全文获取类型
收费全文 | 155603篇 |
免费 | 11162篇 |
国内免费 | 617篇 |
专业分类
耳鼻咽喉 | 1762篇 |
儿科学 | 3860篇 |
妇产科学 | 2606篇 |
基础医学 | 20434篇 |
口腔科学 | 3387篇 |
临床医学 | 15296篇 |
内科学 | 32710篇 |
皮肤病学 | 3240篇 |
神经病学 | 14401篇 |
特种医学 | 6933篇 |
外国民族医学 | 14篇 |
外科学 | 25040篇 |
综合类 | 1938篇 |
一般理论 | 109篇 |
预防医学 | 11512篇 |
眼科学 | 3293篇 |
药学 | 10074篇 |
中国医学 | 235篇 |
肿瘤学 | 10538篇 |
出版年
2023年 | 805篇 |
2022年 | 586篇 |
2021年 | 3030篇 |
2020年 | 2079篇 |
2019年 | 3118篇 |
2018年 | 3592篇 |
2017年 | 2797篇 |
2016年 | 3136篇 |
2015年 | 3584篇 |
2014年 | 5090篇 |
2013年 | 6848篇 |
2012年 | 10338篇 |
2011年 | 11004篇 |
2010年 | 6307篇 |
2009年 | 6014篇 |
2008年 | 9745篇 |
2007年 | 10188篇 |
2006年 | 10096篇 |
2005年 | 10142篇 |
2004年 | 9305篇 |
2003年 | 8593篇 |
2002年 | 8244篇 |
2001年 | 2125篇 |
2000年 | 1781篇 |
1999年 | 2002篇 |
1998年 | 1655篇 |
1997年 | 1289篇 |
1996年 | 1075篇 |
1995年 | 1215篇 |
1994年 | 1101篇 |
1993年 | 990篇 |
1992年 | 1267篇 |
1991年 | 1187篇 |
1990年 | 1027篇 |
1989年 | 972篇 |
1988年 | 899篇 |
1987年 | 877篇 |
1986年 | 879篇 |
1985年 | 860篇 |
1984年 | 910篇 |
1983年 | 781篇 |
1982年 | 938篇 |
1981年 | 836篇 |
1980年 | 719篇 |
1979年 | 646篇 |
1978年 | 643篇 |
1977年 | 516篇 |
1976年 | 491篇 |
1974年 | 504篇 |
1973年 | 439篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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
62.
63.
64.
Wilson Mathias Jeane M. Tsutsui Bruno G. Tavares Agostina M. Fava Miguel O.D. Aguiar Bruno C. Borges Mucio T. Oliveira Alexandre Soeiro Jose C. Nicolau Henrique B. Ribeiro Hsu Po Chiang João C.N. Sbano Abdulrahman Morad Andrew Goldsweig Carlos E. Rochitte Bernardo B.C. Lopes José A.F. Ramirez Roberto Kalil Filho Thomas R. Porter 《Journal of the American College of Cardiology》2019,73(22):2832-2842
BackgroundPreclinical studies have demonstrated that high mechanical index (MI) impulses from a diagnostic ultrasound transducer during an intravenous microbubble infusion (sonothrombolysis) can restore epicardial and microvascular flow in acute ST-segment elevation myocardial infarction (STEMI).ObjectivesThis study tested the clinical effectiveness of sonothrombolysis in patients with STEMI.MethodsPatients with their first STEMI were prospectively randomized to either diagnostic ultrasound–guided high MI impulses during an intravenous Definity (Lantheus Medical Imaging, North Billerica, Massachusetts) infusion before, and following, emergent percutaneous coronary intervention (PCI), or to a control group that received PCI only (n = 50 in each group). A reference first STEMI group (n = 203) who arrived outside the randomization window was also analyzed. Angiographic recanalization before PCI, ST-segment resolution, infarct size by magnetic resonance imaging, and systolic function (LVEF) at 6 months were compared.ResultsST-segment resolution occurred in 16 (32%) high MI PCI versus 2 (4%) PCI-only patients before PCI, and angiographic recanalization was 48% in high MI/PCI versus 20% in PCI only and 21% in the reference group (p < 0.001). Infarct size was reduced (29 ± 22 g high MI/PCI vs. 40 ± 20 g PCI only; p = 0.026). LVEF was not different between groups before treatment (44 ± 11% vs. 43 ± 10%), but increased immediately after PCI in the high MI/PCI group (p = 0.03), and remained higher at 6 months (p = 0.015). Need for implantable defibrillator (LVEF ≤30%) was reduced in the high MI/PCI group (5% vs. 18% PCI only; p = 0.045).ConclusionsSonothrombolysis added to PCI improves recanalization rates and reduces infarct size, resulting in sustained improvements in systolic function after STEMI. (Therapeutic Use of Ultrasound in Acute Coronary Artery Disease; NCT02410330). 相似文献
65.
Non‐melanoma skin cancer frequently results from chronic exposure to ultraviolet (UV) irradiation. UV‐induced DNA damage activates cell cycle arrest checkpoints through degradation of the cyclin‐dependent kinase activators, the cell division cycle 25 (CDC25) phosphatases. We previously reported increased CDC25A in nonmelanoma skin cancer, but CDC25B and CDC25C had not been previously examined. Consequently, we hypothesized that increased expression of CDC25B and CDC25C increases tumor cell proliferation and skin tumor growth. We found that CDC25B and CDC25C were increased in mouse and human skin cancers. CDC25B was primarily cytoplasmic in skin and skin tumors and was significantly increased in the squamous cell carcinoma (SCC), while CDC25C was mostly nuclear in the skin, with an increased cytoplasmic signal in the premalignant and malignant tumors. Surprisingly, forced expression of CDC25B or CDC25C in cultured SCC cells did not affect proliferation, but instead suppressed apoptosis, while CDC25C silencing increased apoptosis without impacting proliferation. Targeting CDC25C to the nucleus via mutation of its nuclear export sequence, however, increased proliferation in SCC cells. Overexpression of CDC25C in the nuclear compartment did not hinder the ability of CDC25C to suppress apoptosis, neither did mutation of sites necessary for its interaction with 14‐3‐3 proteins. Analysis of apoptotic signaling pathways revealed that CDC25C increased activating phosphorylation of Akt on Ser473, increased inhibitory phosphorylation of proapoptotic BAD on Ser136, and increased the survival protein Survivin. Silencing of CDC25C significantly reduced Survivin levels. Taken together, these data suggest that increased expression of CDC25B or CDC25C are mechanisms by which skin cancers evade apoptotic cell death. 相似文献
66.
Margaret H. Lauerman Karen Irizarry Clint Sliker Brandon R. Bruns Ronald Tesoriero Thomas M. Scalea Deborah M. Stein 《Injury》2019,50(1):131-136
Background
Current blunt cerebrovascular injury (BCVI) grading grossly differentiates injury characteristics such as luminal stenosis (LS) and aneurysmal disease. The effect of increasing degree of LS beyond the current BCVI grading scale on stroke formation is unknown.Study Design
BCVI over a 3-year period were retrospectively reviewed. To investigate influence of LS beyond the BCVI grading scale within aneurysmal and non-aneurysmal BCVI, grade 2 BCVI were subdivided into BCVI with ≥ 25% and ≤ 50% LS and BCVI with > 50% and ≤ 99% LS. Grade 3 BCVI were subdivided into BCVI with pseudoaneurysm (PSA) without LS and BCVI with PSA and LS. We hypothesized increased LS beyond the current BCVI grade distinctions would be associated with higher rates of stroke formation.Results
312 BCVI were included, of which 140 were carotid BCVI and 172 vertebral BCVI. Sixteen carotid BCVI underwent endovascular intervention (EI) and 19 suffered a stroke. In carotid BCVI stroke rates increased sequentially with BCVI grade except in grade 3. There was a stroke rate of 12% in grade 1 carotid BCVI, 18% in grade 2, 6% in grade 3, and 31% in grade 4. In subgroup analysis for grade 2 carotid BCVI, BCVI with > 50% and ≤ 99% LS had higher rates of stroke (22% vs. 15%, p?=?0.44) than BCVI with ≥ 25% and ≤ 50% LS. In subgroup analysis of grade 3 carotid BCVI, BCVI with PSA and LS had higher rates of stroke (9% vs. 4%, p?=?0.48) than BCVI with PSA without LS. Higher rates of EI in grade 2 carotid BCVI with > 50% and ≤ 99% LS (22% vs. 5%, p?=?0.14) and grade 3 carotid BCVI with PSA and LS (35% vs. 4%, p?=?0.01) were noted in subgroup analysis.Conclusion
Higher percentage LS beyond the currently used BCVI grading scale has a non-significantly increased rate of stroke in both aneurysmal and non-aneurysmal BCVI. Grade 3 BCVI with PSA and LS seems to be a high-risk subgroup. Use of EI confounds modern measurement of stroke risk in higher LS BCVI. 相似文献67.
68.
Elise A. Larson David M. German Joseph Shatzel Thomas G. DeLoughery 《European journal of haematology》2019,102(1):3-19
Anticoagulation has multiple roles in the treatment of cardiovascular disease, including in management of acute myocardial infarction, during percutaneous coronary intervention, as stroke prophylaxis in patients with atrial arrhythmias, and in patients with mechanical heart valves. Clinical anticoagulation choices in the aforementioned diseases vary widely, due to conflicting data to support established agents and the rapid evolution of evidence‐based practice that parallels more widespread use of novel oral anticoagulants. This review concisely summarizes evidence‐based guidelines for anticoagulant use in cardiovascular disease, and highlights new data specific to direct oral anticoagulants. 相似文献
69.
Ada Gillissen Thomas van den Akker Camila Caram-Deelder Dacia D. C. A. Henriquez Kitty W. M. Bloemenkamp Jeroen Eikenboom 《Scandinavian journal of clinical and laboratory investigation》2019,79(1-2):32-38
Haemostatic treatment in women experiencing postpartum haemorrhage is increasingly based on point-of-care devices such as ROTEM® thromboelastometry. Recently, a fully automated successor of the ROTEM® Delta device, the ROTEM® Sigma was introduced. To determine whether these devices provide similar results, we compared ROTEM® parameters using the ROTEM® Delta and Sigma devices in women experiencing postpartum haemorrhage. Prospective observational cohort study of 23 women experiencing postpartum haemorrhage. ROTEM® INTEM, EXTEM, FIBTEM and APTEM measurements handled by the ROTEM® Delta and Sigma devices were compared. ROTEM® FIBTEM values were also related to Clauss fibrinogen values. A correlation of Spearman’s r (rs) varying between 0.76 and 0.95 was displayed between clot firmness measured in millimeters at 5 (A5), 10 (A10) and 20 (A20) minutes after start of clot formation measured by EXTEM, INTEM and APTEM assays executed on both devices; A5, A10 and A20 of FIBTEM correlated less well (rS between 0.71 and 0.74), especially after five and ten minutes. Correlation between both devices regarding clotting time (CT) was poor. The observed correlation between levels of Clauss fibrinogen and FIBTEM A5 was rs = 0.70, (95% confidence interval (CI): 0.38 to 0.87) for Delta and rs = 0.85, (CI 0.65 to 0.94) for Sigma. A5, A10 and A20 measured in EXTEM, INTEM and APTEM obtained from ROTEM® Delta and Sigma devices were similar. EXTEM, FIBTEM and APTEM CT values from both devices showed no correlation. Substantial variation was found between FIBTEM assays of the devices. Consequently, results of FIBTEM assays should always be interpreted in the context of device-specific reference values. Correlation with Clauss fibrinogen was better in the ROTEM® Sigma device. 相似文献
70.
Nadege Wesner Louis Drevon Alexis Guedon Jean Baptiste Fraison Salim Trad Jean Emmanuel Kahn Achille Aouba Jerome Gillard Matthieu Ponsoye Thomas Hanslik Clement Gourguechon Eric Liozon Kamel Laribi Julien Rossignol Olivier Hermine Lionel Ads Fabrice Carrat Pierre Fenaux Arsene Mekinian Olivier Fain 《European journal of haematology》2019,102(1):63-69