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   1735392篇
  免费   129479篇
  国内免费   3914篇
耳鼻咽喉   22250篇
儿科学   56490篇
妇产科学   46799篇
基础医学   246855篇
口腔科学   49334篇
临床医学   155230篇
内科学   343528篇
皮肤病学   39111篇
神经病学   135492篇
特种医学   65687篇
外国民族医学   242篇
外科学   264080篇
综合类   39396篇
现状与发展   4篇
一般理论   592篇
预防医学   127180篇
眼科学   40914篇
药学   126296篇
  8篇
中国医学   4520篇
肿瘤学   104777篇
  2021年   13945篇
  2019年   14533篇
  2018年   21273篇
  2017年   16094篇
  2016年   17589篇
  2015年   20121篇
  2014年   27956篇
  2013年   40039篇
  2012年   56254篇
  2011年   58934篇
  2010年   34775篇
  2009年   32457篇
  2008年   54637篇
  2007年   58019篇
  2006年   58411篇
  2005年   55653篇
  2004年   53486篇
  2003年   50733篇
  2002年   48708篇
  2001年   92063篇
  2000年   93797篇
  1999年   77235篇
  1998年   20134篇
  1997年   17655篇
  1996年   17705篇
  1995年   17022篇
  1994年   15515篇
  1993年   14276篇
  1992年   57510篇
  1991年   55383篇
  1990年   53070篇
  1989年   50835篇
  1988年   46206篇
  1987年   45002篇
  1986年   42293篇
  1985年   40078篇
  1984年   29463篇
  1983年   24999篇
  1982年   14017篇
  1979年   25567篇
  1978年   17629篇
  1977年   14962篇
  1976年   13923篇
  1975年   14600篇
  1974年   17669篇
  1973年   16974篇
  1972年   15687篇
  1971年   14467篇
  1970年   13448篇
  1969年   12530篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
41.
42.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
43.
44.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
45.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
46.
47.
48.
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.

Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.

Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.

Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion.  相似文献   
49.
50.
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