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   2737969篇
  免费   211759篇
  国内免费   9606篇
耳鼻咽喉   38646篇
儿科学   90715篇
妇产科学   74339篇
基础医学   369606篇
口腔科学   71264篇
临床医学   260459篇
内科学   558529篇
皮肤病学   69403篇
神经病学   228549篇
特种医学   105608篇
外国民族医学   736篇
外科学   422752篇
综合类   50842篇
现状与发展   77篇
一般理论   1035篇
预防医学   205641篇
眼科学   60036篇
药学   190566篇
  8篇
中国医学   5362篇
肿瘤学   155161篇
  2021年   23597篇
  2019年   23372篇
  2018年   36508篇
  2017年   29377篇
  2016年   33898篇
  2015年   37133篇
  2014年   54560篇
  2013年   75097篇
  2012年   87187篇
  2011年   91434篇
  2010年   60752篇
  2009年   61960篇
  2008年   85425篇
  2007年   88887篇
  2006年   92390篇
  2005年   86131篇
  2004年   82394篇
  2003年   78631篇
  2002年   75927篇
  2001年   131708篇
  2000年   133932篇
  1999年   113294篇
  1998年   34459篇
  1997年   30833篇
  1996年   31001篇
  1995年   30044篇
  1994年   26704篇
  1993年   24724篇
  1992年   86273篇
  1991年   82761篇
  1990年   79691篇
  1989年   77055篇
  1988年   70323篇
  1987年   68716篇
  1986年   64292篇
  1985年   61098篇
  1984年   45389篇
  1983年   38375篇
  1982年   22881篇
  1981年   20321篇
  1979年   39232篇
  1978年   27716篇
  1977年   23590篇
  1976年   21696篇
  1975年   23045篇
  1974年   26989篇
  1973年   25566篇
  1972年   24008篇
  1971年   22136篇
  1970年   20408篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
Although lesions of the pterygopalatine space are uncommon, there are instances in which this relatively inaccessible region must be entered for biopsy or excision of masses. Traditional open approaches to the pterygopalatine space, involving external or intraoral incisions, provide limited visualization and carry associated morbidities. The evolution and advancement of endoscopic sinus surgical technique in recent years has led to its application to anatomic areas outside the strict limits of the sinonasal cavities. Such minimally invasive approaches are safe, effective, and spare unnecessary discomfort to the patient. This article describes the authors' method for performing an endoscopic approach to the pterygopalatine space.  相似文献   
993.
994.
Microvascular thrombosis is a prominent feature in cardiac delayed xenograft rejection (DXR). We investigated the impact of warfarin or low-molecular-weight heparin (LMWH) anti-coagulation on xenograft function using a heterotopic pig-to-primate model. Donor hearts were from CD46 transgenic pigs and baboon immunosuppression included tacrolimus, sirolimus, anti-CD20 and TPC, an alpha-galactosyl-polyethylene glycol conjugate. Three groups of animals were studied. Group 1 (n = 9) was treated with warfarin, Group 2 (n = 13) with LMWH and Group 3, received no anti-coagulant drugs. The median duration of xenograft function was 20 days (range 3-62 days), 18 days (range 5-109 days) and 15 days (range 4-53 days) in Groups 1 to 3 respectively. Anti-coagulation achieved the targeted international normalized prothrombin ratio (INR) and anti-factor Xa levels consistent with effective in vivo therapy yet, no significant impact on median xenograft function was observed. At rejection, a similar histology of thrombosis and ischemia was apparent in each group and the levels of fibrin deposition and platelet thrombi in rejected tissue was the same. Anti-coagulation with warfarin or LMWH did not have a significant impact on the onset of DXR and microvascular thrombosis. However, a role for specific anti-coagulant strategies to achieve long-term xenograft function cannot be excluded.  相似文献   
995.
996.
997.
998.
999.
Occupational diseases Nos. 2108 and 2110 correspond to intervertebral disc-related diseases of the lumbar spine from many years of carrying or lifting heavy loads, occupations in extreme postures of full flexion or oscillation of the whole body when seated, and which compel the cessation of all activities which are or could be the cause for the origin, exacerbation or recurrence of the disease. These occupational diseases came into force at the start of 1993, but there have been considerable problems in their implementation. The present Part I of the contribution is the result of the work of an interdisciplinary study group and contains medical criteria for the assessment of possibly strain-related clinical characteristics and the evaluation of other possible causes. Part II is to be published in Volume 4/2005 and will deal with questions related to forced cessation and to the assessment of the loss of earning ability. Agreement was reached in many areas related to the assessment of occupational claims. This should allow for evidence-based decision making in the future for the occupational diseases Nos. 2108 and 2110.  相似文献   
1000.
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