全文获取类型
收费全文 | 791篇 |
免费 | 37篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 98篇 |
儿科学 | 44篇 |
妇产科学 | 10篇 |
基础医学 | 67篇 |
口腔科学 | 11篇 |
临床医学 | 67篇 |
内科学 | 133篇 |
皮肤病学 | 17篇 |
神经病学 | 41篇 |
特种医学 | 108篇 |
外科学 | 102篇 |
综合类 | 25篇 |
一般理论 | 1篇 |
预防医学 | 52篇 |
眼科学 | 1篇 |
药学 | 46篇 |
中国医学 | 1篇 |
肿瘤学 | 23篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 22篇 |
2014年 | 35篇 |
2013年 | 41篇 |
2012年 | 29篇 |
2011年 | 39篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 33篇 |
2007年 | 44篇 |
2006年 | 56篇 |
2005年 | 34篇 |
2004年 | 23篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 29篇 |
2000年 | 17篇 |
1999年 | 14篇 |
1998年 | 23篇 |
1997年 | 21篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 21篇 |
1990年 | 13篇 |
1989年 | 17篇 |
1988年 | 12篇 |
1987年 | 16篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1965年 | 2篇 |
1900年 | 1篇 |
1898年 | 1篇 |
排序方式: 共有847条查询结果,搜索用时 15 毫秒
1.
Andrea Stracciolini Jennifer Luz Gregory Walker Nicholas M. Edwards Avery D. Faigenbaum Gregory D. Myer 《The Physician and sportsmedicine》2020,48(2):199-207
ABSTRACT
Objective
To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline. 相似文献2.
Limb asymmetries in landing and jumping 2 years following anterior cruciate ligament reconstruction. 总被引:1,自引:0,他引:1
Mark V Paterno Kevin R Ford Gregory D Myer Rachel Heyl Timothy E Hewett 《Clinical journal of sport medicine》2007,17(4):258-262
OBJECTIVE: Female athletes who are at increased risk for anterior cruciate ligament (ACL) injury demonstrate biomechanical differences between limbs during athletic tasks that may persist following anterior cruciate ligament reconstruction (ACLR). This may limit an athlete's potential for safe return to sports competition. The purpose of this study was to determine if female athletes demonstrate lower limb asymmetries in landing and takeoff force following ACLR and clearance for return to competitive sports participation. We hypothesized that females following ACLR would demonstrate side-to-side differences in landing and jumping kinetics after their return to sport (2+ years) that would not be observed in a group of healthy female controls. DESIGN: Case control study. SETTING: The Sports Medicine Biodynamics Center at Cincinnati Children's Hospital Medical Center. PATIENTS: Fourteen female athletes at a mean of 27 months following ACLR and 18 healthy female athletes participated in the study. ASSESSMENT: All subjects executed a drop vertical jump (DVJ) task onto 2 force plates. Vertical ground reaction force (VGRF) was measured during landing and takeoff and was used to calculate landing phase loading rates. A 2-way analysis of variance was used to determine differences between the involved, uninvolved, and control limbs. RESULTS: Females who had undergone ACLR demonstrated increased VGRF (P = 0.001) and loading rate (P < 0.001) on the uninvolved limb during landing when compared with the involved limb and the control group. During takeoff, the involved limb showed significantly less ability to generate force (P = 0.03) than the uninvolved limb and the control limbs. CONCLUSIONS: Female athletes who have undergone ACLR and returned to sport may continue to demonstrate biomechanical limb asymmetries 2 years or more after reconstruction that can be identified during landing. 相似文献
3.
4.
Congenital epulis of the newborn is a rare gingival tumor that occurs along the alveolar ridge. We report the prenatal sonographic and postnatal MR imaging findings in an infant with maxillary and mandibular congenital epulides. 相似文献
5.
Myer H. Roszler M.D. 《Emergency radiology》1994,1(3):166-167
Conclusion This article summarizes the training and teaching of radiology residents before they attempt unsupervised emergency call,
as reported in the radiologic literature. It is hoped that this report will prompt a serious evaluation of the responsibilities
of radiology residents assigned to the emergency center and a reconsideration of the radiologic training and experience provided
to radiology residents before they are required to assume these responsibilities. Clearly, education and training in radiology
appropriate to the responsibilities expected of the on-call emergency radiology resident are required to assure optimum patient
care. 相似文献
6.
7.
Jabulani R. Ncayiyana Leonardo Martinez Elizabeth Goddard Landon Myer Heather J. Zar 《Nutrients》2021,13(5)
Early-life vitamin D deficiency is associated with adverse child health outcomes, but the prevalence of vitamin D deficiency and its correlates in infants remains underexplored, particularly in sub-Saharan Africa. We aimed to investigate the prevalence of vitamin D deficiency and its correlates among young infants in South Africa. This study included 744 infants, aged 6–10 weeks from the Drakenstein Child Health Study, a population-based birth cohort. Infants were categorized into distinct categories based on serum 25(OH)D concentration level including deficient (<50 nmol/L), insufficient (50–74 nmol/L), and sufficient (≥75 nmol/L). Using multivariable Tobit and logistic regression models, we examined the correlates of serum 25(OH)D3 levels. The overall prevalence of vitamin D deficiency was 81% (95% confidence intervals (CI]) 78–83). Multivariable regression analysis showed that serum 25(OH)D3 concentration was independently associated with study site, socioeconomic status, and sex. Birth in winter and breastfeeding were the strongest predictors of lower serum 25(OH)D3 concentration levels. Compared to non-breastfed children, children breastfed were at higher risk of vitamin D deficiency (AOR, 1.96; 95% CI, 1.04–3.67) and breastfeeding for more than one month was associated with greater likelihood of vitamin D deficiency (AOR, 5.40; 95% CI, 2.37–12.32) and lower vitamin D concentrations (−16.22 nmol/L; 95% CI, −21.06, −11.39). Vitamin D deficiency in infants is ubiquitous, under-recognised, and strongly associated with season of birth and breastfeeding in this setting. Nutritional interventions with vitamin D supplementation in national health programs in low- and middle-income countries are urgently needed to improve early-life vitamin D status in infants. 相似文献
8.
Lisa J Frigati Katalin A Wilkinson Stanzi le Roux Karryn Brown Sheena Ruzive Leah Githinji Wonita Petersen Sabine Belard Mark F Cotton Landon Myer Heather J Zar 《Journal of the International AIDS Society》2021,24(3)
IntroductionThere are limited data on Tuberculosis (TB) in adolescents with perinatally acquired HIV (APHIV). We examined the incidence and determinants of TB infection and disease in the Cape Town Adolescent Antiretroviral Cohort (CTAAC).MethodsYouth between nine and fourteen years on antiretroviral therapy (ART) for more than six months in public sector care, and age‐matched HIV‐negative adolescents, were enrolled between July 2013 through March 2015 and followed six‐monthly. Data were censored on 31 October 2018. Symptom screening, chest radiograph, viral load, CD4 count, QuantiFERON (QFT) and sputum for Xpert MTB/RIF, microscopy, culture and sensitivity were performed annually. TB infection was defined by a QFT of >0.35 IU/mL. TB diagnosis was defined as confirmed (culture or Xpert MTB/RIF positive) or unconfirmed (clinical diagnosis and started on TB treatment). Analyses examined the incidence and determinants of TB infection and disease.ResultsOverall 496 HIV+ and 103 HIV‐negative participants (median age at enrolment 12 years (interquartile range, IQR 10.6 to 13.3) were followed for a median of 3.1 years (IQR 3.0 to 3.4); 50% (298/599) were male. APHIV initiated ART at median age 4.4 years (IQR 2.1 to 7.6). At enrolment, 376/496 (76%) had HIV viral load <40 copies/mL, median CD4 count was 713 cells/mm3 and 179/559 (32%) were QFT+, with no difference by HIV status (APHIV 154/468, 33%; HIV negative 25/91, 27%; p = 0.31). The cumulative QFT+ prevalence was similar (APHIV 225/492, 46%; 95%CI 41% to 50%; HIV negative 44/98, 45%; 95% CI 35% to 55%; p = 0.88). APHIV had a higher incidence of all TB disease than HIV‐negative adolescents (2.2/100PY, 95% CI 1.6 to 3.1 vs. 0.3/100PY, 95% CI 0.04 to 2.2; IRR 7.36, 95% CI 1.01 to 53.55). The rate of bacteriologically confirmed TB in APHIV was 1.3/100 PY compared to 0.3/100PY for HIV‐negative adolescents, suggesting a fourfold increased risk of developing TB disease in APHIV despite access to ART. In addition, a positive QFT at enrolment was not predictive of TB in this population.ConclusionsHigh incidence rates of TB disease occur in APHIV despite similar QFT conversion rates to HIV‐negative adolescents. Strategies to prevent TB in this vulnerable group must be strengthened. 相似文献
9.
A M Hartman C C Brown J Palmgren P Pietinen M Verkasalo D Myer J Virtamo 《American journal of epidemiology》1990,132(5):999-1012
The authors conducted a dietary methodology study in 1984 in Finnish men aged 55-69 years in order to validate two dietary assessment instruments being used in the US-Finland Alpha-Tocopherol, Beta-Carotene Lung Cancer Prevention Trial. Twelve 2-day food records collected from 162 men over a 6-month period, including every day of the week, served as the reference measure. This report focuses on three important questions for investigating diet and disease relations: 1) How many days are necessary to classify "usual" intake? 2) Is there loss as a result of using consecutive days? 3) Which days are necessary for assessment and classification of "usual" diet? A repeated-measures regression model was used to estimate the variance components and the effects of consecutive days, weekday (weekday vs. weekend), and season. Correlations between the averages of different numbers of days of food records and "true" usual intake were examined along with the resulting attenuations in relative risk. Results suggest that 7-14 days are required to adequately classify most individuals into categories of intake for most nutrients and some foods. There appears to be some loss of information from using consecutive days rather than days further apart. Weekday/weekend differences in mean intakes are slight, and the rank ordering of individuals appears to be preserved. A moderate seasonal effect is shown for classification of fruits, but only a slight one is seen for micronutrients and berries. Implications for the design of epidemiologic and validation studies are discussed. 相似文献
10.
Myer S. Leonard 《Australian dental journal》1995,40(3):159-163
This article reviews an eclectic collection of problems. There is no particular reason why any one of them was chosen other than that they are more likely to occur in the course of practice than some other complications such as an oro-antral fistula or trauma to the lingual nerve or tissue emphysema. These latter and some other predicaments were discussed in the course of the talks given by the author at the 28th Australian Dental Congress in March 1995. The problems discussed in this paper are:
- 1 1. Dentoalveolar abscess anaesthesia.
- 2 2. Inability to obtain effective anaesthesia.
- 2 1. Post-extraction haemorrhage.
- 2 2. Syncope.
- 3 3. Postoperative infection.