全文获取类型
收费全文 | 484篇 |
免费 | 23篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 12篇 |
妇产科学 | 12篇 |
基础医学 | 65篇 |
口腔科学 | 5篇 |
临床医学 | 41篇 |
内科学 | 128篇 |
皮肤病学 | 9篇 |
神经病学 | 30篇 |
特种医学 | 15篇 |
外科学 | 60篇 |
综合类 | 3篇 |
预防医学 | 34篇 |
眼科学 | 11篇 |
药学 | 55篇 |
中国医学 | 5篇 |
肿瘤学 | 18篇 |
出版年
2023年 | 10篇 |
2022年 | 18篇 |
2021年 | 15篇 |
2020年 | 22篇 |
2019年 | 11篇 |
2018年 | 18篇 |
2017年 | 17篇 |
2016年 | 14篇 |
2015年 | 27篇 |
2014年 | 18篇 |
2013年 | 31篇 |
2012年 | 42篇 |
2011年 | 50篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 39篇 |
2007年 | 31篇 |
2006年 | 20篇 |
2005年 | 15篇 |
2004年 | 18篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有508条查询结果,搜索用时 15 毫秒
21.
22.
23.
Qazi Ehsan Ali Bikramjit Das Syed Hussain Amir Uzma Firdaus Abdulla Zoheb Azhar 《Egyptian Journal of Anaesthesia》2013,29(1):83-85
Meningocele is a neural tube defect where meninges protrude through a skeletal defect. Occipital meningocele compounded with the problems of paediatric airway itself pose challenges to anaesthesiologist in securing and maintaining airway. We present a case report of a 3 month-old-child with occipital meningocele posted for ventriculo-peritoneal shunt for hydrocephalus, who was successfully intubated using a size 1 Airtraq optical laryngoscope. 相似文献
24.
Samad N Khan A Perveen T Haider S Abdul Haleem M Haleem DJ 《Acta neurobiologiae experimentalis》2007,67(4):389-397
The present study concerns responsiveness of pre- and postsynaptic 5-hydroxytryptamine (5-HT)-1A receptors in a rat model of tardive dyskinesia (TD). Vacuous chewing movements (VCMs) in rats are widely accepted as an animal model of TD. Results show that haloperidol injected at a dose of 1 mg/kg twice a day for 5 weeks elicited VCMs, which increased in a time dependent manner following the drug administration for 3-5 weeks. Tolerance was produced in motor coordination during the potentiation of VCMs. Exploratory activity in an open field and in an activity box decreased in haloperidol treated animals. The effects of 8-hydroxy-2-(di-n-propylamino)tetraline (8-OH-DPAT; 0.5 mg/kg) were monitored 48-h after withdrawal from repeated administration of haloperidol. 8-OH-DPAT-induced locomotion was greater in haloperidol treated rats. 5-HT synthesis increased in haloperidol treated animals, while 8-OH-DPAT-induced decreases of 5-HT synthesis were greater in repeated haloperidol than repeated saline injected animals. The results suggest that an increase in the effectiveness of somatodendritic 5-HT-1A receptors may decrease the inhibitory influence of 5-HT on the activity of dopaminergic neurons to precipitate VCMs. The 5-HT-1A agonist may help to alleviate neuroleptic-induced TD. 相似文献
25.
Shahnaz Perveen Sana Mustafa Mehreen Latif Lubna Iqbal Tanzil H. Usmani Khalid Mohammed Khan Wolfgang Voelter 《Medicinal chemistry research》2014,23(7):3585-3592
The objective of this study was to synthesize potent and/or novel inhibitors for α-chymotrypsin activity. Eighteen derivatives of N-methylphenyl-N′-(alkyl/aryl) urea (1–18) were synthesized, and their inhibitory effects on α-chymotrypsin enzyme were evaluated. Two compounds exhibited potent inhibitory activities. The most potent, N-(2-methylphenyl)-2-oxo-1-pyrrolidinecarboxamide (15) having a methyl group at ortho position was the most active inhibitor with an IC50 value of 8.10 ± 0.14 μM, which was comparable to standard chymostatin (IC50 = 8.24 ± 0.11 μM). A slightly less potent, N-(2-acetylphenyl)-N′-(3-methylphenyl) urea (10), exhibited an IC50 of 13.6 ± 0.23 μM. Compounds 3, 4, 7, 11, and 13 exhibited moderate activities. The results demonstrated that α-chymotrypsin inhibition is related to the position of the methyl group and the presence of substituent at the nitrogen of the urea bridge. The inhibitory trend suggests that α-chymotrypsin inhibitory activity declines with ortho > meta > para substitution order. In conclusion, our data suggest that the compound 15 may serve as a lead compound for further designing of other potent or novel α-chymotrypsin inhibitors. 相似文献
26.
Muhammad Shahzad Manzoor Hussain Muhammad Shafique Rukhsana Perveen Nadeem Sheikh 《International journal of legal medicine》2020,134(2):511-512
Insertion–deletion polymorphism (Indels) is valuable diallelic markers for forensic as well as parentage analysis. The Investigator DIPplex Kit (Qiagen) contains thirty autosomal Indels markers along with amelogenin. These thirty markers were tested in the Pakistani Punjabi Population but no significant deviations were observed from Hardy–Weinberg equilibrium rule expectations (Bonferroni corrected) except HLD58, HLD56, HLD99, and HLD40. The mean expected and observed heterozygosity was found 0.4701 and 0.4667 respectively; combined matching probability was computed as 7.31867 × 10−13. However, the use of the 30 Indels markers proved to be a good supplementary tool in forensic casework, particularly when evidence sample is highly degraded. The significant genetic differences were also observed between the Punjabi and other populations of the world. 相似文献
27.
Sajid Mahmood Tahira Perveen Allah Dino Faisa Ibrahim Jaishri Mehraj 《Indian Journal of Community Medicine》2014,39(2):87-93
Objectives:
To assess the effectiveness of school-based interventions program in reducing the prevalence of overweight or obesity among schoolchildren.Data source:
Ovid Medline (1950-December 2012), Embase (1980-2012), CINAHL (1982-2012), secondary references, review articles, and expert in the field.Study selection:
All published clinical trials were eligible for study if were randomized, methodologically strong-based on a validity assessment, aimed to evaluate a school-based intervention for childhood overweight or obesity, and measured outcome in term of prevalence/incidence difference in overweight and obesity among both groups. Studies involved in cost-effective analysis of school-based intervention have been excluded. Data from eligible studies abstracted and pooled for relative risk.Results:
Five trials with 3,904 schoolchildren were included. Mean age of the students (boys and girls) ranges 8.6-12.6 years. Meta-analysis showed a statistical significance beneficial effect of school-based intervention programs on obesity status of schoolchildren (risk ratio (RR) 0.58, 95% confidence interval (CI) 0.43-0.78) and suggested 42% reduction in prevalence of obesity among schoolchildren through school-based intervention programs. Individual studies also showed effectiveness of these school-based interventions.Conclusion:
School-based intervention programs are effective in prevention of childhood overweight and obesity problem and our results quantitatively supported this argument. 相似文献28.
29.
Three novel Schiff bases, namely N-(4-((4-((phenylimino)methyl)phenoxy)methoxy)benzylidene)benzenamine (UA), N-(3-methoxy-4-((2-methoxy-4-((phenylimino)methyl)phenoxy)methoxy)benzylidene)benzenamine (UB), and N-(3-ethyl-4-((2-ethyl-4-((phenylimino)methyl)phenoxy)methoxy)benzylidene)benzenamine (UC), were synthesized and their structures were elucidated through diverse spectroscopic techniques such as FT-IR, GC-MS, 1H NMR and 13C NMR. The corrosion inhibition effect of these Schiff bases on aluminum alloy AA2219-T6 in acidic medium was explored using weight loss, Tafel polarization, and electrochemical impedance spectroscopy. Theoretical quantum chemical calculations using density functional theory were employed to determine the adsorption site. It was found that inhibition efficiencies increase with an increase in the inhibitor concentration. Tafel plots showed that these Schiff bases function as mixed inhibitors. Adsorption of the Schiff bases on aluminum followed the Langmuir adsorption isotherm and the value of showed a dominant chemical mechanism. FT-IR and SEM techniques were used to investigate the surface morphology. The compounds showed a substantial corrosion inhibition for aluminum alloy in 0.1 M HCl at 298 K. UB and UC exhibited superior anticorrosion efficiency compared to UA originating from the electron-donating methoxy and ethoxy group substitutions, respectively. There was found to be good correlation between molecular structure and inhibition efficiencies.Novel Schiff bases characterized through spectroscopic techniques and used as anticorrosive agents for aluminium alloy acidic medium. Electrochemical techniques and DFT studies were used to study inhibition effect and molecular interactions. 相似文献
30.
Sania Naseer Muhammad Aamir Muhammad Aslam Mirza Uzma Jabeen Raja Tahir Muhammad Najam Khan Malghani Qamar Wali 《RSC advances》2022,12(13):7661
ZnO is one of the most promising and efficient semiconductor materials for various light-harvesting applications. Herein, we reported the tuning of optical properties of ZnO nanoparticles (NPs) by co-incorporation of Ni and Ag ions in the ZnO lattice. A sonochemical approach was used to synthesize pure ZnO NPs, Ni–ZnO, Ag–ZnO and Ag/Ni–ZnO with different concentrations of Ni and Ag (0.5%, 2%, 4%, 8%, and 15%) and Ni doped Ag–ZnO solid solutions with 0.25%, 0.5%, and 5% Ni ions. The as-synthesized Ni–Ag–ZnO solid solution NPs were characterized by powdered X-ray diffraction (pXRD), FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), UV-vis (UV) spectroscopy, and photoluminescence (PL) spectroscopy. Ni–Ag co-incorporation into a ZnO lattice reduces charge recombination by inducing charge trap states between the valence and conduction bands of ZnO and interfacial transfer of electrons. The Ni doped Ag–ZnO solid solution NPs have shown superior 4-nitrophenol reduction compared to pure ZnO NPs which do not show this reaction. Furthermore, a methylene blue (MB) clock reaction was also performed. Antibacterial activity against E. coli and S. aureus has inhibited the growth pattern of both strains depending on the concentration of catalysts.The synergic effect of Ni and Ag in Ni–Ag–ZnO solid solutions has tuned the optoelectronic properties of ZnO for photoreduction reactions. 相似文献