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51.
Hiroyuki Kubota Prof. Makoto Ouchi 《Angewandte Chemie (International ed. in English)》2023,62(7):e202217365
The development of polymers with on-demand degradability is required to alleviate the current global issues on polymer-waste pollution. Therefore, we designed a vinyl ether monomer with an o-nitrobenzyl (oNBn) group as a photo-deprotectable pendant (oNBnVE) and synthesized an alternating copolymer with an oNBn-capped acetal backbone via cationic copolymerization with p-tolualdehyde (pMeBzA). The resultant alternating copolymer could be rapidly degraded into lower-molecular-weight compounds upon simple exposure to UV irradiation without any reactants or catalysts, while it was sufficiently stable toward heat and ambient light. This degradation proceeds via cleavage of the hemiacetal structure generated upon photo-deprotection of the oNBn pendant. The oNBn-peculiar degradability allowed the exclusive photo-degradation of the oNBnVE/pMeBzA segments in a diblock copolymer composed of oNBnVE/pMeBzA and benzyl vinyl ether (BnVE)/pMeBzA segments. 相似文献
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Yongchao Qian Yadong Wu Dr. Shuai Qiu Xiaofeng He Prof. Yuyang Liu Dr. Xiang-Yu Kong Prof. Wei Tian Prof. Lei Jiang Prof. Liping Wen 《Angewandte Chemie (International ed. in English)》2023,62(18):e202300167
Biological proton channels play important roles in the delicate metabolism process, and have led to great interest in mimicking selective proton transport. Herein, we designed a bioinspired proton transport membrane by incorporating flexible 14-crown-4 (14C4) units into rigid frameworks of polyimine films by an interfacial Schiff base reaction. The Young's modulus of the membrane reaches about 8.2 GPa. The 14C4 units could grab water, thereby forming hydrogen bond-water networks and acting as jumping sites to lower the energy barrier of proton transport. The molecular chains present a vertical orientation to the membrane, and the ions travel between the quasi-planar molecular sheets. Furthermore, the 14C4 moieties could bond alkali ions through host–guest interactions. Thus, the ion conductance follows H+≫K+>Na+>Li+, and an ultrahigh selectivity of H+/Li+ (ca. 215) is obtained. This study provides an effective avenue for developing ion-selective membranes by embedding macrocycle motifs with inherent cavities. 相似文献
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Xuemei Ma Dr. Hongwei Fu Jingyi Shen Dr. Dianwei Zhang Dr. Jiawan Zhou Prof. Chunyi Tong Prof. Apparao M. Rao Prof. Jiang Zhou Prof. Ling Fan Prof. Bingan Lu 《Angewandte Chemie (International ed. in English)》2023,62(49):e202312973
Ether-based electrolytes are promising for secondary batteries due to their good compatibility with alkali metal anodes and high ionic conductivity. However, they suffer from poor oxidative stability and high toxicity, leading to severe electrolyte decomposition at high voltage and biosafety/environmental concerns when electrolyte leakage occurs. Here, we report a green ether solvent through a rational design of carbon-chain regulation to elicit steric hindrance, such a structure significantly reducing the solvent‘s biotoxicity and tuning the solvation structure of electrolytes. Notably, our solvent design is versatile, and an anion-dominated solvation structure is favored, facilitating a stable interphase formation on both the anode and cathode in potassium-ion batteries. Remarkably, the green ether-based electrolyte demonstrates excellent compatibility with K metal and graphite anode and a 4.2 V high-voltage cathode (200 cycles with average Coulombic efficiency of 99.64 %). This work points to a promising path toward the molecular design of green ether-based electrolytes for practical high-voltage potassium-ion batteries and other rechargeable batteries. 相似文献
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丁建辉 《河南科技大学学报(自然科学版)》2002,23(3):44-47
介绍了采用以太网 ,在以PLC为核心技术实现槽下上料系统、热风炉换炉系统的自动控制 ,以及热风炉、值班室重要参数数据的自动采集处理与监视的基础上开发设计的安阳钢厂 1#高炉局域网控制系统 ,全面实现了高炉主要生产工艺的自动控制和对整个高炉炼铁生产的集中监控 ,应用实践表明 ,该系统运行稳定可靠。 相似文献
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以1,4-二氯甲氧基丁烷为氯甲基化试剂合成线型氯甲基化聚苯乙烯 总被引:3,自引:0,他引:3
采用自制的氯甲基化试剂——1,4-二氯甲氧基丁烷(BCMB),使用Lewis酸催化剂,在均相反应体系中高效地实现了聚苯乙烯的氯甲基化.研究了反应机理,考察了各种因素对氯甲基化反应的影响规律,优化了反应条件,通过红外光谱法与Volhard分析法表征了产物的化学结构与组成.实验结果表明,反应机理可能由苯环亲电取代与伴随着醚键断裂的亲核取代两类反应构成,氯甲基化试剂用量、催化剂的酸性与用量、溶剂的性质与用量及反应温度等因素对反应都有显著的影响,其一,会影响聚苯乙烯的氯甲基化程度,其二,会导致或避免大分子链之间通过Friedel-Crafts反应而发生交联.以四氯化碳为溶剂、以SnCl4为催化剂并在较低温度(18℃)下进行反应,可制得氯甲基化程度达80%且完全线型化的氯甲基化聚苯乙烯. 相似文献
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采用SE- 30毛细柱、FID、程序升温气相色谱法分析了TAME合成原料及产品的C5组成 ,解析出 C5的8个组分 ;采用 GDX1 0 4填充柱、TCD对含醚产品进行了分析 ,解析出水、甲醇及 TAME。为试验研究和工业生产提供了一种快速准确的方法。 相似文献