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   1273605篇
  免费   99840篇
  国内免费   1985篇
耳鼻咽喉   18418篇
儿科学   44335篇
妇产科学   34996篇
基础医学   181837篇
口腔科学   33559篇
临床医学   110824篇
内科学   257104篇
皮肤病学   28008篇
神经病学   100241篇
特种医学   51180篇
外国民族医学   660篇
外科学   196116篇
综合类   27027篇
现状与发展   1篇
一般理论   377篇
预防医学   95353篇
眼科学   27821篇
药学   94689篇
  2篇
中国医学   2421篇
肿瘤学   70461篇
  2018年   13124篇
  2017年   9963篇
  2016年   10897篇
  2015年   12370篇
  2014年   17163篇
  2013年   26212篇
  2012年   36023篇
  2011年   38058篇
  2010年   22802篇
  2009年   21814篇
  2008年   36639篇
  2007年   39261篇
  2006年   39504篇
  2005年   38458篇
  2004年   37599篇
  2003年   36453篇
  2002年   35807篇
  2001年   63990篇
  2000年   66497篇
  1999年   56409篇
  1998年   15129篇
  1997年   13754篇
  1996年   14196篇
  1995年   13383篇
  1994年   12719篇
  1993年   11725篇
  1992年   44500篇
  1991年   43454篇
  1990年   42204篇
  1989年   40090篇
  1988年   36867篇
  1987年   36221篇
  1986年   33594篇
  1985年   32265篇
  1984年   24123篇
  1983年   20222篇
  1982年   11684篇
  1981年   10641篇
  1980年   9459篇
  1979年   21302篇
  1978年   14785篇
  1977年   12489篇
  1976年   11669篇
  1975年   12601篇
  1974年   14643篇
  1973年   14101篇
  1972年   12938篇
  1971年   11714篇
  1970年   11040篇
  1969年   10012篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
21.

Objectives

Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls.

Design

Cross-sectional, laboratory study.

Methods

Fifteen participants with a concussion history (age: 19.7 ± 0.9 years; 9 females; median time since concussion 126 days, range 28–432 days), and 15 matched controls (19.7 ± 1.6 years; 9 females) with no recent concussion history participated. We measured center-of-pressure (COP) outcomes (velocity, path length, speed, dual-task cost) under 4 tandem gait conditions: (1) tandem gait, (2) tandem gait, eyes closed, (3) tandem gait, eyes open, cognitive distraction, and (4) tandem gait, eyes closed, cognitive distraction.

Results

The concussion history group demonstrated slower tandem gait velocity compared to the control group (4.0 cm/s difference), thus velocity was used as a covariate when analyzing COP path length and speed. The concussion history group (23.5%) demonstrated greater COP speed dual-task cost than the control group (16.3%) during the eyes closed dual-task condition. No other comparisons were statistically significant.

Conclusions

There may be subtle dynamic balance differences during tandem gait that are detectable after return-to-activity following concussion, but the clinical significance of these findings is unclear. Longitudinal investigations should identify acute movement deficits in varying visual and cognitive scenarios after concussion in comparison with recovery on traditional concussion assessment tools while also recording musculoskeletal injury outcomes.  相似文献   
22.
23.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  相似文献   

24.
25.
Purpose: Family psychosocial risk in pediatric oncology can be assessed using the Psychosocial Assessment Tool (PAT), a brief parent report screener based on the Pediatric Psychosocial Preventative Health Model (PPPHM; universal, targeted, and clinical). However, little is known about risk over the course of treatment and its association with medical and psychosocial healthcare utilization. Methods: Primary caregivers of children with cancer participated in this prospective multisite investigation, completing the PAT at diagnosis (T1; n = 396) and 6 months later (T2; n = 304). Healthcare utilization data were extracted from electronic health records. Results: The distribution of PPPHM risk levels at T1 and T2 was highly consistent for the samples. Two‐thirds of families remained at the same level of risk, 18% decreased and 16% increased risk level. Risk was not related to sociodemographic or treatment variables. The PAT risk score correlated with psychosocial contacts over the 6‐month period. Conclusions: Although the majority of families reported universal (low) risk on the PAT and were stable in their risk level over 6 months, reassessing risk is helpful in identifying those families who report higher level of risk during treatment than at diagnosis. PAT scores were related to psychosocial services that are provided to most but not all families and could be tailored more specifically to match risk and delivery of evidence‐based care.  相似文献   
26.
27.
28.

Background and objectives

A prompt and effective management of trauma patient is necessary. The aim of this case report is to highlight the importance of intraoperative echocardiography as a useful tool in patients suffering from refractory hemodynamic instability no otherwise explained.

Case report

A 41 year‐old woman suffered a car accident. At the emergency department, no abnormalities were found in ECG or chest X‐ray. Abdominal ultrasound revealed the presence of abdominal free liquid and the patient was submitted to urgent exploratory laparotomy. Nevertheless, she persisted suffering arterial hypotension and metabolic acidosis. Looking for the reason of her hemodynamic instability, intraoperative transthoracic echocardiography was performed, finding out the presence of pericardial effusion. Once the cardiac surgeon extracted pericardial clots, patient's situation improved clinically and analytically.

Conclusion

Every anesthesiologist should be able to use the intraoperative echocardiography as an effective tool in order to establish the appropriate measures to promote the survival of patients suffering severe trauma.  相似文献   
29.
30.
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