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排序方式: 共有178条查询结果,搜索用时 234 毫秒
171.
Yu Wang Wanying Pan Yuxuan Zhang Limin Wang Jianwei Han 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304897
The Truce-Smiles rearrangement is an intramolecular SNAr reaction, enabling the formation of a new arene carbon-carbon bond with sufficiently strong carbon-centered nucleophile. Reported here are ortho-tosylmethylene functionalized diaryliodonium salts, which can undergo an unprecedented Truce-Smiles rearrangement in ionic liquids, resulting in sulfonyl-substituted ortho-iodo diarylmethanes as a powerful class of building blocks in chemical synthesis. The protocol features aryliodo moiety as a hyper nucleofuge, facilitating the formation of Meisenheimer complex within the migratory system. 相似文献
172.
Hermann Neitz Dr. Irene Bessi Valentin Kachler Manuela Michel Prof. Dr. Claudia Höbartner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202214456
Arene-fluoroarene interactions offer outstanding possibilities for engineering of supramolecular systems, including nucleic acids. Here, we implement the tolane-perfluorotolane interaction as base pair replacement in DNA. Tolane (THH) and perfluorotolane (TFF) moieties were connected to acyclic backbone units, comprising glycol nucleic acid (GNA) or butyl nucleic acid (BuNA) building blocks, that were incorporated via phosphoramidite chemistry at opposite positions in a DNA duplex. Thermodynamic analyses by UV thermal melting revealed a compelling stabilization by THH/TFF heteropairs only when connected to the BuNA backbone, but not with the shorter GNA linker. Detailed NMR studies confirmed the preference of the BuNA backbone for enhanced polar π-stacking. This work defines how orthogonal supramolecular interactions can be tailored by small constitutional changes in the DNA backbone, and it inspires future studies of arene-fluoroarene-programmed assembly of DNA. 相似文献
173.
Dr. Jingyu Guo Junben Huang Abudukadi Tudi Prof. Xueling Hou Dr. Shujuan Han Prof. Zhihua Yang Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304238
It is important to establish and clarify the relationship between stereochemically active lone pairs and birefringence, since it is one of the significantly effective routes to explore birefringent crystals by introducing Sn-centered polyhedra with stereochemically active lone pairs. Herein, four tin(II)-based ternary halides A3SnCl5 and ASn2Cl5 (A=NH4 and Rb) have been synthesized successfully. The experimental birefringence of Rb3SnCl5 and RbSn2Cl5 is larger than or equal to 0.046 and 0.123@546 nm, respectively. Through investigating the alkali or alkaline-earth metal tin(II)-based ternary halides, the structure-performance relationship has been concluded between stereochemically active lone pairs and optical anisotropy. It is beneficial to the analysis and prediction of birefringence in tin-based halides and provides a guide for exploring tin(II)-based optoelectronic functional materials. 相似文献
174.
Maximilian Franta Johannes Gramüller Philipp Dullinger Simon Kaltenberger Prof. Dr. Dominik Horinek Prof. Dr. Ruth M. Gschwind 《Angewandte Chemie (International ed. in English)》2023,62(27):e202301183
Chiral phosphoric acids (CPA) have become a privileged catalyst type in organocatalysis, but the selection of the optimum catalyst is still challenging. So far hidden competing reaction pathways may limit the maximum stereoselectivities and the potential of prediction models. In CPA-catalyzed transfer hydrogenation of imines, we identified for many systems two reaction pathways with inverse stereoselectivity, featuring as active catalyst either one CPA or a hydrogen bond bridged dimer. NMR measurements and DFT calculations revealed the dimeric intermediate and a stronger substrate activation via cooperativity. Both pathways are separable: Low temperatures and high catalysts loadings favor the dimeric pathway (ee up to −98 %), while low temperatures with reduced catalyst loading favor the monomeric pathway and give significantly enhanced ee (92–99 % ee; prior 68–86 % at higher temperatures). Thus, a broad impact is expected on CPA catalysis regarding reaction optimization and prediction. 相似文献
175.
Ruiqing Li Zirui Wang Tingting Zhu Huang Ye Jianbo Wu Prof. Xitao Liu Prof. Junhua Luo 《Angewandte Chemie (International ed. in English)》2023,62(45):e202308445
Bulk photovoltaic effect, a promising optoelectronic phenomenon for generating polarized dependent steady-state photocurrent, has been widely applied in various photodetectors. However, incorporating stereochemically active lone pair to construct bulk photovoltage in organic-inorganic hybrid perovskite (OIHP) is still elusive and challenging. Herein, bulk photovoltage (1.2 V) has been successfully achieved by introducing the stereo-chemically active lone pair perovskitizer to construct a polar tri-layered hybrid perovskite, namely, (IBA)2MHy2Pb3Br10 ( 1 , IBA=iso-butylamine, MHy=methylhydrazine). Strikingly, owning to the promising bulk photovoltage, 1 -based detectors exhibit an ultra-highly sensitive polarized photodetection (polarization ratio of up to 24.6) under self-powered mode. This ratio surpasses all the reported two-dimension OIHP single-crystal photodetectors. In addition, detectors exhibit outstanding responsivity (≈200 mA W−1) and detectivity (≈2.4×1013 Jones). More excitingly, further investigation confirms that lone pair electrons in MHy+ result in the separation of positive and negative charges to produce directional dipoles, which further directional alignment to generate bulk photovoltage, thereby resulting in polarization-dependent photocurrent. Our findings provide a new demonstration for polar multilayer materials’ construction and may open opportunities for a host of high-sensitive polarized photodetection. 相似文献
176.
Benedikt Sieland Marcel Stahn Dr. Roland Schoch Dr. Constantin Daniliuc Dr. Sebastian Spicher Prof. Dr. Stefan Grimme Dr. Andreas Hansen Prof. Dr. Jan Paradies 《Angewandte Chemie (International ed. in English)》2023,62(35):e202308752
An isostructural series of boron/phosphorus Lewis pairs was systematically investigated. The association constants of the Lewis pairs were determined at variable temperatures, enabling the extraction of thermodynamic parameters. The stabilization of the Lewis adduct increased with increasing size of the dispersion energy donor groups, although the donor and acceptor properties of the Lewis pairs remained largely unchanged. This data was utilized to challenge state-of-the-art quantum chemical methods, which finally led to an enhanced workflow for the determination of thermochemical properties of weakly bound Lewis pairs within an accuracy of 0.6 to 1.0 kcal mol−1 for computed association free energies. 相似文献
177.
Xianglin Zhu Huibin Zong Camilo J. Viasus Pérez Honghai Miao Wei Sun Zhimin Yuan Shenghua Wang Guixin Zeng Hui Xu Zaiyong Jiang Geoffrey A. Ozin 《Angewandte Chemie (International ed. in English)》2023,62(22):e202218694
To overcome the thermodynamic and kinetic impediments of the Sabatier CO2 methanation reaction, the process must be operated under very high temperature and pressure conditions, to obtain an industrially viable conversion, rate, and selectivity. Herein, we report that these technologically relevant performance metrics have been achieved under much milder conditions using solar rather than thermal energy, where the methanation reaction is enabled by a novel nickel-boron nitride catalyst. In this regard, an in situ generated HOB⋅⋅⋅B surface frustrated Lewis's pair is considered responsible for the high Sabatier conversion 87.68 %, reaction rate 2.03 mol gNi−1h−1, and near 100 % selectivity, realized under ambient pressure conditions. This discovery bodes well for an opto-chemical engineering strategy aimed at the development and implementation of a sustainable ‘Solar Sabatier’ methanation process. 相似文献
178.
Prof. Shujuan Han Abudukadi Tudi Wenbin Zhang Prof. Xueling Hou Prof. Zhihua Yang Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(26):e202302025
The combination of SnII or SbIII with π, non-π-conjugated units has produced birefringent crystals with birefringence ranging from 0.005 to 0.468@1064 nm. It is proven that introducing SnII or SbIII into crystals is a feasible strategy to enlarge the birefringence, which not only promotes the miniaturization of fabricated devices, but also effectively modulates polarized light. Herein, recently discovered SnII, SbIII-based birefringent crystals with birefringence investigated are summarized, including their crystal structure and optical properties, especially birefringence. This review also presents the influence of SnII, SbIII with stereochemically active lone pair on the optical anisotropy. We hope that this work provides a clear perspective on the crystal chemistry of SnII, SbIII-based optical functional crystals and promotes the development of new birefringent crystals with large optical anisotropy. 相似文献