Wogonin crystallizes in two related but distinct hydrated forms. These have very similar powder diffractograms, indicating that such issues need to be addressed for its pharmaceutical formulation. 相似文献