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排序方式: 共有726条查询结果,搜索用时 234 毫秒
91.
Who's talking first? Consensus or lack thereof in coevolving opinion formation models 总被引:1,自引:0,他引:1
We investigate different opinion formation models on adaptive network topologies. Depending on the dynamical process, rewiring can either (i) lead to the elimination of interactions between agents in different states, and accelerate the convergence to a consensus state or break the network in noninteracting groups or (ii), counterintuitively, favor the existence of diverse interacting groups for exponentially long times. The mean-field analysis allows us to elucidate the mechanisms at play. Strikingly, allowing the interacting agents to bear more than one opinion at the same time drastically changes the model's behavior and leads to fast consensus. 相似文献
92.
Adeniyi Adebayo A. Akintayo Cecilia O. Akintayo Emmanuel T. Conradie Jeanet 《Structural chemistry》2020,31(3):861-875
Structural Chemistry - Natural-based polyols are seen by polyurethane industries as an alternative to the petroleum-based polyols because of increasing challenges due to the oil crisis and global... 相似文献
93.
94.
Ferroxidase Activity in Eukaryotic Ferritin is Controlled by Accessory‐Iron‐Binding Sites in the Catalytic Cavity
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Dr. Caterina Bernacchioni Dr. Cecilia Pozzi Flavio Di Pisa Prof. Stefano Mangani Prof. Paola Turano 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(45):16213-16219
Ferritins are iron‐storage nanocage proteins that catalyze the oxidation of Fe2+ to Fe3+ at ferroxidase sites. By a combination of structural and spectroscopic techniques, Asp140, together with previously identified Glu57 and Glu136, is demonstrated to be an essential residue to promote the iron oxidation at the ferroxidase site. However, the presence of these three carboxylate moieties in close proximity to the catalytic centers is not essential to achieve binding of the Fe2+ substrate to the diferric ferroxidase sites with the same coordination geometries as in the wild‐type cages. 相似文献
95.
96.
Dr. Miriam Corredor Dr. Daniel Carbajo Cecilia Domingo Dr. Yolanda Pérez Dr. Jordi Bujons Prof. Dr. Angel Messeguer Dr. Ignacio Alfonso 《Angewandte Chemie (International ed. in English)》2018,57(37):11973-11977
Despite heparin being the most widely used macromolecular drug, the design of small‐molecule ligands to modulate its effects has been hampered by the structural properties of this polyanionic polysaccharide. Now a dynamic covalent selection approach is used to identify a new ligand for heparin, assembled from extremely simple building blocks. The amplified molecule strongly binds to heparin (KD in the low μm range, ITC) by a combination of electrostatic, hydrogen bonding, and CH–π interactions as shown by NMR and molecular modeling. Moreover, this ligand reverts the inhibitory effect of heparin within an enzymatic cascade reaction related to blood coagulation. This study demonstrates the power of dynamic covalent chemistry for the discovery of new modulators of biologically relevant glycosaminoglycans. 相似文献
97.
Fast Exfoliation and Functionalisation of Two‐Dimensional Crystalline Carbon Nitride by Framework Charging
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Dr. Jingjing Jia Dr. Edward R. White Dr. Adam J. Clancy Dr. Noelia Rubio Theo Suter Dr. Thomas S. Miller Kit McColl Prof. Paul F. McMillan Dr. Veronika Brázdová Prof. Furio Corà Dr. Christopher A. Howard Robert V. Law Dr. Cecilia Mattevi Prof. Milo S. P. Shaffer 《Angewandte Chemie (International ed. in English)》2018,57(39):12656-12660
Two‐dimensional (2D) layered graphitic carbon nitride (gCN) nanosheets offer intriguing electronic and chemical properties. However, the exfoliation and functionalisation of gCN for specific applications remain challenging. We report a scalable one‐pot reductive method to produce solutions of single‐ and few‐layer 2D gCN nanosheets with excellent stability in a high mass yield (35 %) from polytriazine imide. High‐resolution imaging confirmed the intact crystalline structure and identified an AB stacking for gCN layers. The charge allows deliberate organic functionalisation of dissolved gCN, providing a general route to adjust their properties. 相似文献
98.
Gagliardi LG Castells CB Ràfols C Rosés M Bosch E 《Journal of separation science》2008,31(6-7):969-980
We propose a general simple equation for accurately predicting the retention factors of ionizable compounds upon simultaneous changes in mobile phase pH and column temperature at a given hydroorganic solvent composition. Only four independent experiments provide the input data: retention factors measured in two pH buffered mobile phases at extreme acidic and basic pH values (e. g., at least +/- 2 pH units far from the analyte pK(a)) and at two column temperatures. The equations, derived from the basic thermodynamics of the acid-base equilibria, additionally require the knowledge of the solute pK(a )and enthalpies of acid-base dissociation of both the solute and the buffer components in the hydroorganic solvent mixture. The performance of the predictive model is corroborated with the comparison between theoretical and experimental retention factors of several weak acids and bases of important pharmacological activity, in mobile phases containing different buffer solutions prepared in 25% w/w ACN in water and at several temperatures. 相似文献
99.
Donatella Senatra C. Ziparo Cecilia M. C. Gambi L. Lanzi 《Journal of Thermal Analysis and Calorimetry》2008,92(2):535-541
A water-in-oil microemulsion composed of water, AOT and decane with volume fraction φ=0.50 and molar ratio X=40.8 was analysed by DSC. The percolation and the bicontinuous transitions as well as the melting endotherms and the freezing
exotherms were measured. The main attention was focussed on the system energy balance. It was found that, by freezing the
samples after the occurrence of the percolative transition, the total heat released is significantly less than the heat absorbed
in the melting endotherms. A simple geometrical model was used as an analysis tool of the aforementioned energy difference.
Since the system studied exhibits a percolative transition of dynamic type, on approaching the percolation threshold temperature
(T≤T
p) and a static percolation for T≥T
p, the structural change from the connecting water-droplet-cluster to a connecting water channel was schematised in the model
as a change from a sphere-necklace to a water-cylindrical channel of equal volume and equal length. The surface energy associated
with the formation of the two different geometrical surfaces was evaluated and the amount of saved energy compared with the
experimentally measured one. 相似文献
100.
Enantiopure chiral amidic derivatives of sinapic acid were oxidised with hydrogen peroxide using horseradish peroxidase (HRP) as the catalyst to give the aryltetraline dilignol thomasidioic acid. Trans-diastereoselectivity and enantioselectivity in the formation of thomasidioic acid was observed. Computational methods show that the enantioselectivity is controlled by the beta-beta oxidative coupling step, while the diastereoselectivity is controlled by the stability of the reactive conformation of the intermediate quinomethide. 相似文献