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751.
Chong Wang Chang-Yi Tian Ya Zhao Shuai Jiang Tiantong Wang Huijun Zheng Wenhui Yan Prof. Dr. Gang Li Prof. Dr. Hua Xie Prof. Dr. Jun Li Prof. Dr. Han-Shi Hu Prof. Dr. Xueming Yang Prof. Dr. Ling Jiang 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305490
Spectroscopic characterization of neutral highly-coordinated compounds is essential in fundamental and applied research, but has been proven to be a challenging experimental target because of the difficulty in mass selection. Here, we report the preparation and size-specific infrared-vacuum ultraviolet (IR-VUV) spectroscopic identification of group-3 transition metal carbonyls Sc(CO)7 and TM(CO)8 (TM=Y, La) in the gas phase, which are the first confinement-free neutral heptacarbonyl and octacarbonyl complexes. The results indicate that Sc(CO)7 has a C2v structure and TM(CO)8 (TM=Y, La) have a D4h structure. Theoretical calculations predict that the formation of Sc(CO)7 and TM(CO)8 (TM=Y, La) is both thermodynamically exothermic and kinetically facile in the gas phase. These highly-coordinated carbonyls are 17-electron complexes when only those valence electrons that occupy metal−CO bonding orbitals are considered, in which the ligand-only 4b1u molecular orbital is ignored. This work opens new avenues toward the design and chemical control of a large variety of compounds with unique structures and properties. 相似文献
752.
Dr. Soroush Naseri Dr. Inès Taarit Dr. Hélène Bolvin Prof. Dr. Jean-Claude Bünzli Dr. Alexandre Fürstenberg Dr. Laure Guénée Dr. Giau Le-Hoang Dr. Mohsen Mirzakhani Dr. Homayoun Nozary Dr. Arnulf Rosspeintner Prof. Dr. Claude Piguet 《Angewandte Chemie (International ed. in English)》2023,62(50):e202314503
Previously limited to highly symmetrical homoleptic triple-helical complexes [Er( Lk )3]3+, where Lk are polyaromatic tridentate ligands, single-center molecular-based upconversion using linear optics and exploiting the excited-state absorption mechanism (ESA) greatly benefits from the design of stable and low-symmetrical [ Lk Er(hfa)3] heteroleptic adducts (hfa−=hexafluoroacetylacetonate anion). Depending on (i) the extended π-electron delocalization, (ii) the flexibility and (iii) the heavy atom effect brought by the bound ligand Lk , the near-infrared (801 nm) to visible green (542 nm) upconversion quantum yield measured for [ Lk Er(hfa)3] in solution at room temperature can be boosted by up to three orders of magnitude. 相似文献
753.
Laura M. H. Pascual Dr. Stéphanie Boudesocque Prof. Dr. Laurent Dupont Prof. Dr. Eric Hénon Prof. Dr. Aminou Mohamadou Prof. Dr. Richard Plantier-Royon Dr. Sylvain Gatard 《欧洲无机化学杂志》2023,26(9):e202200581
A short and convenient approach to the original xyloside-based ligands, has been achieved, using d -xylose as a starting material. The complexation properties of these ligands towards Au(III) cations were studied by different methods, such as multinuclear NMR, mass spectrometry, elemental analysis. A preliminary study using protometric titrations has been carried out in aqueous solution under various pH conditions, thus in order to investigate the binding of Au(III) cations to these ligands. Furthermore, molecular calculations were performed to obtain additional structural information. The catalytic activity of the most stable Au(III) complexes was evaluated for the homogeneous reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4. 相似文献
754.
Tongyu Li Dongwei Wang Yi Heng Dr. Guohua Hou Prof. Guofu Zi Dr. Wanjian Ding Prof. Dr. Laurent Maron Prof. Dr. Marc D. Walter 《Angewandte Chemie (International ed. in English)》2023,62(50):e202313010
Uranium diazomethanediide complexes can be prepared and their synthesis, structure and reactivity were explored. Reaction of the uranium imido compound [η5-1,2,4-(Me3Si)3C5H2]2U=N(p-tolyl)(dmap) ( 1 ) or [η5-1,3-(Me3C)2C5H3]2U=N(p-tolyl)(dmap) ( 4 ) with Me3SiCHN2 cleanly yields the first isocyanoimido metal complexes [η5-1,2,4-(Me3Si)3C5H2]2U(=NNC)(μ-CNN=)U(dmap)[η5-1,2,4-(Me3Si)3C5H2]2 ( 2 ) and {[η5-1,3-(Me3C)2C5H3]2U[μ-(=NNC)]}6 ( 5 ), respectively. Both compounds exhibit remarkable thermal stability and were fully characterized. According to density functional theory (DFT) studies the bonding between the Cp2U2+ and [NNC]2− moieties is strongly polarized with a significant 5 f orbital contribution, which is also reflected in the reactivity of these complexes. For example, complex 5 acts as a nucleophile toward alkylsilyl halides and engages in a [2+2] cycloaddition with CS2, but no reaction occurs in the presence of internal alkynes. 相似文献
755.
Jian-Fei Ge Xi-Zhang Zou Xin-Ru Liu Chong-Lei Ji Xin-Yuan Zhu Prof. Dr. De-Wei Gao 《Angewandte Chemie (International ed. in English)》2023,62(32):e202307447
Asymmetric cross-couplings based on 1,2-carbon migration from B-ate complexes have been developed efficiently to access valuable organoboronates. However, enantioselective reactions triggered by 1,2-boron shift have remained to be unaddressed synthetic challenge. Here, Ir-catalyzed asymmetric allylic alkylation enabled by 1,2-boron shift was developed. In this reaction, we disclosed that excellent enantioselectivities were achieved through an interesting dynamic kinetic resolution (DKR) process of allylic carbonates at the elevated temperature. Notably, the highly valuable (bis-boryl)alkenes have enabled an array of diversifications to access versatile molecules. Extensive experimental and computational studies were conducted to elucidate the reaction mechanism of DKR process and clarify the origin of excellent enantioselectivities. 相似文献
756.
Yan Chen Dr. Yusheng Shi Dr. Zhanming Gao Dr. Lei Wang Yutian Tang Prof. Dr. Jinxuan Liu Prof. Dr. Chun Liu 《Angewandte Chemie (International ed. in English)》2023,62(28):e202302581
Supramolecular copolymers have attracted much attention due to their potential functionalities. However, the co-assembly strategies to construct co-assemblies of small molecules with well-defined sequence structures are still limited, especially for more complex crystalline block co-assemblies. Herein, we target this challenge by designing IrIII complexes 1 and 2 , which possess unique self-assembly pathways and are capable of forming crystalline assemblies in aqueous systems. Specifically, block and random co-assemblies of 1 and 2 can be synthesized by kinetic and thermodynamic control, respectively. Meanwhile, by adjusting the water content to orthogonalize the on-pathway and the off-pathway, an unprecedented pathway-switching approach is realized to synthesize block and random co-assemblies. By coupling the kinetic pathways, the present co-assembly strategies are expected to pave the way for the synthesis of crystalline co-assemblies of small molecules and the construction of organic heterostructures. 相似文献
757.
Dr. Fan Xie Dr. Wenhao Sun Dr. Pablo Pinacho Prof. Dr. Melanie Schnell 《Angewandte Chemie (International ed. in English)》2023,62(14):e202218539
The initial stages of the gas-phase nucleation between CO2 and monoethanolamine were investigated via broadband rotational spectroscopy with the aid of extensive theoretical structure sampling. Sub-nanometer-scale aggregation patterns of monoethanolamine-(CO2)n, n=1–4, were identified. An interesting competition between the monoethanolamine intramolecular hydrogen bond and the intermolecular interactions between monoethanolamine and CO2 upon cluster growth was discovered, revealing an intriguing CO2 binding priority to the hydroxyl group over the amine group. These findings are in sharp contrast to the general results for aqueous solutions. In the quinary complex, a cap-like CO2 tetramer was observed cooperatively surrounding the monoethanolamine. As the cluster approaches the critical size of new particle formation, the contribution of CO2 self-assembly to the overall stability increases. 相似文献