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81.
《中国化学会会志》2018,65(4):383-394
Published data on the preparation of biscoumarin derivatives is discussed in this review. Biscoumarins are synthesized via the reaction of 4‐hydroxy coumarin and different aldehydes. Many attempts have been made to apply various catalysts and also different reaction conditions to synthesize biscoumarins. The role of the catalyst and the reaction conditions on the reaction time and yield of the products is discussed. 相似文献
82.
Antioxidant coumarin and pyrone derivatives from the insect-associated fungus Aspergillus Versicolor
Tian-Xiao Li Dan-Dan Meng Ying Wang Jin-Lu An Jia-Feng Bai Xue-Wei Jia 《Natural product research》2020,34(10):1360-1365
AbstractTwo new compounds, versicolones A and B (1 and 2), and three known pyrone derivatives (3?5) were isolated from the insect-associated fungus Aspergillus versicolor. Their structures were elucidated through a combination of HRESIMS and NMR spectroscopic analysis. Versicolone A (1) was revealed as a coumarin derivative with the rare 5-alkyl side chain substitution. Compound 5 exhibited significant antioxidant activity with EC50 value of 8.0?μM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was more than 2-fold potency of the positive control trolox. 相似文献
83.
Sebastiano Di Pietro Dalila Iacopini Aldo Moscardini Ranieri Bizzarri Mauro Pineschi Valeria Di Bussolo Giovanni Signore 《Molecules (Basel, Switzerland)》2021,26(5)
Europium (III) luminescent chelates possess intrinsic photophysical properties that are extremely useful in a wide range of applications. The lack of examples of coumarin-based lanthanide complexes is mainly due to poor photo-sensitization attempts. However, with the appeal of using such a versatile scaffold as antenna, especially in the development of responsive molecular probes, it is worth the effort to research new structural motifs. In this work, we present a series of two new tris coumarin-dipicolinate europium (III) complexes, specifically tailored to be either a mono or a dual emitter, tuning their properties with a simple chemical modification. We also encountered a rich chemical speciation in solution, studied in detail by means of paramagnetic NMR and emission spectroscopy. 相似文献
84.
Coumarins are omnipresent in several plants and exhibit a plethora of pharmacological properties, making them an important scaffold in organic synthesis. Naturally, the chemistry of this motif has attracted ever-increasing attention, among which palladium-catalyzed coupling reactions are the most prevalent one. Numerous useful, easy, and concise syntheses and reactions have been achieved using palladium-catalyzed coupling reactions. This review focuses on recent advances in palladium-catalyzed cross-coupling reactions such as Suzuki, Heck, Stille, Sonogoshira etc. reactions of coumarin derivatives and covers the literature from 2001 to 2020. 相似文献
85.
Multi‐Fluorinated Azido Coumarins for Rapid and Selective Detection of Biological H2S in Living Cells 下载免费PDF全文
Zhentao Zhu Yanyan Li Chao Wei Xin Wen Prof. Dr. Zhen Xi Prof. Dr. Long Yi 《化学:亚洲杂志》2016,11(1):68-71
Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule with multiple biological functions. In order to visualize the endogenous in situ production of H2S in living cells in real time, here we developed multi‐fluorinated azido coumarins as fluorescent probes for the rapid and selective detection of biological H2S. Kinetic studies indicated that an increase in fluorine substitution leads to an increased rate of H2S‐mediated reduction reaction, which is also supported by our theoretical calculations. To our delight, tetra‐fluorinated coumarin 1 could react with H2S fast (t1/2≈1 min) and selectively, which could be further used for continuous enzymatic assays and for visualization of intracellular H2S. Bioimaging results obtained with 1 revealed that d ‐Cys could induce a higher level of endogenous H2S production than l ‐Cys in a time‐dependent manner in living cell. 相似文献
86.
Keto‐benzo[h]‐Coumarin‐Based Near‐Infrared Dyes with Large Stokes Shifts for Bioimaging Applications 下载免费PDF全文
Guangle Niu Prof. Dr. Weimin Liu Prof. Dr. Hongyan Xiao Prof. Dr. Hongyan Zhang Jianhong Chen Qing Dai Prof. Dr. Jiechao Ge Prof. Dr. Jiasheng Wu Prof. Dr. Pengfei Wang 《化学:亚洲杂志》2016,11(4):498-504
Fluorescence imaging is a promising tool for the visualization of biomolecules in living systems and there is great demand for new fluorescent dyes that absorb and emit in the near‐infrared (NIR) region. Herein, we constructed three new fluorescent dyes ( NBC dyes) based on keto‐benzo[h]coumarin ( k‐BC ) and benzopyrilium salts. These dyes showed large Stokes shifts (>100 nm) and NIR emission (>800 nm). The relationship between the structures and optical properties of these dyes was further investigated by using density functional theory calculations at the B3LYP/6‐3G level of theory. Fluorescence images indicated that the fabricated dyes exhibited good photostability and low cytotoxicity and, thus, have potential applications as imaging agents in living cells and animals. 相似文献
87.
One new coumarin, 3,5-dihydroxy-7-O-α-L-rhamno pyranosyl-2H-chromen-2-one (1), was isolated from the whole plant of Sarcandra glabra. The structure was elucidated by spectroscopic methods. Our results indicated that 1 significantly inhibit nitric oxide (NO) production in LPS-induced RAW264.7 macrophages. RT-PCR analysis indicated it inhibited iNOS mRNA expression. In addition, Western blot analysis showed that 1 attenuated LPS-induced synthesis of iNOS protein in the macrophages. These results suggest that 1 could be potential anti-inflammatory agent by down-regulating iNOS expression. 相似文献
88.
使用溶剂诱导相变萃取对中成药及原料药进行预处理,建立了中成药中香豆素的超高效合相色谱(UPC2)检测方法。样品经粉碎(60目)、乙腈-水(7∶3,体积比)提取,二氯甲烷诱导分相后,使用UPC2对样品中的香豆素进行检测。以3倍信噪比(S/N)确定香豆素的检出限为0.1 mg/L;线性范围为0.3~10.0mg/L;加标回收率为89.8%~102.3%;相对标准偏差为0.31%~1.0%。同时与UPLC进行比较,结果表明该方法的选择性高,检测成本低,且分析时间仅为UPLC的1/4。该研究为高通量检测香豆素提供了一种全新的前处理及检测方法。 相似文献
89.
Weerachai Phutdhawong Apiwat Chuenchid Thongchai Taechowisan Jitnapa Sirirak Waya S. Phutdhawong 《Molecules (Basel, Switzerland)》2021,26(6)
A series of novel coumarin-3-carboxamide derivatives were designed and synthesized to evaluate their biological activities. The compounds showed little to no activity against gram-positive and gram-negative bacteria but specifically showed potential to inhibit the growth of cancer cells. In particular, among the tested compounds, 4-fluoro and 2,5-difluoro benzamide derivatives (14b and 14e, respectively) were found to be the most potent derivatives against HepG2 cancer cell lines (IC50 = 2.62–4.85 μM) and HeLa cancer cell lines (IC50 = 0.39–0.75 μM). The activities of these two compounds were comparable to that of the positive control doxorubicin; especially, 4-flurobenzamide derivative (14b) exhibited low cytotoxic activity against LLC-MK2 normal cell lines, with IC50 more than 100 μM. The molecular docking study of the synthesized compounds revealed the binding to the active site of the CK2 enzyme, indicating that the presence of the benzamide functionality is an important feature for anticancer activity. 相似文献
90.
Joo Sarrato Ana Lucia Pinto Gabriela Malta Eva G. Rck Joo Pina Joo Carlos Lima A. Jorge Parola Paula S. Branco 《Molecules (Basel, Switzerland)》2021,26(10)
A set of 3-ethynylaryl coumarin dyes with mono, bithiophenes and the fused variant, thieno [3,2-b] thiophene, as well as an alkylated benzotriazole unit were prepared and tested for dye-sensitized solar cells (DSSCs). For comparison purposes, the variation of the substitution pattern at the coumarin unit was analyzed with the natural product 6,7-dihydroxycoumarin (Esculetin) as well as 5,7-dihydroxycomarin in the case of the bithiophene dye. Crucial steps for extension of the conjugated system involved Sonogashira reaction yielding highly fluorescent molecules. Spectroscopic characterization showed that the extension of conjugation via the alkynyl bridge resulted in a strong red-shift of absorption and emission spectra (in solution) of approximately 73–79 nm and 52–89 nm, respectively, relative to 6,7-dimethoxy-4-methylcoumarin (λabs = 341 nm and λem = 410 nm). Theoretical density functional theory (DFT) calculations show that the Lowest Unoccupied Molecular Orbital (LUMO) is mostly centered in the cyanoacrylic anchor unit, corroborating the high intramolecular charge transfer (ICT) character of the electronic transition. Photovoltaic performance evaluation reveals that the thieno [3,2-b] thiophene unit present in dye 8 leads to the best sensitizer of the set, with a conversion efficiency (η = 2.00%), best VOC (367 mV) and second best Jsc (9.28 mA·cm−2), surpassed only by dye 9b (Jsc = 10.19 mA·cm−2). This high photocurrent value can be attributed to increased donor ability of the 5,7-dimethoxy unit when compared to the 6,7 equivalent (9b). 相似文献