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   2769162篇
  免费   204756篇
  国内免费   7535篇
耳鼻咽喉   36112篇
儿科学   90463篇
妇产科学   74549篇
基础医学   398048篇
口腔科学   78800篇
临床医学   259416篇
内科学   536015篇
皮肤病学   59596篇
神经病学   223866篇
特种医学   103067篇
外国民族医学   597篇
外科学   405214篇
综合类   62521篇
现状与发展   5篇
一般理论   1008篇
预防医学   220127篇
眼科学   63976篇
药学   203214篇
  12篇
中国医学   6810篇
肿瘤学   158037篇
  2021年   22573篇
  2019年   23500篇
  2018年   33368篇
  2017年   25283篇
  2016年   27872篇
  2015年   31724篇
  2014年   43931篇
  2013年   65460篇
  2012年   90805篇
  2011年   95896篇
  2010年   56585篇
  2009年   52531篇
  2008年   88232篇
  2007年   93785篇
  2006年   94051篇
  2005年   90374篇
  2004年   86557篇
  2003年   82031篇
  2002年   79614篇
  2001年   132288篇
  2000年   135554篇
  1999年   113122篇
  1998年   31594篇
  1997年   27808篇
  1996年   27573篇
  1995年   26411篇
  1994年   24419篇
  1993年   22678篇
  1992年   87413篇
  1991年   84787篇
  1990年   81707篇
  1989年   78258篇
  1988年   71829篇
  1987年   70153篇
  1986年   66578篇
  1985年   63374篇
  1984年   47130篇
  1983年   40177篇
  1982年   23411篇
  1979年   42122篇
  1978年   29588篇
  1977年   24756篇
  1976年   23511篇
  1975年   24513篇
  1974年   29812篇
  1973年   28931篇
  1972年   26804篇
  1971年   24847篇
  1970年   23150篇
  1969年   21450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.
Cognitive Therapy and Research - Despite interest in psychological inflexibility as a marker of suicide risk, no measure of psychological inflexibility specific to SI exists. The present study...  相似文献   
26.
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.  相似文献   
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.
29.
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