首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1824篇
  免费   52篇
  国内免费   17篇
耳鼻咽喉   27篇
儿科学   203篇
妇产科学   69篇
基础医学   137篇
口腔科学   152篇
临床医学   127篇
内科学   298篇
皮肤病学   22篇
神经病学   179篇
特种医学   23篇
外科学   373篇
综合类   24篇
一般理论   1篇
预防医学   20篇
眼科学   54篇
药学   85篇
中国医学   1篇
肿瘤学   98篇
  2023年   7篇
  2022年   10篇
  2021年   17篇
  2020年   12篇
  2019年   12篇
  2018年   19篇
  2017年   19篇
  2016年   36篇
  2015年   64篇
  2014年   72篇
  2013年   100篇
  2012年   122篇
  2011年   143篇
  2010年   82篇
  2009年   63篇
  2008年   120篇
  2007年   132篇
  2006年   117篇
  2005年   143篇
  2004年   118篇
  2003年   107篇
  2002年   104篇
  2001年   39篇
  2000年   42篇
  1999年   42篇
  1998年   15篇
  1997年   16篇
  1996年   16篇
  1995年   12篇
  1994年   11篇
  1993年   12篇
  1992年   10篇
  1991年   15篇
  1990年   4篇
  1989年   6篇
  1988年   5篇
  1987年   3篇
  1986年   4篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   2篇
  1976年   1篇
  1974年   2篇
  1973年   1篇
  1972年   2篇
  1970年   1篇
  1969年   2篇
  1967年   1篇
排序方式: 共有1893条查询结果,搜索用时 15 毫秒
21.
This study compared two groups of patients who were elderly and edentulous, one group included subjects who had mandibular overdentures supported by two implants (Group I); the other groups wore conventional complete dentures (Group II). This retrospective study included 100 edentulous patients (50 from each group) with an average age of 67.86 years, who had been followed for 4 years. The groups were compared in terms of patient satisfaction, quality of life (QOL), and bite force. The bite force and patient satisfaction scores of Group I were found to be statistically significantly higher than Group II (p < .05). However, no statistically significant difference was found between the two groups’ QOL scores (p > .05) except on the physical pain subscale (p = .013). Based on these results, it can be concluded that after 4 years of function, subjects wearing mandibular overdentures supported by two implants had higher values for bite force and patient satisfaction scores, but similar QOL scores when compared to conventional complete denture‐wearers.  相似文献   
22.
23.
Introduction. This study was designed to investigate whether 3-amino benzamide (3-AB), a poly (ADP-ribose) polymerase (PARP) inhibitor, has a protective effect on kidney injury induced by renal ischemia/reperfusion (I/R) by decreasing oxidative and nitrosative stress on renal dysfunction and injury. Materials and Methods. Thirty-two male Sprague-Dawley rats were divided into four groups: sham-operated, sham-operated + 3-AB, I/R, I/R + 3-AB. Rats were given 3-AB (100 mg/kg/day ip) 14 days prior to I/R. I/R and I/R + 3-AB groups underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehide, protein carbonyl content, and nitrite/nitrate level (NOx) were determined in the renal tissue. Serum creatinine (SCr), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. Results. 3-AB significantly reduced the I/R-induced increases in SCr, BUN, and AST. In addition, 3-AB markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Moreover, 3-AB attenuated the tissue NOx levels, indicating reduced NO production. Conclusions. 3-AB has beneficial effect on renal glomerular and tubular dysfunction in rats' kidneys subjected to I/R injury. Moreover, 3-AB has ameliorating effect on both oxidative stress and nitrosative stress of the kidneys, which correlated with histopathological evaluation.  相似文献   
24.
25.
26.
27.
Alagille syndrome is associated with various ocular abnormalities, including pseudopapilledema or optic disk edema due to increased intracranial pressure. Several mechanisms have been proposed to explain the mechanism of intracranial hypertension in Alagille syndrome. Craniosynostosis is an unusual but significant cause of increased intracranial hypertension in Alagille syndrome. It has recently been demonstrated in animal models that Jagged1 gene in which mutations are responsible for Alagille syndrome may also take part in cranial suture formation. We report a child with Alagille syndrome and craniosynostosis who presented with pruritus, elevated liver enzymes, and suspected increased intracranial pressure.  相似文献   
28.
The aim of this study was to evaluate the histopathological and apoptotic changes occurring in the rat ipsilateral and contralateral testes, after experimental spermatic cord torsion, and to explore and the role of poly(ADP‐ribose) polymerase (PARP) cleavage in testicular torsion–detorsion injury. A total of 37 Wistar albino rats were subjected to 720° unilateral spermatic cord torsion for 1, 2 and 4 h, followed by 4‐h reperfusion, or else to a sham operation (control group). Histology of the testicle was evaluated using haematoxylin–eosin (H&E) staining and Johnsen's scoring system. Germ cell apoptosis was evaluated via active caspase‐3 immunostaining, and PARP expression levels were evaluated via Western blotting. The mean Johnsen's tubular biopsy scores (JTBS) of the ipsilateral testicles were lower for all torsion groups than for the controls (P < 0.05), but the JTBS of the contralateral testicles were only lower in the 4‐h torsion group (P < 0.05). The mean apoptosis score (AS) of the ipsilateral and contralateral testicles was significantly higher in the torsion groups than in the sham group. AS increased correlatively with torsion time, in both testicles. The effect of testicular torsion on PARP cleavage was time dependent, with the highest effect observed after 4 h of testicular torsion (P < 0.05). Testicular torsion caused time‐dependent histological changes, apoptosis and increases in PARP cleavage. Our results suggest that testicular torsion–detorsion injury caused cell damage and germ cell apoptosis that apparently involved cleavage of PARP. Increased PARP cleavage could, in turn, lead to enhanced apoptosis.  相似文献   
29.
Objectives:It is suggested that excessive calcium entry into neurons is the main triggering event in the initiation of epileptic discharges. We aimed to investigate the role of T and N type calcium channels in absence epilepsy experimental model.Results:Beta and delta recording ratios in 1 μM/5 μl mibefradil group was significantly different from basal and other dose-injected groups. Beta, alpha, and theta recordings in 0.2 μM/5 μl w-Conotoxin MVIIA group was significantly different from basal and other dose-injected groups. In w-Conotoxin MVIIA after mibefradil group, beta, alpha, and theta recording ratios were significantly different from basal and mibefradil group. Mibefradil and w-Conotoxin MVIIA significantly decreased the frequency and duration of SWDs. The decrease of frequency and duration of SWDs in mibefradil group was significantly different from w-Conotoxin MVIIA group. The frequency and duration of SWDs significantly decreased in w-Conotoxin MVIIA after mibefradil group compared with basal, mibefradil, and w-Conotoxin MVIIA groups.Conclusions:We concluded that both T and L type calcium channels play activator roles in SWDs and have positive effects on frequency and duration of these discharges. These results are related with their central effects more than peripheral effects.KEY WORDS: Epilepsy, mibefradil, T and N type calcium channels, Wistar Albino Glaxo/Rij rats, w-Conotoxin MVIIA  相似文献   
30.
The role of apoptosis in childhood Henoch–Schonlein purpura   总被引:2,自引:0,他引:2  
The pathogenesis of vasculitis is complex and is yet to be fully elucidated, although it is known that inflammatory cells play a major role. Dysregulation of apoptosis and defective clearance of inflammatory cells could lead to the persistence of inflammation and excessive tissue injury. In this study we aimed to investigate Fas (CD95) and apoptosis on peripheral blood (PB) neutrophil and lymphocytes in Henoch–Schonlein purpura, both in the acute phase and after resolution to determine the role of apoptosis in this self-limited vasculitis. Leukocytoclastic vasculitis presenting with Henoch–Schonlein purpura (HSP) was diagnosed according to ACR 1990 criteria and confirmed by skin biopsy. Thirty-seven patients (22 boys, 15 girls) aged 2.5–17 years (9 ± 3.3) were enrolled in the study. Expression of CD95 and apoptosis were investigated by the annexin/PI method on peripheral blood neutrophils and lymphocytes in both the acute and the resolution phases of the disease. The mean neutrophil and lymphocyte CD95 expression was 65.4 ± 37.6% and 33.3 ± 7.3%, respectively, in the acute stage and 62.8 ± 44.2% and 41 ± 20%, respectively, in the resolution (P > 0.05). The percentage of apoptotic peripheral blood neutrophils and lymphocytes as determined by annexin positivity was 13.3 ± 11.31% and 8.6 ± 9.5%, respectively, during the acute phase and 4.6 ± 3.4% and 3.1 ± 3.1%, respectively, in the resolution (P = 0.002, P = 0.008). These results suggest that increased apoptotic process in the immune effector cells in the acute phase of the disease may play an important role in the early control of inflammatory response and repair in leukocytoclastic vasculitis, thereby contributing to the self-limited nature of the disease.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号