全文获取类型
收费全文 | 962篇 |
免费 | 66篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 62篇 |
妇产科学 | 12篇 |
基础医学 | 120篇 |
口腔科学 | 20篇 |
临床医学 | 124篇 |
内科学 | 159篇 |
皮肤病学 | 10篇 |
神经病学 | 75篇 |
特种医学 | 112篇 |
外科学 | 165篇 |
综合类 | 18篇 |
预防医学 | 71篇 |
眼科学 | 9篇 |
药学 | 39篇 |
中国医学 | 1篇 |
肿瘤学 | 68篇 |
出版年
2021年 | 10篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 10篇 |
2015年 | 11篇 |
2014年 | 22篇 |
2013年 | 25篇 |
2012年 | 27篇 |
2011年 | 31篇 |
2010年 | 19篇 |
2009年 | 37篇 |
2008年 | 28篇 |
2007年 | 66篇 |
2006年 | 23篇 |
2005年 | 33篇 |
2004年 | 25篇 |
2003年 | 25篇 |
2002年 | 23篇 |
2001年 | 27篇 |
2000年 | 34篇 |
1999年 | 20篇 |
1998年 | 27篇 |
1997年 | 15篇 |
1996年 | 24篇 |
1995年 | 21篇 |
1994年 | 23篇 |
1993年 | 15篇 |
1992年 | 20篇 |
1991年 | 27篇 |
1990年 | 33篇 |
1989年 | 35篇 |
1988年 | 28篇 |
1987年 | 36篇 |
1986年 | 25篇 |
1985年 | 20篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 6篇 |
1981年 | 15篇 |
1980年 | 6篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1975年 | 5篇 |
1974年 | 12篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 8篇 |
1909年 | 5篇 |
排序方式: 共有1080条查询结果,搜索用时 15 毫秒
31.
Nastassja Köhn Johannes Maubach Rene Warschkow Catherine Tsai Daniel P. Nussbaum Daniel Candinas Beat Gloor Bruno M. Schmied Dan G. Blazer Mathias Worni 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2018,20(11):1073-1081
Background
Current consensus guidelines suggest that gallbladder cancer (GBC) patients with resected T1a disease can be observed while patients with T1b or greater lesions should undergo lymphadenectomy (LNE). The primary aim of this study was to critically explore the impact of LNE in early-stage GBC on overall survival (OS) on a population-based level.Method
The 2004–2014 National Cancer Database was reviewed to identify non-metastatic GBC patients with T1a, T1b, or T2 disease and grouped whether a dedicated LNE was performed. OS and relative survival were assessed using Cox proportional hazard regression analyses before and after propensity score adjustments.Results
4015 patients were included, 246 (6%) had T1a, 654 (16%) T1b, and 3115 (78%) T2 GBC. The rate of positive lymph nodes was 13%, 12%, and 40% for T1a, T1b, and T2 tumors, respectively. Even after propensity score adjustment, no OS benefit was found if LNE was performed for T1a disease (HR:0.63, 95%CI:0.35–1.13) while OS was improved for T1b (HR:0.65, 95%CI:0.49–0.87) and T2 tumors (HR:0.65, 95%CI:0.57–0.73).Conclusion
Despite a higher rate of nodal positivity among patients with T1a disease compared to previous reports, there was no impact on survival and current treatment guidelines appear appropriate for the management of T1a disease. 相似文献32.
BACKGROUND:
Flavonoids are polyphenolic substances with antioxidant properties, and they are found in different vegetables and fruits. Epidemiological studies have shown that the consumption of flavonoids reduces the prevalence of cardiovascular diseases. The use of synthetic antioxidants, however, has been limited because of their toxicity. Therefore, medical researchers have intensified their quest to find natural antioxidants.OBJECTIVES:
To investigate the effect of several pure flavonoids, such as kaempferol, quercetin, morin and rutin, on red blood cell hemolysis and evaluate their -SH capacity as an indicator of membrane protection.METHODS:
The rate of hemolysis and cell membrane -SH capacity were determined by spectrophotometry. Red blood cell peroxidation was induced using 2,2′-azo-bis-(2-amidinopropane) dihydrochloride. The effect of each flavonoid on hemolysis was examined at three concentrations (0.5 μg/mL, 5 μg/mL and 10 μg/mL), however, only the greatest concentration (10 μg/mL) of each flavonoid was used to study the effect on -SH groups.RESULTS:
In all cases, the antioxidant activity was dose-dependent. Rutin showed the highest inhibitory effect on hemolysis among flavonoids (42.5%). The protective effect of kaempferol, rutin and morin against -SH group oxidation measured 7.7%, 23.3% and 26.4%, respectively.CONCLUSIONS:
Results showed that flavonoids and flavonoid-containing plants can be used as natural antioxidants for the treatment and prevention of disease conditions, the pathogenesis of which is mediated by lipid peroxidation. 相似文献33.
Melanie Rylander Carolyn Valdez Abraham M. Nussbaum 《The American journal of drug and alcohol abuse》2014,40(4):269-273
Introduction: Suicide is among the 10 most common causes of death in the United States. Researchers have identified a number of factors associated with completed suicide, including marijuana use, and increased land elevation. Colorado is an ideal state to test the strength of these associations. The state has a completed suicide rate well above the national average and over the past 15 years has permitted first the medical and, as 2014, the recreational use of marijuana. Objectives: To determine if there is a correlation between medical marijuana use, as assessed by the number of medical marijuana registrants and completed suicides per county in Colorado. Methods: The number of medical marijuana registrants was used as a proxy for marijuana use. Analysis variables included total medical marijuana registrants, medical marijuana dispensaries per county, total suicide deaths, mechanism of suicide death, gender, total suicide hospitalizations, total unemployment, and county-level information such as mean elevation and whether the county was urban or rural. Analysis was performed with mixed model Poisson regression using generalized linear modeling techniques. Results: We found no consistent association between the number of marijuana registrants and completed suicide after controlling for multiple known risk factors for completed suicide. Conclusion: The legalization of medical marijuana may not have an adverse impact on suicide rates. Given the concern for the increased use of marijuana after its legalization, our negative findings provide some reassurance. However, this conclusion needs to be examined in light of the limitations of our study and may not be generalizable to those with existing severe mental illness. This finding may have significant public health implications for the presumable increase in marijuana use that may follow legalization. 相似文献
34.
35.
Purpose
Plastic bronchitis is the occlusion of the major bronchial airways by a firm, gelatinous mucoid cast. It is a rare condition, which while classically described in asthma and sickle cell disease has greater mortality in patients with congenital heart disease. The management of this disease is obscure given the lack of clinical data regarding treatment therapies.Methods
We describe a case of an 11-year-old female status after Fontan surgery who presented with respiratory distress secondary to atelectasis of the right lung.Results
A bronchoscopy was performed demonstrating an obstructing bronchial cast with successful extraction. The plastic bronchitis continued to recur and she was placed on multiple inhaled mucolytics as well as inhaled tissue plasminogen activator with temporary resolution. Further evaluation of the etiology of her casts revealed that she had elevated pulmonary arterial pressures. Repeated bronchoscopic removal of the casts was utilized as well as continuation of the aggressive airway clearance. Ultimately fenestration of her Fontan was performed along with treatment of pulmonary vasodilators sildenafil and bosentan. Although there was improvement of the cast formation, her airway clearance could only be weaned to four times a day therapy with which she was discharged home after a 3-month hospitalization. She continues to remain on this therapy and has not required hospitalization since the initial incident over 1?year ago.Conclusions
Plastic bronchitis in a patient with Fontan physiology presents a treatment dilemma that may require comprehensive therapy in severe cases such as described. 相似文献36.
Background
Bivalirudin is an ultrashort acting direct thrombin inhibitor, which has been used in place of heparin in selected settings. We describe our preliminary experience with the use of bivalirudin in patients who required anticoagulation for a deep vein thrombosis, prosthetic heart valve, or hypercoagulable state but were felt to be at high risk for the use of heparin.Methods
Eight patients in our neurocritical care unit required anticoagulation but were felt to be poor candidates for heparin either due to heparin-induced thrombocytopenia or due to high risk for intracranial hemorrhage. A standard protocol was utilized for bivalirudin with a loading dose of 0.75 mg/kg followed by a continuous infusion of 0.15 mg/kg hr. Serial aPTT levels were checked on a routine basis to monitor therapeutic effect. The bivalirudin infusion was continued for a period of 2 days to 2 weeks prior to starting coumadin therapy.Results
These patients were in the early postoperative period (within 48 h) following craniotomy, had suffered a recent large hemispheric infarct with hemorrhagic conversion, or had presented with an acute intracerebral hemorrhage. In this small series of patients, no intracranial hemorrhagic complications were encountered. No patients demonstrated progressive systemic thrombotic issues while on bivalirudin.Conclusion
Based on these findings, bivalirudin may represent a reasonable alternative in patients for whom heparin anticoagulation is contraindicated. A larger multicenter trial of bivalirudin in this setting may be appropriate 相似文献37.
38.
Samuel R. Nussbaum Marissa J. Carter Caroline E. Fife Joan DaVanzo Randall Haught Marcia Nusgart Donna Cartwright 《Value in health》2018,21(1):27-32
Objective
The aim of this study was to determine the cost of chronic wound care for Medicare beneficiaries in aggregate, by wound type and by setting.Methods
This retrospective analysis of the Medicare 5% Limited Data Set for calendar year 2014 included beneficiaries who experienced episodes of care for one or more of the following: arterial ulcers, chronic ulcers, diabetic foot ulcers, diabetic infections, pressure ulcers, skin disorders, skin infections, surgical wounds, surgical infections, traumatic wounds, venous ulcers, or venous infections. The main outcomes were the prevalence of each wound type, Medicare expenditure for each wound type and aggregate, and expenditure by type of service.Results
Nearly 15% of Medicare beneficiaries (8.2 million) had at least one type of wound or infection (not pneumonia). Surgical infections were the largest prevalence category (4.0%), followed by diabetic infections (3.4%). Total Medicare spending estimates for all wound types ranged from $28.1 to $96.8 billion. Including infection costs, the most expensive estimates were for surgical wounds ($11.7, $13.1, and $38.3 billion), followed by diabetic foot ulcers ($6.2, $6.9, and $18.7 billion,). The highest cost estimates in regard to site of service were for hospital outpatients ($9.9–$35.8 billion), followed by hospital inpatients ($5.0–$24.3 billion).Conclusions
Medicare expenditures related to wound care are far greater than previously recognized, with care occurring largely in outpatient settings. The data could be used to develop more appropriate quality measures and reimbursement models, which are needed for better health outcomes and smarter spending for this growing population. 相似文献39.
Nussbaum EL, Locke M. Heat shock protein expression in rat skeletal muscle after repeated applications of pulsed and continuous ultrasound.
Objective
To determine whether repeated ultrasound treatments are capable of increasing the expression of heat shock protein (HSP) 72 and HSP 25 in rat skeletal muscles.Design
In vivo, experimental, controlled study.Setting
Animal laboratory.Animals
Male Sprague-Dawley rats (n=9).Interventions
Ultrasound (1MHz, 15min, 2.0cm2 transducer) continuous at 1.0W/cm2 spatial average temporal average intensity (CONTUS) or pulsed at 2.0W/cm2 spatial average temporal peak intensity 50% duty cycle (PULS50) was applied on 4 consecutive days to the lower leg muscles of 1 hindlimb in each rat (n=9).Main Outcome Measures
Twenty-four hours after the final ultrasound application, hindlimb muscles were removed, weighed, and assessed for HSP 72 and HSP 25 content by Western blotting. Bands from blots were quantified and data were assessed using t tests (α=.05).Results
Ultrasound did not affect core or contralateral hindlimb muscle temperature. Average muscle temperatures during the final day ultrasound treatments were 38.71°±0.30°C when using PULS50 and 38.16°±0.57°C when using CONTUS. PULS50 significantly increased HSP 25 content in the plantaris and soleus muscles and HSP 72 content in the plantaris muscles. CONTUS significantly increased HSP 72 content in the white gastrocnemius muscle.Conclusions
HSPs can be induced in skeletal muscle when ultrasound is used on a repeated basis to treat soft tissue. 相似文献40.
Deficiency in the p110alpha subunit of PI3K results in diminished Tie2 expression and Tie2(-/-)-like vascular defects in mice 下载免费PDF全文
Phosphoinositide 3-kinase (PI3K) is activated by transmembrane tyrosine kinases such as vascular endothelial growth factor (VEGF) receptors and Tie2 (tunica intima endothelial kinase 2), both of which are key regulators of vascular development. However, the in vivo role of PI3K during developmental vascularization remains to be defined. Here we demonstrate that mice deficient in the p110alpha catalytic subunit of PI3K display multiple vascular defects, including dilated vessels in the head, reduced branching morphogenesis in the endocardium, lack of hierarchical order of large and small branches in the yolk sac, and impaired development of anterior cardinal veins. These vascular defects are strikingly similar to those in mice defective in the Tie2 signaling pathway. Indeed, Tie2 protein levels were significantly lower in p110alpha-deficient mice. Furthermore, RNA interference of p110alpha in cultured endothelial cells significantly reduced Tie2 protein levels. These findings raise the possibility that PI3K may function as an upstream regulator of Tie2 expression during mouse development. 相似文献