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31.
A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (1H, 13C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c–5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand–receptor interactions, and to hypothesize potential refinements for the compound.  相似文献   
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Tea is one of the most widely consumed beverages worldwide after water, and green tea accounts for 20% of the total tea consumption. The health benefits of green tea are attributed to its natural antioxidants, namely, catechins, which are phenolic compounds with diverse beneficial effects on human health. The beneficial effects of green tea and its major bioactive component, (−)-epigallocatechin-3-gallate (EGCG), on health include high antioxidative, osteoprotective, neuroprotective, anti-cancer, anti-hyperlipidemia and anti-diabetic effects. However, the review of green tea’s benefits on female reproductive disorders, including polycystic ovary syndrome (PCOS), endometriosis and dysmenorrhea, remains scarce. Thus, this review summarises current knowledge on the beneficial effects of green tea catechins on selected female reproductive disorders. Green tea or its derivative, EGCG, improves endometriosis mainly through anti-angiogenic, anti-fibrotic, anti-proliferative and proapoptotic mechanisms. Moreover, green tea enhances ovulation and reduces cyst formation in PCOS while improving generalised hyperalgesia, and reduces plasma corticosterone levels and uterine contractility in dysmenorrhea. However, information on clinical trials is inadequate for translating excellent findings on green tea benefits in animal endometriosis models. Thus, future clinical intervention studies are needed to provide clear evidence of the green tea benefits with regard to these diseases.  相似文献   
33.
Structural Chemistry - Binding affinity and intermolecular interactions are essential characteristics that could be used to comprehend molecular recognition between molecules in supramolecular...  相似文献   
34.
The present research work describes the productive synthesis of novel bisbenzopyronopyran derivatives 4(a-h) and 5(a-h) via the photocyclization reactions of bischromones 3(a-h) under the inert conditions. The latter compounds have been realized efficiently through the O-alkylation reactions of the 3-hydroxychromone 2 with suitable dihalogenated aliphatic/aromatic/heteroaromatic reagents in the presence of dry acetone/anhydrous K2CO3/Bu4N+I (PTC). The cyclization reaction of chalcone 1 under the Algar-Flynn-Oyamada reaction conditions (KOH/H2O2) could results in the formation of compound 2 in the good yield. The structural scaffolds of the newly prepared bischromones and resultant bisbenzopyronopyrans have been certified from the meticulous analysis of their various spectroscopic parameters such as UV-Vis, IR, 1H/13C-NMR, and ESI-MS. It was found that o/m/p-xylene and pyridine-linked final symmetrical bistetracycles exhibited higher antimicrobial potencies as compared to alkyl chain-linked cyclized products. The bischromones 3(a-h) could be able to endow modest level of antimicrobial behavior.  相似文献   
35.
Mycotoxins are highly toxic compounds often found in the food. It is of paramount importance to have analytical technique for point‐of‐care on‐spot detection for authorised personnel to immediately take the action required. Electrochemistry offers the portability for miniaturized sensor of mycotoxins. Here we show that edge‐plane pyrolytic electrode offers excellent selectivity and sensitivity towards simultaneous detection of zearalenone and citrinin. This will have a great impact for point‐of‐care mycotoxin detection.  相似文献   
36.
The synthesis and physical characterization of a new class of N‐heterocycle–boryl radicals is presented, based on five membered ring ligands with a N(sp2) complexation site. These pyrazole–boranes and pyrazaboles exhibit a low bond dissociation energy (BDE; B?H) and accordingly excellent hydrogen transfer properties. Most importantly, a high modulation of the BDE(B?H) by the fine tuning of the N‐heterocyclic ligand was obtained in this series and could be correlated with the spin density on the boron atom of the corresponding radical. The reactivity of the latter for small molecule chemistry has been studied through the determination of several reaction rate constants corresponding to addition to alkenes and alkynes, addition to O2, oxidation by iodonium salts and halogen abstraction from alkyl halides. Two selected applications of N‐heterocycle–boryl radicals are also proposed herein, for radical polymerization and for radical dehalogenation reactions.  相似文献   
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Inspired by biological polymers, sequence‐controlled synthetic polymers are highly promising materials that integrate the robustness of synthetic systems with the information‐derived activity of biological counterparts. Polymer–biopolymer conjugates are often targeted to achieve this union; however, their synthesis remains challenging. We report a stepwise solid‐phase approach for the generation of completely monodisperse and sequence‐defined DNA–polymer conjugates using readily available reagents. These polymeric modifications to DNA display self‐assembly and encapsulation behavior—as evidenced by HPLC, dynamic light scattering, and fluorescence studies—which is highly dependent on sequence order. The method is general and has the potential to make DNA–polymer conjugates and sequence‐defined polymers widely available.  相似文献   
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Abstract

5-fluorouracil (5-FU) refers to a fluorinated pyrimidine analogue that has been widely used as an anticancer agent for colon, head, and neck cancers. Detection of 5-FU and its metabolites; 5-fluorouridine and 5-fluoro-2-deoxyuridine in biological samples allows optimization of pharmacotherapy and encourages fundamental investigations of this medication. The development of accurate and reliable sample preparation, as well as analytical methods, is critical to isolate targeted analytes from complex matrices, apart from increasing detection sensitivity of analytes. With that, this paper presents a review of prior studies pertaining to chromatographic and electrophoretic methods that focused on the analysis of 5-FU and its metabolites in biological matrices such as plasma and urine. This paper concentrates on HPLC, GC and CE systems, which are the most commonly used strategies for analytical separation of 5-FU and its metabolites from samples. Detection of these antineoplastic agents at trace level demands highly sensitive and selective analytical methodologies. Application of these analytical techniques to biological matrices is reviewed with a focus on method development strategies, including types of mobile phases and background electrolytes employed in LC and CE systems.  相似文献   
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