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   20538篇
  免费   1322篇
  国内免费   137篇
耳鼻咽喉   165篇
儿科学   449篇
妇产科学   371篇
基础医学   2400篇
口腔科学   810篇
临床医学   1973篇
内科学   4318篇
皮肤病学   421篇
神经病学   1320篇
特种医学   475篇
外国民族医学   5篇
外科学   3024篇
综合类   506篇
一般理论   17篇
预防医学   1651篇
眼科学   780篇
药学   1906篇
中国医学   242篇
肿瘤学   1164篇
  2024年   21篇
  2023年   256篇
  2022年   562篇
  2021年   1189篇
  2020年   770篇
  2019年   974篇
  2018年   1146篇
  2017年   828篇
  2016年   845篇
  2015年   856篇
  2014年   1157篇
  2013年   1332篇
  2012年   1829篇
  2011年   1890篇
  2010年   1128篇
  2009年   877篇
  2008年   1251篇
  2007年   1106篇
  2006年   915篇
  2005年   766篇
  2004年   615篇
  2003年   501篇
  2002年   415篇
  2001年   59篇
  2000年   69篇
  1999年   62篇
  1998年   56篇
  1997年   48篇
  1996年   48篇
  1995年   39篇
  1994年   20篇
  1993年   34篇
  1992年   27篇
  1991年   23篇
  1990年   23篇
  1989年   21篇
  1988年   19篇
  1987年   12篇
  1986年   18篇
  1985年   14篇
  1984年   21篇
  1983年   19篇
  1982年   18篇
  1981年   13篇
  1980年   14篇
  1979年   14篇
  1978年   12篇
  1976年   12篇
  1974年   8篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.

Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.

Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.

Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion.  相似文献   
4.
5.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  相似文献   
6.

Background

Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA.

Methods

We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year.

Results

Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time.

Conclusion

In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room.  相似文献   
7.
8.
9.
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