全文获取类型
收费全文 | 11023篇 |
免费 | 712篇 |
国内免费 | 485篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 292篇 |
妇产科学 | 35篇 |
基础医学 | 748篇 |
口腔科学 | 141篇 |
临床医学 | 1089篇 |
内科学 | 1846篇 |
皮肤病学 | 56篇 |
神经病学 | 245篇 |
特种医学 | 931篇 |
外科学 | 3861篇 |
综合类 | 1239篇 |
现状与发展 | 1篇 |
预防医学 | 224篇 |
眼科学 | 31篇 |
药学 | 837篇 |
2篇 | |
中国医学 | 206篇 |
肿瘤学 | 411篇 |
出版年
2023年 | 198篇 |
2022年 | 280篇 |
2021年 | 534篇 |
2020年 | 443篇 |
2019年 | 605篇 |
2018年 | 540篇 |
2017年 | 448篇 |
2016年 | 320篇 |
2015年 | 368篇 |
2014年 | 672篇 |
2013年 | 629篇 |
2012年 | 556篇 |
2011年 | 579篇 |
2010年 | 545篇 |
2009年 | 509篇 |
2008年 | 519篇 |
2007年 | 472篇 |
2006年 | 455篇 |
2005年 | 400篇 |
2004年 | 340篇 |
2003年 | 282篇 |
2002年 | 228篇 |
2001年 | 198篇 |
2000年 | 176篇 |
1999年 | 145篇 |
1998年 | 157篇 |
1997年 | 135篇 |
1996年 | 97篇 |
1995年 | 102篇 |
1994年 | 106篇 |
1993年 | 90篇 |
1992年 | 97篇 |
1991年 | 73篇 |
1990年 | 66篇 |
1989年 | 65篇 |
1988年 | 54篇 |
1987年 | 56篇 |
1986年 | 39篇 |
1985年 | 64篇 |
1984年 | 69篇 |
1982年 | 59篇 |
1981年 | 66篇 |
1980年 | 62篇 |
1979年 | 42篇 |
1978年 | 58篇 |
1977年 | 38篇 |
1976年 | 48篇 |
1975年 | 31篇 |
1974年 | 26篇 |
1973年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):591-604.e3
ObjectivesGuidelines suggest aortic valve replacement (AVR) for low-risk asymptomatic patients. Indications for transcatheter AVR now include low-risk patients, making it imperative to understand state-of-the-art surgical AVR (SAVR) in this population. Therefore, we compared SAVR outcomes in low-risk patients with those expected from Society of Thoracic Surgeons (STS) models and assessed their intermediate-term survival.MethodsFrom January 2005 to January 2017, 3493 isolated SAVRs were performed in 3474 patients with STS predicted risk of mortality <4%. Observed operative mortality and composite major morbidity or mortality were compared with STS-expected outcomes according to calendar year of surgery. Logistic regression analysis was used to identify risk factors for these outcomes. Patients were followed for time-related mortality.ResultsWith 15 observed operative deaths (0.43%) compared with 55 expected (1.6%), the observed:expected ratio was 0.27 for mortality (95% confidence interval [CI], 0.14-0.42), stroke 0.65 (95% CI, 0.41-0.89), and reoperation 0.50 (95% CI, 0.42-0.60). Major morbidity or mortality steadily declined, with probabilities of 8.6%, 6.7%, and 5.2% in 2006, 2011, and 2016, respectively, while STS-expected risk remained at approximately 12%. Mitral valve regurgitation, ventricular hypertrophy, pulmonary, renal, and hepatic failure, coronary artery disease, and earlier surgery date were residual risk factors. Survival was 98%, 91%, and 82% at 1, 5, and 9 years, respectively, superior to that predicted for the US age-race-sex–matched population.ConclusionsSTS risk models overestimate contemporary SAVR risk at a high-volume center, supporting efforts to create a more agile quality assessment program. SAVR in low-risk patients provides durable survival benefit, supporting early surgery and providing a benchmark for transcatheter AVR. 相似文献
3.
《The Annals of thoracic surgery》2023,115(1):88-95
BackgroundRecent guidelines for the treatment of moderate or severe ischemic mitral regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) have changed. This study assessed the real-world impact of changing guidelines on the management of IMR during CABG over time. We hypothesized that the utilization of mitral valve repair for IMR would decrease over time, whereas mitral valve replacement for severe IMR would increase.MethodsPatients undergoing CABG in a statewide collaborative database (2011-2020) were stratified by severity of IMR. Trends in mitral valve repair or replacement were evaluated. To account for differences of the patients, propensity score–matched analyses were used to compare patients with and without mitral intervention.ResultsA total of 11,676 patients met inclusion criteria, including 1355 (11.6%) with moderate IMR and 390 (3.3%) with severe IMR. The proportion of patients undergoing mitral intervention for moderate IMR decreased over time (2011, 17.7%; 2020, 7.5%; Ptrend = .001), whereas mitral replacement for severe IMR remained stable (2011, 11.1%; 2020, 13.3%; Ptrend = .14). Major morbidity was higher for patients with moderate IMR who underwent mitral intervention (29.1% vs 19.9%; P = .005). In a propensity analysis of 249 well-matched pairs, there was no difference in major morbidity (29.3% with mitral intervention vs 23.7% without; P = .16) or operative mortality (1.2% vs 2.4%; P = .5).ConclusionsConsistent with recent guideline updates, patients with moderate IMR were less likely to undergo mitral repair. However, the rate of replacement for severe IMR did not change. Mitral intervention during CABG did not increase operative mortality or morbidity. 相似文献
4.
目的 研究胸段食管癌逆向调强放射治疗(IMRT)中累及野照射与扩大野照射对危及器官(OAR)受照剂量的影响。方法 40例胸段食管癌患者分别行累及野靶区勾画和扩大野靶区勾画并勾画危及器官,制定IMRT计划,评估2个计划的靶区适形指数(CI)和均匀性指数(HI)及危及器官的剂量学参数,剂量学参数比较采用配对t检验。结果 2种计划的PTV均能满足处方剂量要求,PTV在CI、HI上相近(P = 0.317、0.130)。两组间平均肺剂量、两肺V5、两肺V20、两肺V30、脊髓Dmean、心脏Dmean、心脏Dmax、心脏V30、心脏V40、心脏V60差异均存在统计学意义(P < 0.01)。结论 胸段食管癌患者行累及野照射与扩大野比较,可降低正常器官的受照剂量,从而降低放射性损伤风险。 相似文献
5.
《Morphologie : bulletin de l'Association des anatomistes》2022,106(353):136-140
6.
目的探讨耳郭软骨骨化的发病机制、临床表现、诊断依据、鉴别诊断、治疗方法。方法回顾性分析1例耳郭软骨骨化患者的临床资料并复习相关文献进行总结。结果耳郭软骨骨化的发病机制暂不明确,通常无明显不适症状,少数患者可伴有局部疼痛、听力下降等症状。颞骨CT可辅助诊断,最终确诊依赖于组织病理检查。症状不明显时可暂予观察,若症状严重影响了生活和工作,可予手术治疗。结论耳郭软骨骨化在临床上较为少见,目前尚无有效逆转耳郭骨化的办法。积极寻找病因,及早干预,有利于避免病情进一步发展。 相似文献
7.
《Revista portuguesa de cardiologia》2022,41(4):299-307
AimsMyocardial strain analysis enables more precise assessment of cardiac performance but is relatively load dependent. New tools have been developed with afterload adjustment. Our objective was to assess myocardial work (MW) in patients with repaired aortic coarctation (rACo).MethodsProspective study of consecutive patients with rACo who underwent a routine transthoracic echocardiogram in 2018 and 2019 at our center. Patients with significant aortic valve disease, pacemaker, or other congenital heart diseases (except for mild bicuspid aortic valve disease) were excluded. Global longitudinal strain with two dimensional speckle tracking analysis and MW were obtained (GWI:Global Work Index; GCW: Global Constructive Work; GWW: Global Wasted Work; GWE: Global Work Efficiency). Blood pressure was measured in the patient's right arm.ResultsWe included 42 patients in the analysis, mean age of 37±10 years, 38% males. In this group, 52% had hypertension and 64% had a concomitant bicuspid aortic valve. In comparison to previously published reference values, patients with rACo had significantly lower GWI (1807 vs. 1896 mmHg%) and GCW (2173 vs. 2232 mmHg%) (p<0.001), particularly in males. Systolic blood pressure is an independent predictor for GWI (β=0.432) and for GCW (β=0.534) and GLS an independent predictor of all MW parameters (β>0.594). Neither age nor gender were independent predictors.ConclusionsIn patients with rACo, there are some signs of left ventricular dysfunction with a reduction in GCW and GWI and with preserved GWE, despite normal ejection fraction and strain. 相似文献
8.
9.
10.
《European journal of surgical oncology》2020,46(6):982-990
IntroductionLung cancer is the leading cause of cancer-death worldwide. The U.S. Preventative Services Task Force (USPTSF) approved screening for current or former smokers aged 55–80 based on the results of the National Lung Screening trial (NLST). Following the NLST, new evidence has emerged from clinical trials and updates to previous trials prior to the anticipated update to the USPSTF guideline. We review the new evidence on lung cancer screening with low dose computed tomography (LDCT) and the surgical implications.MethodsA review of new literature was performed pertaining to lung cancer screening since implementation of UPSTF guidelines. Articles for inclusion were identified by both authors’, then search of the Pubmed and Cochrane database was performed from January 1st, 2013 through February 4th, 2020 using the MeSH search terms: “lung cancer”; “screening”; “low dose CT”. The results of these studies are summarized.ResultsWe identified multiple prospective randomized control trials and meta-analysis since the NLST supporting lung cancer-specific mortality with screening. We identified new nodule classification systems and the development of risk-models which may reduce false positive rates and identify high risk patients not currently eligible for screening. Finally, we discussed the surgical implications of screening.ConclusionNew data supports NLST findings and show ongoing benefit to LDCT for lung cancer screening. Standardized LDCT screening classification has been shown to reduce harm and lower false positive rates. Further study is needed regarding use of risk-modeling. Screening will require an increase in the thoracic workforce to accommodate the amount of surgically operable cancers. 相似文献