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   1716450篇
  免费   107725篇
  国内免费   3470篇
耳鼻咽喉   23696篇
儿科学   53370篇
妇产科学   45736篇
基础医学   233690篇
口腔科学   46357篇
临床医学   140899篇
内科学   340648篇
皮肤病学   36737篇
神经病学   140815篇
特种医学   68476篇
外国民族医学   529篇
外科学   263277篇
综合类   34161篇
现状与发展   6篇
一般理论   488篇
预防医学   127453篇
眼科学   38255篇
药学   124041篇
  3篇
中国医学   4261篇
肿瘤学   104747篇
  2018年   38696篇
  2017年   29839篇
  2016年   32850篇
  2015年   18074篇
  2014年   23050篇
  2013年   34924篇
  2012年   54878篇
  2011年   69542篇
  2010年   45633篇
  2009年   36624篇
  2008年   64642篇
  2007年   70522篇
  2006年   51218篇
  2005年   51367篇
  2004年   50783篇
  2003年   49527篇
  2002年   46649篇
  2001年   69089篇
  2000年   71007篇
  1999年   60330篇
  1998年   15852篇
  1997年   14490篇
  1996年   13749篇
  1995年   13017篇
  1994年   12162篇
  1992年   45522篇
  1991年   43807篇
  1990年   43010篇
  1989年   41773篇
  1988年   39061篇
  1987年   38330篇
  1986年   36728篇
  1985年   34742篇
  1984年   26060篇
  1983年   22110篇
  1982年   13294篇
  1981年   12064篇
  1979年   24942篇
  1978年   17808篇
  1977年   15518篇
  1976年   13947篇
  1975年   15943篇
  1974年   18927篇
  1973年   18430篇
  1972年   17622篇
  1971年   16534篇
  1970年   15695篇
  1969年   15181篇
  1968年   14187篇
  1967年   12611篇
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
31.
Introduction: The treatment of classical Hodgkin lymphoma (cHL) in children is a story of success. Nowadays, more than 90% of patients are cured and overall survival is nearly 100% at 5 years. Efforts have been made to avoid related effects of therapies; therefore, children are treated using different chemotherapy schemes in comparison with adults.

Areas covered: This review includes a view of the clinical classification and risk assessment in children suffering from HL. The chemotherapy more commonly employed is revisited. The use of PET/CT to evaluate the disease in order to guide therapy is analyzed. New options of chemotherapy and emerging immunotherapy are also included.

Expert opinion: In order to make the right treatment choice, a proper initial assessment of risk is mandatory. The choice of therapy in these kinds of patients must be done according to the experience of the team, and also, the cost and logistics related to the eligible scheme are very important. If possible, efforts must be made to include PET/CT in guiding therapy and avoiding overtreatment and long-term adverse effects in children. New options in immunotherapy are emerging and must be considered with caution in selected patients.  相似文献   

32.
33.
34.

Background and objectives

A prompt and effective management of trauma patient is necessary. The aim of this case report is to highlight the importance of intraoperative echocardiography as a useful tool in patients suffering from refractory hemodynamic instability no otherwise explained.

Case report

A 41 year‐old woman suffered a car accident. At the emergency department, no abnormalities were found in ECG or chest X‐ray. Abdominal ultrasound revealed the presence of abdominal free liquid and the patient was submitted to urgent exploratory laparotomy. Nevertheless, she persisted suffering arterial hypotension and metabolic acidosis. Looking for the reason of her hemodynamic instability, intraoperative transthoracic echocardiography was performed, finding out the presence of pericardial effusion. Once the cardiac surgeon extracted pericardial clots, patient's situation improved clinically and analytically.

Conclusion

Every anesthesiologist should be able to use the intraoperative echocardiography as an effective tool in order to establish the appropriate measures to promote the survival of patients suffering severe trauma.  相似文献   
35.
36.
37.
38.
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   
39.
40.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  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