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101.
102.
Muhammad Bilal;Syed Muhammad Alay-e-Abbas;Ghulam Abbas;Farrukh Javed;Waqas Zulfiqar;Nasir Amin; 《physica status solidi b》2024,261(2):2300373
The emergence of robust surface electronic states in topological insulators such as bulk Sr3PbO inverse-perovskite makes them suitable candidates for spintronic devices and solid-state quantum computers. Herein, the atomic structure, surface energetics, and electronic properties of Sr3PbO inverse-perovskite Sr2O (SO)-terminated and SrPb-terminated (001) surfaces are examined using density functional theory. A comparison of the computed structural properties of SO-termianted and SrPb-terminated (001) surfaces reveals maximum surface rumpling and changes in interlayer distances for the SrPb-terminated surface of Sr3PbO. However, the calculated surface energies indicate that both SO-termianted and SrPb-terminated (001) surfaces of Sr3PbO are energetically feasible, indicating that these surfaces can coexist in a polycrystalline sample of this material. Due to the presence of Pb in Sr3PbO, a comprehensive examination of the electronic structure of bulk and supercell slab structures of Sr3PbO by taking spin–orbit coupling effects into consideration is conducted. Noninsulating nature of electronic structure for the two possible (001) terminations of Sr3PbO is found. The domination of Pb-6p states at the Fermi energy and the hole screening observed at the SrPb-terminated surface of Sr3PbO support the p-type nature observed in the experiment. 相似文献
103.
Tabassum Jannat Md. Jamal Hossain Ahmed M. El-Shehawi Md. Ruhul Kuddus Mohammad A. Rashid Sarah Albogami Ibrahim Jafri Mohamed El-Shazly Mohammad Rashedul Haque 《Molecules (Basel, Switzerland)》2022,27(13)
The aim of the study was to conduct phytochemical and pharmacological investigations of Wrightia coccinea (Roxb. ex Hornem.) Sims via several in vitro, in vivo, and in silico models. A total of four compounds were identified and isolated from the methanol extract of the bark and the methanol extract of the seed pulp of W. coccinea through successive chromatographic techniques and were characterized as 3β-acetyloxy-olean-12-en-28-ol (1), wrightiadione (2), 22β-hydroxylupeol (3), and β-sitosterol (4) by spectroscopic analysis. The aqueous fraction of the bark and chloroform fraction of the fruits provided the most potent antioxidant capacity (IC50 = 7.22 and 4.5 µg/mL, respectively) in DPPH free radical scavenging assay compared with the standard ascorbic acid (IC50 = 17.45 µg/mL). The methanol bark extract and the methanol fruit coat extract exerted anti-diarrheal activity by inhibiting 74.55 ± 0.67% and 77.78 ± 1.5% (mean ± SEM) of the diarrheal episode in mice, respectively, after four hours of loading the samples. In the hypoglycemic test, the methanol bark extract and the methanol fruit coat extract (400 mg/kg) produced a significant (p < 0.05) reduction in the blood glucose level in mice. Both doses of the plant extracts (200 mg/kg and 400 mg/kg) used in the study induced a significant (p < 0.05) increase in pain reaction time. The in vitro and in vivo findings were supported by the computational studies. The isolated compounds exhibited higher binding affinity compared with the standard drugs towards the active binding sites of glutathione reductase, epidermal growth factor receptor (EGFR), kappa opioid receptor, glucose transporter 3 (GLUT 3), Mu opioid receptor, and cyclooxygenase 2 (COX-2) proteins due to their potent antioxidant, cytotoxic, anti-diarrheal, hypoglycemic, and central and peripheral analgesic properties, respectively. The current findings concluded that W. coccinea might be a potential natural source for managing oxidative stress, diarrhea, hyperglycemia, and pain. Further studies are warranted for extensively phytochemical screening and establishing exact mechanisms of action. 相似文献
104.
Jamal Afzal Yaomei Fu Tian-Xiang Luan Zhongmin Su Pei-Zhou Li 《Molecules (Basel, Switzerland)》2022,27(13)
Developing a low-cost and effective proton-conductive electrolyte to meet the requirements of the large-scale manufacturing of proton exchange membrane (PEM) fuel cells is of great significance in progressing towards the upcoming “hydrogen economy” society. Herein, utilizing the one-pot acylation polymeric combination of acyl chloride and amine precursors, a polyamide with in-built -SO3H moieties (PA-PhSO3H) was facilely synthesized. Characterization shows that it possesses a porous feature and a high stability at the practical operating conditions of PEM fuel cells. Investigations of electrochemical impedance spectroscopy (EIS) measurements revealed that the fabricated PA-PhSO3H displays a proton conductivity of up to 8.85 × 10−2 S·cm−1 at 353 K under 98% relative humidity (RH), which is more than two orders of magnitude higher than that of its -SO3H-free analogue, PA-Ph (6.30 × 10−4 S·cm−1), under the same conditions. Therefore, matrix-mixed membranes were fabricated by mixing with polyacrylonitrile (PAN) in different ratios, and the EIS analyses revealed that its proton conductivity can reach up to 4.90 × 10−2 S·cm−1 at 353 K and a 98% relative humidity (RH) when the weight ratio of PA-PhSO3H:PAN is 3:1 (labeled as PA-PhSO3H-PAN (3:1)), the value of which is even comparable with those of commercial-available electrolytes being used in PEM fuel cells. Additionally, continuous tests showed that PA-PhSO3H-PAN (3:1) possesses a long-life reusability. This work demonstrates, using the simple acylation reaction with the sulfonated module as precursor, that low-cost and highly effective proton-conductive electrolytes for PEM fuel cells can be facilely achieved. 相似文献
105.
Ovarian cancer (OC) is the second most common type of gynecological malignancy. Platinum (Pt)-based chemotherapy is the standard of care for OC, but toxicity and acquired chemoresistance has proven challenging. Recently, we reported that sensitivity to platinum was significantly reduced in a co-culture of OC cells with MSC. To discover compounds capable of restoring platinum sensitivity, we screened a number of candidates and monitored ability to induce PARP cleavage. Moreover, we monitored platinum uptake and expression of ABC transporters in OC cells. Our results showed that 2-hydroxyestradiol (2HE2), a metabolite of estradiol, and dasatinib, an Abl/Src kinase inhibitor, were significantly effective in overcoming MSC-mediated platinum drug resistance. Dasatinib activity was dependent on ERK1/2 activation, whereas 2HE2 was independent of the activation of ERK1/2. MSC-mediated platinum drug resistance was accompanied by reduced intracellular platinum concentrations in OC cells. Moreover, MSC co-cultured with OC cells resulted in downregulation of the expression of cellular transporters required for platinum uptake and efflux. Exposure to 2HE2 and other modulators resulted in an increase in intracellular platinum concentrations. Thus, 2HE2 and dasatinib might act as sensitizers to restore platinum drug sensitivity to OC cells and thus to limit TME-mediated chemoresistance in OC. 相似文献
106.
Amir Mahgoub Awadelkareem Eyad Al-Shammari Abd Elmoneim O. Elkhalifa Mohd Adnan Arif Jamal Siddiqui Mejdi Snoussi Mohammad Idreesh Khan Z R Azaz Ahmad Azad Mitesh Patel Syed Amir Ashraf 《Molecules (Basel, Switzerland)》2022,27(4)
Eruca sativa Mill. (E. sativa) leaves recently grabbed the attention of scientific communities around the world due to its potent bioactivity. Therefore, the present study investigates the metabolite profiling of the ethanolic crude extract of E. sativa leaves using high resolution-liquid chromatography-mass spectrometry (HR-LC/MS), including antibacterial, antioxidant and anticancer potential against human colorectal carcinoma cell lines. In addition, computer-aided analysis was performed for determining the pharmacokinetic properties and toxicity prediction of the identified compounds. Our results show that E. sativa contains several bioactive compounds, such as vitamins, fatty acids, alkaloids, flavonoids, terpenoids and phenols. Furthermore, the antibacterial assay of E. sativa extract showed inhibitory effects of the tested pathogenic bacterial strains. Moreover, the antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2) were found to be IC50 = 66.16 μg/mL and 76.05 μg/mL, respectively. E. sativa also showed promising anticancer activity against both the colorectal cancer cells HCT-116 (IC50 = 64.91 μg/mL) and Caco-2 (IC50 = 83.98 μg/mL) in a dose/time dependent manner. The phytoconstituents identified showed promising pharmacokinetics properties, representing a valuable source for drug or nutraceutical development. These investigations will lead to the further exploration as well as development of E. sativa-based nutraceutical products. 相似文献
107.
Rajapandiyan Krishnamoorthy Jegan Athinarayanan Vaiyapuri Subbarayan Periyasamy Mohammad A. Alshuniaber Ghedeir Alshammari Mohammed Jamal Hakeem Mohammed Asif Ahmed Ali A. Alshatwi 《Molecules (Basel, Switzerland)》2022,27(8)
The increase in β-lactam-resistant Gram-negative bacteria is a severe recurrent problem in the food industry for both producers and consumers. The development of nanotechnology and nanomaterial applications has transformed many features in food science. The antibacterial activity of zinc oxide nanoparticles (ZnO NPs) and their mechanism of action on β-lactam-resistant Gram-negative food pathogens, such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Klebsiella pneumoniae, and Proteus mirabilis, are investigated in the present paper. The study results demonstrate that ZnO NPs possesses broad-spectrum action against these β-lactamase-producing strains. The minimal inhibitory and minimal bactericidal concentrations vary from 0.04 to 0.08 and 0.12 to 0.24 mg/mL, respectively. The ZnO NPs elevate the level of reactive oxygen species (ROS) and malondialdehyde in the bacterial cells as membrane lipid peroxidation. It has been confirmed from the transmission electron microscopy image of the treated bacterial cells that ZnO NPs diminish the permeable membrane, denature the intracellular proteins, cause DNA damage, and cause membrane leakage. Based on these findings, the action of ZnO NPs has been attributed to the fact that broad-spectrum antibacterial action against β-lactam-resistant Gram-negative food pathogens is mediated by Zn2+ ion-induced oxidative stress, actions via lipid peroxidation and membrane damage, subsequently resulting in depletion, leading to β-lactamase enzyme inhibition, intracellular protein inactivation, DNA damage, and eventually cell death. Based on the findings of the present study, ZnO NPs can be recommended as potent broad-spectrum antibacterial agents against β-lactam-resistant Gram-negative pathogenic strains. 相似文献
108.
Andrei Khrennikov Farrukh Mukhamedov 《Nonlinear Analysis: Theory, Methods & Applications》2009,71(11):5327-5331
In the present paper we consider countable state of p-adic Potts model on the tree. Under some condition on weights we establish uniqueness of Gibbs measures for the model. Note that this condition does not depend on values of the prime p. An analogous fact is not true when the number of spins is finite. 相似文献
109.
Jamal T. Manassah 《Laser Physics》2012,22(3):559-565
Using eigenmode analysis I calculate in the linear regime the emission characteristics from a slab of two-level resonant atoms
excited by a delta-pulse propagating normal to the surface of the slab. I show that the qualitative features of the emitted
spectra in the forward and backward directions to be different from each other; I also find the effects of the total linewidth
of the resonance line and of the deviation in the spatial periodicity of the initial atomic polarization from k
0, where k
0 = ω0/c and ω0 is the two level resonant frequency, on the spectra. The dominant spatial mode of the system is identified as the key parameter
for determining the forward emission spectral width. 相似文献
110.
In order to find informations on the native structure of the Leu-Enkephalin opiate peptide, the parent peptide and its two thioamide analogs (Thio-Gly2)Leu-Enkephalin and (Thio-Gly3)Leu-Enkephalin were studied by the theoretical method PEPSEA. This comparative conformational analysis showed that the active conformation is a β turn structure centered on Gly3 and Phe4. Moreover, this study showed also that the more active analog (Thio-Gly2)Leu-Enk has a lower tendency to adopt this structure. Consequently, its high activity can only be explained by its long lifetime due to its resistance to enzymatic hydrolysis, following the substitution of the amide linkage by the thioamide one. The weakly active analog (Thio-Gly3)Leu-Enk does not adopt this structure and prefers instead a β turn structure centered on Gly2 and Gly3. This study also confirmed the importance of the distances between the Tyr and Phe residues at positions 1 and 4, and that of the terminal Tyrosine N-H group which must be free of any intramolecular hydrogen bond in order to be available in the molecular recognition process. 相似文献