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排序方式: 共有1718条查询结果,搜索用时 15 毫秒
61.
62.
Bin Su Yang Wang Bo Feng Yongsheng Yan Enwei Zhu Bo Wang Guangbo Che 《Chinese Journal of Physics (Taipei)》2017,55(2):350-354
Organic ultraviolet photodetectors (OUV-PDs) were fabricated utilizing 2-TNATA as an electron donor with Bphen and TPBi as electron acceptors. A high sensitivity of OUV-PDs to UV light was obtained in the range of 300–420 nm. The optimized OUV-PDs composed of Bphen as the acceptor offered a photocurrent density up to 336 µA/cm2 at ?8 V with 365 nm UV light at a power of 1.2 mW/cm2. The high response is attributed to the excellent electron transport ability of Bphen and the matched energy level between 2-TNATA and Bphen. 相似文献
63.
Xue Liu Wenting Mao Dr. Jingang Jiang Dr. Xinqing Lu Mingming Peng Dr. Hao Xu Prof. Lu Han Prof. Shun-ai Che Prof. Peng Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(17):4520-4529
The conversion of the alkali-treated intergrowth germanosilicate CIT-13 into the single-crystalline high-silica ECNU-21 (named after East China Normal University) zeolite, with a novel topology and a highly crystalline zeolite framework, has been realized through a creative top-down strategy involving a mild alkaline-induced multistep process consisting of structural degradation and reconstruction. Instead of acid treatment, hydrolysis in aqueous ammonia solution not only readily cleaved the chemically weak Ge(Si)−O−Ge bonds located within the interlayer double four ring (D4R) units of CIT-13, but also cleaved the metastable Si−O−Si bonds therein. This led to extensive removal of the D4R units, and also generated silanol groups on adjacent silica-rich layers, which then condensed to form a novel daughter structure upon calcination. Individual oxygen bridges in the reassembled ECNU-21 replaced the germanium-rich D4R units in CIT-13, thereby eliminating the original intergrowth phenomenon along the b axis. With an ordered crystalline structure of 10-ring (R) channels as well as suitable germanium-related Lewis acid sites, ECNU-21 serves as a stable solid Lewis acid catalyst for the shape-selective hydration of ethylene oxide (EO) to ethylene glycol (EG) at greatly reduced H2O/EO ratios and reaction temperature in comparison with the noncatalytic industrial process. 相似文献
64.
Harun Muhammad Arif Bin Gunnasegaran Prem A./L. Sidik Nor Azwadi Che Beriache M’hamed Ghaderian Javad 《Journal of Thermal Analysis and Calorimetry》2021,144(4):1435-1449
Journal of Thermal Analysis and Calorimetry - High heat generation from electronic devices needs to cool down properly to prevent overheating. Loop heat pipe (LHP) is one of the excellent cooling... 相似文献
65.
Tongmou Geng Guofeng Chen Can Zhang Lanzhen Ma Weiyong Zhang Hongyu Xia 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):1004-1011
AbstractA mesoporous covalent triazine framework, PCPDI, was synthesized via an aromatic nitrile trimerization reaction of N,N′-di(4-cyanphenyl)- 3,4,9,10-tetracarboxydiimide (CPDI) by CF3SO3H catalyzed at 40?°C and this method avoids the use of noble metal catalyzers or high temperature reaction. PCPDI exhibits high thermal stability and strong fluorescence. The PCPDI shows ultrahigh sensitivity to tracing o-nitrophenol in chloroform with KSV constant of 1.74?×?105 L mol?1 and detection limit (LOD) of 1.72?×?10?11?mol L?1. 相似文献
66.
67.
The electronic structure and redox properties of the highly oxidizing, isolable RuV?O complex [RuV(N4O)(O)]2+, its oxidation reactions with saturated alkanes (cyclohexane and methane) and inorganic substrates (hydrochloric acid and water), and its intermolecular coupling reaction have been examined by DFT calculations. The oxidation reactions with cyclohexane and methane proceed through hydrogen atom transfer in a transition state with a calculated free energy barrier of 10.8 and 23.8 kcal mol?1, respectively. The overall free energy activation barrier (ΔG≠=25.5 kcal mol?1) of oxidation of hydrochloric acid can be decomposed into two parts: the formation of [RuIII(N4O)(HOCl)]2+ (ΔG=15.0 kcal mol?1) and the substitution of HOCl by a water molecule (ΔG≠=10.5 kcal mol?1). For water oxidation, nucleophilic attack on RuV?O by water, leading to O? O bond formation, has a free energy barrier of 24.0 kcal mol?1, the major component of which comes from the cleavage of the H? OH bond of water. Intermolecular self‐coupling of two molecules of [RuV(N4O)(O)]2+ leads to the [(N4O)RuIV? O2? RuIII(N4O)]4+ complex with a calculated free energy barrier of 12.0 kcal mol?1. 相似文献
68.
Xiuquan Jia Jiping Ma Penghua Che Fang Lu Hong Miao Jin Gao Jie Xu 《Journal of Energy Chemistry》2013,22(1):93-97
Direct conversion of fructose-based carbohydrates to 5-ethoxymethylfurfural (EMF) catalyzed by Lewis acid in ethanol was investigated. It was found that BF3·(Et)2O was favorable for 5-hydroxymethylfurfural (HMF) etherification to EMF. BF3·(Et)2O combination with AlCl3·6H2O with the molar ratio of 1 was an effective catalyst system for synthesis of EMF from fructose-based carbohydrates. 55.0%, 45.4% and 23.9% of EMF yields were obtained from fructose, inulin and sucrose under optimized conditions, respectively. 相似文献
69.
Two new nickel(II) complexes, [Ni(4, 4′‐bpy)(H2O)4]n · n(cpp) · 0.5nH2O ( 1 ) and [Ni(cpp)(4, 4′‐bpy)(H2O)2]n ( 2 ) [4, 4′‐bpy = 4, 4′‐bipyridine, H2cpp = 3‐(4‐carboxyphenyl)propionic acid] were synthesized and characterized by single‐crystal X‐ray diffraction, elemental analysis, IR spectroscopy, and thermal analysis. In complex 1 , NiII ions are bridged by 4, 4′‐bpy into 1D chains, and cpp ligands are not involved in the coordination, whereas in complex 2 , cpp ligands adopt a bis(monodentate) mode and link NiII ions into 2D (4, 4) grids with the help of 4, 4′‐bpy ligands. Triple interpenetration occurs, which results in the formation of a complicated 3D network. The difference in the structures of the two complexes can be attributed to the different reaction temperatures and bases. 相似文献
70.
The solubility of icariin in the binary solvent system of ethanol and water was measured by UV–Vis spectrophotometry from 288.2 to 328.2 K. The solubility of icariin in the system increased with increasing temperature. A synergistic effect appeared at x 2 = 0.4 (equivalent to 68.34 % ethanol, v/v) binary mixture. Solubility data were correlated with the modified Apelblat equation. The enthalpy and entropy of solution were evaluated using van’t Hoff plots. 相似文献