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261.
YI Yangjie XU Leitao LIU Yuyang LI Mingfang ZHANG Lijuan YE Jiao HU Aixi 《高等学校化学研究》2023,39(2):318-324
Iodized salts are widely used as mediators to promote C—H functionalization. Solvents and additives have been described as significant roles in these reactions. However, the further electrochemical investigations have rarely been reported. Herein, a KI mediated electrochemical annulation between acetophenones and 2-amniopyridines was developed. We revealed the effect of acids and solvents by cyclic voltammetry(CV), differential pulse voltammetry(DPV), and square wave voltammetry(SWV). The oxidation of 2-aminopyridine is inhibited at the potential window with the addition of strong acids, and the lowest oxidation potential difference of KI was obtained by utilizing EtOH as solvent. The experimental studies also show that the mixture solvent of EtOH/DMSO(9/1, volume ratio) facilitates the electrochemical cyclization due to the solubility improvement of KI. CF3SO3H has been screened as the optimal acid. A range of Imidazo[1,2-a]- pyridines have been synthesized in yields of 42% to 96%. Electrochemical investigations present that the KI mediated electro- chemical reaction is probably solvent-dependence. 相似文献
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Modification of nano-fibriform silica by dimethyldichlorosilane 总被引:1,自引:0,他引:1
The modification of nano-fibriform silica by dimethyldichlorosilane was studied by transmission electron microscopy, X-ray powder diffraction, infrared spectroscopy, Raman spectroscopy, physical N2 adsorption techniques, differential thermal and thermogravimetric analysis, scanning electron microscopy, and elemental analyzer.The results show that dimethyl silane derivatives have been successfully covalently grafted on nano-fibriform silica. The polarity of the modified product decreases with the substitution of -OH groups by siloxyl groups. Therefore, the modified product can be easily dispersed in organic solvent and its compatibility with organic molecules is improved. After modification the pore volume decreases and the ductility greatly increases, indicating that the modified product is of a higher strength than before. The study demonstrates that the modified product can be used as an ideal additive to reinforce the strength of organic materials. 相似文献
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Jianhong Yang Wenyu Liu Shucai Li Haoyu Ye Huan Tang Lijuan Chen Aihua Peng 《Helvetica chimica acta》2014,97(2):278-282
A new coumarinolignan, cleomiscosin E ( 1 ), together with the known compound cleomiscosin A ( 2 ), has been isolated from the seeds of Brucea javanica (L.) Merr . Their structures were assigned on the basis of spectral studies. These two compounds exhibited potent anti‐inflammatory activities by inhibiting the nitric oxide (NO) production in lipopolysaccharide (LPS)‐activated RAW264.7 macrophages. 相似文献
268.
In this work, a label-free electrochemical aptamer-based sensor (aptasensor) was constructed on account of the direct immobilization of redox probes on an electrode surface. For this proposed aptasensor, a gold nanoparticles (AuNPs)-coated electrode was firstly modified with redox probes-nickel hexacyanoferrates nanoparticles (NiHCFNPs) through chemisorption and electrostatic adsorption. Then, platinum-gold alloy nanoparticles (Pt-AuNPs) and horseradish peroxidase (HRP) were respectively assembled onto the modified electrode surface, which formed the multilayer films for amplifying the electrochemical signal of NiHCFNPs and immobilizing thiolated thrombin aptamers (TBAs). In the presence of target thrombin, the TBA on the multilayer could catch the thrombin onto the electrode surface, which resulted in a barrier for electro-transfer, leading to the decrease of the electrochemical signal of NiHCFNPs amplified by the Pt-AuNPs and HRP toward H(2)O(2). The proposed method avoided the redox probes labeling process, increased the amount of redox probes, and further amplified the electrochemical signal. Thus, the approach showed a high sensitivity and a wider linearity to thrombin in the range between 0.01 nM and 50 nM with a detection limit of 6.3 pM. 相似文献
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Qiu F Tu C Wang R Zhu L Chen Y Tong G Zhu B He L Yan D Zhu X 《Chemical communications (Cambridge, England)》2011,47(34):9678-9680
By using a cosolvent self-assembly approach, the emission of multi-micelle aggregates from star copolymer unimolecular micelles is enhanced greatly through restriction of concentration self-quenching and intermolecular aggregation of a conjugated polymer core, due to the existence of a PEG shell of HCP-star-PEG unimolecular micelles. 相似文献
270.
Mingyue Qiu Haonan Wu Yi Huang Huijuan Guo Dan Gao Feng Pei Lijuan Shi Qun Yi 《Molecules (Basel, Switzerland)》2022,27(18)
The design of high-efficiency CO2 adsorbents with low cost, high capacity, and easy desorption is of high significance for reducing carbon emissions, which yet remains a great challenge. This work proposes a facile construction strategy of amino-functional dynamic covalent materials for effective CO2 capture from flue gas. Upon the dynamic imine assembly of N-site rich motif and aldehyde-based spacers, nanospheres and hollow nanotubes with spongy pores were constructed spontaneously at room temperature. A commercial amino-functional molecule tetraethylenepentamine could be facilely introduced into the dynamic covalent materials by virtue of the dynamic nature of imine assembly, thus inducing a high CO2 capacity (1.27 mmol·g−1) from simulated flue gas at 75 °C. This dynamic imine assembly strategy endowed the dynamic covalent materials with facile preparation, low cost, excellent CO2 capacity, and outstanding cyclic stability, providing a mild and controllable approach for the development of competitive CO2 adsorbents. 相似文献