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   8247篇
  免费   425篇
  国内免费   83篇
耳鼻咽喉   113篇
儿科学   201篇
妇产科学   89篇
基础医学   1133篇
口腔科学   182篇
临床医学   454篇
内科学   2206篇
皮肤病学   286篇
神经病学   771篇
特种医学   312篇
外科学   1106篇
综合类   22篇
一般理论   1篇
预防医学   504篇
眼科学   104篇
药学   388篇
中国医学   5篇
肿瘤学   878篇
  2023年   40篇
  2022年   99篇
  2021年   159篇
  2020年   79篇
  2019年   119篇
  2018年   159篇
  2017年   147篇
  2016年   159篇
  2015年   186篇
  2014年   231篇
  2013年   296篇
  2012年   517篇
  2011年   551篇
  2010年   321篇
  2009年   301篇
  2008年   480篇
  2007年   573篇
  2006年   571篇
  2005年   541篇
  2004年   577篇
  2003年   575篇
  2002年   567篇
  2001年   116篇
  2000年   71篇
  1999年   88篇
  1998年   126篇
  1997年   109篇
  1996年   110篇
  1995年   103篇
  1994年   85篇
  1993年   71篇
  1992年   60篇
  1991年   55篇
  1990年   45篇
  1989年   44篇
  1988年   45篇
  1987年   32篇
  1986年   38篇
  1985年   33篇
  1984年   30篇
  1983年   21篇
  1982年   26篇
  1981年   21篇
  1980年   23篇
  1979年   22篇
  1977年   14篇
  1975年   11篇
  1973年   10篇
  1972年   11篇
  1970年   14篇
排序方式: 共有8755条查询结果,搜索用时 15 毫秒
951.
This study assessed the contextual and individual effects of social trust on health. Methods consisted of a multilevel regression analysis of self-rated poor health among 21,456 individuals nested within 40 US communities included in the 2000 Social Capital Community Benchmark Survey. Controlling for demographic covariates, a strong income and education gradient was observed for self-rated health. Higher levels of cominunity social trust were associated with a lover probability of reporting poor health. Individual demographic and socioeconomic preditors did not explain the association of community social trust with self-rated health. Controlling for individual trust perception, however, rendered the main effect of community social trust statistically insignificant, but a complex interaction effect was observed, such that the health-promoting effect of community social trust was significantly greater for high-trust individuals. For low-trust individuals, the effect of community social trust on self-rated health was the opposite. Using the latest data available on community social trust, we conclude that the role of community social trust in explaining average population health achievements and health inequalities is complex and is contingent on individual perceptions of social trust. Future multilevel investigations of social capital and population health should routinely consider the cross-level nature of community or neighborbood effects.  相似文献   
952.
953.
954.
An 83-y-old man was admitted to our hospital with pneumonia and critical cardiac failure. He had severe calcific stenosis of a bicuspid aortic valve, with a pressure gradient of about 100 mmHg, poor left ventricular function and an ascending aortic aneurysm. His family requested the surgery, but there was an unacceptably high surgical risk because of the presence of serious infection. We tried percutaneous transluminal balloon aortic valvuloplasty (PTAV) with a small sized (12 mm) peripheral percutaneous transluminal angioplasty balloon as a bridge to surgery. We managed to control his critical hemodynamics and infection after the procedure. Thereafter, he underwent successful aortic valve replacement and ascending aorta replacement. PTAV may be a useful palliative therapy, but there are various procedure-related complications. To avoid such complications, we used a small sized balloon. Actually we could not completely normalize the pressure gradient, but it was enough to control his critical cardiac failure until he could undergo surgery.  相似文献   
955.
The efficacy of erythromycin (EM) and clarithromycin (CAM) is well documented for the management of chronic inflammatory respiratory tract disease. However, the precise mechanism of action of these drugs is still controversial. We previously reported that EM increased serum glucocorticoid (GC) levels and suggested that this increase may be a mechanism of action of the drug. To investigate whether other macrolides had similar activity, we studied the effect of a new macrolide, CAM, on serum GC levels in mice. Intraperitoneal injections of CAM increased the serum GC levels in a dose-dependent manner, with the increase completely suppressed by pretreatment with dexamethasone. These results suggest that CAM increases serum GC levels through activation of the hypothalamo-pituitary adrenocortical axis, and that the antiinflammatory activity of CAM appears to exert its influence via an increase in serum GC levels.  相似文献   
956.
Prior animal studies of vascularized epiphyseal transfers placed growth plates in 2 bone systems where the independent growth of epiphyses and their response to altered stresses has been difficult to assess. This study assessed growth of vascularized ulnar epiphyses transferred to the ipsilateral humerus of 12-week-old puppies. Growth was permitted by a specially designed extensible plate. Control groups showed that humeral dissection, osteotomy and ostectomy alone do not stimulate growth. In 4 puppies initial growth of the transferred epiphysis was seen but late collapse and formation of bridging callus occurred so that overall humeral length at maturity was not significantly different from control humeri. Physical forces inherent in heterotopic transfer may preclude long term growth of transferred epiphyses particularly in sites of higher relative load. The extensible plate used here may be a useful device in the fixation of transferred epiphyses with growth potential. © 1994 Wiley-Liss, Inc.  相似文献   
957.
We experienced a case of cholesterosis of the common bile duct in which peroral cholangioscopy (POCS) was very useful for making a diagnosis. The patient was a 66‐year‐old man. He was admitted for examination of an asymptomatic mass in the pancreas. The mass was diagnosed as a serous cystic tumor of the pancreas. While examining the tumor, endoscopic retrograde cholangiopancreatography (ERCP) incidentally revealed a 7 mm irregular filling defect in the distal common bile duct. EST was then performed, followed by POCS, which revealed a clump of yellowish‐white Ip or Isp polyps in the distal bile duct. Histological examination of biopsy specimens taken under direct vision gave a diagnosis of cholesterol polyps containing foamy cells. POCS was useful for allowing direct observation of the characteristic color of cholesterol polyps, and for obtaining biopsy specimens under direct vision.  相似文献   
958.
Gastritis cystica polyposa (GCP) is a well‐known precancerous lesion of the remnant stomach. We report a case of carbohydrate antigen (CA) 19–9‐producing well‐differentiated adenocarcinoma of the remnant stomach that resembled GCP. The patient was a 66‐year‐old Japanese man who had undergone subtotal gastrectomy 20 years previously. The tumor developed in the remnant stomach at the anastomotic line. Histologically, the lesion completely encircled the gastroenterostomy stoma. There was florid growth of glands with cystic dilatation and minimal atypia extending through the thickened muscularis propria into the subserosa. Small foci of less well‐differentiated adenocarcinoma were also detected, including irregular glands or small clusters of mucus‐producing cells with moderate atypia. Immunostaining revealed that numerous tumor cells were positive for carcinoembryonic antigen and CA19‐9, whereas only a few cells were positive for p53. The macroscopic, histopathological and immunohistochemical findings indicated a diagnosis of CA19‐9‐producing well‐differentiated adenocarcinoma of the remnant stomach. To avoid underdiagnosis, careful attention should be paid to the above‐mentioned morphological features and immunohistochemical findings, in addition to the endoscopic findings.  相似文献   
959.
European Radiology - We report a case of sarcoidosis of the breast in a 31-year-old woman who presented with a palpable breast mass. The mammography showed a spiculated mass without any...  相似文献   
960.
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