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   1838篇
  免费   94篇
  国内免费   11篇
耳鼻咽喉   31篇
儿科学   87篇
妇产科学   22篇
基础医学   195篇
口腔科学   52篇
临床医学   158篇
内科学   385篇
皮肤病学   54篇
神经病学   75篇
特种医学   138篇
外科学   239篇
综合类   67篇
预防医学   73篇
眼科学   60篇
药学   151篇
中国医学   13篇
肿瘤学   143篇
  2023年   17篇
  2022年   28篇
  2021年   71篇
  2020年   35篇
  2019年   50篇
  2018年   56篇
  2017年   24篇
  2016年   51篇
  2015年   45篇
  2014年   81篇
  2013年   77篇
  2012年   103篇
  2011年   120篇
  2010年   85篇
  2009年   68篇
  2008年   83篇
  2007年   95篇
  2006年   84篇
  2005年   58篇
  2004年   61篇
  2003年   53篇
  2002年   43篇
  2001年   44篇
  2000年   29篇
  1999年   29篇
  1998年   31篇
  1997年   29篇
  1996年   23篇
  1995年   21篇
  1994年   21篇
  1993年   18篇
  1992年   21篇
  1991年   21篇
  1990年   21篇
  1989年   28篇
  1988年   29篇
  1987年   23篇
  1986年   26篇
  1985年   18篇
  1984年   13篇
  1983年   14篇
  1982年   9篇
  1981年   4篇
  1980年   9篇
  1979年   17篇
  1978年   10篇
  1977年   14篇
  1976年   10篇
  1975年   10篇
  1973年   5篇
排序方式: 共有1943条查询结果,搜索用时 15 毫秒
1.
2.
Teratomas are true neoplasms composed of tissues from all three germinal layers and may exhibit variable levels of maturity. They have an unknown origin and eccentric microscopic appearance. Teratomas arising from the oral cavity are rare in the newborn; only 22 cases have been reported in the literature. We describe a female neonate with an oral teratoma originating from the tongue that was successfully treated with surgery.  相似文献   
3.
Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.  相似文献   
4.
5.
Four patients with mild to moderate obstructive sleep apnea were monitored first in the supine posture to establish a diagnosis of obstructive sleep apnea (apnea indices 33, 12, 22, 36). A second polysomnogram, obtained while the patients slept in the lateral posture, showed a dramatic decrease in apnea (apnea indices 5, 0, 0.2, and 0) and snoring. Each patient had an enlarged uvula, which moved to the side in the lateral posture. We conclude that sleeping in the lateral posture may be therapeutic in some patients with obstructive sleep apneas.  相似文献   
6.
High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.   相似文献   
7.
8.
9.
Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).  相似文献   
10.
Management of post-cholecystectomy bile duct strictures can be complex.Traditional treatment has been surgical reconstruction. In recent years endoscopic stenting has been successful in a selected subgroup of patients with iatrogenic bile duct strictures. Adequate information about long-term results of endoscopic stenting as definite treatment for such strictures is still awaited. Surgery is a reliable and time-tested method and results of numerous studies show its long-term success in relieving biliary obstruction with minimal morbidity.  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