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   2536709篇
  免费   177363篇
  国内免费   4874篇
耳鼻咽喉   33778篇
儿科学   83202篇
妇产科学   68510篇
基础医学   359566篇
口腔科学   71781篇
临床医学   227313篇
内科学   488382篇
皮肤病学   56498篇
神经病学   198314篇
特种医学   97248篇
外国民族医学   437篇
外科学   385078篇
综合类   55095篇
现状与发展   5篇
一般理论   767篇
预防医学   187654篇
眼科学   59612篇
药学   190569篇
  13篇
中国医学   6315篇
肿瘤学   148809篇
  2021年   19162篇
  2019年   19550篇
  2018年   36724篇
  2017年   28449篇
  2016年   32312篇
  2015年   27543篇
  2014年   37834篇
  2013年   55142篇
  2012年   78035篇
  2011年   87349篇
  2010年   53293篇
  2009年   48569篇
  2008年   81334篇
  2007年   88030篇
  2006年   79159篇
  2005年   76889篇
  2004年   74442篇
  2003年   71988篇
  2002年   68361篇
  2001年   128370篇
  2000年   131542篇
  1999年   108923篇
  1998年   28691篇
  1997年   25135篇
  1996年   25141篇
  1995年   24045篇
  1994年   21962篇
  1993年   20504篇
  1992年   82234篇
  1991年   79320篇
  1990年   77109篇
  1989年   73988篇
  1988年   67252篇
  1987年   65536篇
  1986年   61941篇
  1985年   58723篇
  1984年   42991篇
  1983年   36621篇
  1982年   20617篇
  1979年   38328篇
  1978年   26361篇
  1977年   22913篇
  1976年   20824篇
  1975年   22598篇
  1974年   27017篇
  1973年   26001篇
  1972年   24292篇
  1971年   22672篇
  1970年   20985篇
  1969年   19849篇
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
11.
12.
13.
14.
Inflammatory bowel disease (IBD) is a chronic disease that requires chronic treatment throughout the evolution of the disease, with a complex physiopathology that entails great challenges for the development of new and specific treatments for ulcerative colitis and Crohn´s disease. The anti-tumor necrosis factor alpha therapy has impacted the clinical course of IBD in those patients who do not respond to conventional treatment, so there is a need to develop new therapies and markers of treatment response. Various pathways involved in the development of the disease are known and the new therapies have focused on blocking the inflammatory process at the gastrointestinal level by oral, intravenous, subcutaneous, and topical route. All these new therapies can lead to more personalized treatments with higher success rates and fewer relapses. These treatments have not only focused on clinical remission, but also on achieving macroscopic changes at the endoscopic level and microscopic changes by achieving mucosal healing. These treatments are mainly based on modifying signaling pathways, by blocking receptors or ligands, reducing cell migration and maintaining the integrity of the epithelial barrier. Therefore, this review presents the efficacy and safety of the new treatments that are currently under study and the advances that have been made in this area in recent years.  相似文献   
15.
16.
17.
18.
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   
19.
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   
20.
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