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   21268篇
  免费   1511篇
  国内免费   62篇
耳鼻咽喉   239篇
儿科学   668篇
妇产科学   584篇
基础医学   3060篇
口腔科学   272篇
临床医学   2892篇
内科学   3863篇
皮肤病学   259篇
神经病学   2178篇
特种医学   617篇
外科学   1738篇
综合类   253篇
一般理论   41篇
预防医学   2732篇
眼科学   366篇
药学   1417篇
中国医学   71篇
肿瘤学   1591篇
  2023年   160篇
  2022年   265篇
  2021年   511篇
  2020年   295篇
  2019年   437篇
  2018年   520篇
  2017年   383篇
  2016年   453篇
  2015年   593篇
  2014年   750篇
  2013年   1095篇
  2012年   1535篇
  2011年   1594篇
  2010年   897篇
  2009年   753篇
  2008年   1347篇
  2007年   1429篇
  2006年   1430篇
  2005年   1359篇
  2004年   1164篇
  2003年   1104篇
  2002年   1079篇
  2001年   241篇
  2000年   189篇
  1999年   213篇
  1998年   237篇
  1997年   172篇
  1996年   161篇
  1995年   133篇
  1994年   139篇
  1993年   136篇
  1992年   106篇
  1991年   77篇
  1990年   82篇
  1989年   80篇
  1988年   72篇
  1987年   63篇
  1986年   83篇
  1985年   83篇
  1984年   92篇
  1983年   71篇
  1982年   98篇
  1981年   74篇
  1980年   91篇
  1978年   72篇
  1977年   59篇
  1976年   48篇
  1975年   55篇
  1974年   50篇
  1973年   58篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
Maternal and Child Health Journal - Early life exposures can have an impact on a child’s developmental trajectory and children born late preterm (34–36&nbsp;weeks gestational age)...  相似文献   
3.
4.
5.
6.
In the United States, renal cell carcinoma (RCC) incidence and the prevalence of obesity, an established risk factor for RCC, have been increasing for several decades. RCC is more common among older individuals. We sought to quantify the contribution of excess adiposity to the rising incidence of RCC among individuals 60 years or older. National Institutes of Health-American Association of Retired Persons Diet and Health Study data (n = 453 859 participants, enrolled in 1995-1996, age at enrollment 50-71 years) were used to estimate multivariable-adjusted hazard ratios (HRs) for RCC across body mass index categories and HRs associated with smoking. Population attributable fractions (PAFs) were calculated using estimated HRs and annual overweight/obesity prevalence from the National Health Interview Survey (1985-2008). PAF estimates were combined with RCC incidence from Surveillance, Epidemiology and End Results-13 to calculate annual percent changes in RCC incidence attributable (and unrelated) to overweight/obesity. We found that between 1995 and 2018, among individuals aged 60 years and older, PAF for overweight/obesity increased from 18% to 29% for all RCCs. In comparison, the PAF for smoking declined from 12% to 9%. RCC incidence increased 1.8% per year (95% confidence interval [CI] 1.5%-2.1%) overall, while RCC incidence attributable to overweight/obesity increased 3.8% per year (95%CI 3.5%-4.2%) and RCC incidence unrelated to overweight/obesity increased 1.2% per year (95% CI 0.9%-1.4%). In conclusion, overweight/obesity appears to have contributed importantly to the rising incidence of RCC in the United States since the mid-1990s. Public health interventions focused on reducing overweight and obesity could help substantially in curbing this trend.  相似文献   
7.
8.
9.
Background Although prostate cancer is a leading cause of cancer death, its aetiology is not well understood. We aimed to identify novel biochemical factors for prostate cancer incidence and mortality in UK Biobank.Methods A range of cardiovascular, bone, joint, diabetes, renal and liver-related biomarkers were measured in baseline blood samples collected from up to 211,754 men at recruitment and in a subsample 5 years later. Participants were followed-up via linkage to health administrative datasets to identify prostate cancer cases. Hazard ratios (HRs) and 95% confidence intervals were calculated using multivariable-adjusted Cox regression corrected for regression dilution bias. Multiple testing was accounted for by using a false discovery rate controlling procedure.Results After an average follow-up of 6.9 years, 5763 prostate cancer cases and 331 prostate cancer deaths were ascertained. Prostate cancer incidence was positively associated with circulating vitamin D, urea and phosphate concentrations and inversely associated with glucose, total protein and aspartate aminotransferase. Phosphate and cystatin-C were the only biomarkers positively and inversely, respectively, associated with risk in analyses excluding the first 4 years of follow-up. There was little evidence of associations with prostate cancer death.Conclusion We found novel associations of several biomarkers with prostate cancer incidence. Future research will examine associations by tumour characteristics.Subject terms: Predictive markers, Prostate cancer, Risk factors  相似文献   
10.
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