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   349篇
  免费   33篇
  国内免费   1篇
耳鼻咽喉   5篇
儿科学   8篇
妇产科学   3篇
基础医学   31篇
口腔科学   4篇
临床医学   27篇
内科学   127篇
神经病学   65篇
特种医学   14篇
外国民族医学   1篇
外科学   43篇
综合类   5篇
预防医学   15篇
眼科学   18篇
药学   13篇
肿瘤学   4篇
  2023年   2篇
  2022年   8篇
  2021年   10篇
  2020年   9篇
  2019年   9篇
  2018年   21篇
  2017年   14篇
  2016年   8篇
  2015年   10篇
  2014年   19篇
  2013年   18篇
  2012年   35篇
  2011年   22篇
  2010年   11篇
  2009年   10篇
  2008年   12篇
  2007年   13篇
  2006年   14篇
  2005年   19篇
  2004年   10篇
  2003年   12篇
  2002年   10篇
  2001年   10篇
  2000年   13篇
  1999年   8篇
  1998年   3篇
  1995年   1篇
  1994年   2篇
  1992年   2篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   2篇
  1987年   4篇
  1985年   4篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1973年   1篇
  1971年   5篇
  1969年   1篇
  1968年   1篇
  1967年   2篇
  1966年   2篇
  1965年   1篇
排序方式: 共有383条查询结果,搜索用时 15 毫秒
51.
PURPOSE: To assess the intraoperator repeatability and interoperator reproducibility of central corneal thickness measurements by the Pentacam Scheimpflug imaging system (Oculus) and the optical low-coherence reflectometer (OLCR) pachymeter (Haag-Streit) and to compare them with those of ultrasound (US) pachymetry. SETTING: Assaf Harofe Medical Center Ophthalmology Outpatient Clinic, Zerifin, Israel. METHODS: Repeatability was determined from 10 successive measurements in each of 4 healthy patients. Reproducibility for the Pentacam Scheimpflug system was determined from measurements by 2 operators in each of 24 patients; in these 24 patients, central corneal thickness measurements were compared between the Pentacam and US pachymetry. For the OLCR pachymeter, reproducibility was determined from measurements by 2 operators in each of 16 patients, in whom central corneal thickness was also measured with the Pentacam. RESULTS: Mean coefficient of repeatability was 0.84% for the Pentacam Scheimpflug system and 0.33% for the OLCR pachymeter. For the Pentacam, the coefficient of interoperator reproducibility was 1.10% and the 95% limits of agreement were -10.2 microm to +11.9 microm. Mean difference between Pentacam and US was 6.09 microm. For the OLCR pachymeter, the coefficient of interoperator reproducibility was 0.59% and the 95% limits of agreement were -5.4 microm to +7.0 microm. Mean difference between central corneal thickness values obtained with the OLCR pachymeter and Pentacam Scheimpflug system was 1.7 microm. CONCLUSIONS: Objective, noncontact measurement of central corneal thickness with the Pentacam Scheimpflug system and OLCR pachymeter was convenient and yielded excellent intraoperator repeatability and interoperator reproducibility. Central corneal thickness values obtained with the Pentacam were similar to those obtained with both the OLCR pachymeter and an US pachymeter. Further research is needed to corroborate whether central corneal thickness measurements by the Pentacam and OLCR devices can be used interchangeably and are more clinically useful than US pachymetry.  相似文献   
52.
MR urography (MRU) has been widely accepted as a substitute to intravenous urography for investigating children with a dilated urinary tract after preliminary assessment by US and voiding cystourethrography. Hydronephrosis is by far the main indication for MRU because upper tract dilatation is a frequent condition in infants and children. Recent advances in technology have allowed MR to go beyond morphology and to assess renal function parameters such as split renal function and drainage. In this article we report our routine practice of the F0 MRU technique. The main advantages of our protocol are no requirement for general anaesthesia, no bladder catheterization, use of low-dose gadolinium-based contrast agent (0.05–0.1 mmol/kg) and total acquisition time of 30 min or less.  相似文献   
53.
A 33 year old woman suffered a lateral myocardial infarction for the first time, and was treated by pre-hospital thrombolysis and secondary angioplasty on the diagonal artery. Fifteen days before the cardiac event she had undergone a left ovarian cyst excision and left salpingectomy for an ectopic pregnancy. She was a moderate smoker and had been taking a second-generation biphasic minidose oral contraceptive (ethinyl-estradiol 30-40mg and levonorgestrel 150-200 mg) for about ten years. Fifteen days before the myocardial infarction and due to the ectopic pregnancy she had changed to a combined monophasic minidose oral contraceptive pill containing ethinylestradiol (30 mg) and drospirenone (3 mg). The eventual outcome was favourable, with no complications. In this article we discuss the possible implications of the various factors (oral contraceptive, tobacco use, and surgical intervention) in this young woman with a myocardial infarction.  相似文献   
54.
Slow walking speed is associated with increased mortality in the elderly, but it is unknown whether a similar association is present in late midlife. Our aim was to examine walking speed in late midlife as a predictor of mortality, as well as factors that may explain this association. Data are drawn from the Whitehall II longitudinal cohort study of British civil servants. The analyses are based on 6,266 participants (29% women; mean age?=?61 years, SD?=?6) for whom “walking speed at usual pace” was measured over 8 ft (2.44 m) at baseline. Participants were followed for all-cause and cause-specific mortalities during a mean of 6.4 (SD?=?0.8) years. During this period, 227 participants died. Participants in the bottom sex-specific third of walking speed (men, <1.26 m/s; women, <1.09 m/s) had an increased risk of death compared to those in the middle and top thirds (age- and sex-adjusted hazard ratio?=?1.89, 95% confidence interval (CI)?=?1.45–2.46), with no evidence of effect modification by age or sex (interactions, P?≥?0.40). The association between walking speed and mortality was partially explained by baseline inflammatory markers (percentage reduction of the association 22.8%), height and body mass index (16.6%), chronic diseases (14.0%), and health behaviors (13.4%). Together these and other baseline factors (socioeconomic status, cardiovascular risk factors, cognitive function) explained 48.5% of the association (adjusted hazard ratio?=?1.39, 95% CI?=?1.04–1.84). In conclusion, walking speed measured in late midlife seems to be an important marker of mortality risk; multiple factors, in particular inflammatory markers, partially explain this association.  相似文献   
55.
Sleep is an essential biological need of all animals studied to date. The sleep disorder narcolepsy is characterized by excessive daytime sleepiness, fragmentation of nighttime sleep, and cataplexy. Narcolepsy is caused by selective degeneration of hypothalamic hypocretin/orexin (HCRT) neurons. In mammals, HCRT neurons primarily regulate the sleep/wake cycle, feeding, reward-seeking, and addiction. The role of HCRT neurons in zebrafish is implicated in both sleep and wake regulation. We established a transgenic zebrafish model enabling inducible ablation of HCRT neurons and used these animals to understand the function of HCRT neurons and narcolepsy. Loss of HCRT neurons increased the expression of the HCRT receptor (hcrtr). Behavioral assays revealed that HCRT neuron-ablated larvae had normal locomotor activity, but demonstrated an increase in sleep time during the day and an increased number of sleep/wake transitions during both day and night. Mild sleep disturbance reduced sleep and increased c-fos expression in HCRT neuron-ablated larvae. Furthermore, ablation of HCRT neurons altered the behavioral response to external stimuli. Exposure to light during the night decreased locomotor activity of wild-type siblings, but induced an opposite response in HCRT neuron-ablated larvae. Sound stimulus during the day reduced the locomotor activity of wild-type sibling larvae, while HCRT neuron-ablated larvae demonstrated a hyposensitive response. This study establishes zebrafish as a model for narcolepsy, and indicating a role of HCRT neurons in regulation of sleep/wake transitions during both day and night. Our results further suggest a key role of HCRT neurons in mediating behavioral state transitions in response to external stimuli.  相似文献   
56.
57.
58.
BACKGROUND: Hepatitis C virus (HCV) infection in Egypt has reached an epidemic proportion and is associated with many extra hepatic manifestations; Glomerulonephritis (GN) is one of the most consequences of HCV infection often resulting in end stage renal disease in some cases. Detection of viral genome or particles within the kidney biopsies from HCV-infected patients has proven to be difficult. Histological characterization of renal lesions still represents a major challenge. The aim of our work was to describe the histological pattern of HCV-associated nephropathy. METHODS: Fifty Patients--out of 233--presented to Mansoura Urology and Nephrology clinic with manifestations of glomerular disease were screened for HCV antibodies by a 3rd generation ELISA test. Those tested positive for HCV antibodies were confirmed by PCR for HCV-RNA and subjected to more detailed clinical, biochemical and histological study. Kidney biopsies and in appropriate cases liver biopsies were examined by LM and electron microscopy (EM). RESULTS: Histological study of renal biopsies revealed membranoproliferative (MPGN) type 1 to be the most common lesion encountered (54%), followed by focal segmental glomerulosclerosis (FSGS) (24%), mesangioproliferative GN (18%), membranous nephropathy (MN) (4%) in that order. EM examinations of renal biopsies were successful in identifying HCV like particles in frozen renal tissue. CONCLUSION: HCV-associated glomerulopathy is a distinct category of glomerulonephritis. Results of LM showed some peculiar features. In addition, we were successful in location and detection of HCV particles in renal tissues by EM.  相似文献   
59.
60.
Hepatitis C virus (HCV) infection is considered as a major public health problem that, worldwide, chronically affects 170 million people. Elderly patients are more likely than younger patients to have increased duration of infection, increased rate of disease progression, and subsequently increased incidence of advanced liver disease. Natural history models predicted that the prevalence of HCV infection and its chronic sequelae as well as extrahepatic manifestations will eventually increase through the next decade and will mostly affect those who are greater than 60 years of age. Moreover, polytherapy and polypharmacy are frequent in elderly patients due to associated comorbidities. As advanced age is associated with increasing risk of development of cirrhosis and hepatocellular carcinoma, elderly patients are in special need of safe and effective antiviral therapies. Achievement of sustained viral responses (SVR) is associated with reduced liver-related complications and overall mortality in such patients with the advanced liver disease. With the recent introduction of interferon-free direct-acting antivirals, successful treatment for chronic HCV infection had dramatically improved, with overall cure rates that exceed 90% SVR. In our study, we aimed to study the efficacy and safety of combined sofosbuvir and daclatasvir, with or without ribavirin, in management of chronically infected HCV elderly patients who are more than 60 years old.  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