全文获取类型
收费全文 | 4848篇 |
免费 | 281篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 66篇 |
妇产科学 | 65篇 |
基础医学 | 731篇 |
口腔科学 | 333篇 |
临床医学 | 383篇 |
内科学 | 992篇 |
皮肤病学 | 112篇 |
神经病学 | 433篇 |
特种医学 | 120篇 |
外科学 | 595篇 |
综合类 | 15篇 |
一般理论 | 1篇 |
预防医学 | 549篇 |
眼科学 | 57篇 |
药学 | 423篇 |
中国医学 | 31篇 |
肿瘤学 | 178篇 |
出版年
2023年 | 49篇 |
2022年 | 122篇 |
2021年 | 164篇 |
2020年 | 125篇 |
2019年 | 128篇 |
2018年 | 178篇 |
2017年 | 135篇 |
2016年 | 143篇 |
2015年 | 165篇 |
2014年 | 223篇 |
2013年 | 285篇 |
2012年 | 419篇 |
2011年 | 434篇 |
2010年 | 201篇 |
2009年 | 210篇 |
2008年 | 322篇 |
2007年 | 302篇 |
2006年 | 270篇 |
2005年 | 210篇 |
2004年 | 157篇 |
2003年 | 157篇 |
2002年 | 149篇 |
2001年 | 112篇 |
2000年 | 102篇 |
1999年 | 73篇 |
1998年 | 28篇 |
1997年 | 21篇 |
1996年 | 11篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 21篇 |
1991年 | 14篇 |
1990年 | 18篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1982年 | 8篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1970年 | 5篇 |
1969年 | 20篇 |
1968年 | 6篇 |
1967年 | 8篇 |
排序方式: 共有5148条查询结果,搜索用时 15 毫秒
1.
Francisco Sampaio Pedro Mateus Nuno Bettencourt Carla Costa Dias Luís Ad?o Lino Santos Madalena Teixeira Lino Sim?es Vasco Gama 《Revista portuguesa de cardiologia》2006,25(3):321-327
INTRODUCTION: Ischemic heart disease is a major cause of heart failure in western societies. However, the factors that may influence left ventricular function (LVF) recovery after an acute coronary syndrome (ACS) are still unclear. OBJECTIVE: To identify variables that may influence LVF evolution one year after ACS. METHODS: 104 patients hospitalized with ACS between 7/1/2001 and 12/31/2002 and with systolic dysfunction--defined as an echocardiographic ejection fraction (EF) < or = 45%--were randomly allocated to a planned coronary follow-up program (FUP) or a general cardiology clinic (GC); patients from both groups were also randomly referred to a structured cardiac rehabilitation program (CRP). EF was re-assessed at one year. We compared differences between patients who recovered left ventricular function (EF > 45%; group 1) and those who did not (group 2). RESULTS: One year after discharge, 44.2% of the patients had recovered function. There were no significant differences between the groups in gender (77.7 vs. 76.5% male), age (56 vs. 59 years), hypertension, diabetes, dyslipidemia, smoking habits or family history. A previous history of cardiovascular events was more frequent in group 2 (11.1% vs. 35.3%, p = 0.03). Cardiac catheterization was performed before discharge in 88.8% and 88.2% in groups 1 and 2 respectively (p = NS); no differences were found in coronary anatomy between the two groups. Angioplasty was performed in 54.2% in group 1 and 50% in group 2 (p = NS). There were no differences in the use of angiotensin-converting enzyme inhibitors (83.3% vs. 87.5%), beta-blockers (87.5% vs. 87.5%), nitrates (37.5% vs. 33.3%), aspirin (95.8% vs. 95.8%), statins (79.1% vs. 75%) or diuretics (20.8% vs. 45.8%). There was no significant difference in LVF recovery between patients randomized to FUP or GC (38.5% vs. 54.5%). 87.5% of patients who completed the CRP had normal EF at one year compared to 32.7% of patients not referred to the program (p = 0.009). Although EF improved in both groups, this improvement was greater in patients who completed a CRP (EF 8% vs. 5%, p = 0.003). CONCLUSION: A previous cardiovascular event and completion of a CRP were the only variables that influenced LVF recovery. Thus, enrollment in a CRP, in addition to standard therapy, could be an important therapeutic measure in patients with systolic dysfunction after ACS; our data suggest that these programs should be more widely used. 相似文献
2.
E. Angelini M. Teixeira J.-M. Aran E. Ferrary 《European archives of oto-rhino-laryngology》1998,255(7):331-333
Taurine is a β-aminosulfonic acid and is a ubiquitous amino acid whose role in the cochlea is not well established. In this
study, its entry from blood into perilymph was investigated in the guinea pig as animal model. The penetration rate of [3H]taurine (molecular weight 125) into the perilymph of the scala vestibuli was measured 1 and 2 h after the intravenous infusion
of [3H]taurine in nephrectomized animals. Results showed a rate of penetration in perilymph related to plasma at 36 ± 4.7% (n = 5) after 1 h and 43 ± 5.6% (n = 5) after 2 h. Compared to the penetration rate of urea (molecular weight 60) and mannitol (molecular weight 186) reported
previously in rats, a passive entry of taurine into perilymph through the blood-perilymph barrier is suggested.
Received: 30 July 1997 / Accepted: 15 January 1998 相似文献
3.
E Marchi F S Vargas M M Acencio L Antonangelo E H Genofre L R Teixeira 《The European respiratory journal》2006,28(5):929-932
Intrapleural instillation of talc is used to produce pleurodesis in cases of recurrent malignant pleural effusions. The mechanisms by which pleurodesis is produced remain unknown but may involve either injury or activation of the mesothelium. The aim of the current study was to assess the inflammatory response of pleural mesothelial cells to talc in an experimental model in rabbits. A group of 10 rabbits were injected intrapleurally with talc (200 mg.kg(-1)) and undiluted pleural fluid was collected after 6, 24 or 48 h for measurement of interleukin (IL)-8, vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta1. Samples of pleura were studied to assess the inflammatory infiltrate and mesothelial cell viability. The pleural fluid IL-8 concentration peaked at 6 h, whereas VEGF and TGF-beta1 concentrations increased steadily over 48 h. Immunohistochemistry for cytokeratin showed a preserved layer of mesothelial cells despite the intense inflammatory pleural reaction. In conclusion, it is proposed that the mesothelial cell, although injured by the talc, may actively mediate the primary inflammatory pleural response in talc-induced pleurodesis. 相似文献
4.
Sandra Guerra A Teixeira Pinto José Ribeiro José Oliveira José Duarte Jorge Mota 《Revista portuguesa de cardiologia》2003,22(2):167-182
An important aspect of preventive medicine is to identify subjects at risk as soon as possible, so preventive strategies can be introduced at early ages. The justification for this strategy is twofold: firstly, the assumption that children maintain a particular high value of a risk factor for disease throughout life; and secondly, the assumption that lowering the level of the risk factor in early life will have a greater impact on the disease than will risk factor changes in later life. In epidemiology the analysis of such factors over time is referred to as tracking. Tracking analysis has been applied to risk factors for cardiovascular diseases (CVD) in pediatric years. The aims of this study were: I) to analyze the stability of biological risk factors [high blood pressure (BP), high percentage of fat mass (%FM) and high total cholesterol (TC)] and lifestyle risk factors [low physical activity index (PAI)] in isolation; and II) to analyze the stability of zero, one, two or three biological risk factors. There were two evaluations in 692 children and adolescents (325 boys and 367 girls), aged between 8 and 15 years. The quartiles, adjusted for age and gender, were the criterion used to identify subjects with biological risk factors (fourth quartile) and with lifestyle risk factors (first quartile) for CVD. The stability was calculated through the relative frequency of subjects who maintained or changed quartile between the two evaluations. There is stability for biological risk factors as well as for behavioral and/or lifestyle risk factors. However, the highest stability is seen in biological risk factors. 相似文献
5.
Proximal radioulnar transposition in an elbow dislocation is rare. Only three cases have been recorded. Translocation can easily be missed unless radiographs are carefully examined. Proximal radioulnar translocation has been believed to be iatrogenic. The injury we report was not iatrogenic, and mechanical locking of radial head and neck fracture necessitated open reduction. 相似文献
6.
Fabricio B Teixeira 《Practical procedures & aesthetic dentistry》2006,18(3):S7-11
Several factors can contribute to the clinician's ability to achieve success in endodontic therapy. The importance of the coronal seal to positive endodontic outcomes has been established in numerous studies; fracture strength also has a significant influence on the prognosis of an endodontically treated tooth. This presentation discusses the role of these two factors in contemporary endodontic therapy and demonstrates how the utilization of an adhesively bonded, synthetic root-filling system can support the practitioner's management of nonvital teeth. 相似文献
7.
8.
F. Teixeira Brandt C. D. Costa Albuquerque J. W. Barros Leal 《International urogynecology journal》1997,8(6):332-335
We report on the vaginal mucosal folds (VMF) at the urethral external meatus. Resection of the VMF reduces the dispersed micturition
and other urinary symptoms.
EDITORIAL COMMENT: The investigators describe the presence of a vaginal mucosal fold (VMF) just dorsal to the urethral meatus
and its relationship to voiding abnormalities. VMF were found on physical examination in 8.9% of the clinic population, all
of whom complained of dispersed micturition, and 79% also experienced other voiding abnormalities. The complaint of dispersed
micturition was successfully treated with excision of the VMF, and the other associated symptoms were improved. This structure
should be routinely looked for on physical examination, especially in patients with voiding symptoms. Only further investigation
of this newly described entity at other centers around the world will determine the incidence of the anatomic finding and
the prevalence of associated voiding disturbances across different populations. 相似文献
9.
10.
Aberrant cellular retinol binding protein 1 (CRBP1) gene expression and promoter methylation in prostate cancer 总被引:3,自引:0,他引:3 下载免费PDF全文
Jerónimo C Henrique R Oliveira J Lobo F Pais I Teixeira MR Lopes C 《Journal of clinical pathology》2004,57(8):872-876
AIMS: Retinoids are involved in cell growth, differentiation, and carcinogenesis. Their effects depend on cytosolic transport and binding to nuclear receptors. CRBP1 encodes a protein involved in this process. Because altered CRBP1 expression and promoter hypermethylation occur in several tumours, these changes were investigated in prostate tumorigenesis. METHODS: The CRBP1 promoter was assessed by methylation specific polymerase chain reaction on tissue samples from 36 radical prostatectomy specimens (paired normal tissue, adenocarcinoma, and high grade prostatic intraepithelial neoplasia (HGPIN)), 32 benign prostatic hyperplasias (BPHs), and 13 normal prostate tissue samples from cystoprostatectomies. Methylation of DNA extracted from microdissected tissue was examined blindly. CRBP1 expression was assessed by immunohistochemistry on formalin fixed, paraffin wax embedded tissue. RESULTS: Loss of CRBP1 expression was seen in 15 of 36 adenocarcinomas and 18 of 36 HGPINs. Fifteen adenocarcinomas and nine HGPINs showed overexpression, whereas the remainder showed normal expression. BPH displayed normal expression. No significant associations were found between CRBP1 expression and Gleason score or stage. CRBP1 promoter hypermethylation was found in 17 of 36 adenocarcinomas, three of 35 HGPINs, one of 36 normal prostate tissues from the same patients, none of 32 BPHs, and none of 13 normal prostate tissues from cystoprostatectomies. Loss of expression and hypermethylation of CRBP1 were not significantly associated. CONCLUSIONS: Altered CRBP1 expression and hypermethylation are common in prostate carcinoma, although CRBP1 hypermethylation is not an early event in tumorigenesis. Moreover, both adenocarcinoma and HGPIN show frequent CRBP1 overexpression. The molecular mechanisms underlying altered CRBP1 expression in prostate cancer deserve further study. 相似文献