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   547篇
  免费   21篇
耳鼻咽喉   1篇
儿科学   29篇
妇产科学   6篇
基础医学   44篇
口腔科学   11篇
临床医学   26篇
内科学   99篇
皮肤病学   92篇
神经病学   30篇
特种医学   4篇
外科学   44篇
预防医学   45篇
眼科学   6篇
药学   35篇
中国医学   2篇
肿瘤学   94篇
  2023年   3篇
  2022年   1篇
  2021年   7篇
  2020年   6篇
  2019年   4篇
  2018年   13篇
  2017年   7篇
  2016年   8篇
  2015年   16篇
  2014年   18篇
  2013年   22篇
  2012年   38篇
  2011年   46篇
  2010年   38篇
  2009年   29篇
  2008年   34篇
  2007年   45篇
  2006年   41篇
  2005年   39篇
  2004年   35篇
  2003年   26篇
  2002年   21篇
  2001年   8篇
  2000年   15篇
  1999年   5篇
  1998年   2篇
  1995年   1篇
  1993年   2篇
  1992年   2篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1987年   5篇
  1986年   4篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1979年   3篇
  1978年   2篇
  1977年   1篇
  1975年   3篇
  1974年   1篇
  1970年   2篇
  1968年   1篇
  1967年   2篇
排序方式: 共有568条查询结果,搜索用时 15 毫秒
1.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  相似文献   
2.
3.
Penbutolol is a beta-adrenoceptor antagonist that is extensively bound to alpha 1-acid glycoprotein (alpha 1-AGP), a protein that increases in inflammatory diseases thereby binding more drug in such conditions. Changes in serum binding can lead to modifications in the pharmacokinetics and pharmacodynamics of a drug, therefore, the central effect (as the anticonvulsant response) and brain uptake of penbutolol given intravenously to mice with experimental inflammation have been measured. A significant decrease of the central effect of penbutolol and its brain uptake was seen in diseased when compared with control animals (P less than 0.01). A parallel decrease in free fraction of penbutolol in diseased vs normal animals was detected. These results suggest that there is an increase in serum binding of basic drugs related to increments in alpha 1-AGP concentration, which reduces their central pharmacological effect.  相似文献   
4.
Summary Diffuse distribution of small, faintly staining, beaded deposits of rat immunoglobulin M (IgM) around the glomerular capillary blood vessels, and a more intensely staining larger deposition in the mesangium, were observed on the kidney sections of normal rats. As glomerular-fixed nephritogenic antigens are known to be present on the epithelial aspect of the glomerular basement membrane (GBM), especially at the soles of foot processes and at the slit pores, it was assumed that the IgM antibodies were directed against these antigens. Investigation by immunofluorescent antibody double-staining techniques of rat kidney sections obtained from normal and rabbit anti-FX1A-injected rats stained for the nephritogenic antigen showed that a number of antigenic sites in the glomeruli and in the mesangium shared antibody hits by heterologous rabbit IgG and autologous rat IgM antibodies. Most sites in the glomeruli stained specifically for rat IgM or rabbit IgG, but preferentially for the latter. The intensely fluorescent mesangial deposits stained mainly for rat IgM, indicating that at these sites the antigenic material was virtually saturated, while areas at the entry to the mesangial space also stained for rabbit IgG, indicating that at these locations free nephritogenic epitopes were still available for reaction with the anti-FX1A antibody. Western blot analysis have shown that the rabbit anti-rat FX1A IgG and the rat anti-rat KF3 IgM antibodies are directed against the same renal tubular-derived antigen with a molecular weight of 70,000. These experimental findings collectively demonstrate that the heterologous IgG and autologous IgM antibodies are directed against the same nephritogenic antigen, which is found in the glomeruli, the mesangium and the proximal convoluted tubules. Thus, the IgM autoantibody has a possible physiological role but, in addition, there is evidence of active immunophagocytic events, manifested in a rapid and continuous entrapment and expulsion of macromolecules after their processing by the mesangial cells of normal and passive Heymann nephritis rats.  相似文献   
5.
A new case of arginase deficiency is reported in a male newborn from Spain. In contrast with the majority of the earlier cases, this infant showed severe protein intolerance of early onset. The diagnosis was based on the assay of the urea cycle enzymes in a postmortem liver sample. Levels of erythrocyte arginase were also determined in the parents and in a sister of the patient, and were consistent with heterozygosity. From a study of the pedigree it appears that arginase deficiency in this family presents a dramatic course.  相似文献   
6.
Teas of Bidens pilosa and Mikania glomerata are popularly consumed to medicinal ends. The capacity to induce DNA damages and mutagenic effects of these teas were evaluated, in vitro, on HTC cells, with comet assay and micronucleus test. The teas tested at various doses were prepared differently: infusion of Mikania glomerata (IM) and Bidens pilosa (IB), macerate of Mikania glomerata in 80% ethanol (MM80) and decoction of Bidens pilosa (DB). In IM and MM80, the quantity of coumarin was determined by high-performance liquid chromatography (HPLC) with UV detection. Methylmethanesulfonate was utilized as positive control, phosphate-buffered saline as negative control, 80% ethanol as solvent control and 2-aminoanthracene as drug metabolism control. The comet assay demonstrated genotoxic effects for both plants. The genotoxic potential of IB was upper than DB, showing dose-response. In the MN test, excepting IM 40 microL/mL, all treatments was not mutagenic. The effects did not show direct relation with cumarin quantity present in IM and MM80. The results demonstrated DNA damages at the highest concentrations of alcoholic macerate (10 and 20 microL/mL) and infusion of Mikania glomerata (20 and 40 microL/mL) and of Bidens pilosa infusion (40 microL/mL). Thus, both dose and preparation-form suggest caution in the phytotherapeutic use of these plants.  相似文献   
7.
BACKGROUND AND AIM OF THE STUDY: The study aim was to determine whether beta-blocker treatment (atenolol) improves cardiopulmonary exercise performance and ventilatory response in patients with mitral stenosis in sinus rhythm. METHODS: A prospective study comparing the results of cardiopulmonary exercise tests (CPETs) was performed before and after atenolol therapy in 17 patients in NYHA classes I and II with mitral stenosis in sinus rhythm. Transthoracic echocardiography was performed pre-study, and left ventricular diameters, ejection fraction and mitral valve area monitored. CPETs (Naughton protocol) were performed by two different investigators before and after one-week atenolol therapy (50 mg/day). The second investigator was blinded to the result of the baseline test. O2 consumption, CO2 production, ventilatory parameters and respiratory exchange ratios were measured on line. RESULTS: Maximal O2 uptake (VO2max) did not differ significantly before and after beta-blockade (median 16.8 and 15.0 ml/kg/min, respectively. Median heart rate at rest (72 versus 55 beats/min; p = 0.0003) and during peak exercise (153 versus 105 beats/min; p = 0.0003), and anaerobic threshold (10 versus 8.9 ml/kg/min; p = 0.02) were lower with beta-blockade compared with the baseline state. Minute ventilation at maximum exercise (41 versus 40 l/min) and ventilatory equivalent for CO2 (34 versus 35) were unchanged with atenolol therapy, indicating no improvement in ventilatory performance. When patients were grouped into those in whom VO2max was improved with atenolol therapy (n = 7) and those in whom it was impaired (n = 10), there were no inter-group differences with respect to age, left ventricular function, severity of mitral stenosis, NYHA class and grade of beta-blockade reached. Four patients felt symptomatically worse during atenolol treatment (lower NYHA functional class). CONCLUSION: Beta-blockade does not improve exercise tolerance in patients with mitral stenosis in sinus rhythm. In addition, ventilatory performance does not change with treatment.  相似文献   
8.
9.
Most studies on immune tolerance induction (ITI) therapy in haemophilia A patients are focused on primary ITI in children. Here we report on the ITI outcome in a large retrospective cohort, including adults and patients with rescue ITI, treated with a pdFVIII/VWF concentrate. Retrospective data from haemophilic patients (FVIII< 2%) with inhibitors from 22 centres in Spain, Italy and Germany, who underwent primary or rescue ITI with pdFVIII/VWF concentrate, were collected. Complete success (CS), partial success (PS) and failure were defined based on the criteria of the consensus recommendations of the 2006 International ITI Workshop. A total of 41 cases of primary ITI (32 children and 9 adults) and 19 cases of rescue ITI (17 children and 2 adults) were evaluated. Success (CS+PS) rate of 87% was achieved in primary ITI and 74% in the higher risk profile of rescue ITI. Eight of nine (85%) patients with poorest prognosis (three or more of the known risk factors of poor response to ITI) achieved success (CS+PS). CS of 100% was observed in eight primary ITI patients with titre at start of ITI ≤2.5 BU and inhibitor peak ≤25 BU. The favourable response rates in primary and rescue ITI in children and in adult patients, even in the presence of poor prognostic factors, should be encouraged for broadening the indication of immune tolerance therapy in haemophilia A patients with inhibitors.  相似文献   
10.
Lasers in Medical Science - This study refers to clinical and histologic analysis of effects on photorejuvenation after one single treatment of fractional CO2 laser with low fluence and low...  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