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   194996篇
  免费   35077篇
  国内免费   2603篇
耳鼻咽喉   5619篇
儿科学   6216篇
妇产科学   2971篇
基础医学   9218篇
口腔科学   2510篇
临床医学   31422篇
内科学   57067篇
皮肤病学   8335篇
神经病学   19967篇
特种医学   8706篇
外科学   48504篇
综合类   513篇
现状与发展   72篇
一般理论   13篇
预防医学   9087篇
眼科学   3944篇
药学   3760篇
中国医学   75篇
肿瘤学   14677篇
  2024年   535篇
  2023年   5119篇
  2022年   1708篇
  2021年   4384篇
  2020年   6751篇
  2019年   3357篇
  2018年   8670篇
  2017年   8332篇
  2016年   9599篇
  2015年   9793篇
  2014年   17241篇
  2013年   17818篇
  2012年   9144篇
  2011年   9174篇
  2010年   12482篇
  2009年   16114篇
  2008年   8949篇
  2007年   7274篇
  2006年   9472篇
  2005年   6731篇
  2004年   5656篇
  2003年   4519篇
  2002年   4352篇
  2001年   4181篇
  2000年   3297篇
  1999年   3561篇
  1998年   4087篇
  1997年   3782篇
  1996年   3619篇
  1995年   3409篇
  1994年   2144篇
  1993年   1712篇
  1992年   1499篇
  1991年   1525篇
  1990年   1141篇
  1989年   1252篇
  1988年   1098篇
  1987年   905篇
  1986年   945篇
  1985年   777篇
  1984年   642篇
  1983年   596篇
  1982年   584篇
  1981年   454篇
  1980年   413篇
  1979年   353篇
  1978年   375篇
  1977年   446篇
  1975年   324篇
  1972年   326篇
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
101.
IntroductionPeople with Down syndrome (DS) have high respiratory morbidity, evaluating their respiratory health with standardized, objective tests is desirable. Thus, the objective of this study was to evaluate the technical quality of Pulmonary Function Tests (PFTs) to determine which ones are most suitable for this population.MethodsParticipants included children, teenagers and adults with DS, 5 years of age or older (n = 302). The technical quality of the impulse oscillometry system (IOS), forced spirometry, lung-diffusing capacity for carbon monoxide (DLCO), and 6-min walk test (6MWT) were analyzed by age group. Capnography and pulse oximetry were included in the study. Technical quality was determined on the basis of current international PFTs standards.ResultsFifty-one percent of participants were males. A total of 184 participants (71%) who completed the IOS fulfilled the quality criteria, while 210 (70%) completed the 6MWT. Performance on forced spirometry and DLCO was poor. All pulse oximetries and 96% percent heart rates obtained had good quality, but exhaled carbon dioxide (PetCO2) and respiratory rate (RR) showed deficient repeatability.ConclusionsIOS appears to be the most reliable instrument for evaluating lung mechanics in individuals with DS.  相似文献   
102.
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   
103.
Marielle Kabbouche MD  FAHS 《Headache》2015,55(10):1426-1429
Status migrainosus is defined by the international classification of headache disorders (ICHD) criteria as a debilitating migraine lasting more then 72 hours. The epidemiology of status migrainosus is still unknown in adult and children, and frequently underdiagnosed. Children and adolescents often end up in the emergency room with an intractable headache that failed outpatient therapy. Six to seven percent of these children do not respond to acute infusion therapy and require hospitalization. It is imperative that more aggressive therapy is considered when patients are affected by a severe intractable headache to prevent further disability and returning the child to baseline activity. Multiple therapies are available for adults and children. Studies for acute therapy in the emergency room are available in adults and pediatric groups. Small studies are available for inpatient therapy in children and, along with available therapies for children and adolescents, are described in this review. A review of the literature shows growing evidence regarding the use of dihydroergotamine intravenously once patients are hospitalized. Effectiveness and safety have been proven in the last decades in adults and small studies in the pediatric populations.  相似文献   
104.
105.
106.
107.
108.
109.
Fine‐needle aspiration cytology using a novel ultrasound needle guidance system on the basis of standard needle magnetization was consecutively performed in 30 (15 in‐plane and 15 out‐of‐plane) suspicious thyroid nodules. Nondedicated, commercially available needles were used. The technical effectiveness and safety of the system were satisfying; system failures were observed in 2 cases. The needle tip could be (at least occasionally) visualized inside the thyroid nodule in 96%, and the subjective procedure ratings were excellent in 57%. The out‐of‐plane technique was significantly superior in both respects (P = .021 and .027, respectively). Standard needle magnetization ultrasound needle guidance was easy to apply and cost‐effective and has the potential to improve fine‐needle aspiration cytology performance.  相似文献   
110.
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