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851.
In this paper, the composite nonlinear feedback control method is considered for robust tracking and model following of uncertain linear systems. The control law guarantees that the tracking error decreases asymptotically to zero in the presence of time varying uncertain parameters and disturbances. For performance improvement of the dynamical system, the proposed robust tracking controller consists of linear and nonlinear feedback parts without any switching element. The linear feedback law is designed to allow the closed loop system have a small damping ratio and a quick response while the nonlinear feedback law increases the damping ratio of the system as the system output approaches the output of the reference model. A new collection of different nonlinear functions used in the control law are offered to improve the reference tracking performance of the system. The proposed robust tracking controller improves the transient performance and steady state accuracy simultaneously. Finally, the simulations are provided to verify the theoretical results. 相似文献
852.
The synthesis of novel 1‐(1H‐tetrazol‐5‐yl)‐10‐chloro‐1,2,3,4‐tetrahydropyrazino[1,2‐a] indole derivatives starting from the initially prepared 1‐(2‐bromoethyl)‐3‐chloro‐1H‐indole‐2‐carbaldehyde is described. A variety of likely biologically relevant pyrazino[1,2‐a] indole‐based 1,5‐disubstituted tetrazoles was obtained in moderate to high yields via an Ugi‐azide reaction. These reactions presumably proceed by the imine formation, intramolecular cyclization to iminium ion, and nucleophilic addition tandem reactions, respectively. 相似文献
853.
Fatma M. Saleh Hamdi M. Hassaneen Holger Butenschön Gerald Dräger Ismail A. Abdelhamid 《Tetrahedron letters》2019,60(46):151265
Herein, we report the first synthesis of 10b-azachrysenes via the Hantzsch-like reaction of aldehydes with 2-(6,7-dimethoxy-3,4-dihydroisoquinolin-1-yl)acetonitrile and dimedone in the presence of acetic acid. The regioselectivity was established using X-ray crystallography and 2D-HMBC spectroscopy. 相似文献
854.
Ahmad Hussein Alomari Muneer Aziz Saleh Suhairul Hashim Amal Alsayaheen Ahmad Abukashabeh 《Isotopes in environmental and health studies》2019,55(2):211-226
An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides 226Ra, 232Th, 40K, and 137Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for 226Ra, 232Th, 40K, and 137Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg–1, respectively. The highest mean activity concentration for 226Ra was found to be 138?±?4 Bq kg–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg–1 for 232Th, and 14.2?±?1.9 Bq kg–1 for 137Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of 232Th, 40K, and 137Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to 226Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg–1, and 0.266, respectively. 相似文献
855.
Ibrahim Ahmed Shaikh Uday M. Muddapur Krithika C Shrikanth Badiger Madhura Kulkarni Mater H. Mahnashi Saleh A. Alshamrani Mohammed A. Huneif Sunil S. More Aejaz Abdullatif Khan S. M. Shakeel Iqubal 《Molecules (Basel, Switzerland)》2022,27(5)
Current drug discovery involves finding leading drug candidates for further development. New scientific approaches include molecular docking, ADMET studies, and molecular dynamic simulation to determine targets and lead compounds. Hepatitis B is a disease of concern that is a life-threatening liver infection. The protein considered for the study was HBx. The hepatitis B X-interacting protein crystal structure was obtained from the PDB database (PDB ID-3MSH). Twenty ligands were chosen from the PubChem database for further in silico studies. The present study focused on in silico molecular docking studies using iGEMDOCK. The triethylene glycol monoethyl ether derivative showed an optimum binding affinity with the molecular target HBx, with a high negative affinity binding energy of −59.02 kcal/mol. Lipinski’s rule of five, Veber, and Ghose were followed in subsequent ADMET studies. Molecular dynamic simulation was performed to confirm the docking studies and to analyze the stability of the structure. In these respects, the triethylene glycol monoethyl ether derivative may be a promising molecule to prepare future hepatitis B drug candidates. Substantial research effort to find a promising drug for hepatitis B is warranted in the future. 相似文献
856.
Ghulam Md. Ashraf Debarati DasGupta Mohammad Zubair Alam Saleh S. Baeesa Badrah S. Alghamdi Firoz Anwar Thamer M. A. Alqurashi Sharaf E. Sharaf Waleed Al Abdulmonem Mohammed A. Alyousef Fahad A. Alhumaydhi Anas Shamsi 《Molecules (Basel, Switzerland)》2022,27(14)
Microtubule affinity regulating kinase 4 (MARK4) regulates the mechanism of microtubules by its ability to phosphorylate the microtubule-associated proteins (MAP’s). MARK4 is known for its major role in tau phosphorylation via phosphorylating Ser262 residue in the KXGS motif, which results in the detachment of tau from microtubule. In lieu of this vital role in tau pathology, a hallmark of Alzheimer’s disease (AD), MARK4 is a druggable target to treat AD and other neurodegenerative disorders (NDs). There is growing evidence that NDs and diabetes are connected with many pieces of literature demonstrating a high risk of developing AD in diabetic patients. Metformin (Mtf) has been a drug in use against type 2 diabetes mellitus (T2DM) for a long time; however, recent studies have established its therapeutic effect in neurodegenerative diseases (NDs), namely AD, Parkinson’s disease (PD) and amnestic mild cognitive impairment. In this study, we have explored the MARK4 inhibitory potential of Mtf, employing in silico and in vitro approaches. Molecular docking demonstrated that Mtf binds to MARK4 with a significant affinity of −6.9 kcal/mol forming interactions with binding pocket’s critical residues. Additionally, molecular dynamics (MD) simulation provided an atomistic insight into the binding of Mtf with MARK4. ATPase assay of MARK4 in the presence of Mtf shows that it inhibits MARK4 with an IC50 = 7.05 µM. The results of the fluorescence binding assay demonstrated significant binding of MARK4 with a binding constant of 0.6 × 106 M−1. The present study provides an additional axis towards the utilization of Mtf as MARK4 inhibitor targeting diabetes with NDs. 相似文献
857.
Sabbir Ahmed Md Chayan Ali Rumana Akter Ruma Shafi Mahmud Gobindo Kumar Paul Md Abu Saleh Mohammed Merae Alshahrani Ahmad J. Obaidullah Sudhangshu Kumar Biswas Md Mafizur Rahman Md Mizanur Rahman Md Rezuanul Islam 《Molecules (Basel, Switzerland)》2022,27(14)
Piper betle L. is widely distributed and commonly used medicinally important herb. It can also be used as a medication for type 2 diabetes patients. In this study, compounds of P. betle were screened to investigate the inhibitory action of alpha-amylase and alpha-glucosidase against type 2 diabetes through molecular docking, molecular dynamics simulation, and ADMET (absorption, distribution, metabolism, excretion, and toxicity) analysis. The molecule apigenin-7-O-glucoside showed the highest binding affinity among 123 (one hundred twenty-three) tested compounds. This compound simultaneously bound with the two-target proteins alpha-amylase and alpha-glucosidase, with high molecular mechanics-generalized born surface area (MM/GBSA) values (ΔG Bind = −45.02 kcal mol−1 for alpha-amylase and −38.288 for alpha-glucosidase) compared with control inhibitor acarbose, which had binding affinities of −36.796 kcal mol−1 for alpha-amylase and −29.622 kcal mol−1 for alpha-glucosidase. The apigenin-7-O-glucoside was revealed to be the most stable molecule with the highest binding free energy through molecular dynamics simulation, indicating that it could compete with the inhibitors’ native ligand. Based on ADMET analysis, this phytochemical exhibited a wide range of physicochemical, pharmacokinetic, and drug-like qualities and had no significant side effects, making them prospective drug candidates for type 2 diabetes. Additional in vitro, in vivo, and clinical investigations are needed to determine the precise efficacy of drugs. 相似文献
858.
Mansour Shalaby Eslam Ibrahim Hussin Saleh Ibrahim Dessoky Moawad 《Wireless Personal Communications》2021,121(4):2461-2476
Wireless Personal Communications - Higher data rate, increased capacity, higher mobility, lower latency and better quality are the mobile communication prime objectives need to improve in the near... 相似文献
859.
Motallebi Hasankola Seyed Sadegh Shafaghat Rouzbeh Jahanian Omid Talesh Amiri Saleh Shooghi Mahdi 《Journal of Thermal Analysis and Calorimetry》2020,139(4):2465-2474
Journal of Thermal Analysis and Calorimetry - In this paper, the effects of inlet valve closing temperature (TIVC) and exhaust gas recirculation (EGR) on the emissions and the performance of a... 相似文献
860.
Fekra Somayeh Saleh Fard Narges Elmi Fazaeli Reza 《Russian Journal of Applied Chemistry》2021,94(6):824-834
Russian Journal of Applied Chemistry - This study evaluated a removal efficiency of NLFX from aqueous solutions using a photocatalytic process. In this study, Bi2WO6 were synthesized by microwave... 相似文献