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   1023篇
  免费   103篇
  国内免费   9篇
耳鼻咽喉   3篇
儿科学   109篇
妇产科学   16篇
基础医学   115篇
口腔科学   33篇
临床医学   80篇
内科学   351篇
皮肤病学   20篇
神经病学   35篇
特种医学   136篇
外科学   69篇
综合类   43篇
预防医学   45篇
眼科学   30篇
药学   19篇
肿瘤学   31篇
  2022年   3篇
  2021年   6篇
  2020年   8篇
  2019年   11篇
  2018年   24篇
  2017年   13篇
  2016年   28篇
  2015年   27篇
  2014年   32篇
  2013年   50篇
  2012年   38篇
  2011年   43篇
  2010年   44篇
  2009年   61篇
  2008年   43篇
  2007年   50篇
  2006年   31篇
  2005年   38篇
  2004年   16篇
  2003年   24篇
  2002年   16篇
  2001年   20篇
  2000年   20篇
  1999年   24篇
  1998年   44篇
  1997年   45篇
  1996年   46篇
  1995年   40篇
  1994年   25篇
  1993年   35篇
  1992年   10篇
  1991年   15篇
  1990年   15篇
  1989年   26篇
  1988年   17篇
  1987年   19篇
  1986年   17篇
  1985年   20篇
  1984年   8篇
  1983年   12篇
  1982年   5篇
  1981年   13篇
  1980年   7篇
  1979年   8篇
  1978年   4篇
  1977年   8篇
  1976年   10篇
  1975年   4篇
  1956年   2篇
  1955年   6篇
排序方式: 共有1135条查询结果,搜索用时 0 毫秒
61.
Computed tomography of abdominal fatty masses   总被引:2,自引:0,他引:2  
  相似文献   
62.
OBJECTIVE: To develop diagnostic guidelines for macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (S-JIA). STUDY DESIGN: We followed the classification criteria approach that is based on the comparison of patients with the index disease with patients with a "confusable" disease. The former group included 74 patients with S-JIA-associated MAS reported in the literature or seen by the authors; the latter group included 37 patients with S-JIA who had 51 instances of "high disease activity" seen by the authors. The relative power of clinical, laboratory, and histopathologic variables in discriminating patients with MAS from patients with high disease activity was evaluated by calculating the sensitivity rate, specificity rate, area under the receiver operating characteristic curve, and diagnostic odds ratio (DOR). The combinations of variables that led to best separation between patients and control subjects were identified through "the number of criteria present" method. RESULTS: The strongest clinical discriminators were hemorrhages (DOR = 67) and central nervous system dysfunction (DOR = 63); the strongest laboratory discriminators were decreased platelet count (DOR = 1092), increased aspartate aminotransferase (DOR = 247), leukopenia (DOR = 70), and hypofibrinogenemia (DOR = 165). The best separation between patients and control subjects occurred when any 2 or more laboratory criteria (DOR = 1309) were simultaneously present; the second best performance was provided by the presence of any 2, 3, or more clinical and/or laboratory criteria (DOR = 765 and 743, respectively). CONCLUSION: We identified preliminary diagnostic guidelines for MAS complicating S-JIA. These guidelines deserve prospective validation.  相似文献   
63.

OBJECTIVE:

Inflammation plays an important role in the development of chronic lung disease (CLD), which has become a major cause of morbidity in surviving infants less than 1250 g at birth. The authors hypothesized that the progression of this inflammation and, therefore, the establishment of CLD would be decreased with the use of early prophylactic inhaled corticosteroids. Short, and long term respiratory and neurodevelopmental outcomes were also examined.

DESIGN:

A double-blind, randomized placebo controlled trial.

SETTING:

Level-III neonatal intensive care unit.

POPULATION STUDIED:

Sixty infants less than 1250 g at birth, diagnosed with respiratory distress syndrome and requiring ventilatory support at 72 h of age were enrolled in the study.

INTERVENTION:

Infants enrolled received either placebo or beclomethasone diproprionate by a metered dose inhaler, which was used in-line with the ventilator circuit while the infant was ventilated and then via a spacer until 28 days of age.

RESULTS:

Thirty infants were given beclomethasone and 30 were given placebo. There were two deaths in each group. Among the surviving infants, the frequency of moderate-to-severe CLD was 17% in each study group. Mean time to extubation was not different for beclomethasone compared with placebo at 16.4 and 12.5 days (P=0.12), respectively. The requirement for intravenous corticosteroids was lower in the beclomethasone-treated group (RR 0.67, 95% CI 0.43 to 1.04), although this difference was not statistically significant. The incidence of growth failure, infection and intraventricular hemmorhage did not differ between the two groups. Long term outcomes were not different with respect to the incidence of respiratory re-admissions, cerebral palsy, developmental delay, blindness or deafness.

CONCLUSIONS:

Early treatment with inhaled beclomethasone diproprionate did not reduce the incidence of CLD or decrease the duration of mechanical ventilation. The decrease in intravenous corticosteroid use was not statistically significant. Long term outcome was not affected.  相似文献   
64.
65.
Ventral hernia repair: a study of current practice   总被引:5,自引:5,他引:0  
Ventral wall hernias are common; despite this, there are no guidelines on the best surgical management. The aim of this study was to examine the types of repair in use for abdominal wall hernias in the West of Scotland over a 3-month period. Data were gathered on 120 patients. There were 60 incisional, 32 umbilical, and 28 epigastric hernias. The main indication for repair was pain (78%), while 12 patients (10%), presented acutely with incarceration or strangulation. The most common method of repair was sutured (55%), followed by mesh (29%) and Mayo repair (16%). There was no correlation between use of mesh and hernia size or whether repair was for a recurrent hernia. Surgical practice varies widely in the repair of ventral wall hernias. Clinical trials are required to establish the best method of repair for this common condition. Electronic Publication  相似文献   
66.

Background  

Low grade fibromyxoid sarcomas (LGFMS) are very rarely seen. They commonly arise from deep soft tissues of the lower extremities. Very few cases of intra-abdominal location have been reported.  相似文献   
67.
Intraindividual variation in recent stress exposure and its impact upon cortisol and testosterone was investigated. Over 1 year, 72 young male firefighters completed the Daily Stress Inventories, for 2 shift cycles (16 days), every 3 months. At the end of each 16-day period each participant attended a 1-hr morning assessment session. Saliva samples and blood pressure measurements were taken at 10-min intervals, and at 30 min, a blood sample was drawn. Across the year of assessment, there were significant linear relationships in reported stress and in neuroendocrine activity. In contrast to expectations, as daily stress decreased across the year (p < .008), salivary cortisol increased (p < .001) and testosterone levels decreased (p < .001). Within-subjects comparisons of the sessions with the highest and lowest stress confirmed these linear relationships: Lower stress prior to the assessment session was associated with higher cortisol levels (p < .01). These results, though in contrast to the orthodoxy concerning the association between stress and cortisol, are supported by findings in a number of other studies and may constitute down regulation of cortisol activity following an increment in stress exposure. This research was supported by the Medical Research Council, United Kingdom. We are grateful to the London Fire & Civil Defence Authority for their cooperation.  相似文献   
68.

Objective  

To investigate concordance between physicians and parents in rating the degree of functional ability of children with juvenile idiopathic arthritis (JIA).  相似文献   
69.
The activity of urea cycle enzymes was assayed in duodenal biopsy specimens obtained from a female infant who presented with neonatal hyperammonaemia. All enzyme levels were normal except N-acetyl glutamate-dependent carbamyl phosphate synthetase 1 (CPS1) which was half the mean activity in normal control specimens. A similar deficiency of CPS1 was also shown in duodenal specimens from the patient's mother who became slightly symptomatic after relatively high protein meals and during pregnancy, and had spontaneously modified her diet to one with protein restriction. The patient is growing normally on a dietary regimen similar to that spontaneously adopted by her mother. Urea cycle enzyme activity in the duodenal biopsy material from the controls was similar to that found in the normal human liver and appears to have distinct advantages as a means of assaying for urea cycle defects in patients with hyperammonaemia and their relatives.  相似文献   
70.
Autoantibodies in juvenile dermatomyositis   总被引:2,自引:0,他引:2  
Fourteen patients with juvenile dermatomyositis (JDM) have been investigated for the presence of several serum autoantibodies: antinuclear (ANA), anti-single-stranded and double-stranded DNA, anti-histones, anti-Sm, anti-ribonucleoprotein, anti-SSA/SSB, anti-PM-1, anti-Jo-1, anti-mitochondrial, anti-smooth muscle, anti-gastric parietal cells, anti-cardiolipin (ACA) antibodies and rheumatoid factor. Patients were negative for all autoantibodies except for ANA and ACA. ANA were detected in 50% of the patients when tested on rat liver, but the percentage of positivity rose to 86% when HEp-2 cells were used as substrate. This finding suggests that HEp-2 cells represent a more sensitive substrate than rat liver for the detection of ANA in JDM. Three patients were positive for ACA; two of these presented vascular complications, thus suggesting a possible relationship between ACA and vascular involvement in JDM.  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