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   850篇
  免费   6篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   107篇
妇产科学   19篇
基础医学   54篇
口腔科学   41篇
临床医学   46篇
内科学   271篇
皮肤病学   3篇
神经病学   46篇
特种医学   25篇
外科学   150篇
综合类   7篇
预防医学   15篇
眼科学   12篇
药学   38篇
中国医学   8篇
肿瘤学   14篇
  2024年   1篇
  2023年   4篇
  2022年   4篇
  2021年   11篇
  2020年   6篇
  2019年   58篇
  2018年   73篇
  2017年   46篇
  2016年   4篇
  2014年   9篇
  2013年   2篇
  2012年   2篇
  2011年   3篇
  2010年   2篇
  2009年   1篇
  2008年   1篇
  2007年   4篇
  2004年   1篇
  2003年   1篇
  2001年   1篇
  2000年   1篇
  1994年   1篇
  1985年   39篇
  1984年   54篇
  1983年   51篇
  1982年   70篇
  1981年   54篇
  1980年   60篇
  1979年   58篇
  1978年   44篇
  1977年   43篇
  1976年   43篇
  1975年   35篇
  1974年   40篇
  1973年   31篇
排序方式: 共有858条查询结果,搜索用时 375 毫秒
191.
192.
Neonatal nurse practitioners (NNP) have an increasing and continuous presence in most neonatal intensive care units (NICUs); a presence which has at times been perceived as at odds with the training and development of pediatric residents and neonatal fellows. This is a single-center cohort study of infants born at ≤1000 g and ≤28 weeks of gestation cared for by either a team consisting of residents and a fellow (R/F) or consisting of NNPs (NP). Groups were compared by Student's t-test or chi-square, and associations estimated by logistic regression. There were no differences in primary outcomes between the teams except for a lower incidence of severe retinopathy of prematurity (ROP) in babies on the R/F team compared to the NNP team. In this first post-duty hours cohort, clinical outcomes between the teams were similar. These data suggest that either model can be safely utilized within a level 3 NICU.  相似文献   
193.
194.
The question of how much of the familial aggregation of coronary heart disease is explained by familial clustering of coronary risk factors was approached by a case-control study involving 145 white male survivors of myocardial infarction, 145 age-matched white male blood donors, and the first-degree relatives of both groups. Certain risk factors such as serum cholesterol, triglyceride, and fasting blood glucose levels, blood pressure, and smoking history were determined in patients and control subjects. Relatives were interviewed. If the person was deceased, a copy of the death certificate was obtained. With the exception of high blood pressure, risk factors were significantly more frequent in patients than in control subjects.Among first-degree relatives of survivors of myocardial infarction, 16% had had a myocardial infarction, compared with 8.9% of relatives of control subjects. The frequency of coronary heart disease among first-degree relatives of patients and control subjects was 20.5 and 14.7%, respectively. To find out whether this higher frequency among relatives of patients was fully explained by the existence of known genetic risk factors among survivors of myocardial infarction, 2 approaches were taken. First, statistical analysis that eliminated the role of the various known genetic risk factors (by data stratification according to confounding risk variables and subsequent calculation of a pooled relative risk estimate according to the Mantel-Haenzel method) still indicated an approximately 2-fold (2.14) relative risk for myocardial infarction among families of survivors of myocardial infarction (and a risk of 1.71 for coronary heart disease). Similarly, another approach (Cox's life table regression analysis) confirmed that the classic risk factors could not predict familial occurrence.These results indicate that the familial aggregation of coronary heart disease is not entirely explained by the familial clustering of currently known coronary risk factors. Such familial aggregation could be caused by yet undefined genetic factors, by environmental factors common to family members, or by interaction of genetic factors with environmental agents.  相似文献   
195.
A decrease in systolic blood pressure that occurs with treadmill exercise testing may be a sign of reversible ischemic left ventricular dysfunction. To test this hypothesis, we examined retrospectively the postoperative treadmill responses of 37 patients who had exertional hypotension (end exercise systolic blood pressure less than or equal to initial preexercise levels) before coronary arterial bypass grafting. This group of 37 patients was characterized preoperatively by an abnormal exercise electrocardiogram (36 patients), multiple vessel occlusive disease (36 patients) and a normal ejection fraction at rest (32 patients). Postoperative exercise tests showed improvement in hemodynamic and electrocardiographic changes with reversal of exertional hypotension (33 patients), and conversion to a normal exercise electrocardiogram (29 patients). Coronary bypass surgery can be expected to reverse exertional hypotension in patients with symptomatic angina pectoris and evidence of ischemia in the exercise electrocardiogram.  相似文献   
196.
197.
Information on fetal hazards arising from moderate or low levels of maternal alcohol consumption is unavailable in man. In order to study this question an unselected group of pregnant women was interviewed during pregnancy regarding their alcohol intake. At the time of delivery pairs of high-risk and control infants were examined without knowledge of maternal drinking history. Of 163 infants examined, 11 were judged clinically to show signs compatible with a prenatal effect of alcohol on growth and morphogenesis. Nine of these 11 came from the high-risk drinking group. Only two of these infants were classified as having the fetal alcohol syndrome, and each of the mothers was a very heavy drinker. The other seven infants, who showed lesser alterations of growth and morphogenesis suggestive of fetal alcohol syndrome, were born to women who reported drinking an average of one ounce or more of absolute alcohol per day in the month prior to recognition of pregnancy. These results indicate that both moderate and high levels of alcohol intake during early pregnancy may result in alterations of growth and morphogenesis in the fetus.  相似文献   
198.
199.
Histocompatibility antigens in childhood-onset arthritis.   总被引:5,自引:0,他引:5  
One hundred and twelve well-studied patients with a prior diagnosis of juvenile rheumatoid arthritis were differentiated into seven clinically distinct subgroups, including a group in whom recognizable ankylosing spondylitis had developed by time of follow-up. An apparent increased prevalence of HLA-B27 in the entire series (26%) was clearly related to its increased prevalence in only two subgroups: patients whose disease had progressed to overt ankylosing spondylitis (five of five patients) and boys with pauciarticular arthritis whose disease would be consistent with early ankylosing spondylitis (11 of 18 patients). There were no significant associations of B27 with systemic onset JRA, polyarticular JRA, pauciarticular JRA in girls, or JRA with chronic iridocyclitis. The only other significant alterations found were increased prevalences of HLA-A2 and HLA-BW15 in patients with polyarticular disease without identifiable rheumatoid factor. This study emphasizes that the clinical disorders included under the category of juvenile rheumatoid arthritis represent more than a single disease and that this heterogeneity must be considered in interpreting studies such as those of histocompatibility typing.  相似文献   
200.
The pharmacokinetics of tobramycin in adolescents or young adults with cystic fibrosis and in age-matched controls were prospectively compared. Patients with CF had a higher tobramycin total body clearance (121.2 +/- 14.2 ml/min/1.73 m2) than did controls (102.2 +/- 18.9 ml/min/1.73 m2, P less than 0.05). This was not associated with a higher glomerular filtration rate (iothalamate total body clearance 147.5 +/- 29.2 ml/min/1.73 m2 in patients vs 142.9 +/- 33.3 ml/min/1.73 m2 in controls) or a lower binding of gentamicin to serum proteins (14.3% +/- 2.6% in patients vs 17.4% +/- 3.8% in controls). Tobramycin renal clearance was not significantly different in the two groups (89.5 +/- 17.9 ml/min/1.73 m2 in patients vs 81.0 +/- 15.8 ml/min/1.73 m2 in controls). In the control group, tobramycin total body and renal clearances were highly correlated with iothalamate total body clearance (r = +0.95 and +0.88, P less than 0.01). In patients with cystic fibrosis, the correlation was not significant (r = +0.56, P greater than 0.05 for total body clearance, and r = 0.32, P greater than 0.1 for renal clearance). There was no significant difference in volume of distribution normalized to body surface area or in half-life of elimination. The higher tobramycin total body clearance without an increase in renal clearance, and the lower correlation with glomerular filtration rate indicate that an extrarenal clearance pathway might play a significant role in the elimination of tobramycin from the serum of patients with cystic fibrosis.  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