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   19447篇
  免费   1107篇
  国内免费   153篇
耳鼻咽喉   223篇
儿科学   509篇
妇产科学   666篇
基础医学   2114篇
口腔科学   544篇
临床医学   1597篇
内科学   3847篇
皮肤病学   387篇
神经病学   904篇
特种医学   731篇
外国民族医学   11篇
外科学   3462篇
综合类   368篇
现状与发展   2篇
一般理论   11篇
预防医学   1668篇
眼科学   563篇
药学   1810篇
中国医学   140篇
肿瘤学   1150篇
  2024年   17篇
  2023年   251篇
  2022年   790篇
  2021年   1145篇
  2020年   616篇
  2019年   771篇
  2018年   1036篇
  2017年   614篇
  2016年   639篇
  2015年   651篇
  2014年   907篇
  2013年   1060篇
  2012年   1544篇
  2011年   1695篇
  2010年   964篇
  2009年   696篇
  2008年   987篇
  2007年   1001篇
  2006年   909篇
  2005年   873篇
  2004年   762篇
  2003年   704篇
  2002年   613篇
  2001年   144篇
  2000年   113篇
  1999年   96篇
  1998年   77篇
  1997年   78篇
  1996年   72篇
  1995年   66篇
  1994年   60篇
  1993年   51篇
  1992年   47篇
  1991年   55篇
  1990年   54篇
  1989年   46篇
  1988年   49篇
  1987年   46篇
  1986年   38篇
  1985年   38篇
  1984年   41篇
  1983年   36篇
  1982年   33篇
  1981年   23篇
  1980年   21篇
  1978年   17篇
  1977年   14篇
  1976年   17篇
  1974年   13篇
  1973年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
996.
997.
Purpose: This study investigated the occlusal fracture resistance of Turkom-Cera-fused alumina compared to Procera AllCeram and In-Ceram all-ceramic restorations.
Materials and Methods: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Ten copings of 0.6 mm thickness were fabricated from each type of ceramic, for a total of thirty copings. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented with resin luting cement Panavia F according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37°C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.
Results: The results of the present study showed the following mean loads at fracture: Turkom-Cera (2184 ± 164 N), In-Ceram (2042 ± 200 N), and Procera AllCeram (1954 ± 211 N). ANOVA and Scheffe's post hoc test showed that the mean load at fracture of Turkom-Cera was significantly different from Procera AllCeram ( p < 0.05). Scheffe's post hoc test showed no significant difference between the mean load at fracture of Turkom-Cera and In-Ceram or between the mean load at fracture of In-Ceram and Procera AllCeram.
Conclusion: Because Turkom-Cera demonstrated equal to or higher loads at fracture than currently accepted all-ceramic materials, it would seem to be acceptable for fabrication of anterior and posterior ceramic crowns.  相似文献   
998.
999.
In a previous study, the musculoskeletal affections among kidney recipients (KR) were reported, with 63 KR suffering from joint affections. We sought to determine the prevalence of osteonecrosis (ON) among those KR with joint affections, its distribution among the affected joints, and possible risk predictors. KR were subjected to biochemical, haematological, and hepatitis serology estimations. Radiographic and magnetic resonance imaging were performed. Relevant data were retrieved from Patient Information System. Fourteen KR were suffering from ON, with an incidence of 22.2% in KR with joint affections and 12.0% in the target population of KR. The femoral head was affected in 57.1% and the femoral condyles in 28.6%. Hypocalcaemia was observed in KR with ON. Whether hypocalcaemia is a causative or associative of ON yet remains to be decided in forthcoming studies.  相似文献   
1000.
The purpose of the present study is to investigate the frequency of HLA-B27 and its alleles in reactive arthritis (ReA) and in ankylosing spondylitis (AS) in Tunisia. HLA-B27 alleles were typed by PCR amplification with sequence-specific primers. We studied 17 patients with ReA associated with urethritis or with gastrointestinal infection; 42 HLA-B27-positive patients with AS and 100 healthy controls. Eleven ReA patients (67.7%) were HLA-B27 positive. There was an increased frequencies of HLA-B27 (P = 7.76 × 10−12, OR = 59.30) and a moderate increase of HLA-B51 (P = 0.015; OR = 4.91) alleles in ReA patients when compared with healthy controls. Four B27 subtypes were identified: B*2702, 05, 09 and B*2712. The distribution of these alleles in the ReA patients was 37.5% for B*2702 and B*2705. Only these two subtypes were detected in 18 (42.8%) and 24 (57.1%), respectively, of the AS patients. B*2709 and B*2712 were relatively rare in ReA patients and were identified in one case each. Our results showed a restricted number of HLA-B27 subtypes associated with ReA and AS. B*2702 and 2705 were common in ReA and AS patients.  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