全文获取类型
收费全文 | 1747篇 |
免费 | 128篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 44篇 |
妇产科学 | 42篇 |
基础医学 | 199篇 |
口腔科学 | 18篇 |
临床医学 | 158篇 |
内科学 | 383篇 |
皮肤病学 | 10篇 |
神经病学 | 163篇 |
特种医学 | 33篇 |
外科学 | 254篇 |
综合类 | 13篇 |
一般理论 | 4篇 |
预防医学 | 266篇 |
眼科学 | 34篇 |
药学 | 92篇 |
中国医学 | 1篇 |
肿瘤学 | 115篇 |
出版年
2024年 | 6篇 |
2023年 | 26篇 |
2022年 | 29篇 |
2021年 | 62篇 |
2020年 | 60篇 |
2019年 | 85篇 |
2018年 | 68篇 |
2017年 | 52篇 |
2016年 | 71篇 |
2015年 | 69篇 |
2014年 | 90篇 |
2013年 | 99篇 |
2012年 | 160篇 |
2011年 | 145篇 |
2010年 | 81篇 |
2009年 | 49篇 |
2008年 | 101篇 |
2007年 | 105篇 |
2006年 | 108篇 |
2005年 | 74篇 |
2004年 | 72篇 |
2003年 | 64篇 |
2002年 | 68篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1923年 | 3篇 |
1921年 | 2篇 |
排序方式: 共有1884条查询结果,搜索用时 15 毫秒
1.
2.
3.
Anisha Mahajan Jess Haines Alex Carriero Jaimie L. Hogan Jessica Yu Andrea C. Buchholz Alison M. Duncan Gerarda Darlington David W. L. Ma 《Nutrients》2022,14(10)
There is limited research on the intake of non-nutritive sweeteners (NNS) among preschool-aged children. Canada’s Food Guide suggests limiting intake of NNS for all population groups and Health Canada recommends that young children (<2 years) avoid consuming beverages containing NNS. The aim of this study was to investigate the frequency and type of non-nutritive sweetener (NNS) intake in preschool-aged children participating in the Guelph Family Health Study pilots. Parents (n = 78 families) completed 3-day food records (n = 112 children; n = 55 females, n = 57 males; 3.6 years ± 1.3). Nineteen children (17%) reported consumption of foods or beverages containing NNS. Food sources with NNS included: freezies, oral nutritional supplements, flavored water, carbonated drinks, sugar free jam and protein powder. The majority of NNS contained in these foods were identified as stevia leaf extract, acesulfame K, sucralose, monk fruit extract and aspartame. Future research should continue to study NNS intake patterns longitudinally in children and examine the association of NNS intake with diet quality and health outcomes. 相似文献
4.
Warren JE Silver RM Dalton J Nelson LT Branch DW Porter TF 《Obstetrics and gynecology》2007,110(3):619-624
OBJECTIVE: To estimate whether polymorphisms in the collagen 1Alpha1 gene (COL1Alpha1) and the transforming growth factor-beta gene (TGF-beta;1) are more common in women with cervical insufficiency than in those without the condition. METHODS: Medical, obstetric, and family histories and blood were obtained from women with (n=121) and those without (n=165) cervical insufficiency. DNA was extracted and purified by using commercial DNA isolation kits. Samples were analyzed for variants in two genes, the COL1A1 intron 1SP1 and TGF-beta Arg-25-Pro polymorphism, by using an allele-specific polymerase chain reaction assay. RESULTS: Thirty-four of 125 (27.2%) women with cervical insufficiency had at least one first-degree female relative affected. The frequency of the homozygous TT genotype in the COL1A1 gene was increased in women with a history of cervical insufficiency compared with controls (10.8% compared with 3.1%, P=.04). The TGF-beta polymorphisms (ArgPro and ProPro) also were increased in cases (38.3% compared with 14.6%, P<.001). CONCLUSION: Over one fourth of women with cervical insufficiency have a family history of cervical insufficiency, and the COL1A1 intron 1SP1 and TGF-beta Arg-25-Pro polymorphisms are associated with the condition. These observations suggest that, in part, cervical insufficiency is mediated by genetic factors. LEVEL OF EVIDENCE: II. 相似文献
5.
6.
Adri Ramírez Mena Ndeye Fatou Ngom Judicaël Tine Kine Ndiaye Louise Fortes Ousseynou Ndiaye Maguette Fall Assietou Gaye Daye Ka Moussa Seydi Gilles Wandeler 《Viruses》2022,14(8)
Hepatitis B virus (HBV) infection is the first cause of liver cirrhosis and cancer in West Africa. Although the exposure to additional environmental and infectious risk factors may lead to the faster progression of liver disease, few large-scale studies have evaluated the determinants of HBV-related liver fibrosis in the region. We used transient elastography to evaluate the prevalence of liver fibrosis and assessed the association between HBV markers and significant liver fibrosis in a cohort of people living with HBV in Dakar, Senegal. The prevalence of significant liver fibrosis was 12.5% (95% confidence interval [CI] 9.6%–15.9%) among 471 people with HBV mono-infection (pwHBV) and 6.4% (95% CI 2.6%–12.7%) in 110 people with HIV/HBV co-infection (pwHIV/HBV) on tenofovir-containing antiretroviral therapy (p = 0.07). An HBV viral load > 2000 IU/mL was found in 133 (28.3%) pwHBV and 5 (4.7%) pwHIV/HBV, and was associated with significant liver fibrosis (adjusted odds ratio (aOR) 1.95, 95% CI 1.04–3.66). Male participants (aOR 4.32, 95% CI 2.01–8.96) and those with elevated ALT (aOR 4.32, 95% CI 2.01–8.96) were especially at risk of having significant liver fibrosis. Our study shows that people with an HBV viral load above 2000 IU/mL have a two-fold increase in the risk of liver fibrosis and may have to be considered for antiviral therapy, independent of other disease parameters. 相似文献
7.
8.
9.
10.