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排序方式: 共有416条查询结果,搜索用时 31 毫秒
361.
Prangya Rath Anuj Ranjan Arabinda Ghosh Abhishek Chauhan Manisha Gurnani Hardeep Singh Tuli Hamza Habeeballah Mustfa F. Alkhanani Shafiul Haque Kuldeep Dhama Naval Kumar Verma Tanu Jindal 《Molecules (Basel, Switzerland)》2022,27(7)
The increase in the number of cases of type 2 diabetes mellitus (T2DM) and the complications associated with the side effects of chemical/synthetic drugs have raised concerns about the safety of the drugs. Hence, there is an urgent need to explore and identify natural bioactive compounds as alternative drugs. Protein tyrosine phosphatase 1B (PTP1B) functions as a negative regulator and is therefore considered as one of the key protein targets modulating insulin signaling and insulin resistance. This article deals with the screening of a database of polyphenols against PTP1B activity for the identification of a potential inhibitor. The research plan had two clear objectives. Under first objective, we conducted a quantitative structure–activity relationship analysis of flavonoids with PTP1B that revealed the strongest correlation (R2 = 93.25%) between the number of aromatic bonds (naro) and inhibitory concentrations (IC50) of PTP1B. The second objective emphasized the binding potential of the selected polyphenols against the activity of PTP1B using molecular docking, molecular dynamic (MD) simulation and free energy estimation. Among all the polyphenols, silydianin, a flavonolignan, was identified as a lead compound that possesses drug-likeness properties, has a higher negative binding energy of −7.235 kcal/mol and a pKd value of 5.2. The free energy-based binding affinity (ΔG) was estimated to be −7.02 kcal/mol. MD simulation revealed the stability of interacting residues (Gly183, Arg221, Thr263 and Asp265). The results demonstrated that the identified polyphenol, silydianin, could act as a promising natural PTP1B inhibitor that can modulate the insulin resistance. 相似文献
362.
Mohammed Kara Amine Assouguem Mohamed El Fadili Safa Benmessaoud Samar Zuhair Alshawwa Omkulthom Al Kamaly Hamza Saghrouchni Abdou Rachid Zerhouni Jamila Bahhou 《Molecules (Basel, Switzerland)》2022,27(3)
Vinegar is a natural product widely used in food and traditional medicine thanks to its physicochemical properties and its richness in bioactive molecules. However, its direct use by consumers can have complications and undesirable effects. Therefore, this study contributes to investigating the physicochemical and biological properties of eleven vinegars marketed in Morocco. Determination of pH, acetic acid, conductivity, total soluble solids and alcohol content in vinegar was carried out. The polyphenols (TP), flavonoids (TF), and condensed tannins (CT) content was determined, and their antioxidant activities were evaluated using 2,2-diphenyl-1-picryl Hydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP) and Phosphomolybdenum Reduction Assay (TAC). Then, the antimicrobial activity was studied against four pathogenic bacteria and two fungal strains, using the disk diffusion and the microdilution method. This study showed a wide range of acetic acid values from 0.65 ± 0.29 to 5.15 ± 0.20%. The high value of TP, TF, and CT in our samples V10, V9, and V4 was 655.00 ± 22.2 µgGAE/mL, 244.53 ± 11.32 µgQE/mL and 84.63 ± 1.00 µgTAE/mL, respectively. The tested strains showed variable sensitivities to the different samples with inhibition zones ranging from 6.33 ± 2.08 to 34.33 ± 0.58 mm. The lowest minimum inhibition concentrations were recorded against Staphylococcus aureus ATCC29213 ranging from 1.95 to 7.81 µL/mL. While Aspergillus niger ATCC16404 showed resistance against all of the analyzed samples. In general, vinegar commercialized in Morocco presents a variable range of products with variable properties. Indeed, must take into account this diversity when using it. A future study is needed to identify the phytochemical composition that will further the comprehension of this variability and contribute to its valorization. 相似文献
363.
Driss Ousaaid Hamza Mechchate Hassan Laaroussi Christophe Hano Meryem Bakour Asmae El Ghouizi Raffaele Conte Badiaa Lyoussi Ilham El Arabi 《Molecules (Basel, Switzerland)》2022,27(1)
The popularity of fruits vinegar (FsV) has been increased recently as a healthy drink wealthy in bioactive compounds that provide several beneficial properties. This review was designed in the frame of valorization of fruits vinegar as a by-product with high value added by providing overall information on its biochemical constituents and beneficial potencies. It contains a cocktail of bioactive ingredients including polyphenolic acids, organic acids, tetramethylperazine, and melanoidins. Acetic acid is the most abundant organic acid and chlorogenic acid is the major phenol in apple vinegar. The administration of fruits vinegar could prevent diabetes, hypercholesterolemia, oxidative stress, cancer, and boost immunity as well as provide a remarkable antioxidant ability. The production techniques influence the quality of vinegar, and consequently, its health benefits. 相似文献
364.
Dr. Jérôme Rey Dr. Céline Chizallet Dr. Dario Rocca Dr. Tomáš Bučko Prof. Michael Badawi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(6):e202312392
For the first time, we report calculations of the free energies of activation of cracking and isomerization reactions of alkenes that combine several different electronic structure methods with molecular dynamics simulations. We demonstrate that the use of a high level of theory (here Random Phase Approximation—RPA) is necessary to bridge the gap between experimental and computed values. These transformations, catalyzed by zeolites and proceeding via cationic intermediates and transition states, are building blocks of many chemical transformations for valorization of long chain paraffins originating, e.g., from plastic waste, vegetable oils, Fischer–Tropsch waxes or crude oils. Compared with the free energy barriers computed at the PBE+D2 production level of theory via constrained ab initio molecular dynamics, the barriers computed at the RPA level by the application of Machine Learning thermodynamic Perturbation Theory (MLPT) show a significant decrease for isomerization reaction and an increase of a similar magnitude for cracking, yielding an unprecedented agreement with the results obtained by experiments and kinetic modeling. 相似文献
365.
Driss Ousaaid Hassan Laaroussi Hamza Mechchate Meryem Bakour Asmae El Ghouizi Ramzi A. Mothana Omar Noman Imane Es-safi Badiaa Lyoussi Ilham El Arabi 《Molecules (Basel, Switzerland)》2022,27(2)
The main objective of the current study was to determine the physicochemical properties, antioxidant activities, and α-glucosidase and α-amylase inhibition of apple vinegar produced by artisanal and industrial methods. Apple vinegar samples were analyzed to identify their electrical conductivity, pH, titratable acidity, total dry matter, Brix, density, mineral elements, polyphenols, flavonoids, and vitamin C. The antioxidant activity of apple vinegar samples was evaluated using two tests, total antioxidant capacity (TAC) and DPPH radical scavenging activity. Finally, we determined α-glucosidase and α-amylase inhibitory activities of artisanal and industrial apple vinegar. The results showed the following values: pH (3.69–3.19); electrical conductivity (2.81–2.79 mS/cm); titratable acidity (3.6–5.4); ash (4.61–2.90); °Brix (6.37–5.2); density (1.02476–1.02012), respectively, for artisanal apple vinegar and industrial apple vinegar. Concerning mineral elements, potassium was the most predominant element followed by sodium, magnesium, and calcium. Concerning bioactive compounds (polyphenols, flavonoids, and vitamin C), the apple vinegar produced by the artisanal method was the richest sample in terms of bioactive compounds and had the highest α-glucosidase and α-amylase inhibition. The findings of this study showed that the quality and biological activities of artisanal apple vinegar were more important than industrial apple vinegar. 相似文献
366.
The structural stability and internal rotation in 3-cylopropenecarboxaldehyde were investigated by ab initio calculations with 6-311++G** basis set. The calculations were carried out at the restricted Hartree–Fock (HF) and the Density Functional B3LYP levels. The vibrational frequencies were computed at HF and DFT-B3LYP levels. Normal coordinate calculations were carried out and potential energy distributions were calculated for the cis and the trans conformers of the molecule. 相似文献
367.
Spectral dispersion curves of the refractive indices and birefringence of highly oriented fibres [poly(ethylene 2,6-naphthalene-dicarboxylate) (1000 denier/248 filaments, PEN-Q50M4; PEN), poly(ethylene terephthalate) (PET), Seun yarn (meta-aramid fibres, Teijin Japan; CONEX) and Technora T-240 (1000 denier/667 filaments aramid fibres, Teijin Japan; TECHNORA)] have investigated using the automatic variable-wavelength interferometric (VAWI) technique. This technique is especially recommended for measuring the refractive indices of highly oriented fibres. The polarizabilities per unit volume are calculated for these fibres and the molecular orientation function of PEN and PET are determined. Microinterferograms are given for illustration. 相似文献
368.
H M Badawi W F?rner 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(7):1471-1489
The conformational behavior and structural stability of 3,3-dichloropropanal and 3,3,3-trichloropropanal were investigated by ab initio calculations. The 6-311 + + G** basis set was employed to include polarization and diffuse functions in the calculations at B3LYP level. From the calculation, the trans conformer of 3,3,3-trichloropropanal was predicted to be the predominant conformer with about 2 kcal mol(-1) of energy lower than the cis form. Additionally, 3,3 dichloro-propanal was predicted to exist as a mixture of three stable conformers. The potential function scans were calculated for the two molecules from which the rotational barriers could be estimated. The vibrational frequencies were computed at B3LYP level and complete vibrational assignments were made based on normal coordinate calculations for the conformers of the two molecules. Vibrational Raman and infrared spectra of the mixture of the stable conformers were computed at 300 K. 相似文献
369.
Recently a basis-set-superposition-error-free second-order perturbation theory was introduced based on the “chemical Hamiltonian
approach” providing the full antisymmetry of all wave functions by using second quantization. Subsequently, the “Heitler–London”
interaction energy corresponding to the sum of the zero- and first-order perturbational energy terms was decomposed into different
physically meaningful components, like electrostatics, exchange and overlap effects. The first-order wave function obtained
in the framework of this perturbation theory also consists of terms having clear physical significance: intramolecular correlation,
polarization, charge transfer, dispersion and combined polarization–charge transfer excitations. The second-order energy,
however, does not represent a simple sum of the respective contributions, owing to the intermolecular overlap. Here we propose
an approximate energy decomposition scheme by defining some “partial Hylleraas functionals” corresponding to the different
physically meaningful terms of the first-order wave functions. The sample calculations show that at large and intermediate
intermolecular distances the total second-order intermolecular interaction energy contribution is practically equal to the
sum of these “physical” terms, while at shorter distances the overlap-caused interferences become of increasing importance.
Received: 18 June 2001 / Accepted: 28 August 2001 / Published online: 16 November 2001 相似文献
370.
Some polarity terms of two groups of nitrogen-containing surfactants ( six alkanolamides and nine polyoxyethylenated long chain amines) are measured through gas chromatography. The apparent methanol carbon number (CMeOH) and polarity index (IP) values are determined on the investigated surfactants as stationary phases in packed columns. Similarly, CMeOH and IP values are determined on simulated hydrophobic tail (SHT)models. The obtained results reveal that the introduction of SHT approach permits the distinction between the polarities of different surfactants and their head groups. The measured polarity terms are discussed as related to hydrophile-lipophile balance (HLB) number and the hydrophobic group carbon number (RCN). Some equations relating the measured polarity values and these variable have been developed. 相似文献