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   29428篇
  免费   2664篇
  国内免费   51篇
耳鼻咽喉   307篇
儿科学   854篇
妇产科学   673篇
基础医学   3976篇
口腔科学   399篇
临床医学   3376篇
内科学   6118篇
皮肤病学   383篇
神经病学   2502篇
特种医学   963篇
外国民族医学   3篇
外科学   4590篇
综合类   513篇
一般理论   27篇
预防医学   2801篇
眼科学   644篇
药学   2068篇
中国医学   22篇
肿瘤学   1924篇
  2023年   221篇
  2022年   179篇
  2021年   736篇
  2020年   525篇
  2019年   813篇
  2018年   934篇
  2017年   646篇
  2016年   688篇
  2015年   770篇
  2014年   1096篇
  2013年   1336篇
  2012年   2009篇
  2011年   2074篇
  2010年   1121篇
  2009年   931篇
  2008年   1562篇
  2007年   1534篇
  2006年   1335篇
  2005年   1273篇
  2004年   1185篇
  2003年   1108篇
  2002年   918篇
  2001年   573篇
  2000年   577篇
  1999年   483篇
  1998年   220篇
  1997年   182篇
  1996年   154篇
  1995年   181篇
  1994年   159篇
  1993年   163篇
  1992年   419篇
  1991年   420篇
  1990年   424篇
  1989年   366篇
  1988年   388篇
  1987年   377篇
  1986年   333篇
  1985年   314篇
  1984年   269篇
  1983年   221篇
  1979年   240篇
  1978年   188篇
  1977年   145篇
  1976年   161篇
  1975年   156篇
  1974年   158篇
  1973年   177篇
  1972年   143篇
  1970年   138篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Background

Vaccination prevents severe morbidity and mortality from COVID-19 in the general population. The immunogenicity and efficacy of SARS-CoV-2 vaccines in patients with antibody deficiency is poorly understood.

Objectives

COVID-19 in patients with antibody deficiency (COV-AD) is a multi-site UK study that aims to determine the immune response to SARS-CoV-2 infection and vaccination in patients with primary or secondary antibody deficiency, a population that suffers from severe and recurrent infection and does not respond well to vaccination.

Methods

Individuals on immunoglobulin replacement therapy or with an IgG less than 4 g/L receiving antibiotic prophylaxis were recruited from April 2021. Serological and cellular responses were determined using ELISA, live-virus neutralisation and interferon gamma release assays. SARS-CoV-2 infection and clearance were determined by PCR from serial nasopharyngeal swabs.

Results

A total of 5.6% (n?=?320) of the cohort reported prior SARS-CoV-2 infection, but only 0.3% remained PCR positive on study entry. Seropositivity, following two doses of SARS-CoV-2 vaccination, was 54.8% (n?=?168) compared with 100% of healthy controls (n?=?205). The magnitude of the antibody response and its neutralising capacity were both significantly reduced compared to controls. Participants vaccinated with the Pfizer/BioNTech vaccine were more likely to be seropositive (65.7% vs. 48.0%, p?=?0.03) and have higher antibody levels compared with the AstraZeneca vaccine (IgGAM ratio 3.73 vs. 2.39, p?=?0.0003). T cell responses post vaccination was demonstrable in 46.2% of participants and were associated with better antibody responses but there was no difference between the two vaccines. Eleven vaccine-breakthrough infections have occurred to date, 10 of them in recipients of the AstraZeneca vaccine.

Conclusion

SARS-CoV-2 vaccines demonstrate reduced immunogenicity in patients with antibody deficiency with evidence of vaccine breakthrough infection.

  相似文献   
3.

Objective

To assess the effectiveness of a hospital physical therapy (PT) referral triggered by scores on a mobility assessment embedded in the electronic health record (EHR) and completed by nursing staff on hospital admission.

Data Sources

EHR and billing data from 12 acute care hospitals in a western Pennsylvania health system (January 2017–February 2018) and 11 acute care hospitals in a northeastern Ohio health system (August 2019–July 2021).

Study Design

We utilized a regression discontinuity design to compare patients admitted to PA hospitals with stroke who reached the mobility score threshold for an EHR-PT referral (treatment) to those who did not (control). Outcomes were hospital length of stay (LOS) and 30-day readmission or mortality. Control variables included demographics, insurance, income, and comorbidities. Hospital systems with EHR-PT referrals were also compared to those without (OH hospitals as alternative control). Subgroup analyses based on age were also conducted.

Data Extraction

We identified adult patients with a primary or secondary diagnosis of stroke and mobility assessments completed by nursing (n = 4859 in PA hospitals, n = 1749 in OH hospitals) who completed their inpatient stay.

Principal Findings

In the PA hospitals, patients with EHR-PT referrals had an 11.4 percentage-point decrease in their 30-day readmission or mortality rates (95% CI −0.57, −0.01) relative to the control. This effect was not observed in the OH hospitals for 30-day readmission (β = 0.01; 95% CI −0.25, 0.26). Adults over 60 years old with EHR-PT referrals in PA had a 26.2 percentage-point (95% CI −0.88, −0.19) decreased risk of readmission or mortality compared to those without. Unclear relationships exist between EHR-PT referrals and hospital LOS in PA.

Conclusions

Health systems should consider methodologies to facilitate early acute care hospital PT referrals informed by mobility assessments.  相似文献   
4.
The Extracellular Vesicle Flow Cytometry Working Group ( http://www.evflowcytometry.org ) is formed by members of the International Society for Extracellular Vesicles (ISEV), the International Society for Advancement of Cytometry (ISAC), and the International Society on Thrombosis and Haemostasis (ISTH). This working group of flow cytometry experts develops guidelines for best practices regarding flow cytometry detection of extracellular vesicles. To improve rigor and standardization, this working group published a framework outlining the minimal information to report about a flow cytometry experiment on extracellular vesicles (MIFlowCyt-EV) in the Journal of Extracellular Vesicles, the ISEV journal, in 2020. In parallel, an article explaining MIFlowCyt-EV was published in Cytometry Part A, one of the ISAC journals, and now will be introduced to the ISTH as an SSC Communication in the Journal of Thrombosis and Haemostasis. The goal of this SSC Communication is to explain why flow cytometry is becoming the instrument of choice to characterize single extracellular vesicles, the obstacles that have been identified and (mostly) overcome by developing procedures to calibrate flow cytometers, and the relevance of reporting minimal information to improve reliability and reproducibility of experiments in which flow cytometers are used for characterization of extracellular vesicles.  相似文献   
5.
6.
Journal of Thrombosis and Thrombolysis - Alteplase treatment can cause a systemic coagulopathy although the incidence and contributory factors are unknown in pulmonary embolism (PE). Fixed-dosing...  相似文献   
7.
8.
European Journal of Orthopaedic Surgery & Traumatology - Intertrochanteric femur fracture nonunions are a rare complication that can be difficult to treat with limited evidence regarding...  相似文献   
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