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排序方式: 共有535条查询结果,搜索用时 728 毫秒
91.
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93.
Dariusz Cie? 《Tetrahedron》2007,63(21):4510-4515
Oxidative homocoupling of titanium(IV) enolates of 2-isothiocyanato-carboxylic esters resulted in the synthesis of 2,3-diisothiocyanato-succinic acid diesters. The reactions were carried out using DIPEA/TiCl4 oxidizing system and led to chiral dimers (instead of meso) as main products. Titanium(IV) enolates derived from hindered 2-isothiocyanato-carboxylates did not undergo the oxidative homocoupling but gave 3,6-dithioxo-piperazines. 相似文献
94.
A strategy has been developed for the efficient application of automated parallel synthesis to specific aspects of the lead optimization processes employed in drug discovery. The method involves the synthesis of collections of compounds using sets of precursors designed to encompass established medicinal chemistry principles and that have been concurrently optimized with respect to a specific chemical transformation. The strategy is illustrated using an automated Mitsunobu protocol employing sets of aliphatic alcohols and phenols as precursors. The former has been formatted to perform simple alkyl homologation exercises, with the latter being designed for use in diversity-based studies. 相似文献
95.
Zbigniew J. Kamiński Stanislaw W. Markowicz Beata Kolesińska Dariusz Martynowski Marek L. Główka 《合成通讯》2013,43(14):2689-2696
Chiral mono-di-and trimenthoxy-1,3,5-triazines ware obtained from natural menthol and cyanuric chloride and applied as enantioselective coupling reagents in the synthesis of dipeptides. 相似文献
96.
Dandan Chen Dr. Dariusz W. Szczepanik Prof. Jun Zhu Prof. Miquel Solà 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(57):12964-12971
Species with adaptive aromaticity are aromatic in the ground and lowest-lying triplet excited states and they have normally intermediate singlet-triplet gaps. Few examples of compounds with adaptive aromaticity are known to date, including 16-valence-electron (16e) metallapentalenes. A sweeping search could be conducted to discover new members of this group, but efficient designs with an explicit strategy would facilitate the quest for new members of this elusive family. Density functional theory calculations and aromaticity evaluations have been performed to reveal the nature of triplet-state aromaticity in 16e metallapentalenes. Our results show that coordination of strong σ- or π-donor ligands helps achieving adaptive aromaticity of 16e metallapentalenes by means of a spin delocalization mechanism. These results have important implications for understanding the unusual properties of the organometallic adaptive aromatics, leading the way to efficient design of new compounds with tunable singlet-triplet gaps. 相似文献
97.
Król Mariusz Staszuk Marcin Mikuszewski Tomasz Kuc Dariusz 《Journal of Thermal Analysis and Calorimetry》2018,134(1):333-341
Journal of Thermal Analysis and Calorimetry - The effect of 2 mass% rare earth elements (RE) as in mischmetal state on the structure, thermal behaviour and mechanical properties of... 相似文献
98.
ukasz Gondek Dariusz Kaczorowski Andrzej Szytua 《Solid State Communications》2009,149(47-48):2181-2184
Magnetic, electrical transport and heat capacity measurements have been performed on polycrystalline sample of the compound TmRu2Si2, which crystallizes with the tetragonal ThCr2Si2-type crystal structure. The results show paramagnetic behaviour down to 0.3 K, at variance with the literature data. On the basis of the collected data, possible origins of non-magnetic behaviour are discussed. Mixed valence of Tm ions or hybridisation between Tm 4f and Ru 4d states are the most probable reasons for paramagnetic behaviour of the TmRu2Si2. 相似文献
99.
Dr. Dariusz G. Piekarski Pascal Steinforth Dr. Melania Gómez-Martínez Dr. Julia Bamberger Florian Ostler Prof. Dr. Monika Schönhoff Prof. Dr. Olga García Mancheño 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17598-17603
H-bond donor catalysts able to modulate the reactivity of ionic substrates for asymmetric reactions have gained great attention in the past years, leading to the development of cooperative multidentate H-bonding supramolecular structures. However, there is still a lack of understanding of the forces driving the ion recognition and catalytic performance of these systems. Herein, insight into the cooperativity nature, anion binding strength, and folding mechanism of a model chiral triazole catalyst is presented. Our combined experimental and computational study revealed that multi-interaction catalysts exhibiting weak binding energies (≈3–4 kcal mol−1) can effectively recognize ionic substrates and induce chirality, while strong dependencies on the temperature and solvent were quantified. These results are key for the future design of catalysts with optimal anion binding strength and catalytic activity in target reactions. 相似文献
100.
Sadlej-Sosnowska Nina Ocios-Bębenek Agnieszka Dobrowolski Jan Cz. Boczar Dariusz 《Structural chemistry》2022,33(2):479-490
Structural Chemistry - Cumulenes and polyynes have the potential to be applied as linear, sp-hybridized, one-dimensional all-carbon nanowires in molecular electronics and optoelectronics. The... 相似文献