全文获取类型
收费全文 | 757篇 |
免费 | 61篇 |
国内免费 | 105篇 |
专业分类
儿科学 | 44篇 |
妇产科学 | 25篇 |
基础医学 | 66篇 |
口腔科学 | 44篇 |
临床医学 | 139篇 |
内科学 | 212篇 |
皮肤病学 | 7篇 |
神经病学 | 15篇 |
特种医学 | 73篇 |
外科学 | 46篇 |
综合类 | 45篇 |
预防医学 | 32篇 |
眼科学 | 6篇 |
药学 | 101篇 |
中国医学 | 1篇 |
肿瘤学 | 67篇 |
出版年
2021年 | 5篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 16篇 |
2014年 | 11篇 |
2013年 | 29篇 |
2012年 | 10篇 |
2011年 | 23篇 |
2010年 | 22篇 |
2009年 | 23篇 |
2008年 | 11篇 |
2007年 | 64篇 |
2006年 | 15篇 |
2005年 | 34篇 |
2004年 | 22篇 |
2003年 | 25篇 |
2002年 | 27篇 |
2001年 | 14篇 |
2000年 | 28篇 |
1999年 | 16篇 |
1998年 | 47篇 |
1997年 | 36篇 |
1996年 | 41篇 |
1995年 | 19篇 |
1994年 | 22篇 |
1993年 | 18篇 |
1992年 | 20篇 |
1991年 | 11篇 |
1990年 | 23篇 |
1989年 | 28篇 |
1988年 | 22篇 |
1987年 | 28篇 |
1986年 | 15篇 |
1985年 | 16篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1969年 | 6篇 |
1968年 | 7篇 |
1967年 | 6篇 |
1966年 | 8篇 |
排序方式: 共有923条查询结果,搜索用时 0 毫秒
921.
Joseph H. Puyat James Wilton Adeleke Fowokan Naveed Zafar Janjua Jason Wong Troy Grennan Catharine Chambers Abigail Kroch Cecilia T. Costiniuk Curtis L. Cooper Darren Lauscher Monte Strong Ann N. Burchell Aslam Anis Hasina Samji COVAXHIV Study Team 《Journal of the International AIDS Society》2023,26(10):e26178
Introduction
People living with HIV (PLWH) and/or who inject drugs may experience lower vaccine effectiveness (VE) against SARS-CoV-2 infection.Methods
A validated algorithm was applied to population-based, linked administrative datasets in the British Columbia COVID-19 Cohort (BCC19C) to ascertain HIV status and create a population of PLWH and matched HIV-negative individuals. The study population was limited to individuals who received an RT-PCR laboratory test for SARS-CoV-2 between 15 December 2020 and 21 November 2021 in BC, Canada. Any history of injection drug use (IDU) was ascertained using a validated administrative algorithm. We used a test-negative study design (modified case−control analysis) and multivariable logistic regression to estimate adjusted VE by HIV status and history of IDU.Results
Our analysis included 2700 PLWH and a matched population of 375,043 HIV-negative individuals, among whom there were 351 and 103,049 SARS-CoV-2 cases, respectively. The proportion of people with IDU history was much higher among PLWH compared to HIV-negative individuals (40.7% vs. 4.3%). Overall VE during the first 6 months after second dose was lower among PLWH with IDU history (65.8%, 95% CI = 43.5–79.3) than PLWH with no IDU history (80.3%, 95% CI = 62.7–89.6), and VE was particularly low at 4–6 months (42.4%, 95% CI = −17.8 to 71.8 with IDU history vs. 64.0%; 95% CI = 15.7–84.7 without), although confidence intervals were wide. In contrast, overall VE was 88.6% (95% CI = 88.2–89.0) in the matched HIV-negative population with no history of IDU and remained relatively high at 4–6 months after second dose (84.6%, 95% CI = 83.8–85.4). Despite different patterns of vaccine protection by HIV status and IDU history, peak estimates were similar (≥88%) across all populations.Conclusions
PLWH with a history of IDU may experience lower VE against COVID-19 infection, although findings were limited by a small sample size. The lower VE at 4–6 months may have implications for booster dose prioritization for PLWH and people who inject drugs. The immunocompromising effect of HIV, substance use and/or co-occurring comorbidities may partly explain these findings. 相似文献922.
923.
Is a Depth Camera in Agreement with an Electromagnetic Tracking Device when Measuring Head Position?
Vienna-Jaye Burchell Gemma Arblaster David Buckley Jonathan Wheat 《The British and Irish orthoptic journal》2021,17(1):142
Introduction:Clinicians typically observe and describe abnormal head postures (AHPs) and may also measure them. Depth cameras have been suggested as a reliable measurement device for measuring head position using face-tracking technology. This study compared a depth camera (Microsoft Kinect) to a gold standard electromagnetic tracking system (Polhemus device) to measure head position.Method:Twenty healthy volunteers (mean age 21 years) had their head position simultaneously recorded using the depth camera (Kinect) and the electromagnetic tracking system (Polhemus). Participants were asked to make 30-degree head movements into chin up, chin down, head turn and head tilt positions. The head movement made and the stability of the head at each position were recorded and analysed.Results:Compared to the electromagnetic tracking system (Polhemus), the depth camera (Kinect) always measured a smaller head movement. Measurements with the two devices were not statistically significantly different for turn right (P = 0.3955, p > 0.05), turn left (P = 0.4749, p > 0.05), tilt right (P = 0.7086, p > 0.05) and tilt left (P = 0.4091, p > 0.05) head movements. However, the smaller depth camera measurement of chin up and chin down head movements were statistically significant, chin up (P = 0.0001, p < 0.01) and chin down (P = 0.0005, p < 0.001). At each eccentric position, the depth camera (Kinect) recordings were more variable than the electromagnetic tracking system (Polhemus).Conclusions:Compared to the electromagnetic tracking system (Polhemus), the depth camera (Kinect) was comparable for measuring head turns and tilts but was less accurate at measuring chin up and chin down head positions. Further research is needed before the depth cameras are considered for clinical recordings of head position. 相似文献