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   1611220篇
  免费   134505篇
  国内免费   2634篇
耳鼻咽喉   21747篇
儿科学   53107篇
妇产科学   46558篇
基础医学   228539篇
口腔科学   47853篇
临床医学   141516篇
内科学   316999篇
皮肤病学   34449篇
神经病学   131121篇
特种医学   65584篇
外国民族医学   474篇
外科学   246344篇
综合类   39740篇
现状与发展   3篇
一般理论   544篇
预防医学   122615篇
眼科学   36679篇
药学   122613篇
  2篇
中国医学   2923篇
肿瘤学   88949篇
  2018年   15107篇
  2016年   13244篇
  2015年   15379篇
  2014年   21137篇
  2013年   31924篇
  2012年   43462篇
  2011年   45804篇
  2010年   26863篇
  2009年   25799篇
  2008年   43916篇
  2007年   46172篇
  2006年   46960篇
  2005年   45575篇
  2004年   44950篇
  2003年   42945篇
  2002年   42099篇
  2001年   76342篇
  2000年   78938篇
  1999年   66743篇
  1998年   16954篇
  1997年   15534篇
  1996年   15469篇
  1995年   16105篇
  1994年   15131篇
  1993年   14277篇
  1992年   55943篇
  1991年   54285篇
  1990年   53083篇
  1989年   51328篇
  1988年   47638篇
  1987年   46947篇
  1986年   44656篇
  1985年   43197篇
  1984年   32228篇
  1983年   27719篇
  1982年   16156篇
  1981年   14453篇
  1980年   13574篇
  1979年   30617篇
  1978年   21141篇
  1977年   17813篇
  1976年   16729篇
  1975年   17608篇
  1974年   21533篇
  1973年   20720篇
  1972年   18931篇
  1971年   17839篇
  1970年   16348篇
  1969年   15342篇
  1968年   14007篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
23.
24.
25.
26.
27.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
28.
Kinase alterations are increasingly recognised as oncogenic drivers in mesenchymal tumours. Infantile fibrosarcoma and the related renal tumour, congenital mesoblastic nephroma, were among the first solid tumours shown to harbour recurrent tyrosine kinase fusions, with the canonical ETV6::NTRK3 fusion identified more than 20 years ago. Although targeted testing has long been used in diagnosis, the advent of more robust sequencing techniques has driven the discovery of kinase alterations in an array of mesenchymal tumours. As our ability to identify these genetic alterations has improved, as has our recognition and understanding of the tumours that harbour these alterations. Specifically, this study will focus upon mesenchymal tumours harbouring NTRK or other kinase alterations, including tumours with an infantile fibrosarcoma-like appearance, spindle cell tumours resembling lipofibromatosis or peripheral nerve sheath tumours and those occurring in adults with a fibrosarcoma-like appearance. As publications describing the histology of these tumours increase so, too, do the variety kinase alterations reported, now including NTRK1/2/3, RET, MET, RAF1, BRAF, ALK, EGFR and ABL1 fusions or alterations. To date, these tumours appear locally aggressive and rarely metastatic, without a clear link between traditional features used in histological grading (e.g. mitotic activity, necrosis) and outcome. However, most of these tumours are amenable to new targeted therapies, making their recognition of both diagnostic and therapeutic import. The goal of this study is to review the clinicopathological features of tumours with NTRK and other tyrosine kinase alterations, discuss the most common differential diagnoses and provide recommendations for molecular confirmation with associated treatment implications.  相似文献   
29.
Bulletin of Experimental Biology and Medicine - We studied the effect of microalgae of various systematic groups added to the ration on the biochemical parameters of blood serum and liver and...  相似文献   
30.
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