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   6040篇
  免费   400篇
  国内免费   37篇
耳鼻咽喉   63篇
儿科学   92篇
妇产科学   149篇
基础医学   783篇
口腔科学   61篇
临床医学   674篇
内科学   1423篇
皮肤病学   75篇
神经病学   534篇
特种医学   226篇
外科学   991篇
综合类   39篇
预防医学   317篇
眼科学   113篇
药学   384篇
中国医学   5篇
肿瘤学   548篇
  2024年   9篇
  2023年   59篇
  2022年   85篇
  2021年   235篇
  2020年   162篇
  2019年   219篇
  2018年   261篇
  2017年   169篇
  2016年   180篇
  2015年   160篇
  2014年   252篇
  2013年   326篇
  2012年   489篇
  2011年   401篇
  2010年   246篇
  2009年   235篇
  2008年   362篇
  2007年   364篇
  2006年   359篇
  2005年   337篇
  2004年   278篇
  2003年   256篇
  2002年   259篇
  2001年   70篇
  2000年   57篇
  1999年   54篇
  1998年   58篇
  1997年   49篇
  1996年   47篇
  1995年   40篇
  1994年   27篇
  1993年   15篇
  1992年   28篇
  1991年   29篇
  1990年   28篇
  1989年   29篇
  1988年   23篇
  1987年   21篇
  1986年   21篇
  1985年   16篇
  1984年   11篇
  1983年   9篇
  1982年   7篇
  1981年   10篇
  1976年   10篇
  1974年   7篇
  1973年   7篇
  1972年   12篇
  1970年   11篇
  1969年   9篇
排序方式: 共有6477条查询结果,搜索用时 203 毫秒
981.
982.
983.
An aging population has prompted us to evaluate the indications of liver transplantation (LT) in elderly patients more frequently. In this review, we summarize the short- and long-term results after LT in elderly patients and also discuss the criteria used to select patients and how recipient age can challenge current allocation systems. Briefly, the feasibility and early outcomes of LT in elderly patients compare favorably with those of younger patients. Although long-term survival is less than satisfactory, large-scale studies show that the transplant survival benefit is similar for elderly and younger patients. Therefore, age alone does not contraindicate LT; however, screening for cardiopulmonary comorbidities, and asymptomatic malignancies, evaluating nutritional status, and frailty, is crucial to ensure optimal results and avoid futile transplantation.  相似文献   
984.
Background: Studies have demonstrated inconsistent results regarding the association between video gaming time and substance use in teenagers. Understating intricacies of this association can help with substance use reduction in teenagers. Objectives: This study aimed to untangle this complex relationship by theorizing and examining a U-shaped association. Methods: We analyzed two large samples (n1 = 7313 [52.5% female] and n2 = 8079 [51.6% female]) of 8th and 10th graders in the United States. Substance use was operationalized as the sum of self-reported number of lifetime use instances of 14 unprescribed substances. Video game use time (hours per week) was self-reported on a 1 (none) to 9 (40+) scale. Common covariates/risk factors were included. Results: Consistently across datasets, partial-correlation between squared video gaming time and substance use (r?=?.10, p?<?.001 in 2014 and r?=?.08, p?<?.001 in 2015) supported the hypothesized u-shaped association. Analysis of covariance revealed that teenagers playing video games for 1–5?h a week report on significantly fewer instances of substance use compared with non-gamers (p?<?.001–.007). Post hoc analyses revealed that those who play at least 30?h per week report on significantly (p?<?.001) more instances of substance use (3.92 in 2014 and 3.38 in 2015) compared with teenagers playing video games for 1–5?h a week (2.17 in 2015 and 1.96 in 2015). Conclusions: Video gaming time and substance use follow a u-shaped association; light video gaming can be protective in terms of substance use, while too much video gaming is associated with increased substance use.  相似文献   
985.
In liver transplantation, tacrolimus trough concentrations (Cmin) above 20 ng/mL during the first days led to worse outcome at 1 year but data in the kidney transplant (KT) era are scarce. The aim of this study was to evaluate the impact of tacrolimus overexposure during the first week post‐transplantation on the kidney function (KF) of KT recipients. In this retrospective study, 105 KT recipients were attributed to overexposure group (OG) or normal group according to their Cmin during the first week of treatment. KF was evaluated by comparing the rate of delayed graft function (DGF) and by collecting plasma creatinine from day 1, 2, 3, 4, 5, 6, 7, 14, 21, 28 and at 1 year. Risk factors for developing DGF were also investigated using a multivariate model. DGF was more frequent in OG (43% of patients; P = 0.027) which has higher plasma creatinine on day 7, 14, and 21. OG patients were older with more extended criteria donor's grafts. In the multivariate analysis, only cold ischemia time (CIT) remained associated with DGF (OR = 1.003), while TAC overexposure did not reach significance (P = 0.06; OR = 3.9). In this study, we confirmed the predominant role of CIT as a risk factor for the onset of DGF in kidney transplantation. 43% of KT recipients were overexposed with more DGF, especially older patients.  相似文献   
986.
987.
988.
989.
990.
Journal of Gastroenterology - Small bowel cancer is not a single entity. Population-based studies taking into account histological diversity are scarce. The aim of this study was to report on their...  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