全文获取类型
| 收费全文 | 4041278篇 |
| 免费 | 287319篇 |
| 国内免费 | 9120篇 |
专业分类
| 耳鼻咽喉 | 56263篇 |
| 儿科学 | 132317篇 |
| 妇产科学 | 111201篇 |
| 基础医学 | 576449篇 |
| 口腔科学 | 112696篇 |
| 临床医学 | 373159篇 |
| 内科学 | 779196篇 |
| 皮肤病学 | 93141篇 |
| 神经病学 | 327596篇 |
| 特种医学 | 153022篇 |
| 外国民族医学 | 1142篇 |
| 外科学 | 603212篇 |
| 综合类 | 84081篇 |
| 现状与发展 | 15篇 |
| 一般理论 | 1622篇 |
| 预防医学 | 317529篇 |
| 眼科学 | 94133篇 |
| 药学 | 297729篇 |
| 19篇 | |
| 中国医学 | 7891篇 |
| 肿瘤学 | 215304篇 |
出版年
| 2019年 | 32593篇 |
| 2018年 | 45039篇 |
| 2017年 | 34122篇 |
| 2016年 | 39173篇 |
| 2015年 | 44105篇 |
| 2014年 | 61591篇 |
| 2013年 | 93381篇 |
| 2012年 | 125895篇 |
| 2011年 | 133619篇 |
| 2010年 | 80309篇 |
| 2009年 | 76328篇 |
| 2008年 | 125006篇 |
| 2007年 | 132923篇 |
| 2006年 | 134856篇 |
| 2005年 | 130147篇 |
| 2004年 | 125215篇 |
| 2003年 | 120631篇 |
| 2002年 | 116739篇 |
| 2001年 | 183602篇 |
| 2000年 | 188558篇 |
| 1999年 | 159378篇 |
| 1998年 | 47489篇 |
| 1997年 | 41707篇 |
| 1996年 | 41863篇 |
| 1995年 | 40222篇 |
| 1994年 | 36923篇 |
| 1993年 | 34747篇 |
| 1992年 | 125039篇 |
| 1991年 | 121194篇 |
| 1990年 | 117908篇 |
| 1989年 | 114289篇 |
| 1988年 | 105168篇 |
| 1987年 | 103053篇 |
| 1986年 | 97029篇 |
| 1985年 | 93021篇 |
| 1984年 | 69566篇 |
| 1983年 | 59249篇 |
| 1982年 | 35371篇 |
| 1981年 | 31862篇 |
| 1979年 | 63165篇 |
| 1978年 | 44937篇 |
| 1977年 | 37947篇 |
| 1976年 | 35724篇 |
| 1975年 | 38131篇 |
| 1974年 | 45498篇 |
| 1973年 | 43364篇 |
| 1972年 | 40848篇 |
| 1971年 | 38353篇 |
| 1970年 | 35305篇 |
| 1969年 | 33949篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
51.
Kyle E. Embertson Diann M. Krywko Eric R. Bunch 《The American journal of emergency medicine》2019,37(5):1005.e3-1005.e4
Nephrolithiasis is a common pathology encountered in the primary care and emergency department (ED) setting. In 2009 alone, there were over one million ED visits related to nephrolithiasis Higa et al. (2017) [1]. Emergent treatment options range from non-invasive pain control and patient education to lithotripsy and other invasive urologic procedures depending on stone location and related pathology. Urethral calculi are estimated to represent 0.3% of all urinary stone diseases Verit et al. (2006) [2]. There are very few case reports documenting distal urethral stone removal in the ED. Here we present a case of distal urethral stone impaction and the removal of this stone by ED providers, leading to expedited care and prevention of consultation and possible admission. 相似文献
52.
Devin B. Gillaspie Kimberly A. Davis Kevin M. Schuster 《American journal of surgery》2019,217(1):98-102
Background
We hypothesized that trends in total bilirubin in the context of cholecystitis and symptomatic cholelithiasis could be used to guide testing for the presence of common bile duct stones (CBDS).Methods
A review of adult patients with acute cholecystitis or biliary colic with elevated total bilirubin and at least two levels drawn prior to procedural intervention was performed. Trends of total bilirubin and other serum makers were examined to predict the presence of CBDS.Results
The total bilirubin level at presentation, average over 24?h and average over 48?h (3.74?mg/dl vs. 2.29?mg/dl, p?=?0.005; 3.72?mg/dl vs. 2.40?mg/dl, p?=?0.009; 2.41?mg/dl vs. 1.47?mg/dl, p?<?0.001) respectively, were all higher in those with CBDS. However, prediction was not improved by following levels over time.Conclusion
Patients presenting with elevated serum bilirubin, should undergo immediate imaging or procedural intervention rather than obtaining follow-up bilirubin levels. 相似文献53.
B. Kowall N. Lehmann A.A. Mahabadi S. Moebus R. Erbel K.H. Jöckel A. Stang 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(3):228-235
Background and aims
There is controversy on the potentially benign nature of metabolically healthy obesity (MHO), i.e., obese persons with few or no metabolic abnormalities. So far, associations between MHO and coronary artery calcification (CAC), a measure of subclinical atherosclerosis, have mainly been studied cross-sectionally in Asian populations. We assessed cross-sectional and longitudinal MHO CAC associations in a Caucasian population.Methods and results
In the Heinz Nixdorf Recall Study, a population-based cohort study in Germany, CAC was assessed by electron-beam tomography at baseline and at 5-year follow-up. For cross-sectional and longitudinal analyses, we included 1585 participants free of coronary heart disease at baseline, with CAC measurements at baseline and at follow-up, and with either normal weight (BMI 18.5–24.9 kg/m2) or obesity (BMI ≥30.0 kg/m2) at baseline. We used four definitions of MHO. In our main analysis, we defined obese persons as metabolically healthy if they met ≤1 of the NCEP ATP III criteria for the definition of the metabolic syndrome – waist circumference was not taken into account because of collinearity with BMI.Persons with MHO had a higher prevalence of CAC than metabolically healthy normal weight (MHNW) persons (prevalence ratio = 1.59 (95% confidence interval 1.38–1.84) for the main analysis). Persons with MHO had slightly larger odds of CAC progression than persons with MHNW (odds ratios ranged from 1.17 (0.69–1.99) to 1.48 (1.02–2.13) depending on MHO definition and statistical approach).Conclusion
Our analyses on MHO CAC associations add to the evidence that MHO is not a purely benign health condition. 相似文献54.
Bo Yang Elizabeth L. Norton Terry Shih Linda Farhat Xiaoting Wu Whitney E. Hornsby Karen M. Kim Himanshu J. Patel G. Michael Deeb 《The Journal of thoracic and cardiovascular surgery》2019,157(4):1313-1321.e2
Objective
To compare perioperative and long-term outcomes in patients undergoing hemiarch and aggressive arch replacement for acute type A aortic dissection (ATAAD).Methods
From 1996 to 2017, we compared outcomes of hemiarch (n = 322) versus aggressive arch replacements (zones 2 and 3 arch replacement with implantation of 2-4 arch branches, n = 150) in ATAAD. Indications for aggressive arch were arch aneurysm >4 cm or intimal tear in the aortic arch that was not resectable by hemiarch replacement, or dissection of arch branches with malperfusion.Results
Patients in the aggressive arch group were significantly younger (mean age: 57 vs 61 years old) and had significantly longer hypothermic circulatory arrest, cardiopulmonary bypass, and aortic crossclamp times. There were no significant differences in perioperative outcomes between hemiarch and aggressive arch groups, including 30-day mortality (5.3% vs 7.3%, P = .38) and postoperative stroke rate (7% vs 7%, P = .96). Over 15 years, Kaplan–Meier survival was similar between hemiarch and aggressive arch groups (log-rank P = .55, 10-year survival 70% vs 72%). Given death as a competing factor, incidence rates of reoperation over 15 years (2.1% vs 2.0% per year, P = 1) and 10-year cumulative incidence of reoperation (14% vs 12%, P = .89) for arch and distal aorta pathology were similar between the 2 groups.Conclusions
Both hemiarch and aggressive arch replacement are appropriate approaches for select patients with ATAAD. Aggressive arch replacement should be considered for an arch aneurysm >4 cm or an intimal tear at the arch unable to be resected by hemiarch replacement, or dissection of the arch branches with malperfusion. 相似文献55.
56.
M. Corral-Blanco V.C. Prudencio-Ribera M.E. Jarrín-Estupiñán R. Alonso-Moralejo V. Pérez-González J.C. Meneses-Pardo A. Hermira-Anchuelo A. De Pablo-Gafas 《Transplantation proceedings》2019,51(2):380-382
Background
Pulmonary hypertension (PH) is a comorbidity associated with interstitial lung disease (ILD). The purpose of this study was to evaluate the influence of PH on intrahospital mortality in lung transplantation (LT) for ILD.Methods
We conducted a retrospective cohort study of 66 patients who underwent LT for ILD at the 12 de Octubre University Hospital (Madrid, Spain) from October 2008 to June 2014. PH was defined as mean pulmonary arterial pressure (mPAP) ≥25 mmHg on right-sided heart catheterization and intrahospital mortality as any death taken place after the transplantation of patients not being discharged.Results
We retrospectively analyzed data of 66 patients; they were stratified by the presence or absence of PH before LT. Twenty-seven patients (41%) had PH. The PH group had a lower diffusing capacity of carbon monoxide (DLCO), carbon monoxide transfer coefficient (KCO), and 6-minute walk distance test (6MWT) and a higher total lung capacity (TLC), modified medical research council dyspnea scale (mMRC), and lung allocation score (LAS) than the non-PH group. Patients with PH more often underwent double lung transplantation (DLT; 59%) than single lung transplantation (SLT).Intrahospital mortality was 13% (9/66). No significant differences were observed in Kaplan-Meier survival curves for the PH and non-PH groups with a median survival time of 46 days versus 33 days (IQR 26–74; log-rank P = .056); however, the postoperative length of stay in the hospital was greater in the PH group.Conclusions
In our cohort, pulmonary hypertension was not related to early mortality in lung transplantation recipients for interstitial lung diseases. 相似文献57.
Amgad El Mekabaty Monica S. Pearl Bommy Mershon Ivor Berkowitz Philippe Gailloud Thierry A.G.M. Huisman 《Journal of neuroradiology. Journal de neuroradiologie》2019,46(3):214-221
Background and purpose
The vein of Galen aneurysmal malformation (VGAM) is a rare congenital vascular malformation with a higher morbidity and mortality, especially in neonates. Ultrasound, CT and MR are usually used in diagnosis and treatment monitoring of these disorders. In this current study, we aim to examine utility of SWI in evaluation of treatment response in infants with VGAM.Materials and methods
We performed a retrospective chart analysis of children with VGAM in our institution between January 2008 and December 2016. Inclusion criteria included; confirmed VGAM on DSA; available SWI sequence at baseline and at follow up after at least a single embolization session; age at initial MR of 18?years or younger. Signal intensity and Angioarchitecture of VGAM and cerebral veins on SWI, as well as hydrocephalus and clinical outcome were evaluated.Results
Of 11 patients identified with VGAM in our institution, 5 children (3 males and 2 females) satisfied the inclusion criteria. The average age at initial MR was 29?days (range 1–120). Fourteen MRI were available for review. All children had VGAM of mural type. Intramedullary veins were dilated and SWI-hypointense in all children, while subependymal and sulcal veins were dilated and SWI-hypointense in 4 patients on initial MRI. On the first available follow up MRI, cerebral veins have mostly normalized in 4 children and remained mostly dilated and SWI-hypointense in 1 child; even after complete treatment of the VGAM.Conclusion
Our preliminary findings show that SWI seems to offer a beneficial non-invasive tool in evaluating passive venous congestion patterns in pediatric patients with VGAM. It remains to be determined in larger studies, the clinical significance of these SWI changes. 相似文献58.
59.
Chancellor F. Gray Hernan A. Prieto Justin T. Deen Hari K. Parvataneni 《The Journal of arthroplasty》2019,34(2):206-210
Background
Revision total joint arthroplasty (TJA) is associated with increased readmissions, complications, and expense compared to primary TJA. Bundled payment methods have been used to improve value of care in primary TJA, but little is known of their impact in revision TJA patients. The purpose of this study is to evaluate the impact of a care redesign for a bundled payment model for primary TJA on quality metrics for revision patients, despite absence of a targeted intervention for revisions.Methods
We compared quality metrics for all revision TJA patients including readmission rate, use of post–acute care facility after discharge, length of stay, and cost, between the year leading up to the redesign and the 2 years following its implementation. Changes in the primary TJA group over the same time period were also assessed for comparison.Results
Despite a volume increase of 37% over the study period, readmissions declined from 8.9% to 5.8%. Use of post–acute care facilities decreased from 42% to 24%. Length of stay went from 4.84 to 3.92 days. Cost of the hospital episode declined by 5%.Conclusion
Our health system experienced a halo effect from our bundled payment-influenced care redesign, with revision TJA patients experiencing notable improvements in several quality metrics, though not as pronounced as in the primary TJA population. These changes benefitted the patients, the health system, and the payers. We attribute these positive changes to an altered institutional mindset, resulting from an invested and aligned care team, with active physician oversight over the care episode. 相似文献60.
Katherine M. Stenson Benjamin O. Patterson Matthew Joe Grima Jorg L. De Bruin Peter J.E. Holt Ian Loftus 《Journal of vascular surgery》2019,69(1):53-62.e1