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   36300篇
  免费   3129篇
  国内免费   74篇
耳鼻咽喉   149篇
儿科学   1255篇
妇产科学   1269篇
基础医学   2594篇
口腔科学   495篇
临床医学   3224篇
内科学   7048篇
皮肤病学   551篇
神经病学   2892篇
特种医学   1137篇
外科学   5069篇
综合类   265篇
一般理论   5篇
预防医学   6776篇
眼科学   618篇
药学   1372篇
  1篇
中国医学   28篇
肿瘤学   4755篇
  2024年   47篇
  2023年   1721篇
  2022年   2366篇
  2021年   2537篇
  2020年   3041篇
  2019年   2031篇
  2018年   2182篇
  2017年   2408篇
  2016年   2384篇
  2015年   2184篇
  2014年   4033篇
  2013年   3035篇
  2012年   1390篇
  2011年   971篇
  2010年   2174篇
  2009年   1784篇
  2008年   587篇
  2007年   672篇
  2006年   499篇
  2005年   436篇
  2004年   272篇
  2003年   311篇
  2002年   258篇
  2001年   277篇
  2000年   225篇
  1999年   270篇
  1998年   249篇
  1997年   207篇
  1996年   206篇
  1995年   202篇
  1994年   136篇
  1993年   96篇
  1992年   55篇
  1991年   65篇
  1990年   47篇
  1989年   47篇
  1988年   29篇
  1987年   7篇
  1986年   3篇
  1985年   11篇
  1984年   9篇
  1983年   8篇
  1982年   8篇
  1981年   8篇
  1980年   5篇
  1979年   5篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
BackgroundThe common causes of subaortic left ventricular outflow tract obstruction (LVOTO) are hypertrophic cardiomyopathy (HCM) and membranous/tunnel subaortic stenosis (SAS). Reoperation after corrective surgery may be due to recurrent disease, associated congenital defects, or complications of the initial procedure. This study compares the late outcomes of young patients with HCM and SAS.MethodsWe studied clinical, echocardiographic, and operative data of patients ≤21 years of age at the time of surgery for LVOTO between August 1963 and August 2018. We stratified patients into HCM (n = 152) and congenital SAS (n = 63) groups and compared survival and cumulative incidence of reoperation.ResultsAt initial repair, patients with HCM were older than patients with SAS (median [interquartile range] age, 15 [10-19] years vs 8 [5-13] years; P < .001), and patients with HCM were more symptomatic with dyspnea (P < .001), chest pain (P = .002), and presyncope/syncope (P = .005). Thirty-day mortality was 1.3% vs 0% for HCM and SAS groups. During a median follow-up of 13.1 years, survival was similar through the first 10 years; but during the second decade, patients with HCM had poorer survival (survival at 20 years, 80% vs 91% for patients with SAS; P = .007). Ten years after repair, reoperation for recurrent LVOTO was performed in 5% of patients with HCM vs 31% in those with SAS (P < .001).ConclusionsIn this surgical cohort, patients with HCM were more symptomatic preoperatively than those with SAS. Late survival of patients with SAS was superior to that of patients with HCM despite a greater need for reoperation.  相似文献   
16.
17.
18.
19.
20.
ObjectivesClinical trials have shown a beneficial effect from biological disease-modifying antirheumatic drugs (bDMARDs) on hand or axial bone loss in patients with rheumatoid arthritis; however, it is unclear if this translates to a reduced fracture risk. We investigated the effect of bDMARDs on osteoporotic fracture risk compared to no biological treatment in rheumatoid arthritis.MethodsA cohort of patients with rheumatoid arthritis aged 18+ from DANBIO was linked to population-based health registries in Denmark (2006-2016). Adopting a prevalent new-user design, we matched bDMARD users to bDMARD-naïve patients using time-conditional propensity scores. The risk of incident osteoporotic fractures (including hip, vertebrae, humerus, and forearm) was estimated among the matched patients by Cox proportional hazards models.ResultsOut of 24,678 patients with rheumatoid arthritis, 4265 bDMARD users were matched to the same number of bDMARD-naïve patients (mean age 56.2 years, 74% female). During follow-up, 229 osteoporotic fractures occurred among bDMARD users and 205 fractures among bDMARD-naïve patients (incidence rates 12.1 and 13.0 per 1000 person-years, respectively). The use of bDMARDs was not associated with a reduced risk of osteoporotic fractures among patients with rheumatoid arthritis (hazard ratio 0.97, 95% confidence interval 0.78-1.20), compared with no biological treatment. The risk estimates were similar for all osteoporotic fracture sites.ConclusionWe found no independent beneficial effect from using bDMARDs on reducing the risk of osteoporotic fractures in patients with rheumatoid arthritis.  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