全文获取类型
收费全文 | 460951篇 |
免费 | 36768篇 |
国内免费 | 11461篇 |
专业分类
耳鼻咽喉 | 5097篇 |
儿科学 | 10837篇 |
妇产科学 | 7790篇 |
基础医学 | 42801篇 |
口腔科学 | 12541篇 |
临床医学 | 49576篇 |
内科学 | 54229篇 |
皮肤病学 | 6128篇 |
神经病学 | 27511篇 |
特种医学 | 12098篇 |
外国民族医学 | 42篇 |
外科学 | 45952篇 |
综合类 | 70595篇 |
现状与发展 | 23篇 |
一般理论 | 32篇 |
预防医学 | 53920篇 |
眼科学 | 6928篇 |
药学 | 46106篇 |
529篇 | |
中国医学 | 37122篇 |
肿瘤学 | 19323篇 |
出版年
2023年 | 7522篇 |
2022年 | 11205篇 |
2021年 | 18326篇 |
2020年 | 18095篇 |
2019年 | 22884篇 |
2018年 | 20317篇 |
2017年 | 17777篇 |
2016年 | 15257篇 |
2015年 | 14760篇 |
2014年 | 28437篇 |
2013年 | 30819篇 |
2012年 | 26428篇 |
2011年 | 28509篇 |
2010年 | 22505篇 |
2009年 | 20993篇 |
2008年 | 20434篇 |
2007年 | 20917篇 |
2006年 | 18131篇 |
2005年 | 15833篇 |
2004年 | 12966篇 |
2003年 | 11425篇 |
2002年 | 8903篇 |
2001年 | 8072篇 |
2000年 | 6692篇 |
1999年 | 5691篇 |
1998年 | 4506篇 |
1997年 | 4186篇 |
1996年 | 3656篇 |
1995年 | 3728篇 |
1994年 | 3615篇 |
1993年 | 2857篇 |
1992年 | 2811篇 |
1991年 | 2407篇 |
1990年 | 2133篇 |
1989年 | 1933篇 |
1988年 | 1793篇 |
1987年 | 1571篇 |
1986年 | 1391篇 |
1985年 | 4242篇 |
1984年 | 5140篇 |
1983年 | 3545篇 |
1982年 | 4043篇 |
1981年 | 3741篇 |
1980年 | 3347篇 |
1979年 | 3046篇 |
1978年 | 2627篇 |
1977年 | 1976篇 |
1976年 | 2232篇 |
1975年 | 1666篇 |
1974年 | 1480篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
《Journal of the American Medical Directors Association》2022,23(10):1741.e1-1741.e18
ObjectiveThis study aimed to analyze national influenza infection control policy documents within aged care settings by identifying the consistencies, inconsistencies, and gaps with the current evidence and by evaluating methodological quality. Aged care providers can use these findings to identify their policy documents' strengths and weaknesses.DesignA quality and content analysis of national level policy documents.Setting and ParticipantsAged care settings rely on national agencies' policy recommendations to control and prevent outbreaks. There is limited research on the effectiveness of control measures to prevent and treat influenza within aged care settings. Because of the complexities around aged care governance, the primary responsibility in developing a comprehensive facility-level, infection-prevention policy, falls to the providers.MethodsThe analysis was conducted using the (1) International Appraisal of Guidelines, Research and Evaluation assessment tool, containing 23 items across 6 domains; and the (2) Influenza Related Control Measures in Aged Care settings checklist, developed by the authors, with 82 recommendations covering: medical interventions, nonmedical interventions, and physical layout.ResultsThere were 19 documents from 9 different high-income countries, with a moderately high methodological quality in general. The quality assessment's average score was 40.2% (95% CI 31.9%–44.7%). “Stakeholder involvement” ranked third, and “Editorial independence” and “Rigor of development” had the lowest average scores across all domains. The content analysis' average score was 37.2% (95% CI 10.5%–21.5%). The highest scoring document (59.1%) included term definitions, cited evidence for recommendations, and clear measurable instructions. “Physical Layout” had the least coverage and averaged 21.9% (95% CI 4.2%–37.5%), which shows a substantial gap in built environment recommendations.Conclusions and ImplicationsExisting policy documents vary in their comprehensiveness. The higher scoring documents provide an ideal model for providers. The checklist tools can be used to assess and enhance documents. Further research on document end-user evaluation would be useful, as there is room for improvement in methodological quality and coverage of recommendation coverage, especially related to physical layout. 相似文献
43.
《Journal of the Academy of Nutrition and Dietetics》2022,122(12):2288-2294
BackgroundDental caries is the most common chronic childhood disease. Past studies revealed that grandparents provide their grandchildren with cariogenic foods and beverages (eg, those with free sugars and/or modified starches). Qualitative research can help identify what drives this phenomenon.ObjectiveOur aim was to examine mothers’ explanations for why grandparents in north central and central Appalachia give their grandchildren cariogenic foods and beverages.DesignA qualitative study on children’s oral health in Pennsylvania and West Virginia from 2018 through 2020 was performed. In-person, semi-structured interviews were conducted. Qualitative data from interviews were recorded, transcribed, and then coded using NVivo. Data analysis for this study was performed using thematic analysis with iterative theme development.Participants/settingThe participants were 126 mothers of children aged 3-5 years from West Virginia (n = 66) and Pittsburgh, PA (n = 60).Main outcome measuresMothers’ perspectives about why grandparents give their grandchildren cariogenic foods and beverages were analyzed.ResultsIn the study sample, 85% of mothers (n = 107/126) named at least 1 of their children’s grandparents as a member of their social network responsible for their children’s oral health. From these interviews, 85% of mothers (n = 91/107) discussed that grandparents gave their grandchildren cariogenic foods and beverages. The mothers described the following 4 themes to explain why grandparents gave their grandchildren cariogenic foods and beverages: privilege of the grandparent role; responsibilities of the grandparent role; symbol of care and affection; and limited consideration or understanding of the detrimental impact.ConclusionsGrandparents play a role in giving their grandchildren cariogenic foods and beverages, which could potentially contribute to childhood caries. Research is needed to develop effective social interventions to help some grandparents understand the implications of a cariogenic diet on their grandchildren’s oral health and/or decrease their provision of cariogenic foods and beverages. 相似文献
44.
《Journal of vascular and interventional radiology : JVIR》2022,33(9):1073-1082.e2
PurposeTo create a nonsurgical animal model of osteoarthritis (OA) to evaluate the effects of embolotherapy during geniculate artery embolization (GAE).Materials and MethodsFluoroscopy-guided injections of 700 mg of sodium monoiodoacetate were performed into the left stifle in 6 rams. Kinematic data were collected before and after induction. At 10 weeks after induction, Subjects 1 and 4–6 underwent magnetic resonance (MR) imaging with dynamic contrast enhancement (DCE) and Subjects 1, 3, and 4–6 underwent angiography with angiographic scoring to identify regions with greatest disease severity for superselective embolization (75–250-μm microspheres). Target vessel size was measured. At 24 weeks after angiography, DCE-MR imaging, angiography, and euthanasia were performed, and bilateral stifles were harvested. Medial/lateral tibial and femoral condylar, patellar, and synovial samples were cut, preserved, decalcified, and scored using the Osteoarthritis Research Society International criteria. The stifle and synovium Whole-Organ Magnetic Resonance Imaging Score and Multicenter Osteoarthritis Study score were determined. The volume transfer constant (Ktrans) and extracellular volume fraction (ve) were calculated from DCE-MR imaging along the lateral synovial regions of interest.ResultsThe mean gross and microscopic pathological scores were elevated at 38 and 61, respectively. Mean synovitis score was elevated at 9.2. Mean pre-embolization and postembolization angiographic scores were 5 and 3.8, respectively. Mean superior, transverse, and inferior geniculate artery diameters were 3.1 mm ± 1.21, 2.0 mm ± 0.50, and 1.6 mm ± 0.41 mm, respectively. Mean pre-embolization and postembolization cartilage and synovitis scores were elevated at 35.13 and 73.3 and 5.5 and 9.2, respectively. The Ktrans/ve values of Subjects 4, 5, and 6 were elevated at 0.049/0.38, 0.074/0.53, and 0.065/0.51, respectively. Altered gait of the hind limb was observed in all subjects after induction, with reduced joint mobility. No skin necrosis or osteonecrosis was observed.ConclusionsA nonsurgical ovine animal knee OA model was created, which allowed the collection of angiographic, histopathological, MR imaging, and kinematic data to study the effects of GAE. 相似文献
45.
46.
47.
目的探讨白细胞介素37b重组蛋白(rmIL-37b)通过调节CD39/ATP轴抑制树突状细胞(DC)诱导类风湿性关节炎(RA)大鼠炎症反应的机制。方法将SD大鼠随机分为空白对照组(CTL)、CIA模型组、rmIL-37b 5μg/kg组、rmIL-37b 10μg/kg组,每组各10只。除了空白对照组外,其余大鼠采用含有卡介苗的完全弗氏佐剂和牛Ⅱ型胶原混合乳液免疫刺激,建立CIA模型。确定建模成功当天(D0),rmIL-37b组分别尾静脉注射5μg/kg、10μg/kg rmIL-37b;CTL组和CIA模型组注射相同体积的(1 ml/kg)生理盐水,连续给药15 d。免疫组化法检测滑膜组织Nod样受体蛋白3(NRPL3)炎症小体的表达,流式细胞术检测DC表型,另外试剂盒检测血清三磷酸腺苷(ATP)和免疫学指标。结果与CIA模型组相比,rmIL-37b 10μg/kg组大鼠足容积、AI值、NLRP3炎症小体表达量、血清ATP、IL-1β、IL-18、肿瘤坏死因子α(TNF-α)、抗Ⅱ型胶原抗体亚型(anti-ColⅡ-IgG、anti-ColⅡ-IgG2a)水平均降低,同时DC表面CD... 相似文献
48.
Corti器的感音过程容易受到内部结构属性变化的影响。外柱细胞血管舒张刺激磷蛋白缺失会减缓肌动蛋白丝的形成,从而产生听力延迟。本研究运用COMSOL建立三维有限元模型研究肌动蛋白缺失导致外柱细胞软化时,Corti器感音过程中基底膜和外毛细胞与Deiters细胞结合点的力学行为变化。结果表明,外柱细胞软化会削弱外毛细胞主动力对基底膜位移增益的放大作用,但削弱作用并不会立即产生,Corti器存在维持正常功能的"缓冲"阶段。在100 dB和120 dB之间可能存在一个声压级临界值,在该临界值两侧外柱细胞软化对基底膜应力变化的影响是截然相反的。另外外柱细胞软化对不同外毛细胞与Deiters细胞结合点力学行为的影响也不同,位移增益优先级会因此产生改变。 相似文献
49.
50.