全文获取类型
收费全文 | 18379篇 |
免费 | 1370篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 99篇 |
儿科学 | 564篇 |
妇产科学 | 531篇 |
基础医学 | 2505篇 |
口腔科学 | 323篇 |
临床医学 | 2597篇 |
内科学 | 3359篇 |
皮肤病学 | 385篇 |
神经病学 | 1824篇 |
特种医学 | 350篇 |
外科学 | 1611篇 |
综合类 | 176篇 |
一般理论 | 38篇 |
预防医学 | 2371篇 |
眼科学 | 429篇 |
药学 | 1351篇 |
3篇 | |
中国医学 | 43篇 |
肿瘤学 | 1241篇 |
出版年
2024年 | 82篇 |
2023年 | 244篇 |
2022年 | 335篇 |
2021年 | 694篇 |
2020年 | 452篇 |
2019年 | 628篇 |
2018年 | 671篇 |
2017年 | 495篇 |
2016年 | 552篇 |
2015年 | 572篇 |
2014年 | 744篇 |
2013年 | 1055篇 |
2012年 | 1493篇 |
2011年 | 1472篇 |
2010年 | 829篇 |
2009年 | 675篇 |
2008年 | 1130篇 |
2007年 | 1156篇 |
2006年 | 1057篇 |
2005年 | 1050篇 |
2004年 | 922篇 |
2003年 | 878篇 |
2002年 | 733篇 |
2001年 | 103篇 |
2000年 | 72篇 |
1999年 | 95篇 |
1998年 | 145篇 |
1997年 | 125篇 |
1996年 | 111篇 |
1995年 | 95篇 |
1994年 | 83篇 |
1993年 | 94篇 |
1992年 | 54篇 |
1991年 | 49篇 |
1990年 | 39篇 |
1989年 | 30篇 |
1988年 | 41篇 |
1987年 | 41篇 |
1986年 | 34篇 |
1985年 | 37篇 |
1984年 | 46篇 |
1983年 | 44篇 |
1982年 | 48篇 |
1981年 | 45篇 |
1980年 | 53篇 |
1979年 | 22篇 |
1978年 | 32篇 |
1977年 | 29篇 |
1974年 | 20篇 |
1973年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
A realist qualitative study to explore how low‐income pregnant women use Healthy Start food vouchers
Heather Ohly Nicola Crossland Fiona Dykes Nicola Lowe Victoria Hall Moran 《Maternal & child nutrition》2019,15(1)
Healthy Start is the UK government's food voucher programme for low‐income pregnant women and young children. It was introduced in 2006, but the impact of the programme on nutritional outcomes remains understudied. This study sought to explore potential outcomes of the Healthy Start programme (including intended and unintended outcomes) and develop explanations for how and why these outcomes might occur. A realist review preceded this study, in which programme theories were developed and tested using existing evidence. This qualitative study aimed to further refine and consolidate the programme theories from the realist review while remaining open to new and emerging theories (or hypotheses) about how low‐income pregnant women use Healthy Start vouchers. Semistructured interviews were conducted with 11 low‐income women from North West England, who received Healthy Start vouchers during pregnancy. A realist logic of analysis was applied to generate clear and transparent linkages between outcomes and explanations. The findings suggested that some women used the vouchers to improve their diets during pregnancy (intended outcome), whereas some women were diverted towards alternative or unintended outcomes. Women's circumstances, values, beliefs, and motivations influenced how they perceived and responded to the vouchers. This paper presents four evidence‐based programme theories to explain four contrasting (and potentially overlapping) outcomes: dietary improvements (theory refined from review), shared benefits (new theory), financial assistance (theory refined from review), and stockpiling formula (new theory). It considers how the Healthy Start programme could be improved, to increase the possibilities for low‐income women to experience the intended outcome of dietary improvements. 相似文献
62.
Tim Du Kelly B. Choi Anada Silva George R. Golding Linda Pelude Romeo Hizon Ghada N. Al-Rawahi James Brooks Blanda Chow Jun C. Collet Jeannette L. Comeau Ian Davis Gerald A. Evans Charles Frenette Guanghong Han Jennie Johnstone Pamela Kibsey Kevin C. Katz Joanne M. Langley Bonita E. Lee Yves Longtin Dominik Mertz Jessica Minion Michelle Science Jocelyn A. Srigley Paula Stagg Kathryn N. Suh Nisha Thampi Alice Wong Susy S. Hota 《Emerging infectious diseases》2022,28(6):1128
We investigated epidemiologic and molecular characteristics of healthcare-associated (HA) and community-associated (CA) Clostridioides difficile infection (CDI) among adult patients in Canadian Nosocomial Infection Surveillance Program hospitals during 2015–2019. The study encompassed 18,455 CDI cases, 13,735 (74.4%) HA and 4,720 (25.6%) CA. During 2015–2019, HA CDI rates decreased by 23.8%, whereas CA decreased by 18.8%. HA CDI was significantly associated with increased 30-day all-cause mortality as compared with CA CDI (p<0.01). Of 2,506 isolates analyzed, the most common ribotypes (RTs) were RT027, RT106, RT014, and RT020. RT027 was more often associated with CDI-attributable death than was non-RT027, regardless of acquisition type. Overall resistance C. difficile rates were similar for all drugs tested except moxifloxacin. Adult HA and CA CDI rates have declined, coinciding with changes in prevalence of RT027 and RT106. Infection prevention and control and continued national surveillance are integral to clarifying CDI epidemiology, investigation, and control. 相似文献
63.
64.
Alessandro Dal Bosco Alice Cartoni Mancinelli Gaetano Vaudo Massimiliano Cavallo Cesare Castellini Simona Mattioli 《Nutrients》2022,14(15)
Chicken meat is becoming the most consumed in the world for both economic and nutritional reasons; regarding the latter, the lipid profile may play positive or negative roles in the prevention and treatment of diseases. In this study, we define the state of the art of lipid-based nutritional indexes and used the lipid content and fatty acid profile (both qualitative and quantitative) of breast meat of two poultry genotypes with different growth rates and meat traits. Further, we summarize and review the definitions, implications, and applications of nutritional indexes used in recent years and others of our own design to provide a useful tool to researchers working in the field of meat quality (not only in poultry) to select the most appropriate index for their own scientific purposes. All indexes show advantages and disadvantages; hence, a rational choice should be applied to consider the nutritional effect of meat on human health and for a possible assessment of the most suitable rearing systems (genotype, feeding, farming system or postmortem handling). 相似文献
65.
Infantile hypercalcemia type 1 (HCINF1), previously known as idiopathic infantile hypercalcemia, is caused by mutations in the 25-hydroxyvitamin D 24-hydroxylase gene, CYP24A1. The R396W loss-of-function mutation in CYP24A1 is the second most frequent mutated allele observed in affected HCINF1 patients. We have introduced the site-specific R396W mutation within the murine Cyp24a1 gene in knock-in mice to generate a humanized model of HCINF1. On the C57Bl6 inbred background, homozygous mutant mice exhibited high perinatal lethality with 17% survival past weaning. This was corrected by crossbreeding to the CD1 outbred background. Mutant animals had hypercalcemia in the first week of life, developed nephrolithiasis, and had a very high 25(OH)D3 to 24,25(OH)2D3 ratio which is a diagnostic hallmark of the HCINF1 condition. Expression of the mutant Cyp24a1 allele was highly elevated while Cyp27b1 expression was abrogated. Impaired bone fracture healing was detected in CD1-R396w/w mutant animals. The augmented lethality of the C57Bl6-R396W strain suggests an influence of distinct genetic backgrounds. Our data point to the utility of unique knock-in mice to probe the physiological ramifications of CYP24A1 variants in isolation from other biological and environmental factors. 相似文献
66.
67.
68.
69.
70.