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   1350429篇
  免费   103309篇
  国内免费   4344篇
耳鼻咽喉   16927篇
儿科学   43960篇
妇产科学   36667篇
基础医学   200122篇
口腔科学   36423篇
临床医学   131551篇
内科学   262092篇
皮肤病学   26672篇
神经病学   113351篇
特种医学   48759篇
外国民族医学   366篇
外科学   186220篇
综合类   29075篇
现状与发展   1篇
一般理论   494篇
预防医学   115884篇
眼科学   29446篇
药学   99846篇
  6篇
中国医学   3177篇
肿瘤学   77043篇
  2021年   11150篇
  2019年   11853篇
  2018年   16551篇
  2017年   12474篇
  2016年   13488篇
  2015年   15479篇
  2014年   21182篇
  2013年   32813篇
  2012年   45105篇
  2011年   47816篇
  2010年   27603篇
  2009年   25405篇
  2008年   43521篇
  2007年   45908篇
  2006年   46066篇
  2005年   44497篇
  2004年   42461篇
  2003年   40348篇
  2002年   39190篇
  2001年   61039篇
  2000年   62683篇
  1999年   52471篇
  1998年   14777篇
  1997年   13480篇
  1996年   13307篇
  1995年   12621篇
  1994年   11768篇
  1993年   11076篇
  1992年   41722篇
  1991年   40900篇
  1990年   39604篇
  1989年   37482篇
  1988年   34721篇
  1987年   33830篇
  1986年   32291篇
  1985年   30790篇
  1984年   23205篇
  1983年   19735篇
  1982年   11934篇
  1979年   20920篇
  1978年   14934篇
  1977年   12194篇
  1976年   12009篇
  1975年   12218篇
  1974年   14913篇
  1973年   14557篇
  1972年   13439篇
  1971年   12497篇
  1970年   11536篇
  1969年   10472篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
The coronavirus 2019 pandemic has affected almost every aspect of health care delivery in the United States, and the emergency medicine system has been hit particularly hard while dealing with this public health crisis. In an unprecedented time in our history, medical systems and clinicians have been asked to be creative, flexible, and innovative, all while continuing to uphold the important standards in the US health care system. To continue providing quality services to patients during this extraordinary time, care providers, organizations, administrators, and insurers have needed to alter longstanding models and procedures to respond to the dynamics of a pandemic. The Emergency Medicine Treatment and Active Labor Act of 1986, or EMTALA, is 1 example of where these alterations have allowed health care facilities and clinicians to continue their work of caring for patients while protecting both the patients and the clinicians themselves from infectious exposures at the same time.  相似文献   
14.
15.
16.
17.
18.
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   
19.
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   
20.
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   
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