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   213篇
  免费   3篇
儿科学   15篇
妇产科学   13篇
基础医学   7篇
口腔科学   10篇
临床医学   28篇
内科学   47篇
皮肤病学   1篇
神经病学   1篇
特种医学   5篇
外科学   43篇
综合类   2篇
预防医学   11篇
眼科学   15篇
药学   3篇
肿瘤学   15篇
  2022年   3篇
  2021年   6篇
  2020年   8篇
  2019年   50篇
  2018年   43篇
  2017年   10篇
  2015年   2篇
  2014年   3篇
  2013年   3篇
  2012年   2篇
  2011年   3篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2006年   2篇
  2005年   1篇
  2004年   1篇
  1999年   1篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1985年   4篇
  1984年   7篇
  1983年   3篇
  1982年   5篇
  1981年   6篇
  1980年   6篇
  1979年   9篇
  1978年   6篇
  1977年   2篇
  1976年   7篇
  1975年   10篇
  1974年   4篇
  1973年   2篇
  1972年   1篇
排序方式: 共有216条查询结果,搜索用时 15 毫秒
1.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are efficacious lipid-lowering agents, but more precise estimates of their effects on major adverse cardiovascular events (MACE), mortality, and safety are needed. We systematically reviewed and meta-analyzed randomized controlled trials with durations ≥ 6 months comparing MACE, mortality, and safety with PCSK9 inhibitors vs control. We searched CENTRAL, Embase, MedLine and the grey literature to November 7, 2018. From 2048 articles, we included 23 trials (n = 60,723). PCSK9 inhibitors reduced MACE (relative risk, 0.83; 95% confidence interval, 0.78-0.88), but did not clearly reduce mortality (relative risk, 0.93; 95% confidence interval, 0.85-1.02) or increase adverse events. In conclusion, PCSK9 inhibitors reduce nonfatal MACE, are well tolerated, but effects on mortality remain unclear.  相似文献   
2.
3.

Objective

To determine the effectiveness of a macular buckle procedure without vitrectomy for the treatment of symptomatic myopic macular schisis.

Design

Retrospective case series.

Participants and methods

All patients who underwent surgery with placement of an NPB macular buckle (AJL Ophthalmic, Miñano, Álava, Spain) without vitrectomy for symptomatic myopic macular schisis were included. Visual acuity and anatomical outcomes based on optical coherence tomography (OCT) were reviewed.

Results

Eight consecutive eyes from 7 patients were included. Six of the 7 patients were female and the mean age was 59 ± 6 years (range, 49–66 years). The mean follow-up duration was 11 ± 7 months (range, 3–23 months). Mean preoperative axial length was 29.54 ± 1.28 mm (range, 27.88–31.96 mm). Mean preoperative best-corrected visual acuity (BCVA) was 0.71 ± 0.29 logMAR (Snellen equivalent 20/103); mean postoperative BCVA was 0.46 ± 0.44 (Snellen equivalent 20/58; p = 0.19) and 87.5% of patients maintained or improved vision. Pre- and postoperative OCT images are included and discussed within. Preoperative ellipsoid zone status and postoperative central macular buckle indentation appear to be important in visual outcomes. Two patients required a buckle repositioning for persistent schisis. One patient developed a macular hole postoperatively that resolved with subsequent vitrectomy. There were no other complications.

Conclusions

The macular buckle is an effective and promising therapeutic option for myopic macular schisis.  相似文献   
4.
Patients with congenital heart disease (CHD) have been surviving late into adulthood, with atrial arrhythmias being the most common long-term complication. In recent reports, atrial fibrillation (AF) tended to be the most common form of arrhythmias among groups of patients with adult CHD (ACHD) older than 50 years of age. When compared with their adult counterparts without CHD, AF in patients with ACHD has been characterized by a higher incidence and prevalence, younger age of onset, and a greater risk of progression to persistent AF. Risk factors for the development of AF are not well known but include older age, left atrial dilation, systemic hypertension, and multiple cardiac surgeries. Data on management options such as optimal antiarrhythmic drug therapy, indications for anticoagulation, and efficacy and safety of catheter ablation are limited. There is a crucial need for further research exploring management, prevention, and monitoring strategies for the growing ACHD patient population with AF. This report will provide a contemporary review of the epidemiology, pathophysiology, and management options for AF in this complex patient population.  相似文献   
5.

Background

Cardiovagal baroreflex gain (cBRG) reflects an individual's ability to buffer swings in blood pressure. It is not well understood how this mechanism is influenced by physical activity in pregnancy. Because pregnant women tend to engage in low levels of moderate-to-vigorous physical activity (MVPA) and high levels of sedentary behaviour, we sought to determine the influence of MVPA and sedentary behaviour on cBRG and mean arterial pressure (MAP) in pregnancy.

Methods

Fifty-eight third trimester (31.9 ± 3.0 weeks) normotensive pregnant women (31.2 ± 2.8 years) were tested. Heart rate (electrocardiogram) and blood pressure (systolic blood pressure and MAP; finger photoplethysmography) were collected on a beat-by-beat basis, and averaged over 3 minutes of rest. Spontaneous cBRG was calculated as the slope of the relationship between fluctuations in systolic blood pressure and heart rate. Objective measures of MVPA and sedentary behaviour were collected over a 7-day period using an ActiGraph accelerometer (model wGTX3-BT; ActiGraph LLC, Pensacola, FL).

Results

Participants spent 67.5 ± 7.9% of waking hours engaged in sedentary behaviour, and performed 68.6 ± 91.9 minutes of MVPA per week. Sedentary behaviour was not related to cBRG (r = ?0.035; P = 0.793) or MAP (r = ?0.033; P = 0.803). However, MVPA was positively associated with cBRG (r = 0.315; P = 0.016), but not MAP (r = ?0.115; P = 0.389). The association between MVPA and cBRG remained significant after controlling for age, pre-pregnancy body mass index, gestational age, and wear time (r = 0.338; P = 0.013), indicating that women who engaged in greater amounts of MVPA showed increased cBRG.

Conclusions

Our data suggest that increased MVPA, but not necessarily reduced sedentary behaviour, might be beneficial for reflex control of blood pressure during pregnancy.  相似文献   
6.

Background

Dietary habits formed during youth may result in the development of obesity and chronic diseases in adulthood. We aimed to determine the frequency of the consumption of foods and beverages and the degree of adherence to Canada's Food Guide recommendations among multi‐ethnic youths.

Methods

Participants were recruited from 12 schools in the Edmonton, Alberta area by use of posters, school newsletters and advertisements. A 30‐item food frequency questionnaire was administered by a trained interviewer to assess dietary intake in a convenience sample of 557 (328 females and 229 males) youths aged 11–23 years; for the purpose of the present study, only the 14–18 years age group was considered in the analysis. Participants were divided by sex and self‐identified ethnicity into four groups [Indigenous, African & Middle Eastern (AME ), Asian, and European]. Statistical analysis of the data was undertaken using t ‐tests, Welch's analysis of variance and Games‐Howell tests. P  < 0.05 was considered statistically significant.

Results

Vegetables and Fruit recommendations were the least likely to be followed, with 90.7–96.8% of participants in all groups not consuming the recommended number of servings day–1. The mean frequency of fruit consumption was lower among Indigenous youths compared to Asian youths (0.90 versus 1.37 times day–1). A greater proportion of males than females (55.9% versus 44.3%) did not meet the minimum recommendations for Meat and Alternatives (P  = 0.016). The percentage of youths not adhering to recommendations for Milk and Alternatives was 81.7% for Indigenous, 73.3% for AME , 78.6% for Asian and 63.5% for European youths. Indigenous youths more frequently consumed potato chips and soft drinks compared to other ethnic youths. The most frequently consumed beverage was milk (1.25 times day–1).

Conclusions

The majority of youths did not consume minimum daily recommended servings of Vegetables and Fruit, Milk and Alternatives, and/or Meat and Alternatives food groups. Evidence‐based dietary interventions and public health strategies are needed.
  相似文献   
7.

Background

Data regarding health care resource utilization (HRU) in early childhood among children with congenital heart disease (CHD) are scarce. Therefore, we sought to describe the extent of HRU incurred among children with CHD in the first 5 years of life.

Methods

This population-based retrospective cohort study included all children born between January 2005 and March 2014 in Alberta, Canada. We linked inpatient, outpatient, practitioner claims, and drug dispensing databases with vital statistics (birth and death registries).

Results

In the first year of life, the cumulative hospitalization rate per 100 children was 335 (95% confidence interval: 312-360) for single ventricle (SV) children, 200 (194-206) for moderate-complex CHD, and 152 (149-156) for simple CHD vs 109 (108-109) among children without CHD (P < 0.001). The ambulatory-care visit rate per 100 children was 4871 (4780-4963) for SV, 2278 (2258-2299) for moderate-complex, and 1416 (1405-1426) for simple CHD vs 246 (246-247) for children without CHD (P < 0.001). The rates of physician claims and drug dispensing also demonstrated similar patterns. The median total hospitalization length of stay during the first year of life was 54 days (interquartile range: 26-95) in SV, 15 (4-39) in moderate-complex, and 6 (2-26) in simple CHD compared with 2 (1-3) among children without CHD (P < 0.001). These differences remained throughout the first 5 years of life, with children with CHD having consistently higher hospitalization rates and emergency department visit rates in every year of age compared with children without CHD.

Conclusions

Cumulative HRU is high among children with CHD in the first 5 years of life and increases with increasing CHD severity. Improving survival of SV lesions will require increasing resource allocation to this group.  相似文献   
8.
9.
The ketogenic potential of Intralipid was studied in two groups of infants: 12 were SGA and 15 AGA; all were clinically stable and less than 48 hours of age. During four-hour Intralipid tolerance tests, the SGA infants achieved significantly higher plasma TG and FFA levels. Both groups of infants significantly increased the concentration of ketone bodies; however, there was no difference in the levels achieved. In view of the slower clearance rate of TG and the higher levels of FFA in SGA infants, it is speculated that in addition to a possible defective lipoprotein lipase system and a decrease in number and size of the adipose cells, beta-oxidation of FFA to ketones may be occurring at a slower rate. The generation of high levels of ketones during Intralipid infusion period in both groups of infants indicates that SGA infants can handle ketone bodies as readily as AGA infants.  相似文献   
10.
Recent studies have shown that ventilation in the newborn period is affected by sleep state. We investigated various measures affecting ventilation using the single breath airway occlusion technique in ten healthy, full-term newborn infants. There was a significant increase in respiratory rate and in minute ventilation in rapid eye movement sleep compared to non-REM sleep, and there was no significant change in tidal volume between the two sleep states. The variability of ventilation was increased in REM sleep, and inspiratory pressure at one-tenth of a second following airway occlusion was significantly increased in REM sleep. Effective elastance was similar in both sleep states. Measures that reflect activity of the Hering-Breuer reflex were significantly increased in non-REM sleep as compared with REM sleep. These results document the interdependence of sleep state and respiratory control mechanisms in full-term infants.  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