全文获取类型
收费全文 | 12927篇 |
免费 | 1020篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 119篇 |
儿科学 | 226篇 |
妇产科学 | 183篇 |
基础医学 | 1784篇 |
口腔科学 | 404篇 |
临床医学 | 1300篇 |
内科学 | 3018篇 |
皮肤病学 | 194篇 |
神经病学 | 1166篇 |
特种医学 | 378篇 |
外科学 | 2003篇 |
综合类 | 122篇 |
一般理论 | 13篇 |
预防医学 | 1162篇 |
眼科学 | 243篇 |
药学 | 849篇 |
中国医学 | 14篇 |
肿瘤学 | 821篇 |
出版年
2023年 | 107篇 |
2022年 | 79篇 |
2021年 | 369篇 |
2020年 | 217篇 |
2019年 | 378篇 |
2018年 | 388篇 |
2017年 | 280篇 |
2016年 | 299篇 |
2015年 | 354篇 |
2014年 | 488篇 |
2013年 | 629篇 |
2012年 | 998篇 |
2011年 | 970篇 |
2010年 | 552篇 |
2009年 | 519篇 |
2008年 | 824篇 |
2007年 | 885篇 |
2006年 | 838篇 |
2005年 | 894篇 |
2004年 | 829篇 |
2003年 | 701篇 |
2002年 | 642篇 |
2001年 | 123篇 |
2000年 | 92篇 |
1999年 | 107篇 |
1998年 | 132篇 |
1997年 | 99篇 |
1996年 | 83篇 |
1995年 | 92篇 |
1994年 | 67篇 |
1993年 | 66篇 |
1992年 | 51篇 |
1991年 | 42篇 |
1990年 | 46篇 |
1989年 | 45篇 |
1988年 | 49篇 |
1987年 | 54篇 |
1986年 | 55篇 |
1985年 | 42篇 |
1984年 | 51篇 |
1983年 | 47篇 |
1982年 | 51篇 |
1981年 | 29篇 |
1980年 | 30篇 |
1979年 | 30篇 |
1978年 | 14篇 |
1977年 | 25篇 |
1976年 | 23篇 |
1973年 | 14篇 |
1970年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
2.
3.
Maciej Zacharski Alicja Tomaszek Liliana Kiczak Maciej Ugorski Jacek Bania Urszula Pasławska Ilona Rybinska Ewa Anita Jankowska Adrian Janiszewski Piotr Ponikowski 《Journal of cardiac failure》2021,27(6):682-692
BackgroundSteroid hormones play an important role in heart failure (HF) pathogenesis, and clinical data have revealed disordered steroidogenesis in male patients with HF. However, there is still a lack of studies on steroid hormones and their receptors during HF progression. Therefore, a porcine model of tachycardia-induced cardiomyopathy corresponding to HF was used to assess steroid hormone concentrations in serum and their nuclear receptor levels in heart tissue during the consecutive stages of HF.Methods and ResultsMale pigs underwent right ventricular pacing and developed a clinical picture of mild, moderate, or severe HF. Serum concentrations of dehydroepiandrosterone, testosterone, dihydrotestosterone, estradiol, aldosterone, and cortisol were assessed by enzyme-linked immunosorbent assay. Androgen receptor, estrogen receptor alpha, mineralocorticoid receptor, and glucocorticoid receptor messenger RNA levels in the left ventricle were determined by qPCR.The androgen level decreased in moderate and severe HF animals, while the corticosteroid level increased. The estradiol concentration remained stable. The quantitative real-time polymerase chain reaction revealed the downregulation of androgen receptor in consecutive stages of HF and increased expression of mineralocorticoid receptor messenger RNA under these conditions.ConclusionsIn the HF pig model, deteriorated catabolic/anabolic balance, manifested by upregulation of aldosterone and cortisol and downregulation of androgen signaling on the ligand level, was augmented by changes in steroid hormone receptor expression in the heart tissue. 相似文献
4.
Lorena Martin-Morales Sara Manzano Maria Rodrigo-Faus Adrian Vicente-Barrueco Victor Lorca Gonzalo Núñez-Moreno Paloma Bragado Almudena Porras Trinidad Caldes Pilar Garre Alvaro Gutierrez-Uzquiza 《International journal of cancer. Journal international du cancer》2023,152(2):283-297
Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future. 相似文献
5.
Tara M. Veasey Catherine K. Floroff Sara E. Strout Krista L. McElray Meredith A. Brisco‐Bacik Jennifer L. Cook John M. Toole Michael L. Craig Adrian B. Van Bakel Holly B. Meadows Walter E. Uber 《Artificial organs》2019,43(8):736-744
Continuous‐flow left ventricular assist device (LVAD) placement has become a standard of care in advanced heart failure treatment. Bleeding is the most frequently reported adverse event after LVAD implantation and may be increased by antithrombotic agents used for prevention of pump thrombosis. This retrospective cohort included 85 adult patients implanted with a Heartmate II LVAD. Major bleeding was defined as occurring >7 days after implant and included intracranial hemorrhage, events requiring 2 units of packed red blood cells within a 24‐h period, and death from bleeding. Primary outcome was intensity of anticoagulation between patients with or without at least one incidence of nonsurgical major bleeding. Major bleeding occurred in 35 (41%) patients with 0.48 events per patient year and a median (IQR) time to first bleed of 134.5 (39.3, 368.5) days. The median (IQR) INR at time of bleed was 1.7 (1.4, 2.5). Median INR during follow‐up did not differ between groups and patients with major bleeding were not more likely to have a supra‐therapeutic INR. Patients who bled were more likely to have received LVAD for destination therapy, to have lower weight, worse renal function, and lower hemoglobin at baseline. Duration of LVAD support and survival were similar between groups with no difference in occurrence of thrombosis. Incidence of nonsurgical major bleeding was not significantly associated with degree of anticoagulation. Certain baseline characteristics may be more important than anticoagulation intensity to identify patients at risk for bleeding after LVAD implant. Modification of anticoagulation alone is not a sufficient management strategy and early intervention may be required to mitigate bleeding impact. 相似文献
6.
7.
8.
Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease
Abhinav Sharma Adrian Coles Nishant K. Sekaran Neha J. Pagidipati Michael T. Lu Daniel B. Mark Kerry L. Lee Hussein R. Al-Khalidi Udo Hoffmann Pamela S. Douglas 《Journal of the American College of Cardiology》2019,73(8):893-902
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献9.
Milan Milojevic Patrick W. Serruys Joseph F. Sabik David E. Kandzari Erick Schampaert Ad J. van Boven Ferenc Horkay Imre Ungi Samer Mansour Adrian P. Banning David P. Taggart Manel Sabaté Anthony H. Gershlick Andrzej Bochenek Jose Pomar Nicholas J. Lembo Nicolas Noiseux John D. Puskas Arie Pieter Kappetein 《Journal of the American College of Cardiology》2019,73(13):1616-1628
Background
The randomized EXCEL (Evaluation of XIENCE versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial reported a similar rate of the 3-year composite primary endpoint of death, myocardial infarction (MI), or stroke in patients with left main coronary artery disease (LMCAD) and site-assessed low or intermediate SYNTAX scores treated with percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). Whether these results are consistent in high-risk patients with diabetes, who have fared relatively better with CABG in most prior trials, is unknown.Objectives
In this pre-specified subgroup analysis from the EXCEL trial, the authors sought to examine the effect of diabetes in patients with LMCAD treated with PCI versus CABG.Methods
Patients (N = 1,905) with LMCAD and site-assessed low or intermediate CAD complexity (SYNTAX scores ≤32) were randomized 1:1 to PCI with everolimus-eluting stents versus CABG, stratified by the presence of diabetes. The primary endpoint was the rate of a composite of all-cause death, stroke, or MI at 3 years. Outcomes were examined in patients with (n = 554) and without (n = 1,350) diabetes.Results
The 3-year composite primary endpoint was significantly higher in diabetic compared with nondiabetic patients (20.0% vs. 12.9%; p < 0.001). The rate of the 3-year primary endpoint was similar after treatment with PCI and CABG in diabetic patients (20.7% vs. 19.3%, respectively; hazard ratio: 1.03; 95% confidence interval: 0.71 to 1.50; p = 0.87) and nondiabetic patients (12.9% vs. 12.9%, respectively; hazard ratio: 0.98; 95% confidence interval: 0.73 to 1.32; p = 0.89). All-cause death at 3 years occurred in 13.6% of PCI and 9.0% of CABG patients (p = 0.046), although no significant interaction was present between diabetes status and treatment for all-cause death (p = 0.22) or other endpoints, including the 3-year primary endpoint (p = 0.82) or the major secondary endpoints of death, MI, or stroke at 30 days (p = 0.61) or death, MI, stroke, or ischemia-driven revascularization at 3 years (p = 0.65).Conclusions
In the EXCEL trial, the relative 30-day and 3-year outcomes of PCI with everolimus-eluting stents versus CABG were consistent in diabetic and nondiabetic patients with LMCAD and site-assessed low or intermediate SYNTAX scores.(Evaluation of XIENCE versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization [EXCEL]; NCT01205776) 相似文献10.