全文获取类型
收费全文 | 1747篇 |
免费 | 121篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 41篇 |
妇产科学 | 71篇 |
基础医学 | 178篇 |
口腔科学 | 60篇 |
临床医学 | 164篇 |
内科学 | 305篇 |
皮肤病学 | 34篇 |
神经病学 | 105篇 |
特种医学 | 62篇 |
外科学 | 226篇 |
综合类 | 43篇 |
预防医学 | 138篇 |
眼科学 | 65篇 |
药学 | 191篇 |
中国医学 | 40篇 |
肿瘤学 | 93篇 |
出版年
2024年 | 3篇 |
2023年 | 26篇 |
2022年 | 73篇 |
2021年 | 98篇 |
2020年 | 73篇 |
2019年 | 86篇 |
2018年 | 95篇 |
2017年 | 79篇 |
2016年 | 66篇 |
2015年 | 68篇 |
2014年 | 86篇 |
2013年 | 92篇 |
2012年 | 145篇 |
2011年 | 125篇 |
2010年 | 70篇 |
2009年 | 53篇 |
2008年 | 109篇 |
2007年 | 71篇 |
2006年 | 82篇 |
2005年 | 58篇 |
2004年 | 45篇 |
2003年 | 46篇 |
2002年 | 44篇 |
2001年 | 20篇 |
2000年 | 16篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1969年 | 2篇 |
1928年 | 1篇 |
排序方式: 共有1881条查询结果,搜索用时 421 毫秒
71.
Context: Solanum xanthocarpum Schard. and Wendl. (Solanaceae) has been used in traditional Indian medicines for its antioxidant, anti-inflammatory, and antiasthmatic properties.Objective: The present study demonstrates the antioxidant and hepatoprotective effects of S. xanthocarpum. On the basis of in vitro antioxidant properties, the active fraction from column chromatography of the methanol extract of S. xanthocarpum leaves (SXAF) was chosen as the potent fraction and used for hepatoprotective studies in rats.Materials and methods: The antioxidant activity was evaluated by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and reducing power assays. Rats were pre-treated with 100 and 200?mg/kg b.w. of SXAF for 14?d with a single dose of CCl4 in the last day. Hepatoprotective properties were determined by serum biochemical enzymes, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), antioxidant enzymes (SOD, CAT, GSH, and GST), and histopathology studies.Results: SXAF exhibited significant antioxidant activity in scavenging free radicals with IC50 values of 11.72?µg (DPPH) and 17.99?µg (ABTS). Rats pre-treated with SXAF demonstrated significantly reduced levels of serum LDH (1.7-fold), ALP (1.6-fold), and AST (1.8-fold). Similarly, multiple dose SXAF administration at 200?mg/kg b.w. demonstrated significantly enhanced levels of SOD (1.78?±?0.13), CAT (34.63?±?1.98), GST (231.64?±?14.28), and GSH (8.23?±?0.48) in liver homogenates. Histopathological examination showed lowered liver damage in SXAF-treated groups.Discussion and conclusion: These results demonstrate that SXAF possesses potent antioxidant properties as well as hepatoprotective effects against CCl4-induced hepatotoxicity. 相似文献
72.
Hadi Tabibi Atefeh As’habi Mitra Mahdavi-Mazdeh Mehdi Hedayati Behnaz Nozary-Heshmati 《International urology and nephrology》2014,46(10):2015-2020
Purpose
The present study was designed to compare novel risk factors for cardiovascular diseases (CVD) between hemodialysis (HD) patients with or without protein-energy wasting (PEW) for determining novel risk factors for CVD in HD patients with PEW.Methods
In this cross-sectional study, 291 HD patients were randomly selected from among 2,302 adult HD patients in Tehran hemodialysis centers. The presence of PEW in HD patients was determined by subjective global assessment. In addition, 4 mL blood was obtained before dialysis and analyzed for serum concentrations of novel risk factors for CVD, including C-reactive protein (CRP), soluble intercellular adhesion molecule type 1 (sICAM-1), soluble vascular cell adhesion molecule type 1 (sVCAM-1), sE-selectin, malondialdehyde (MDA), nitric oxide (NO), endothelin-1 and lipoprotein (a) [Lp (a)].Results
Serum CRP and sICAM-1 were significantly higher in HD patients with PEW as compared to those without PEW (P < 0.01), whereas there were no significant differences in serum sVCAM-1, sE-selectin, MDA, NO, endothelin-1 and Lp (a) between the two groups. Serum CRP and sICAM-1 were significantly higher in HD patients with PEW type IIa and IIb than in those with PEW type I (P < 0.01).Conclusion
The present study indicates that serum CRP and sICAM-1, as two CVD risk factors, increase in HD patients with PEW as compared to those without PEW and these increases occur in HD patients with PEW type IIa and IIb who have inflammation. 相似文献73.
74.
Structural Response of Steel Jacket-UHPC Retrofitted Reinforced Concrete Columns under Blast Loading
The lateral capacity of exterior concrete columns subjected to a blast load is the key factor in the building collapse probability. Due to potentially severe consequences of the collapse, efforts have been made to improve the blast resistance of existing structures. One of the successful approaches is the use of ultra-high-performance-concrete (UHPC) jacketing for retrofitting a building’s columns. The columns on the first floor of a building normally have higher slenderness due to the higher first story. Since an explosion is more likely to take place at the ground level, retrofitting the columns of the lower floors is crucial to improve a building’s blast resistance. Casting a UHPC tube around a circular RC column can increase the moment of inertia of the column and improve the flexural strength. In this study, a retrofitting system consisting of a UHPC layer enclosed by a thin steel jacket is proposed to improve the blast resistance of buildings in service. Most of the previous research is focused on design aspects of blast-resistant columns and retrofitting systems are mostly based on fiber reinforced polymers or steel jackets. A validated FE model is used to investigate the effectiveness of this method. The results showed significant improvement both at the component and building system levels against combined gravity and blast loading. 相似文献
75.
Genome-wide studies highlight indirect links between human replication origins and gene regulation 总被引:1,自引:0,他引:1
76.
77.
78.
Mahmoud Torabinejad Hadi FarasRobert Corr DDS MSD Kenneth R. WrightShahrokh Shabahang DDS MS PhD 《Journal of endodontics》2014
Introduction
A growing body of evidence is building a case for the possibility of tissue regeneration within the root canal of necrotic teeth, allowing for continued root development. However, it remains unknown what type of tissue is produced after regenerative endodontics. The purpose of this study was to use blood clots and platelet-rich plasma (PRP) as scaffolds in regenerative endodontics under ideal conditions in a ferret model to examine the tissues generated within the root canals.Methods
The pulps of 21 canine teeth from 7 young ferrets were extirpated using broaches without filing the canal walls. Bleeding was stimulated from the periapical tissues, and a blood clot was induced in the canal space to the level of the cementoenamel junction in 12 teeth. PRP was prepared and placed in the canals to the level of the cementoenamel junction in 9 teeth. The coronal access was sealed with mineral trioxide aggregate. Seven canines were not operated on and served as controls. Three months later, block sections including each canine and its surrounding tissues were removed for histologic evaluation. The tissues found in the canals of experimental teeth were compared with those in the control teeth.Results
Almost all of the experimental teeth showed the presence of intracanal bonelike tissue. No evidence of dentinal wall thickening or apical narrowing was noted in the experimental teeth.Conclusions
In this experimental model, the use of either PRP or blood clots during regenerative endodontics leads to the formation of intracanal bonelike tissue without continual root maturation. 相似文献79.
80.
Arunkumar Krishnan Ruhee A Patel Yousaf Bashir Hadi Diptasree Mukherjee Sarah Shabih Shyam Thakkar Shailendra Singh Tinsay A Woreta Saleh A Alqahtani 《World journal of hepatology》2023,15(1):68-78
BACKGROUND Patients with autoimmune hepatitis(AIH) require life-long immunosuppressive agents that may increase the risk of poor corona virus disease 2019(COVID-19)outcomes.There is a paucity of large data at the population level to assess whether patients with AIH have an increased risk of severe diseases.AIM To evaluate the impact of pre-existing AIH on the clinical outcomes of patients with COVID-19.METHODS We conducted a population-based,multicenter,propensity score-matched cohort study with... 相似文献