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631.
Yujie Li Xiaofu Tang Yanteng Zhang Jin Li Chengbin Lv Xinling Meng Yilong Huang Chunjin Hang Chunqing Wang 《Colloid and polymer science》2014,292(3):715-722
Cu nanoparticles of well-defined size and stability were synthesized with the aid of a double-template method. The templates consisted of sodium dodecyl sulfate (SDS) aggregates combined with and wrapped by poly(vinylpyrrolidone) (PVP) chains. Copper sulfate was reduced within the templates resulting in multicrystalline Cu nanoparticles. The size of the particles was uniform. They were capped by PVP–SDS complexes and the shape turned out to be non-spherical. PVP used in the experiments has an average molecular weight of 40,000. In this case, the particle dimensions were essentially determined by the chosen concentration of SDS in the reaction solution. No oxidation of the as-grown copper particles was detected even in the absence of inert gas protection during the synthesis process. When exposed to air at room temperature, Cu nanoparticles capped by PVP–SDS complexes showed much better resistance to oxidation than those without the capping agents. Furthermore, the steric and screening effect of the capping agents permitted the preparation of uniform colloidal dispersions stable over months. The material obtained by this double-template method was found to be very sensitive to the synthesis temperature. At synthesis temperatures above 40 °C, CuO instead of Cu was obtained. 相似文献
632.
Metal‐Substituted Zeolitic Imidazolate Framework ZIF‐108: Gas‐Sorption and Membrane‐Separation Properties
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Yujie Ban Prof. Dr. Yanshuo Li Yuan Peng Hua Jin Wenmei Jiao Dr. Xinlei Liu Prof. Dr. Weishen Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11402-11409
A series of dual‐metal zeolitic imidazolate framework (ZIF) crystals with SOD and RHO topologies was synthesised by metal substitution from ZIF‐108 (Zn(2‐nitroimidazolate)2, SOD topology) as the parent material. This was based on the concept that metal substitution of ZIF‐108 requires a much lower activation energy than homogenous nucleation owing to the metastability of ZIF‐108. In‐depth investigations of the formation processes of the daughter ZIFs indicated that the transformation of ZIF‐108 is a dissolution/heterogeneous nucleation process. Typical isostructural Co2+ substitution mainly occurs at the outer surface of ZIF‐108 and results in a core–shell structure. On the contrary, the Cu2+‐substituted ZIF has a RHO topology with a homogeneous distribution of Cu2+ ions in the structure. Substitution with Ni2+ resulted in a remarkable enhancement in adsorption selectivity toward CO2 over N2 by a factor of up to 227. With Co2+‐substituted nanoparticles as inorganic filler, a mixed matrix membrane based on polysulfone displayed greatly improved performance in the separation of H2/CH4, CO2/N2 and CO2/CH4. 相似文献
633.
锂硫电池具有理论能量密度高等优势,被认为是最有前景的一类新型二次电池.硫正极存在硫和硫化锂的导电性差、可溶性多硫化物的扩散/穿梭、循环过程中硫的体积膨胀以及氧化还原过程慢等问题,严重制约着电池的活性和循环稳定性.设计“蛋黄-蛋壳”结构纳米反应器应用于锂硫电池正极,可通过调控其“蛋黄”、“蛋壳”和“空腔”结构缓解充放电过程中电极的体积变化,为离子/电子输运提供快速通道,强化对多硫化物的吸附和催化转换作用等,进而提高电极的活性和循环性能,有利于推进锂硫电池的商业化进程.本文总结了“蛋黄-蛋壳”结构纳米反应器的设计和调控策略,包括单核-单壳、单核-多壳、多核-单壳以及多核-多壳等,并结合锂硫电池的工作特点和目前应用存在的问题,对未来发展前景进行了展望. 相似文献
634.
Jiaqiang Wang Yujie Yang Kexin Li Prof. Liyao Zhang Prof. Zhen Li 《Angewandte Chemie (International ed. in English)》2023,62(30):e202304020
Purely organic materials with visible light excitable fluorescence afterglow are promising for applications. Herein, fluorescence afterglow with various intensity and duration was observed on fluorescent dyes once being dispersed in polymer matrix, thanks to the slow reverse intersystem crossing rate (kRISC) and long delayed fluorescence lifetime (τDF) derived from the coplanar and rigid chemical structure of the dyes. To verify the mechanism, different polymers were used to tune singlet-triplet splitting energy based on solvent effect. And commercial acriflavine (Acf) film showed blue shifted fluorescence compared to purified one, with slower kRISC (≈100 s−1) and longer τDF (0.6 s). Via energy transfer from Acf to rhodamine B, the afterglow color was further regulated, with the largest fluorescence quantum yield of 42.4 %. It was demonstrated that the materials worked on color tunable light sources, and low-cost ($2 for 50 000 labels) anti-counterfeit labels recognized by white light. 相似文献
635.
Dr. Yujie Liang Fritz Paulus Dr. Constantin G. Daniliuc Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2023,62(34):e202305043
Synthesis of bicyclic scaffolds has attracted tremendous attention because they are playing an important role as saturated bioisosteres of benzenoids in modern drug discovery. Here, we report a BF3-catalyzed [2π+2σ] cycloaddition of aldehydes with bicyclo[1.1.0]butanes (BCBs) to access polysubstituted 2-oxabicyclo[2.1.1]hexanes. A new kind of BCB containing an acyl pyrazole group was invented, which not only significantly facilitates the reactions, but can also serve as a handle for diverse downstream transformations. Furthermore, aryl and vinyl epoxides can also be utilized as substrates which undergo cycloaddition with BCBs after in situ rearrangement to aldehydes. We anticipate that our results will promote access to challenging sp3-rich bicyclic frameworks and the exploration of BCB-based cycloaddition chemistry. 相似文献
636.
Daixing Wei Yiqing Wang Prof. Chung-Li Dong Zhengqi Zhang Xinyu Wang Dr. Yu-Cheng Huang Yuchuan Shi Xiaoli Zhao Jialin Wang Prof. Ran Long Prof. Yujie Xiong Prof. Fan Dong Prof. Mingtao Li Prof. Shaohua Shen 《Angewandte Chemie (International ed. in English)》2023,62(19):e202217369
Electrochemical CO2 reduction reaction (ECO2RR) with controlled product selectivity is realized on Ag−Cu bimetallic surface alloys, with high selectivity towards C2 hydrocarbons/alcohols (≈60 % faradaic efficiency, FE), C1 hydrocarbons/alcohols (≈41 % FE) and CO (≈74 % FE) achieved by tuning surface compositions and applied potentials. In situ spectral investigations and theoretical calculations reveal that surface-composition-dependent d-band center could tune *CO binding strengths, regulating the *CO subsequent reaction pathways and then the product selectivity. Further adjusting the applied potentials will alter the energy of participated electrons, which leads to controlled ECO2RR selectivity towards desired products. A predominant region map, with an indicator proposed to evaluate the thermodynamic predominance of the *CO subsequent reactions, is then provided as a reliable theoretical guidance for the controllable ECO2RR product selectivity over bimetallic alloys. 相似文献
637.
Yujie Yang Jiaqiang Wang Dr. Jie Yang Lihuan Tong Dan Li Yuqi Yang Manman Fang Prof. Zhen Li 《Angewandte Chemie (International ed. in English)》2023,62(24):e202218994
No matter photoinduced organic radicals have been reported frequently, they are usually non-luminescent at ambient conditions. The internal mechanism on stability and electronic transitions of photoinduced radicals, is thus crucial for the development of relevant materials. Herein, a series of photoinduced radical emission systems were developed conveniently through doping benzoic acids into the hydrogen donor polyvinyl alcohol (PVA) matrix. Visual photoinduced radical emission and photochromism could be observed on Ph-3COOH @PVA film with the formation of cyclohexadienyl-type structure. For the first time, radical afterglow appeared with energy transfer from triplet state. The appropriate introduction of carboxylic groups to three nonadjacent carbon atoms on the benzene ring was the best for decreasing spin population and promoting electronic transitions of the radical. This study largely expands the radical emission property from both internal mechanism and practical application. 相似文献
638.
Jing Fang Zhiyuan Fu Xiaohong Chen Yaozu Liu Fengqian Chen Dr. Yujie Wang Dr. Hui Li Dr. Yusran Yusran Prof. Kai Wang Prof. Valentin Valtchev Prof. Shilun Qiu Prof. Bo Zou Prof. Qianrong Fang 《Angewandte Chemie (International ed. in English)》2023,62(27):e202304234
Piezochromic materials with pressure-dependent photoluminescence tuning properties are important in many fields, such as mechanical sensors, security papers, and storage devices. Covalent organic frameworks (COFs), as an emerging class of crystalline porous materials (CPMs) with structural dynamics and tunable photophysical properties, are suitable for designing piezochromic materials, but there are few related studies. Herein, we report two dynamic three-dimensional COFs based on aggregation-induced emission (AIE) or aggregation-caused quenching (ACQ) chromophores, termed JUC-635 and JUC-636 (JUC=Jilin University China), and for the first time, study their piezochromic behavior by diamond anvil cell technique. Due to the various luminescent groups, JUC-635 has completely different solvatochromism and molecular aggregation behavior in the solvents. More importantly, JUC-635 with AIE effect exhibits a sustained fluorescence upon pressure increase (≈3 GPa), and reversible sensitivity with high-contrast emission differences (Δλem=187 nm) up to 12 GPa, superior to other CPMs reported so far. Therefore, this study will open a new gate to expand the potential applications of COFs as exceptional piezochromic materials in pressure sensing, barcoding, and signal switching. 相似文献
639.
Preparation of Photo-responsive DNA Supramolecular Hydrogels and Their Application as UV Radiometers
DING Yuqiao LI Yujie YANG Bo PAN Yufan CHENG Jiafeng MENG Siwen LIU Dongsheng XU Lijin DONG Yuanchen 《高等学校化学研究》2023,39(1):115-120
Ultraviolet light(UV) is an essential component of ambient light, but high dose UV would damage genome DNA. While semiconductors and soft materials have been employed to detect the UV, the complex process and the instrumental requirement have limited the application in daily life. In this study, taking advantage of sequence designability, a series of hydrogels with different gel-sol transition rates was constructed under the same UV intensity by introducing competing hybridization to tune the stability of the molecular network. Through estimating the transition time between each system under UV light irradiation, the intensity of UV could be roughly estimated, which provided a convenient method for the visual detection of UV. 相似文献
640.