全文获取类型
收费全文 | 253248篇 |
免费 | 21741篇 |
国内免费 | 8085篇 |
专业分类
耳鼻咽喉 | 1652篇 |
儿科学 | 4569篇 |
妇产科学 | 2778篇 |
基础医学 | 28902篇 |
口腔科学 | 3802篇 |
临床医学 | 21663篇 |
内科学 | 30635篇 |
皮肤病学 | 2834篇 |
神经病学 | 9814篇 |
特种医学 | 5178篇 |
外国民族医学 | 28篇 |
外科学 | 20568篇 |
综合类 | 49177篇 |
现状与发展 | 18篇 |
一般理论 | 34篇 |
预防医学 | 21102篇 |
眼科学 | 4896篇 |
药学 | 24860篇 |
144篇 | |
中国医学 | 33555篇 |
肿瘤学 | 16865篇 |
出版年
2024年 | 948篇 |
2023年 | 3554篇 |
2022年 | 7195篇 |
2021年 | 9650篇 |
2020年 | 8737篇 |
2019年 | 9730篇 |
2018年 | 8909篇 |
2017年 | 8700篇 |
2016年 | 8177篇 |
2015年 | 8121篇 |
2014年 | 15369篇 |
2013年 | 15123篇 |
2012年 | 14898篇 |
2011年 | 16285篇 |
2010年 | 13893篇 |
2009年 | 12527篇 |
2008年 | 11638篇 |
2007年 | 12859篇 |
2006年 | 11345篇 |
2005年 | 10567篇 |
2004年 | 9013篇 |
2003年 | 7931篇 |
2002年 | 5921篇 |
2001年 | 5696篇 |
2000年 | 4669篇 |
1999年 | 4150篇 |
1998年 | 2936篇 |
1997年 | 2655篇 |
1996年 | 2633篇 |
1995年 | 2472篇 |
1994年 | 2172篇 |
1993年 | 1868篇 |
1992年 | 1605篇 |
1991年 | 1422篇 |
1990年 | 1149篇 |
1989年 | 1080篇 |
1988年 | 1016篇 |
1987年 | 793篇 |
1986年 | 594篇 |
1985年 | 1494篇 |
1984年 | 2014篇 |
1983年 | 1476篇 |
1982年 | 1575篇 |
1981年 | 1503篇 |
1980年 | 1299篇 |
1979年 | 1143篇 |
1978年 | 907篇 |
1977年 | 663篇 |
1976年 | 860篇 |
1975年 | 701篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
133.
134.
《Vaccine》2020,38(39):6141-6152
Influenza vaccination is considered the most valuable means to prevent and control seasonal influenza infections, which causes various clinical symptoms, ranging from mild cough and fever to even death. Among various influenza vaccine types, the inactivated subunit type is known to provide improved safety with reduced reactogenicity. However, there are some drawbacks associated with inactivated subunit type vaccines, with the main ones being its low immunogenicity and the induction of Th2-biased immune responses. In this study, we investigated the role of a single-stranded RNA (ssRNA) derived from the intergenic region in the internal ribosome entry site of the Cricket paralysis virus as an adjuvant rather than the universal vaccine for a seasonal inactivated subunit influenza vaccine. The ssRNA adjuvant stimulated not only well-balanced cellular (indicated by IgG2a, IFN-γ, IL-2, and TNF-α) and humoral (indicated by IgG1 and IL-4) immune responses but also a mucosal immune response (indicated by IgA), a key protector against respiratory virus infections. It also increases the HI titer, the surrogate marker of influenza vaccine efficacy. Furthermore, ssRNA adjuvant confers cross-protective immune responses against heterologous influenza virus infection while promoting enhanced viral clearance. Moreover, ssRNA adjuvant increases the number of memory CD4+ and CD8+ T cells, which can be expected to induce long-term immune responses. Therefore, this ssRNA-adjuvanted seasonal inactivated subunit influenza vaccine might be the best influenza vaccine generating robust humoral and cellular immune responses and conferring cross-protective and long-term immunity. 相似文献
135.
C. Knipfer F. Wagner K. Knipfer G. Millesi J. Acero J.A. Hueto E. Nkenke 《International journal of oral and maxillofacial surgery》2019,48(6):841-846
The aim of this study was to evaluate learners’ acceptance of a webinar for continuing medical education that was instigated by the International Association of Oral and Maxillofacial Surgeons (IAOMS). A live, interactive webinar on orthognathic surgery was broadcast via the Internet. The learners’ acceptance of the webinar was evaluated using a standardized, validated questionnaire (Student Evaluation of Educational Quality, SEEQ). One hundred and fifty-three participants attended the webinar; 55 participants (46 male, nine female) completed the questionnaire. The mean age of the respondents was 41.6 ± 10.0 years. The age of male and female respondents did not differ significantly. The respondents were spread over five continents, with the highest number from Brazil. The SEEQ showed a high level of acceptance for almost all subscales. There was no statistically significant difference between male and female respondents concerning acceptance of the webinar (P = 0.614). The wide distribution of participants shows the potential for webinars as facilitators of barrier-free distribution of knowledge. The webinar was well accepted by the attendees independent of sex, specialty, and work experience. However, the sex ratio reflects the underrepresentation of women in oral and maxillofacial surgery. 相似文献
136.
Anand Dayama Nikolaos Tsilimparis Stephen Kolakowski Nathaniel M. Matolo Misty D. Humphries 《Journal of vascular surgery》2019,69(1):156-163.e1
Background
Chronic limb-threatening ischemia (CLTI), defined as ischemic rest pain or tissue loss secondary to arterial insufficiency, is caused by multilevel arterial disease with frequent, severe infrageniculate disease. The rise in CLTI is in part the result of increasing worldwide prevalence of diabetes, renal insufficiency, and advanced aging of the population. The aim of this study was to compare a bypass-first with an endovascular-first revascularization strategy in patients with CLTI due to infrageniculate arterial disease.Methods
We reviewed the American College of Surgeons National Surgical Quality Improvement Program targeted lower extremity revascularization database from 2012 to 2015 to identify patients with CLTI and isolated infrageniculate arterial disease who underwent primary infrageniculate bypass or endovascular intervention. We excluded patients with a history of ipsilateral revascularization and proximal interventions. The end points were major adverse limb event (MALE), major adverse cardiovascular event (MACE), amputation at 30 days, reintervention, patency, and mortality. Multivariable logistic regression was used to determine the association of a bypass-first or an endovascular-first intervention with outcomes.Results
There were 1355 CLTI patients undergoing first-time revascularization to the infrageniculate arteries (821 endovascular-first revascularizations and 534 bypass-first revascularizations) identified. There was no significant difference in adjusted rate of 30-day MALE in the bypass-first vs endovascular-first revascularization cohort (9% vs 11.2%; odds ratio [OR], 0.73; 95% confidence interval [CI], 0.50-1.08). However, the incidence of transtibial or proximal amputation was lower in the bypass-first cohort (4.3% vs 7.4%; OR, 0.60; CI, 0.36-0.98). Patients with bypass-first revascularization had higher wound complication rates (9.7% vs 3.7%; OR, 2.75; CI, 1.71-4.42) compared with patients in the endovascular-first cohort. Compared with the endovascular-first cohort, the incidence of 30-day MACE was significantly higher in bypass-first patients (6.9% vs 2.6%; adjusted OR, 3.88; CI, 2.18-6.88), and 30-day mortality rates were 3.23% vs 1.8% (adjusted OR, 2.77; CI, 1.26-6.11). There was no difference in 30-day untreated loss of patency, reintervention of treated arterial segment, readmissions, and reoperations between the two cohorts. In subgroup analysis after exclusion of dialysis patients, there was also no significant difference in MALE or amputation between the bypass-first and endovascular-first cohorts.Conclusions
CLTI patients with isolated infrageniculate arterial disease treated by a bypass-first approach have a significantly lower 30-day amputation. However, this benefit was not observed when dialysis patients were excluded. The bypass-first cohort had a higher incidence of MACE compared with an endovascular-first strategy. These results reaffirm the need for randomized controlled trials, such as the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL-2) trial and Best Endovascular vs Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI), to provide level 1 evidence for the role of endovascular-first vs bypass-first revascularization strategies in the treatment of this population of challenging patients. 相似文献137.
目的:运用中医传承辅助平台系统(V2.5)深入分析王树声教授治疗上尿路结石的用药经验,挖掘其核心经验 方组成和辨证用药规律。方法:收集王教授门诊治疗上尿路结石的治疗验方304 首,将方药信息录入系统,采用药物频次统计、 关联规则分析和熵聚类分析等方法分析处方用药规律。结果:304 首处方中涉及中药97 味,用药频次超过100 次的有14 味。所用药物药性多寒、温、平,药味多甘、苦,主归肝、肾、脾经;共得出25 组核心组合和9 首新处方。结论:王教授治疗 上尿路结石以益气固本、清热通淋为主,用药的关键在于“扶正固本”的把握和“祛邪通淋”的权衡,为临证用药和新方 开发提供参考。 相似文献
138.
《Arquivos brasileiros de cardiologia》2020,115(2):207
BackgroundTakotsubo syndrome (TTS) is an acquired form of cardiomyopathy. National Brazilian data on this condition are scarce. The Takotsubo Multicenter Registry (REMUTA) is the first to include multicenter data on this condition in Brazil.ObjectiveTo describe the clinical characteristics, prognosis, in-hospital treatment, in-hospital mortality, and mortality during 1 year of follow-up.MethodsThis is an observational, retrospective registry study including patients admitted to the hospital with diagnosis of TTS and patients admitted for other reasons who developed this condition. Evaluated outcomes included triggering factor, analysis of exams, use of medications, complications, in-hospital mortality, and mortality during 1 year of follow-up. A significance level of 5% was adopted.ResultsThe registry included 169 patients from 12 centers in the state of Rio de Janeiro, Brazil. Mean age was 70.9 ± 14.1 years, and 90.5% of patients were female; 63% of cases were primary TTS, and 37% were secondary. Troponin I was positive in 92.5% of patients, and median BNP was 395 (176.5; 1725). ST-segment elevation was present in 28% of patients. Median left ventricular ejection fraction was 40 (35; 48)%. We observed invasive mechanical ventilation in 25.7% of cases and shock in 17.4%. Mechanical circulatory support was used in 7.7%. In-hospital mortality was 10.6%, and mortality at 1 year of follow-up was 16.5%. Secondary TTS and cardiogenic shock were independent predictors of mortality.ConclusionThe results of the REMUTA show that TTS is not a benign pathology, as was once thought, especially regarding the secondary TTS group, which has a high rate of complications and mortality. (Arq Bras Cardiol. 2020; 115(2):207-216) 相似文献
139.
《Alzheimer's & dementia》2019,15(12):1507-1515
IntroductionWe estimated the prevalence and correlates of mild cognitive impairment (MCI) among middle-aged and older diverse Hispanics/Latinos.MethodsMiddle-aged and older diverse Hispanics/Latinos enrolled (n = 6377; 50–86 years) in this multisite prospective cohort study were evaluated for MCI using the National Institute on Aging–Alzheimer's Association diagnostic criteria.ResultsThe overall MCI prevalence was 9.8%, which varied between Hispanic/Latino groups. Older age, high cardiovascular disease (CVD) risk, and elevated depressive symptoms were significant correlates of MCI prevalence. Apolipoprotein E4 (APOE) and APOE2 were not significantly associated with MCI.DiscussionMCI prevalence varied among Hispanic/Latino backgrounds, but not as widely as reported in the previous studies. CVD risk and depressive symptoms were associated with increased MCI, whereas APOE4 was not, suggesting alternative etiologies for MCI among diverse Hispanics/Latinos. Our findings suggest that mitigating CVD risk factors may offer important pathways to understanding and reducing MCI and possibly dementia among diverse Hispanics/Latinos. 相似文献
140.