全文获取类型
收费全文 | 158766篇 |
免费 | 10746篇 |
国内免费 | 625篇 |
专业分类
耳鼻咽喉 | 1769篇 |
儿科学 | 3905篇 |
妇产科学 | 2616篇 |
基础医学 | 20935篇 |
口腔科学 | 3389篇 |
临床医学 | 15551篇 |
内科学 | 33620篇 |
皮肤病学 | 3241篇 |
神经病学 | 14606篇 |
特种医学 | 6964篇 |
外国民族医学 | 14篇 |
外科学 | 25221篇 |
综合类 | 1957篇 |
一般理论 | 109篇 |
预防医学 | 11806篇 |
眼科学 | 3306篇 |
药学 | 10132篇 |
中国医学 | 238篇 |
肿瘤学 | 10758篇 |
出版年
2023年 | 885篇 |
2022年 | 1485篇 |
2021年 | 3374篇 |
2020年 | 2079篇 |
2019年 | 3118篇 |
2018年 | 3591篇 |
2017年 | 2798篇 |
2016年 | 3136篇 |
2015年 | 3584篇 |
2014年 | 5090篇 |
2013年 | 6847篇 |
2012年 | 10335篇 |
2011年 | 11003篇 |
2010年 | 6307篇 |
2009年 | 6013篇 |
2008年 | 9744篇 |
2007年 | 10187篇 |
2006年 | 10094篇 |
2005年 | 10141篇 |
2004年 | 9307篇 |
2003年 | 8617篇 |
2002年 | 8267篇 |
2001年 | 2149篇 |
2000年 | 1840篇 |
1999年 | 2126篇 |
1998年 | 1925篇 |
1997年 | 1551篇 |
1996年 | 1333篇 |
1995年 | 1251篇 |
1994年 | 1125篇 |
1993年 | 1015篇 |
1992年 | 1291篇 |
1991年 | 1189篇 |
1990年 | 1031篇 |
1989年 | 972篇 |
1988年 | 911篇 |
1987年 | 884篇 |
1986年 | 883篇 |
1985年 | 865篇 |
1984年 | 924篇 |
1983年 | 795篇 |
1982年 | 960篇 |
1981年 | 860篇 |
1980年 | 728篇 |
1979年 | 654篇 |
1978年 | 646篇 |
1977年 | 533篇 |
1976年 | 514篇 |
1974年 | 511篇 |
1973年 | 449篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Dupuytren’s disease with severe finger contractures and recurrent contractures following previous surgery often have extensive skin involvement. In these severe cases, excision of the diseased chord along with the involved skin is a good option to reduce the risk of recurrance. The resulting skin defect can be covered with a full thickness skin graft (FTSG) or a cross finger flap. Cross finger flaps have donor finger morbidity and hence a full thickness graft is usually preferred. The FTSG extending to the midlateral margins on both sides of the finger reduces the risk of joint contracture due to graft shrinkage. Once the FTSG is sutured in place, the standard practice is to compress and secure the graft to its recipient bed with a tie-over dressing and this can be time consuming. We present a simple dressing technique to secure the FTSG without the need for a tie-over dressing. 相似文献
12.
13.
Sarah Hallas Andrea Nelson Susan O'Meara Una Adderley Pauline Meskell Jane Nixon Aonghus O'Loughlin Sebastian Probst Wael Tawfick Thomas Wild Georgina Gethin 《Journal of tissue viability》2021,30(3):317-323
BackgroundA venous leg ulcer is a chronic leg wound caused by poor venous blood circulation in the lower limbs. It is a recurring condition causing pain, malodour, reduced mobility, and depression. Randomised controlled trials evaluating treatments for venous leg ulcers provide important evidence to inform clinical decision-making. However, for findings to be useful, outcomes need to be clinically meaningful, consistently reported across trials, and fully reported. Research has identified the large number of outcomes reported in venous leg ulcer trials, impacting both synthesis of results, and clinical decision-making. To address this, a core outcome set will be developed. A core outcome set is an agreed standardised set of outcomes which should be, as a minimum, measured and reported in all trials which evaluate treatment effectiveness for a given indication. A core outcome set has the potential to reduce research waste, improve the utility of RCTs, reduce reporting bias, facilitate treatment comparisons across different sources of evidence and expedite the production of systematic reviews, meta-analyses and evidence-based clinical guidelines.AimThe aim of this project is to develop a core outcome set for research evaluating the effectiveness of interventions for treating venous leg ulceration.MethodsThrough a scoping review of the literature on venous leg ulceration, we will firstly identify a list of candidate outcome domains (broad categories in relation to what is being measured) from randomised controlled trials and qualitative research, and outcomes (specific methods in relation to what is being measured). In two further stages, we will use the resulting lists of outcome domains and outcomes to design two online surveys. A range of stakeholders will be invited to participate in the surveys and they will be asked to indicate which outcome domains and outcomes are most important and should be considered as core in future research reports. 相似文献
14.
15.
Thomas Asendorf Robin Henderson Heinz Schmidli Tim Friede 《Statistics in medicine》2019,38(9):1503-1528
In some diseases, such as multiple sclerosis, lesion counts obtained from magnetic resonance imaging (MRI) are used as markers of disease progression. This leads to longitudinal, and typically overdispersed, count data outcomes in clinical trials. Models for such data invariably include a number of nuisance parameters, which can be difficult to specify at the planning stage, leading to considerable uncertainty in sample size specification. Consequently, blinded sample size re-estimation procedures are used, allowing for an adjustment of the sample size within an ongoing trial by estimating relevant nuisance parameters at an interim point, without compromising trial integrity. To date, the methods available for re-estimation have required an assumption that the mean count is time-constant within patients. We propose a new modeling approach that maintains the advantages of established procedures but allows for general underlying and treatment-specific time trends in the mean response. A simulation study is conducted to assess the effectiveness of blinded sample size re-estimation methods over fixed designs. Sample sizes attained through blinded sample size re-estimation procedures are shown to maintain the desired study power without inflating the Type I error rate and the procedure is demonstrated on MRI data from a recent study in multiple sclerosis. 相似文献
16.
Annals of Surgical Oncology - 相似文献
17.
Alan. B. Franklin Sarah N. Bevins Jeremy W. Ellis Ryan S. Miller Susan A. Shriner J. Jeffrey Root Daniel P. Walsh Thomas J. Deliberto 《Transboundary and Emerging Diseases》2019,66(2):705-714
Using data on waterfowl band recoveries, we identified spatially explicit hotspots of concentrated waterfowl movement to predict occurrence and spatial spread of a novel influenza A virus (clade 2.3.4.4) introduced from Asia by waterfowl from an initial outbreak in North America in November 2014. In response to the outbreak, the hotspots of waterfowl movement were used to help guide sampling for clade 2.3.4.4 viruses in waterfowl as an early warning for the US poultry industry during the outbreak . After surveillance sampling of waterfowl, we tested whether there was greater detection of clade 2.3.4.4 viruses inside hotspots. We found that hotspots defined using kernel density estimates of waterfowl band recoveries worked well in predicting areas with higher prevalence of the viruses in waterfowl. This approach exemplifies the value of ecological knowledge in predicting risk to agricultural security. 相似文献
18.
Marta López-Fauqued Laura Campora Frédérique Delannois Mohamed El Idrissi Lidia Oostvogels Ferdinandus J. De Looze Javier Diez-Domingo Thomas C. Heineman Himal Lal Janet E. McElhaney Shelly A. McNeil Wilfred Yeo Fernanda Tavares-Da-Silva 《Vaccine》2019,37(18):2482-2493
Background
The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.Methods
Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.Results
Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.Conclusions
No safety concerns arose, supporting the favorable benefit-risk profile of RZV. 相似文献19.
Thomas W. McDade Alexander V. Georgiev Christopher W. Kuzawa 《Evolution, Medicine, and Public Health》2016,2016(1):1-16
Immune defenses provide resistance against infectious disease that is critical to survival. But immune defenses are costly, and limited resources allocated to immunity are not available for other physiological or developmental processes. We propose a framework for explaining variation in patterns of investment in two important subsystems of anti-pathogen defense: innate (non-specific) and acquired (specific) immunity. The developmental costs of acquired immunity are high, but the costs of maintenance and activation are relatively low. Innate immunity imposes lower upfront developmental costs, but higher operating costs. Innate defenses are mobilized quickly and are effective against novel pathogens. Acquired responses are less effective against novel exposures, but more effective against secondary exposures due to immunological memory. Based on their distinct profiles of costs and effectiveness, we propose that the balance of investment in innate versus acquired immunity is variable, and that this balance is optimized in response to local ecological conditions early in development. Nutritional abundance, high pathogen exposure and low signals of extrinsic mortality risk during sensitive periods of immune development should all favor relatively higher levels of investment in acquired immunity. Undernutrition, low pathogen exposure, and high mortality risk should favor innate immune defenses. The hypothesis provides a framework for organizing prior empirical research on the impact of developmental environments on innate and acquired immunity, and suggests promising directions for future research in human ecological immunology. 相似文献
20.
Frédéric Janvier Deborah Delaune Thomas Poyot Eric Valade Audrey Mérens Pierre E. Rollin Vincent Foissaud 《Emerging infectious diseases》2016,22(2):292-294
We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa’s environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly. 相似文献