全文获取类型
收费全文 | 203743篇 |
免费 | 18231篇 |
国内免费 | 1738篇 |
专业分类
耳鼻咽喉 | 682篇 |
儿科学 | 5513篇 |
妇产科学 | 5959篇 |
基础医学 | 15624篇 |
口腔科学 | 4030篇 |
临床医学 | 17728篇 |
内科学 | 35391篇 |
皮肤病学 | 2069篇 |
神经病学 | 12988篇 |
特种医学 | 4757篇 |
外国民族医学 | 3篇 |
外科学 | 16042篇 |
综合类 | 8246篇 |
现状与发展 | 19篇 |
一般理论 | 70篇 |
预防医学 | 68371篇 |
眼科学 | 1994篇 |
药学 | 10763篇 |
58篇 | |
中国医学 | 424篇 |
肿瘤学 | 12981篇 |
出版年
2024年 | 375篇 |
2023年 | 7971篇 |
2022年 | 12012篇 |
2021年 | 12241篇 |
2020年 | 12896篇 |
2019年 | 8716篇 |
2018年 | 9326篇 |
2017年 | 9726篇 |
2016年 | 9692篇 |
2015年 | 9185篇 |
2014年 | 15195篇 |
2013年 | 13491篇 |
2012年 | 11022篇 |
2011年 | 10707篇 |
2010年 | 10354篇 |
2009年 | 8907篇 |
2008年 | 6850篇 |
2007年 | 6974篇 |
2006年 | 5806篇 |
2005年 | 4805篇 |
2004年 | 4085篇 |
2003年 | 3753篇 |
2002年 | 3589篇 |
2001年 | 3238篇 |
2000年 | 2857篇 |
1999年 | 2688篇 |
1998年 | 1537篇 |
1997年 | 1341篇 |
1996年 | 1316篇 |
1995年 | 1109篇 |
1994年 | 943篇 |
1993年 | 771篇 |
1992年 | 1328篇 |
1991年 | 1323篇 |
1990年 | 1160篇 |
1989年 | 954篇 |
1988年 | 1014篇 |
1987年 | 583篇 |
1986年 | 391篇 |
1985年 | 303篇 |
1984年 | 383篇 |
1983年 | 278篇 |
1982年 | 268篇 |
1981年 | 265篇 |
1980年 | 208篇 |
1979年 | 142篇 |
1978年 | 163篇 |
1977年 | 136篇 |
1976年 | 138篇 |
1974年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Journal of the Academy of Nutrition and Dietetics》2022,122(11):2060-2071
BackgroundVoices for Food was a longitudinal community, food pantry–based intervention informed by the social ecological model, and designed to improve food security, dietary intake, and quality among clients, which was carried out in 24 rural food pantries across 6 Midwestern states.ObjectiveOur objective was to evaluate changes in adult food security, dietary intake, and quality from baseline (2014) to follow-up (2016), and to assess the role of adult food security on dietary outcomes.DesignA multistate, longitudinal, quasi-experimental intervention with matched treatment and comparison design was used to evaluate treatment vs comparison group changes over time and changes in both groups over time.Participants/settingAdult food pantry clients (n = 617) completed a demographic food security survey, and up to three 24-hour dietary recalls at baseline (n = 590) and follow-up (n = 160).InterventionCommunity coaching served as the experimental component, which only “treatment” communities received, and a food council guide and food pantry toolkit were provided to both “treatment” and matched “comparison” communities.Main outcome measuresChange in adult food security status, mean usual intakes of nutrients and food groups, and Healthy Eating Index-2010 scores were the main outcome measures.Statistical analyses performedLinear mixed models estimated changes in outcomes by intervention group and by adult food security status over time.ResultsImprovements in adult food security score (–0.7 ± 0.3; P = .01), Healthy Eating Index-2010 total score (4.2 ± 1.1; P < .0001), and empty calories component score (3.4 ± 0.5; P <.0001) from baseline to follow-up were observed in treatment and comparison groups, but no statistically significant changes were found for adult food security status, dietary quality, and usual intakes of nutrients and food groups between the 2 groups over time. The intervention effect on dietary quality and usual intake changes over time by adult food security status were also not observed.ConclusionsFood pantry clients in treatment and comparison groups had higher food security and dietary quality at the follow-up evaluation of the Voices for Food intervention trial compared with baseline, despite the lack of difference among the groups as a result of the experimental coaching component. 相似文献
2.
《Health Policy and Technology》2022,11(2):100574
Objective: Since the COVID-19 pandemic, many governments globally have introduced policy measures to contain the spread of the virus. Popular COVID-19 containment measures include lockdowns of various forms (aggregated into government response stringency index [GRSI]) and handwashing (HWF). The effectiveness of these policy measures remains unclear in the academic literature. This study, therefore, examines the effect of government policy stringency and handwashing on total daily reported COVID-19 cases.Method: We use a comprehensive dataset of 176 countries to investigate the effect of government policy stringency and handwashing on daily reported COVID-19 cases. In this study, we apply the Lewbel (2012) two-stage least squares technique to control endogeneity.Results: Our results indicated that GRSI significantly contributes to the increase in the total and new confirmed cases of COVI-19. Sensitivity analyses revealed that the 1st, 4th, and 5th quintiles of GRIS significantly reduce total confirmed cases of COVID-19. Also, the result indicated that while the 1st quintile of GRIS contributes significantly to reducing the new confirmed cases of COVID-19, the 3rd, 4th, and 5th quintiles of GRSI contribute significantly to increasing the new confirmed cases of COVID-19. The results indicated that HWF reduces total and new confirmed cases of COVID-19; however, such effect is not robust to income and regional effects. Nonlinear analysis revealed that while GRSI has an inverted U-shaped relationship with total and new confirmed cases of COVID-19, HWF has a U-shaped relationship.Conclusion: We suggest that policymakers should focus on raising awareness and full engagement of all members of society in implementing public health policies rather than using stringent lockdown measures. 相似文献
3.
4.
《The Canadian journal of cardiology》2022,38(10):1558-1566
BackgroundThe increasing availability of large electronic population-based databases offers unique opportunities to conduct cardiovascular health surveillance traditionally done using surveys. We aimed to examine cardiovascular risk-factor burden, preventive care, and disease incidence among adults in Ontario, Canada—using routinely collected data—and compare estimates with health survey data.MethodsIn the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) initiative, multiple health administrative databases were linked to create a population-based cohort of 10.3 million adults without histories of cardiovascular disease. We examined cardiovascular risk-factor burden and screening and outcomes between 2016 and 2020. Risk- factor burden was also compared with cycles 3 to 5 (2012 to 2017) of the Canadian Health Measures Survey (CMHS), which included 9473 participants across Canada.ResultsMean age of our study cohort was 47.9 ± 17.0 years, and 52.0% were women. Lipid and diabetes assessment rates among individuals 40 to 79 years were 76.6% and 78.2%, respectively, and lowest among men 40 to 49 years of age. Total cholesterol levels and diabetes and hypertension rates among men and women 20 to 79 years were similar to Canadian Health Measures Survey (CHMS) findings (total cholesterol: 4.80/4.98 vs 4.94/5.25 mmol/L; diabetes: 8.2%/7.1% vs 8.1%/6.0%; hypertension: 21.4%/21.6% vs 23.9%/23.1%, respectively); however, patients in the CANHEART study had slightly higher mean glucose (men: 5.79 vs 5.44; women: 5.39 vs 5.09 mmol/L) and systolic blood pressures (men: 126.2 vs 118.3; women: 120.6 vs 115.7 mm Hg).ConclusionsCardiovascular health surveillance is possible through linkage of routinely collected electronic population-based datasets. However, further investigation is needed to understand differences between health administrative and survey measures cross-sectionally and over time. 相似文献
5.
BackgroundProximal tibia vara has drawn interest since the concept of constitutional varus was introduced. Proximal tibia vara is a condition where the knee varus tilt the tibia condyle medially and shift the tibial articular surface medially. This condition affects medial proximal tibial angle measurements and the placement of the tibial implant in knee replacement surgery. Thus, it challenged the neutral knee arthroplasty alignment target because some people may present a proximal tibia vara. This study assesses the prevalence of the proximal tibia vara and the correlation to knee osteoarthritis grade.MethodsThis retrospective study was carried out from January 2021 to June 2021. Eighty-five limbs were included with the following inclusion criteria: knee osteoarthritis patients who received a long view lower extremity radiograph. The exclusions criteria were (1) patients who had undergone arthroplasty and lower extremity surgery before and (2) valgus knee deformity. The outcomes in this study were HKAA, MAD, TAD, MPTA, PTRP, LDFA, and PTS. Intraclass correlation (ICC) using two-way mixed was used to assess the reproducibility of the radiographic parameters. Multiple logistic regression was used to evaluate the correlation between knee osteoarthritis grade and radiographs parameters (MAD and TAD).ResultA total 85 limbs from 52 patients were assessed in this study. Proximal tibia vara was found in 18 knees (21%.). The logistic regression was performed to assess the correlation between the severity of the knee osteoarthritis and radiographic parameters (MAD, TAD, LDFA, and PTS) with an overall p-value < 0.001 and pseudo-R2 = 0.29.ConclusionA significant portion of patients with knee osteoarthritis have proximal tibia vara, and it is a pre-existing condition. Since the pre-existing proximal tibia vara affects preoperative measurements, a long-standing lower extremity x-ray is recommended to be obtained as part of knee replacement preparation. 相似文献
6.
《The Journal of heart and lung transplantation》2022,41(12):1660-1671
- Download : Download high-res image (173KB)
- Download : Download full-size image
7.
8.
9.
10.
A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system. 相似文献