全文获取类型
收费全文 | 1712篇 |
免费 | 74篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 56篇 |
妇产科学 | 41篇 |
基础医学 | 163篇 |
口腔科学 | 80篇 |
临床医学 | 103篇 |
内科学 | 337篇 |
皮肤病学 | 14篇 |
神经病学 | 105篇 |
特种医学 | 73篇 |
外科学 | 360篇 |
综合类 | 47篇 |
预防医学 | 71篇 |
眼科学 | 21篇 |
药学 | 168篇 |
中国医学 | 7篇 |
肿瘤学 | 124篇 |
出版年
2023年 | 16篇 |
2022年 | 16篇 |
2021年 | 46篇 |
2020年 | 26篇 |
2019年 | 35篇 |
2018年 | 45篇 |
2017年 | 24篇 |
2016年 | 35篇 |
2015年 | 38篇 |
2014年 | 54篇 |
2013年 | 66篇 |
2012年 | 98篇 |
2011年 | 131篇 |
2010年 | 56篇 |
2009年 | 59篇 |
2008年 | 89篇 |
2007年 | 105篇 |
2006年 | 91篇 |
2005年 | 88篇 |
2004年 | 61篇 |
2003年 | 47篇 |
2002年 | 63篇 |
2001年 | 55篇 |
2000年 | 44篇 |
1999年 | 35篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1992年 | 23篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 22篇 |
1988年 | 22篇 |
1987年 | 26篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 21篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1974年 | 9篇 |
1973年 | 9篇 |
1970年 | 6篇 |
1968年 | 12篇 |
排序方式: 共有1791条查询结果,搜索用时 15 毫秒
41.
Abdominal Radiology - To discuss the imaging appearances of various pathologies affecting adult male urethra and to review the role of imaging in the assessment of artificial urinary sphincters and... 相似文献
42.
43.
Chidambaram Ramanathan Thomas Lackie Drake H. Williams Paul S. Simone Yufeng Zhang Richard J. Bloomer 《Nutrients》2022,14(2)
As a redox-sensitive coenzyme, nicotinamide adenine dinucleotide (NAD+) plays a central role in cellular energy metabolism and homeostasis. Low NAD+ levels are linked to multiple disease states, including age-related diseases, such as metabolic and neurodegenerative diseases. Consequently, restoring/increasing NAD+ levels in vivo has emerged as an important intervention targeting age-related neurodegenerative diseases. One of the widely studied approaches to increase NAD+ levels in vivo is accomplished by using NAD+ precursors, such as nicotinamide mononucleotide (NMN). Oral administration of NMN has been shown to successfully increase NAD+ levels in a variety of tissues; however, it remains unclear whether NMN can cross the blood–brain barrier to increase brain NAD+ levels. This study evaluated the effects of oral NMN administration on NAD+ levels in C57/B6J mice brain tissues. Our results demonstrate that oral gavage of 400 mg/kg NMN successfully increases brain NAD+ levels in mice after 45 min. These findings provide evidence that NMN may be used as an intervention to increase NAD+ levels in the brain. 相似文献
44.
45.
46.
V K Chadha S P Agarwal P Kumar L S Chauhan C Kollapan P S Jaganath P S Vaidyanathan P G Gopi K P Unnikrishnan S J Savanur 《The international journal of tuberculosis and lung disease》2005,9(5):569-575
SETTING: Twenty-six selected districts in India. OBJECTIVES: To estimate the average annual risk of tuberculous infection (ARTI) in four defined zones in the country. STUDY DESIGN: A tuberculin survey was conducted in selected clusters of 26 districts in four defined zones of India. Children 1-9 years of age were subjected to tuberculin testing with ITU PPD RT23 with Tween 80, and the maximum transverse diameter of induration was measured 72 h later. Prevalence of infection was estimated using the cut-off point method (Method I) and the mirror-image technique (Method II) among children without bacille Calmette-Guérin scar. Results from individual zones have been reported earlier, and the results from all four zones are presented here as a consolidated summary. RESULTS: The ARTI computed from estimated prevalence was found to be lowest in the southern zone (Method I: 1.1%, Method II: 1.0%). It was higher in the eastern zone (1.3% by both methods) and highest in the western (Method I: 1.8%, Method II: 1.6%) and northern zones (1.9% by both methods). The proportion of infected children was found to be significantly higher in urban than in rural areas in all zones. CONCLUSION: The intensified tuberculosis control efforts need to be sustained for many years. 相似文献
47.
Ng KP Saw TL Baki A Rozainah K Pang KW Ramanathan M 《Medical microbiology and immunology》2005,194(3):163-168
The implementation of the Expanded Program of Immunization (EPI) in 1989 has dramatic impact on hepatitis B virus (HBV) infection in school children in Malaysia. A cross-sectional seroprevalence study of HBV infection in 190,077 school children aged 7–12 years from 1997 to 2003 showed a steady decline of HBV surfacce antigen (HBsAg) prevalence rate from 2.5% for children born in 1985 to 0.4% among school children born in 1996. The overall prevalence of HBsAg was 0.6%, 0.7% in males and 0.6% in females. Over 92.7% of school children had been vaccinated with HBV vaccine, in which 93.7% were vaccinated under the EPI and 6.3% on voluntary basis. The school children vaccinated under EPI had a 0.4% HBsAg carrier rate, which was significantly lower than school children vaccinated on a voluntary basis (HBsAg carrier rate 1.3%) and non-vaccinated school children (HBsAg carrier rate 2.7%), suggesting that HBV vaccination of infants was the most effective measure in preventing vertical transmission of HBV in the hyperendemic region. 相似文献
48.
49.
Alicia Zou Sudarshini Ramanathan Russell C. Dale Fabienne Brilot 《Cellular & molecular immunology》2021,18(2):294
Autoimmune neurological disorders, including neuromyelitis optica spectrum disorder, anti-N-methyl-D-aspartate receptor encephalitis, anti-MOG antibody-associated disorders, and myasthenia gravis, are clearly defined by the presence of autoantibodies against neurological antigens. Although these autoantibodies have been heavily studied for their biological activities, given the heterogeneity of polyclonal patient samples, the characteristics of a single antibody cannot be definitively assigned. This review details the findings of polyclonal serum and CSF studies and then explores the advances made by single-cell technologies to the field of antibody-mediated neurological disorders. High-resolution single-cell methods have revealed abnormalities in the tolerance mechanisms of several disorders and provided further insight into the B cells responsible for autoantibody production. Ultimately, several factors, including epitope specificity and binding affinity, finely regulate the pathogenic potential of an autoantibody, and a deeper appreciation of these factors may progress the development of targeted immunotherapies for patients. 相似文献
50.
Magesh H Kamatchi C Vaidyanathan R Sumathi G 《Indian journal of medical microbiology》2011,29(3):262-268
Purpose: Resistance to fluoroquinolones, a commonly prescribed antimicrobial for Gram-negative and Gram-positive microorganisms, is of importance in therapy. The purpose of this study was to screen for the presence of Plasmid-Mediated Quinolone Resistance (PMQR) determinants in clinical isolates of Klebsiella pneumoniae. Materials and Methods: Extended-Spectrum Beta-Lactamase (ESBL) isolates of K. pneumoniae collected during October 2009 were screened by the antimicrobial susceptibility test. The plasmids from these isolates were analysed by specific Polymerase chain Reaction (PCR) for qnrA, qnrB and aac(6’)-1b. The amplified products were sequenced to confirm the allele. Results: Our analysis showed that 61% out of the 23 ESBL K. pneumoniae isolates were resistant to ciprofloxacin and 56% to levofloxacin. The PMQR was demonstrated by transforming the plasmids from two isolates P12 and P13 into E. coli JM109. The PMQR gene qnrA was found in 16 isolates and qnrB in 11 isolates. The plasmid pKNMGR13 which conferred an minimum inhibitory concentration (MIC) of more than 240 µg/ml in sensitive E. coli was found to harbour the qnrA1 and qnrB1 allele. Furthermore, the gene aac(6’)-1b-cr encoding a variant aminoglycoside 6’-N Acetyl transferase which confers resistance to fluoroquinolones was found in the same plasmid. Conclusions: Our report shows the prevalence of PMQR mediated by qnrA and qnrB in multidrug-resistant K. pneumoniae isolates from Chennai. A multidrug-resistant plasmid conferring high resistance to ciprofloxacin was found to harbour another PMQR gene, aac(6’)–1b-cr mutant gene. This is the first report screening for PMQR in K. pneumoniae isolates from India. 相似文献