全文获取类型
收费全文 | 11540篇 |
免费 | 456篇 |
国内免费 | 170篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 327篇 |
妇产科学 | 165篇 |
基础医学 | 796篇 |
口腔科学 | 151篇 |
临床医学 | 1264篇 |
内科学 | 1818篇 |
皮肤病学 | 152篇 |
神经病学 | 198篇 |
特种医学 | 306篇 |
外科学 | 1676篇 |
综合类 | 1771篇 |
预防医学 | 2392篇 |
眼科学 | 32篇 |
药学 | 781篇 |
8篇 | |
中国医学 | 112篇 |
肿瘤学 | 142篇 |
出版年
2024年 | 6篇 |
2023年 | 146篇 |
2022年 | 312篇 |
2021年 | 404篇 |
2020年 | 482篇 |
2019年 | 348篇 |
2018年 | 349篇 |
2017年 | 349篇 |
2016年 | 313篇 |
2015年 | 412篇 |
2014年 | 959篇 |
2013年 | 875篇 |
2012年 | 964篇 |
2011年 | 896篇 |
2010年 | 671篇 |
2009年 | 543篇 |
2008年 | 533篇 |
2007年 | 522篇 |
2006年 | 494篇 |
2005年 | 421篇 |
2004年 | 337篇 |
2003年 | 300篇 |
2002年 | 192篇 |
2001年 | 177篇 |
2000年 | 169篇 |
1999年 | 127篇 |
1998年 | 108篇 |
1997年 | 111篇 |
1996年 | 66篇 |
1995年 | 74篇 |
1994年 | 61篇 |
1993年 | 56篇 |
1992年 | 62篇 |
1991年 | 34篇 |
1990年 | 48篇 |
1989年 | 25篇 |
1988年 | 20篇 |
1987年 | 15篇 |
1986年 | 15篇 |
1985年 | 31篇 |
1984年 | 23篇 |
1983年 | 13篇 |
1982年 | 25篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
《Vaccine》2022,40(22):3027-3037
BackgroundDuring the first half of 2021, we observed high vaccine effectiveness (VE) against SARS-CoV2-infection. The replacement of the alpha-‘variant of concern’ (VOC) by the delta-VOC and uncertainty about the time course of immunity called for a re-assessment.MethodsWe estimated VE against transmission of infection (VET) from Belgian contact tracing data for high-risk exposure contacts between 26/01/2021 and 14/12/2021 by susceptibility (VEs) and infectiousness of breakthrough cases (VEi) for a complete schedule of Ad26.COV2.S, ChAdOx1, BNT162b2, mRNA-1273 as well as infection-acquired and hybrid immunity. We used a multilevel Bayesian model and adjusted for personal characteristics (age, sex, household), background exposure, calendar week, VOC and time since immunity conferring-event.FindingsVET-estimates were higher for mRNA-vaccines, over 90%, compared to viral vector vaccines: 66% and 80% for Ad26COV2.S and ChAdOx1 respectively (Alpha, 0–50 days after vaccination). Delta was associated with a 40% increase in odds of transmission and a decrease of VEs (72–64%) and especially of VEi (71–46% for BNT162b2). Infection-acquired and hybrid immunity were less affected by Delta. Waning further reduced VET-estimates: from 81% to 63% for BNT162b2 (Delta, 150–200 days after vaccination). We observed lower initial VEi in the age group 65–84 years (32% vs 46% in the age group 45–64 years for BNT162b2) and faster waning. Hybrid immunity waned slower than vaccine-induced immunity.InterpretationVEi and VEs-estimates, while remaining significant, were reduced by Delta and waned over time. We observed faster waning in the oldest age group. We should seek to improve vaccine-induced protection in older persons and those vaccinated with viral-vector vaccines. 相似文献
5.
幽门螺杆菌(HP)是革兰阴性微需氧的螺旋样杆菌,主要通过口-口途径在人-人之间感染传播。HP的发现加深了人类对慢性感染、炎症和癌症之间关系的认识。其特定的螺旋形体型、鞭毛及动力、尿素酶和黏附素活性,以及细胞毒素基因A(cagA)、空泡细胞毒素基因A(vacA)等是影响HP感染研究较多的相关致病因素。HP感染在胃癌的发生、发展中可能具有重要作用,但尚未确切证实HP感染是导致胃癌的主因。文章概述了HP感染相关致病因素的研究进展。 相似文献
6.
目的本研究分析舒巴坦治疗老年心力衰竭患者肺部感染的临床效果及不良反应发生情况,为临床治疗提供参考。方法160例老年心力衰竭肺部感染患者为研究对象,分为两组:对照组(n=80)患者在常规治疗的基础上采用头孢曲松钠治疗,观察组(n=80)患者在常规治疗的基础上采用头孢哌酮钠舒巴坦治疗。分析两组患者的细菌清除率、治疗前后心功能和肺功能的改善及不良反应的发生情况。结果观察组患者在细菌清除率明显高于对照组患者的细菌清除率(对照组vs观察组=84.35%vs 87.92%,χ2=5.654,P<0.05);两组患者治疗后心功参数LVEDD、LVESD、LVEF和肺功参数用力呼气容积和用力肺活量均得到显著的改善(P<0.05),且与对照组相比,观察组患者的上述指标改善显著(P<0.05);两组研究对象的不良反应包括凝血功能障碍、肝功能障碍、轻度皮疹和呕吐。结论舒巴坦治疗老年心力衰竭患者肺部感染安全性高,且临床疗效值得认可,可在临床推广应用。 相似文献
7.
8.
《Journal of infection and chemotherapy》2022,28(11):1578-1581
IntroductionLong-term care hospitals (LTCHs) are at a high risk for the inflow and spread of antimicrobial resistance (AMR) pathogens. However, owing to limited laboratory resources, little is known about the extent to which AMR organisms are endemic.MethodsWe performed active surveillance for carbapenem-resistant Enterobacteriaceae (CRE) and extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) in newly admitted patients at Marugame Medical Center, a nearly 200-bedded LTCH located in Kagawa, Japan. From August to December 2021, we tested stool samples from patients wearing diapers and confirmed the genetic variants using specific PCR assays. We also collected clinical variables and compared them between AMR carriers and non-carriers.ResultsStool samples were collected from 75 patients, with a median age of 84 years. CRE strain was not detected, but 37 strains of ESBL-E were isolated from 32 patients (42.7%). During the study period, 4.9% of in-hospital patients (37 per 756 patients) were identified to be ESBL-E carriers in the routine microbiological processing, suggesting that active surveillance detected approximately 9-fold more ESBL-E carriers. The blaCTX-M-9 group was the most common (38.5%), followed by the blaTEM (26.9%). The clinical backgrounds of the ESBL-E non-carriers and carriers were not significantly different.ConclusionOur active screening demonstrated that nearly half of the patients hospitalized or transferred to a Japanese LTCH were colonized with ESBL-E. We highlight the enforcement of universal basic infection prevention techniques at LTCHs where patients carrying AMR pathogens gather. 相似文献
9.
Ceder H. van den Bosch J. Tjomme van der Bruggen Florine N.J. Frakking Cecilia E.J. Terwisscha van Scheltinga Cornelis P. van de Ven Martine van Grotel Lianne M. Wellens Yvette G.T. Loeffen Marta Fiocco Marc H.W.A. Wijnen 《Journal of pediatric surgery》2019,54(9):1894-1900
BackgroundCentral venous access device (CVAD)-related complications are associated with high morbidity rates. This study was performed to underline the importance of CVAD-complication prevention and treatment.MethodsAn audit of practice of CVAD-related complications in pediatric oncology patients receiving a CVAD between January 2015 and June 2017 was performed. CVADs included were totally implantable venous access ports (TIVAPs), Hickman–Broviac® (HB), nontunneled, and peripherally inserted CVADs.ResultsA total of 201 children, with 307 CVADs, were analyzed. The incidence rates per 1000 CVAD-days for the most common complications were 1.66 for malfunctions, and 1.51 for central line-associated bloodstream infections (CLABSIs). Of all CVADs inserted, 37.1% were removed owing to complications, of which 45.6% were owing to CLABSIs. In 42% of the CLABSIs, the CLABSI could be successfully cured with systemic antibiotic treatment only. Of all included patients, 5.0% were admitted to the intensive care unit owing to CLABSI. The HB-CVAD compared to the TIVAP was a risk factor for CVAD-related complications, CLABSIs and dislocations in particular.ConclusionsThe incidence of CVAD-related complications is high. Research on the prevention and treatment of CVAD-related complications in pediatric oncology patients should be a high priority for all health care professionals.Type of studyPrognosis study (retrospective).Level of evidenceLevel II. 相似文献
10.
Andrea Kahlberg Alessandro Grandi Diletta Loschi Frank Vermassen Nathalie Moreels Nabil Chakfé Germano Melissano Roberto Chiesa 《Journal of vascular surgery》2019,69(6):1941-1951.e1
ObjectiveThe objective of this study was to collect and critically analyze the current evidence on the modalities and results of treatment of descending thoracic aortic surgical graft (SG) and endograft (EG) infection, which represents a rare but dramatic complication after both surgical and endovascular aortic repair.MethodsA comprehensive electronic health database search (PubMed/MEDLINE, Scopus, Google Scholar, and the Cochrane Library) identified all articles that were published up to October 2017 reporting on thoracic aortic SG or EG infection. Observational studies, multicenter reports, single-center series and case reports, case-control studies, and guidelines were considered eligible if reporting specific results of treatment of descending thoracic aortic SG or EG infection. Comparisons of patients presenting with SG or EG infection and between invasive and conservative treatment were performed. Odds ratio (OR) meta-analyses were run when comparative data were available.ResultsForty-three studies reporting on 233 patients with infected SG (49) or EG (184) were included. Four were multicenter studies including 107 patients, all with EG infection, associated with a fistula in 91% of cases, with a reported overall survival at 2 years of 16% to 39%. The remaining 39 single-center studies included 49 patients with SG infection and 77 with EG infection. Association with aortoesophageal fistula was significantly more common with EG (60% vs 31%; P = .01). In addition, time interval from index procedure to infection was significantly shorter with EG (17 ± 21 months vs 32 ± 61 months; P = .03). Meta-analysis showed a trend of increased 1-year mortality in patients with SG infection compared with EG infection (pooled OR, 3.6; 95% confidence interval, 0.9-14.7; P = .073). Surgical management with infected graft explantation was associated with a trend toward lower 1-year mortality compared with graft preservation (pooled OR, 0.3; 95% confidence interval, 0.1-1.0; P = .056).ConclusionsThoracic aortic EG infection is likely to occur more frequently in association with aortoesophageal fistulas and in a shorter time compared with SG infection. Survival is poor in both groups, especially in patients with SG infection. Surgical treatment with graft explantation seems to be the preferable choice in fit patients. 相似文献