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   3240293篇
  免费   240868篇
  国内免费   9982篇
耳鼻咽喉   44145篇
儿科学   104926篇
妇产科学   87453篇
基础医学   474364篇
口腔科学   90130篇
临床医学   304311篇
内科学   618876篇
皮肤病学   68968篇
神经病学   260376篇
特种医学   119526篇
外国民族医学   827篇
外科学   474472篇
综合类   76179篇
现状与发展   18篇
一般理论   1228篇
预防医学   263494篇
眼科学   75201篇
药学   242106篇
  46篇
中国医学   8655篇
肿瘤学   175842篇
  2021年   27781篇
  2019年   28112篇
  2018年   38432篇
  2017年   29182篇
  2016年   32081篇
  2015年   36813篇
  2014年   51282篇
  2013年   76898篇
  2012年   105634篇
  2011年   112632篇
  2010年   66656篇
  2009年   62079篇
  2008年   103981篇
  2007年   110457篇
  2006年   111208篇
  2005年   107797篇
  2004年   102282篇
  2003年   98194篇
  2002年   94786篇
  2001年   143238篇
  2000年   147266篇
  1999年   124257篇
  1998年   37126篇
  1997年   32832篇
  1996年   32643篇
  1995年   30867篇
  1994年   28641篇
  1993年   26853篇
  1992年   97050篇
  1991年   95191篇
  1990年   92587篇
  1989年   88732篇
  1988年   81882篇
  1987年   80292篇
  1986年   75801篇
  1985年   72623篇
  1984年   54267篇
  1983年   46392篇
  1982年   27782篇
  1979年   50010篇
  1978年   35735篇
  1977年   29583篇
  1976年   28583篇
  1975年   30257篇
  1974年   36544篇
  1973年   35214篇
  1972年   32857篇
  1971年   30979篇
  1970年   28699篇
  1969年   26909篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
31.
32.
33.
“三全育人”是高校思政教育工作的关键一环,也是中医药高校推动思政教育的重要内容。以“三全育人”为视角对北京中医药大学思想政治教育举措“杏林成长导师”计划路径、内容深入分析,运用统计分析和文献研究方法,剖析该计划对中医学专业大学生的学业、思想和实践等多个层面的现实成效,从而为“三全育人”理念在中医药院校制度建构中的应用提供新的视角与方法。  相似文献   
34.
35.
36.
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   
37.
38.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  相似文献   
39.
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   
40.
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