全文获取类型
收费全文 | 1591256篇 |
免费 | 133520篇 |
国内免费 | 2561篇 |
专业分类
耳鼻咽喉 | 21625篇 |
儿科学 | 52805篇 |
妇产科学 | 46271篇 |
基础医学 | 226026篇 |
口腔科学 | 47168篇 |
临床医学 | 140145篇 |
内科学 | 312161篇 |
皮肤病学 | 34056篇 |
神经病学 | 129229篇 |
特种医学 | 64714篇 |
外国民族医学 | 474篇 |
外科学 | 243262篇 |
综合类 | 39673篇 |
现状与发展 | 3篇 |
一般理论 | 544篇 |
预防医学 | 122115篇 |
眼科学 | 36317篇 |
药学 | 120956篇 |
2篇 | |
中国医学 | 2877篇 |
肿瘤学 | 86914篇 |
出版年
2018年 | 14771篇 |
2016年 | 12909篇 |
2015年 | 15037篇 |
2014年 | 20667篇 |
2013年 | 31380篇 |
2012年 | 42596篇 |
2011年 | 44789篇 |
2010年 | 26350篇 |
2009年 | 25326篇 |
2008年 | 43028篇 |
2007年 | 45289篇 |
2006年 | 46075篇 |
2005年 | 44730篇 |
2004年 | 44129篇 |
2003年 | 42106篇 |
2002年 | 41231篇 |
2001年 | 75602篇 |
2000年 | 78170篇 |
1999年 | 66004篇 |
1998年 | 16703篇 |
1997年 | 15343篇 |
1996年 | 15287篇 |
1995年 | 15947篇 |
1994年 | 14990篇 |
1993年 | 14151篇 |
1992年 | 55381篇 |
1991年 | 53780篇 |
1990年 | 52551篇 |
1989年 | 50809篇 |
1988年 | 47197篇 |
1987年 | 46550篇 |
1986年 | 44267篇 |
1985年 | 42836篇 |
1984年 | 32000篇 |
1983年 | 27536篇 |
1982年 | 16096篇 |
1981年 | 14383篇 |
1980年 | 13495篇 |
1979年 | 30417篇 |
1978年 | 21030篇 |
1977年 | 17695篇 |
1976年 | 16652篇 |
1975年 | 17519篇 |
1974年 | 21455篇 |
1973年 | 20646篇 |
1972年 | 18846篇 |
1971年 | 17755篇 |
1970年 | 16275篇 |
1969年 | 15252篇 |
1968年 | 13937篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
51.
52.
Clare Robertson Jan E. Clarkson Magaly Aceves-Martins Craig R. Ramsay Derek Richards Thibault Colloc 《International dental journal》2022,72(2):203-210
IntroductionThe coronavirus disease 2019 (COVID-19) led to the worldwide closure of dental practices or reduction of dental services. By the end of April 2020, governments and professional organisations were publishing recommendations or guidance for the reopening/restructuring of dental services. The aim of this study was to assess how dental aerosol-generating procedures (AGPs) were defined in international dental guidelines, what mitigation processes were advised, and whether they were linked to COVID-19 epidemiology.MethodsElectronic searches of a broad range of databases, along with grey literature searches, without language restriction were conducted up to 13 July 2020. Recommendations for the use of face masks and fallow times with patients without COVID-19 were assessed against the deaths per 1 million population in the included countries and country income level using Pearson Chi-squared statistics.ResultsSixty-three guidance documents were included. Most (98%) indicated that AGPs can be performed with patients without COVID-19 with caveats, including advice to restrict AGPs where possible, with 21% only recommending AGPs for dental emergencies. Face masks were recommended by most documents (94%), with 91% also specifying the use of goggles or face shields. Fallow periods for patients without COVID-19 were mentioned in 48% of documents, ranging from 2 to 180 minutes. There were no significant differences in recommendations for face masks or fallow time in patients without COVID-19 by country death rate (P = .463 and P = .901) or World Bank status (P = .504 and P = .835). Most documents recommended procedural or environmental mitigations such as preprocedural mouthwash (82%) and general ventilation (52%). Few documents provided underpinning evidence for their recommendations.ConclusionsWhile the amount of high-quality direct evidence related to dentistry and COVID-19 remains limited, it is important to be explicit about the considered judgements for recommendations as well as generate new evidence to face this challenge. 相似文献
53.
Combs Katie Massey Buckley Pamela R. Lain Marion Amanda Drewelow Karen M. Urano Grace Kerns Suzanne E. U. 《Prevention science》2022,23(6):969-981
Prevention Science - As evidence-based interventions (EBIs) become more widely disseminated, fidelity of implementation (FOI) often wanes. This study explores the association between FOI and... 相似文献
54.
K. El-Boghdadly T. M. Cook T. Goodacre J. Kua S. Denmark S. McNally N. Mercer S. R. Moonesinghe D. J. Summerton 《Anaesthesia》2022,77(5):580-587
The impact of vaccination and new SARS-CoV-2 variants on peri-operative outcomes is unclear. We aimed to update previously published consensus recommendations on timing of elective surgery after SARS-CoV-2 infection to assist policymakers, administrative staff, clinicians and patients. The guidance remains that patients should avoid elective surgery within 7 weeks of infection, unless the benefits of doing so exceed the risk of waiting. We recommend individualised multidisciplinary risk assessment for patients requiring elective surgery within 7 weeks of SARS-CoV-2 infection. This should include baseline mortality risk calculation and assessment of risk modifiers (patient factors; SARS-CoV-2 infection; surgical factors). Asymptomatic SARS-CoV-2 infection with previous variants increased peri-operative mortality risk three-fold throughout the 6 weeks after infection, and assumptions that asymptomatic or mildly symptomatic omicron SARS-CoV-2 infection does not add risk are currently unfounded. Patients with persistent symptoms and those with moderate-to-severe COVID-19 may require a longer delay than 7 weeks. Elective surgery should not take place within 10 days of diagnosis of SARS-CoV-2 infection, predominantly because the patient may be infectious, which is a risk to surgical pathways, staff and other patients. We now emphasise that timing of surgery should include the assessment of baseline and increased risk, optimising vaccination and functional status, and shared decision-making. While these recommendations focus on the omicron variant and current evidence, the principles may also be of relevance to future variants. As further data emerge, these recommendations may be revised. 相似文献
55.
56.
57.
Alexander D. Sherry MD Kelsey L. Corrigan MD MPH Ramez Kouzy MD Joseph Abi Jaoude MD Yumeng Yang MS Roshal R. Patel MD Douglas J. Totten MD MBA Neil B. Newman MD MS Prajnan Das MD MS MPH Cullen Taniguchi MD PhD Bruce Minsky MD Rebecca A. Snyder MD MPH C. David Fuller MD PhD Ethan Ludmir MD 《Cancer》2023,129(21):3430-3438
58.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion. 相似文献
59.
60.