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   256240篇
  免费   19208篇
  国内免费   893篇
耳鼻咽喉   2673篇
儿科学   6847篇
妇产科学   5258篇
基础医学   33469篇
口腔科学   5561篇
临床医学   24728篇
内科学   53790篇
皮肤病学   3377篇
神经病学   25134篇
特种医学   8728篇
外国民族医学   68篇
外科学   39497篇
综合类   4110篇
现状与发展   2篇
一般理论   313篇
预防医学   23399篇
眼科学   5556篇
药学   17586篇
  1篇
中国医学   429篇
肿瘤学   15815篇
  2023年   905篇
  2022年   1456篇
  2021年   4095篇
  2020年   2504篇
  2019年   4108篇
  2018年   4735篇
  2017年   3787篇
  2016年   4076篇
  2015年   4886篇
  2014年   7301篇
  2013年   10639篇
  2012年   15684篇
  2011年   16962篇
  2010年   9584篇
  2009年   8660篇
  2008年   16059篇
  2007年   17083篇
  2006年   16455篇
  2005年   16902篇
  2004年   16216篇
  2003年   15188篇
  2002年   14685篇
  2001年   2739篇
  2000年   2287篇
  1999年   2821篇
  1998年   3362篇
  1997年   2948篇
  1996年   2684篇
  1995年   2427篇
  1994年   2178篇
  1993年   2053篇
  1992年   1768篇
  1991年   1639篇
  1990年   1556篇
  1989年   1467篇
  1988年   1459篇
  1987年   1481篇
  1986年   1463篇
  1985年   1514篇
  1984年   1922篇
  1983年   1875篇
  1982年   2201篇
  1981年   2011篇
  1980年   1880篇
  1979年   1184篇
  1978年   1284篇
  1977年   1156篇
  1976年   1104篇
  1975年   936篇
  1974年   953篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
2‐deoxy D‐glucose (2DG) was tested for efficacy in treating alopecia areata using the C3H/HeJ skin graft model. 2DG has proven to be efficacious in treatment of various mouse models of autoimmunity with minimal serious side effects noted. This agent has been shown to normalize abnormally activated T‐cell populations while also preventing cell surface expression of NKG2D; key factors defining alopecia areata disease progression. Daily oral ingestion of 2DG via drinking water to mice with patchy or diffuse alopecia areata for 16 weeks failed to prevent expansion of alopecia or cause regrowth of hair in treated mice. Histologically, there were no differences between treated and control groups. These results indicate that, while 2DG is effective for some autoimmune diseases, it was not efficacious for the cell‐mediated autoimmune mouse disease, alopecia areata.  相似文献   
66.
67.

Background

Most elderly trauma patients suffer blunt head injury and many utilize antithrombotic (AT) medications. The utility of delayed CT-head (D-CTH) in neurologically intact elderly patients using AT who have an intracranial hemorrhage (ICH) on presentation is unknown. We hypothesized that D-CTH would not alter clinical management and aimed to evaluate the role of D-CTH in this population.

Methods

A retrospective cohort study was performed. Patients ≥65 years sustaining blunt head injuries from January 2010 to July 2017 were identified using our level 1 trauma center database. AT-patients presenting with ICH who underwent D-CTH were included. Patients with worsened ICH were compared to those with stable to improved ICH on D-CTH. AT-patients were compared to a cohort of non-AT patients. Fisher’s Exact and Mann-Whitney U tests were utilized and a power analysis conducted.

Results

137?A?T and 34 non-AT patients were identified. There was no difference in hemorrhage progression or appearance of new ICH. No patient had a change in management from D-CTH in either cohort. AT-patients were slightly older (p?<?0.001), but cohorts were otherwise similar.50 AT-patients with worsened ICH were compared to 87 with stable ICH. There was no difference in cohort demographics. Hemorrhage progression did not vary with type of AT used but did increase if multiple types of synchronous ICH were present (p?<?0.001).

Conclusions

Our data supports abstaining from routine D-CTH of elderly ICH patients with an intact neurologic examination who are utilizing aspirin, clopidogrel or warfarin. Conclusions cannot be drawn regarding new oral anticoagulants (NOACs) given low enrollment. Further multicenter study is required to provide adequate power and detect small levels of management change.  相似文献   
68.
69.
70.
Marie Warrer Petersen  Tine Sylvest Meyhoff  Marie Helleberg  Maj-Brit Nørregaard Kjær  Anders Granholm  Carl Johan Steensen Hjortsø  Thomas Steen Jensen  Morten Hylander Møller  Peter Buhl Hjortrup  Mik Wetterslev  Gitte Kingo Vesterlund  Lene Russell  Vibeke Lind Jørgensen  Klaus Tjelle  Thomas Benfield  Charlotte Suppli Ulrik  Anne Sofie Andreasen  Thomas Mohr  Morten H. Bestle  Lone Musaeus Poulsen  Mette Friberg Hitz  Thomas Hildebrandt  Lene Surland Knudsen  Anders Møller  Christoffer Grant Sølling  Anne Craveiro Brøchner  Bodil Steen Rasmussen  Henrik Nielsen  Steffen Christensen  Thomas Strøm  Maria Cronhjort  Rebecka Rubenson Wahlin  Stephan Jakob  Luca Cioccari  Balasubramanian Venkatesh  Naomi Hammond  Vivekanand Jha  Sheila Nainan Myatra  Christian Gluud  Theis Lange  Anders Perner 《Acta anaesthesiologica Scandinavica》2020,64(9):1365-1375

Introduction

Severe acute respiratory syndrome coronavirus-2 has caused a pandemic of coronavirus disease (COVID-19) with many patients developing hypoxic respiratory failure. Corticosteroids reduce the time on mechanical ventilation, length of stay in the intensive care unit and potentially also mortality in similar patient populations. However, corticosteroids have undesirable effects, including longer time to viral clearance. Clinical equipoise on the use of corticosteroids for COVID-19 exists.

Methods

The COVID STEROID trial is an international, randomised, stratified, blinded clinical trial. We will allocate 1000 adult patients with COVID-19 receiving ≥10 L/min of oxygen or on mechanical ventilation to intravenous hydrocortisone 200 mg daily vs placebo (0.9% saline) for 7 days. The primary outcome is days alive without life support (ie mechanical ventilation, circulatory support, and renal replacement therapy) at day 28. Secondary outcomes are serious adverse reactions at day 14; days alive without life support at day 90; days alive and out of hospital at day 90; all-cause mortality at day 28, day 90, and 1 year; and health-related quality of life at 1 year. We will conduct the statistical analyses according to this protocol, including interim analyses for every 250 patients followed for 28 days. The primary outcome will be compared using the Kryger Jensen and Lange test in the intention to treat population and reported as differences in means and medians with 95% confidence intervals.

Discussion

The COVID STEROID trial will provide important evidence to guide the use of corticosteroids in COVID-19 and severe hypoxia.
  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