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排序方式: 共有1669条查询结果,搜索用时 15 毫秒
1.
Won Ja Min Gabriel Marmitt RRT Participants Pedro L. Grande DaeWon Moon 《Surface and interface analysis : SIA》2019,51(7):712-721
Medium-energy ion scattering (MEIS) has been used for quantitative depth profiling with single atomic layer resolution to determine the composition, thickness, and interface structure of ultrathin films and nanoparticles. To assure the consistency of the MEIS analysis, an international round-robin test (RRT) with nominally 1-, 3-, 5-, and 7-nm thick HfO2 films was conducted among 12 institutions. The measurements were performed at each participating laboratory under their own conditions, and the collected data were analyzed. For the data analysis, the Moliere potential, the stopping and range of ions in matter (SRIM) 95 and new fitted electronic stopping power and the Chu straggling were used. For analyzing the MEIS data from the magnetic sector and electrostatic analyzers, the neutralization corrections of Marion and Young for 100-keV H+ and He+ ions and of Armstrong for 400- to 500-keV He+ ions were used. The standard deviations were 5.3% for the composition, 15.3% for the thickness, and 13.3% for the Hf content, and they were improved to 7.3%, 4.5%, and 7.0% by using refitted electronic stopping powers based on the experimental data. Hence, this study suggests that correct electronic stopping powers are critical for quantitative MEIS analysis. 相似文献
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Detoxification of Chemical Warfare Agents Using a Zr6‐Based Metal–Organic Framework/Polymer Mixture 下载免费PDF全文
Dr. Su‐Young Moon Emmanuel Proussaloglou Gregory W. Peterson Dr. Jared B. DeCoste Morgan G. Hall Dr. Ashlee J. Howarth Prof. Joseph T. Hupp Prof. Omar K. Farha 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(42):14864-14868
Owing to their high surface area, periodic distribution of metal sites, and water stability, zirconium‐based metal–organic frameworks (Zr6‐MOFs) have shown promising activity for the hydrolysis of nerve agents GD and VX, as well as the simulant, dimethyl 4‐nitrophenylphosphate (DMNP), in buffered solutions. A hurdle to using MOFs for this application is the current need for a buffer solution. Here the destruction of the simulant DMNP, as well as the chemical warfare agents (GD and VX) through hydrolysis using a MOF catalyst mixed with a non‐volatile, water‐insoluble, heterogeneous buffer is reported. The hydrolysis of the simulant and nerve agents in the presence of the heterogeneous buffer was fast and effective. 相似文献
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Cellulose - In this study, cellulose microparticle were prepared by sulfuric acid hydrolysis, glyoxal crosslinking and acetylation followed by air classifying mill, and their properties including... 相似文献
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Jinho Park Beomsu Jang Yu Ji Moon Hakjun Lee 《Molecular Crystals and Liquid Crystals》2020,705(1):120-126
AbstractIn this study, as the ongoing effort to develop efficient blue OLEDs, two deep blue emitters based on indenoquinoline-substituted anthracene derivatives have been synthesized and characterized. Multilayer organic light emitting diodes were fabricated with the following sequence: indium-tin-oxide (ITO)/4,4’,4’’-tris[2-naphthyl(phenyl)amino (2-TNATA)/4,4’-bis(N-(1-naphthyl)-N-phenylamino) biphenyl (NPB)/Blue emitting materials/Bathophenanthroline (Bphen)/lithium quinolate (Liq)/Al. All the devices showed efficient blue emissions. Particularly, a device using ‘2,7,7,13,13-pentamethyl-9-(10-phenylanthracen-9-yl)?7,13-dihydrobenzo[5,6]-s-indaceno[1,2-g] quinoline’ as an emitter showed a maximum external quantum efficiency (EQE) of 4.92% with the Commission Internationale De L’Énclairage (CIE) coordinates of (0.15, 0.10) at 8.0?V. 相似文献
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Dr. Sook Young Moon Dr. Woo Sik Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(59):13635-13639
Synthesis of continuous spinnable carbon nanotube (CNT) fibers is the most promising method for producing CNT fibers for commercial applications. The floating-catalyst chemical vapor deposition (FC-CVD) method is a rapid process that achieves catalyst formation, CNT nucleation and growth, and aerogel-like sock formation within a few seconds. However, the formation mechanism is unknown. Herein, the progress of CNT fiber formation with bimetallic catalysts was studied, and the effect of catalyst composition to CNT fiber synthesis and their structural properties was investigated. In the case of bimetallic catalysts, the carbon source rapidly decomposes and generates various secondary hydrocarbon species, such as CH4, C2H4, C2H2, C3H6, and C4H10 whereas monometallic catalysts generate only CH4 and C2H4 on decomposition. CNT fiber formation with Fe1Ni0 begins about 400 mm from the reactor entrance, whereas CNT formation with Fe0.8Ni0.2 and Fe0.5Ni0.5 begins at about 500 and 300 mm, respectively. The formed CNT bundles and individual CNTs are oriented along the gas flow at these locations. The enhanced rate of fiber formation and lowering of growth temperature associated with bimetallic catalysts is explained by the synergistic effects between the two metals. The synthesized CNTs become predominantly semiconducting with increasing Ni contents. 相似文献
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Lee Byung-Chul Kim Seon-Byeong Moon Jei-Kwon Park Sang-Yoon 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(1):91-103
Journal of Radioanalytical and Nuclear Chemistry - Complete sets of reaction mechanisms are proposed in the acidic and reductive dissolution of magnetite, nickel ferrite, and chromite using the... 相似文献
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Minkyu Kim Moon Jong Han Hansol Lee Paraskevi Flouda Daria Bukharina Kellina J. Pierce Katarina M. Adstedt Madeline L. Buxton Young Hee Yoon William T. Heller Srikanth Singamaneni Vladimir V. Tsukruk 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305646
Chiral metal–organic frameworks (MOFs) have gained rising attention as ordered nanoporous materials for enantiomer separations, chiral catalysis, and sensing. Among those, chiral MOFs are generally obtained through complex synthetic routes by using a limited choice of reactive chiral organic precursors as the primary linkers or auxiliary ligands. Here, we report a template-controlled synthesis of chiral MOFs from achiral precursors grown on chiral nematic cellulose-derived nanostructured bio-templates. We demonstrate that chiral MOFs, specifically, zeolitic imidazolate framework (ZIF), unc -[Zn(2-MeIm)2, 2-MeIm=2-methylimidazole], can be grown from regular precursors within nanoporous organized chiral nematic nanocelluloses via directed assembly on twisted bundles of cellulose nanocrystals. The template-grown chiral ZIF possesses tetragonal crystal structure with chiral space group of P41, which is different from traditional cubic crystal structure of I-43 m for freely grown conventional ZIF-8. The uniaxially compressed dimensions of the unit cell of templated ZIF and crystalline dimensions are signatures of this structure. We observe that the templated chiral ZIF can facilitate the enantiotropic sensing. It shows enantioselective recognition and chiral sensing abilities with a low limit of detection of 39 μM and the corresponding limit of chiral detection of 300 μM for representative chiral amino acid, D- and L- alanine. 相似文献