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   445127篇
  免费   30082篇
  国内免费   7656篇
耳鼻咽喉   5562篇
儿科学   8905篇
妇产科学   10915篇
基础医学   61266篇
口腔科学   12862篇
临床医学   39104篇
内科学   88235篇
皮肤病学   9228篇
神经病学   30657篇
特种医学   16230篇
外国民族医学   123篇
外科学   67176篇
综合类   21524篇
现状与发展   18篇
一般理论   66篇
预防医学   21563篇
眼科学   11211篇
药学   37987篇
  75篇
中国医学   5795篇
肿瘤学   34363篇
  2022年   3990篇
  2021年   6121篇
  2020年   4203篇
  2019年   5030篇
  2018年   6809篇
  2017年   5405篇
  2016年   5484篇
  2015年   7051篇
  2014年   9513篇
  2013年   10515篇
  2012年   14627篇
  2011年   15673篇
  2010年   9361篇
  2009年   8225篇
  2008年   12747篇
  2007年   13645篇
  2006年   13691篇
  2005年   12633篇
  2004年   10936篇
  2003年   10648篇
  2002年   9956篇
  2001年   29640篇
  2000年   30300篇
  1999年   25410篇
  1998年   6317篇
  1997年   5524篇
  1996年   4800篇
  1995年   4347篇
  1994年   3857篇
  1993年   3318篇
  1992年   16566篇
  1991年   15254篇
  1990年   14543篇
  1989年   14281篇
  1988年   12849篇
  1987年   12264篇
  1986年   11283篇
  1985年   10445篇
  1984年   6989篇
  1983年   5643篇
  1982年   2733篇
  1979年   5506篇
  1978年   3347篇
  1977年   2971篇
  1975年   2641篇
  1974年   3064篇
  1973年   2865篇
  1972年   2828篇
  1971年   2773篇
  1969年   2543篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Helicobacter pylori (H. pylori) is a main risk factor for gastric cancer (GC). Epithelial-mesenchymal transition (EMT) is involved in the development and progression of H. pylori-associated GC. However, the exact molecular mechanism of this process remains unclear. The AKT/GSK3β signaling pathway has been demonstrated to promote EMT in several types of cancer. The present study investigated whether H. pylori infection induced EMT, and promoted the development and metastasis of cancer in the normal gastric mucosa, and whether this process was dependent on AKT activation. The expression levels of the EMT-associated proteins, including E-cadherin and N-cadherin, were determined in 165 gastric mucosal samples of different disease stages by immunohistochemical analysis. The expression levels of E-cadherin, N-cadherin, AKT, phosphorylated (p-)AKT (Ser473), GSK3β and p-GSK3β (Ser9) were further determined in H. pylori-infected Mongolian gerbil gastric tissues and cells co-cultured with H. pylori by immunohistochemical analysis and western blotting. The results indicated that the expression levels of the epithelial marker E-cadherin were decreased, whereas the expression levels of the mesenchymal marker N-cadherin were increased during gastric carcinogenesis. Their expression levels were associated with H. pylori infection. Furthermore, H. pylori infection resulted in downregulation of E-cadherin expression and upregulation of N-cadherin expression in Mongolian gerbils and GES-1 cells. In addition, an investigation of the associated mechanism of action revealed that p-AKT (Ser473) and p-GSK3β (Ser9) were activated in GES-1 cells following co-culture with H. pylori. Furthermore, following pretreatment of the cells with the AKT inhibitor VIII, the expression levels of E-cadherin, N-cadherin, p-AKT and p-GSK3β did not show significant differences between GES-1 cells that were co-cultured with or without H. pylori. The levels of p-AKT and p-GSK3β were increased in H. pylori-infected Mongolian gerbils. In conclusion, the present study demonstrated that H. pylori infection activated AKT and resulted in the phosphorylation and inactivation of GSK3β, which in turn promoted early stage EMT. These effects were AKT-dependent. This mechanism may serve as a prerequisite for GC development.  相似文献   
46.
47.
BackgroundWomen suffering from kidney disease are more prone to fertility problems, due to uremia. Fortunately, their fertility rate increases dramatically after renal transplantation. This study analyzes the predictors/risk factors of successful pregnancy with live birth outcome while presenting an overview of the 7-year experience of a single center.MethodsThis retrospective cohort study includes 239 women of reproductive age (18–40 years) who underwent renal transplantation in a tertiary Turkish clinic between October 1, 2011, and August 24, 2017. The subjects were invited to take part in a survey questioning their obstetric characteristics and they were assessed in 2 groups: fertile and infertile. Multivariable linear regression analysis was conducted to determine the predictors of a successful pregnancy.ResultsThirty-five 35 patients wished to become pregnant: 12 got pregnant spontaneously, while 21 failed to become pregnant (spontaneously). The mean age of the patients at the survey was 34 ± 7. Regular menstrual cycles after renal transplantation, tacrolimus-mycophenolate mofetil maintenance protocol, and age at transplantation were found to be predictors of spontaneous pregnancy. The duration of peritoneal dialysis was significantly longer in the infertile group (48 vs 12 months).ConclusionEnd-stage renal disease's negative impacts, including menstrual abnormality and fertility problems, can be overcome by successful kidney transplantation with appropriate immunosuppression. Minimizing the duration of peritoneal dialysis, particularly in patients who desire future fertility, may be accepted as a logical management strategy.  相似文献   
48.
朱忆  张继春 《护理学杂志》2019,34(22):61-63
目的了解护理人员的科研能力与职业认同现状及其相关性,为采取针对性措施提高护理人员科研能力,增强其职业认同感提供参考。方法采用护理人员科研能力自评量表与护士职业认同评价量表,对350名护理人员进行调查。结果护理人员科研能力及科研实践能力、专业与发现问题能力、沟通协作能力3个维度得分率分别为37.50%、25.00%、50.00%、50.00%,职业认同评价量表总均分为5.52分。护理科研能力与职业认同呈正相关(P0.01)。结论护理人员具有较高的职业认同,其科研能力尚待加强,科研能力与职业认同呈正相关。管理者应注重护理人员科研能力的培养,从而提高其职业认同。  相似文献   
49.
50.
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