全文获取类型
收费全文 | 9618篇 |
免费 | 624篇 |
国内免费 | 82篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 272篇 |
妇产科学 | 215篇 |
基础医学 | 1444篇 |
口腔科学 | 206篇 |
临床医学 | 780篇 |
内科学 | 2360篇 |
皮肤病学 | 188篇 |
神经病学 | 1116篇 |
特种医学 | 327篇 |
外科学 | 1096篇 |
综合类 | 23篇 |
一般理论 | 1篇 |
预防医学 | 521篇 |
眼科学 | 109篇 |
药学 | 717篇 |
中国医学 | 40篇 |
肿瘤学 | 831篇 |
出版年
2024年 | 15篇 |
2023年 | 114篇 |
2022年 | 268篇 |
2021年 | 385篇 |
2020年 | 246篇 |
2019年 | 337篇 |
2018年 | 345篇 |
2017年 | 242篇 |
2016年 | 303篇 |
2015年 | 320篇 |
2014年 | 387篇 |
2013年 | 484篇 |
2012年 | 742篇 |
2011年 | 689篇 |
2010年 | 360篇 |
2009年 | 329篇 |
2008年 | 554篇 |
2007年 | 555篇 |
2006年 | 551篇 |
2005年 | 443篇 |
2004年 | 433篇 |
2003年 | 399篇 |
2002年 | 320篇 |
2001年 | 159篇 |
2000年 | 139篇 |
1999年 | 128篇 |
1998年 | 70篇 |
1997年 | 52篇 |
1996年 | 51篇 |
1995年 | 34篇 |
1994年 | 31篇 |
1993年 | 25篇 |
1992年 | 96篇 |
1991年 | 81篇 |
1990年 | 59篇 |
1989年 | 65篇 |
1988年 | 52篇 |
1987年 | 52篇 |
1986年 | 41篇 |
1985年 | 45篇 |
1984年 | 26篇 |
1983年 | 33篇 |
1982年 | 25篇 |
1981年 | 12篇 |
1980年 | 19篇 |
1979年 | 36篇 |
1978年 | 13篇 |
1977年 | 17篇 |
1973年 | 12篇 |
1966年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Massimo Bellomi Cristiano Rampinelli Giulia Veronesi Sergio Harari Federica Lanfranchi Sara Raimondi Patrick Maisonneuve 《European radiology》2010,20(2):286-292
Purpose
We have little knowledge about the evolution of emphysema, and relatively little is understood about its evolution in relation to smoking habits. This study aims to assess the evolution of emphysema in asymptomatic current and former smokers over 2 years and to investigate the association with subjects’ characteristics. The study was approved by our Ethics Committee and all participants provided written informed consent. 相似文献142.
BS Marino PH Lipkin JW Newburger G Peacock M Gerdes JW Gaynor KA Mussatto K Uzark CS Goldberg WH Johnson J Li SE Smith DC Bellinger WT Mahle;on behalf of the American Heart Association Congenital Heart Defects Committee of the Council on Cardiovascular Disease in the Young Council on Cardiovascular Nursing Stroke Council 《Circulation》2012,126(9):1143-1172
BACKGROUND: The goal of this statement was to review the available literature on surveillance, screening, evaluation, and management strategies and put forward a scientific statement that would comprehensively review the literature and create recommendations to optimize neurodevelopmental outcome in the pediatric congenital heart disease (CHD) population. METHODS AND RESULTS: A writing group appointed by the American Heart Association and American Academy of Pediatrics reviewed the available literature addressing developmental disorder and disability and developmental delay in the CHD population, with specific attention given to surveillance, screening, evaluation, and management strategies. MEDLINE and Google Scholar database searches from 1966 to 2011 were performed for English-language articles cross-referencing CHD with pertinent search terms. The reference lists of identified articles were also searched. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. A management algorithm was devised that stratified children with CHD on the basis of established risk factors. For those deemed to be at high risk for developmental disorder or disabilities or for developmental delay, formal, periodic developmental and medical evaluations are recommended. A CHD algorithm for surveillance, screening, evaluation, reevaluation, and management of developmental disorder or disability has been constructed to serve as a supplement to the 2006 American Academy of Pediatrics statement on developmental surveillance and screening. The proposed algorithm is designed to be carried out within the context of the medical home. This scientific statement is meant for medical providers within the medical home who care for patients with CHD. CONCLUSIONS: Children with CHD are at increased risk of developmental disorder or disabilities or developmental delay. Periodic developmental surveillance, screening, evaluation, and reevaluation throughout childhood may enhance identification of significant deficits, allowing for appropriate therapies and education to enhance later academic, behavioral, psychosocial, and adaptive functioning. 相似文献
143.
Sebastiano Mercadante Francesco Masedu Marco Valenti Alessandro Mercadante Federica Aielli 《Internal and emergency medicine》2016,11(5):713-718
Information regarding advanced cancer patients followed at home who are admitted to the hospital in the last days of life are lacking. The aim of this study was to assess the characteristics of patients who were hospitalized in the last days of life after being assisted by a home palliative care team. The secondary outcome was to identify possible risk factors for hospitalization. The charts were analyzed of a consecutive sample of advanced cancer patients admitted to hospital wards in the last days of life after being followed at home by a palliative care team. Of 550 consecutive patients followed at home, 138 (25.1 %) were admitted to the hospital. Younger patients were more likely to die in the hospital. In a logistic risk analysis adjusted for age, patients with lung and head–neck cancer were more likely to die in the hospital. Patients having a female relative or a female consort as a caregiver were more likely to die at home. CAGE-positive patients (7.25 %), and patients with a shorter period of home assistance were more likely transported to hospital before dying (p = 0.00 and p < 0.024, respectively). The most frequent reason for hospital admission was dyspnea. Admission was more frequent to the oncology ward. Patients who were admitted to the hospital died after a mean of 10.2 days (SD 8.2, range 0–40). This study provides preliminary data on the risk factors of hospitalization at the end of life for advanced cancer patients followed at home. 相似文献
144.
Piccoli M Trambaiolo P Salustri A Cerquetani E Posteraro A Pastena G Amici E Papetti F Marincola E La Carruba S Gambelli G 《Chest》2005,128(5):3413-3420
OBJECTIVES: The aim of this study was to assess the potential value of hand-carried ultrasound (HCU) devices in the diagnosis and follow-up of patients with pleural effusion (PE) after cardiac surgery. METHODS: Seventy consecutive patients were evaluated at bedside early after cardiac surgery, in the upright sitting position, using an HCU device on hospital admission and every 3 days until hospital discharge. The posterior chest wall was scanned along the paravertebral, scapular, and posterior axillary lines. For each hemithorax, an effusion index was derived as the sum of the intercostal spaces between the lower and upper limits of the PE along the lines of scanning, divided by 3. A standard chest radiograph was performed in all patients on hospital admission and at hospital discharge, and was qualitatively scored (0, absent; 1, small; 2, large PE). The findings of the HCU device and radiograph were compared using kappa statistics and the Kruskal-Wallis test. RESULTS: A chest ultrasound was feasible in all patients (mean [+/- SD] time, 5 +/- 2 min). Compared with the chest ultrasound, a physical examination showed a sensitivity of 69% and a specificity of 77%. On hospital admission, the HCU device detected a PE in 72 of 140 hemithoraxes. Agreement with the finding of the radiograph was 76% (kappa = 0.52). In 15 hemithoraxes, the HCU device revealed a PE that had not been diagnosed using the radiograph. Conversely, in 18 hemithoraxes a PE that had been diagnosed with a radiograph was not confirmed by the HCU device. The correlation between ultrasound and radiographic scores was statistically significant (p < 0.001). At hospital discharge, a PE was present in 31 of 140 hemithoraxes according to the findings of the HCU device, and in 38 of 140 hemithoraxes according to the findings of the radiograph (agreement, 78%; kappa = 0.44). CONCLUSIONS: In patients early after cardiac surgery, HCU devices allow rapid PE detection and improve the clinical diagnosis. Compared to a radiograph, this method offers the unique advantage of the bedside evaluation of patients without the need for radiation exposure. 相似文献
145.
Edoardo Giannini Paola Ceppa Federica Botta Alberto Fasoli Paola Romagnoli Elena Cresta Valentina Venturino Domenico Risso Guido Celie Roberto Testa 《Liver international》1999,19(5):432-437
Abstract: Background/Aims: Hepatitis C virus (HCV) related disease follows a long, benign course and most affected patients have mild disease. Liver biopsy is mandatory to grade and stage the disease. Characteristic, though non-specific, HCV histological lesions such as bile duct damage and steatosis have been singled out but their association with non-histological parameters has not been completely defined. Our aim was to study the relationships among these histological lesions and clinical, biochemical, functional and virological characteristics in a group of Northern Italian patients with chronic hepatitis. Methods: We studied 172 patients with HCV-related chronic hepatitis. Patients were divided into groups on the basis of histology including bile duct damage and steatosis. Clinical, biochemical, functional and virological profiles were related to histological findings. Results: Histological grading and staging of disease increased as the age of patients increased. Steatosis was present in 70% of our patients and was related to a higher degree of fibrosis and to decreased functional activity. The prevalence of bile duct damage was 20%. This lesion was present in older patients with higher staging and impaired liver function. Biochemically it was associated with an increase in aspartate aminotransferase, gammaglutamyltranspeptidase, alkaline phosphatase, and total bilirubin. Conclusions: In the population we studied, HCV chronic hepatitis was predominantly a mild disease. Moreover both steatosis and bile duct damage were also mild. Steatosis was associated with fibrosis and this might influence liver metabolic function. Bile duct lesions were found in older patients with advanced disease showing biochemical evidence of cholestasis. The molecular role HCV might play in the pathogenesis of these histological features should be addressed in further studies. 相似文献
146.
Prandoni P Carnovali M Marchiori A;Galilei Investigators 《Archives of internal medicine》2004,164(10):1077-1083
BACKGROUND: Few reports have addressed the value of unfractionated heparin (UFH) or low-molecular-weight heparin in treating the full spectrum of patients with venous thromboembolism (VTE), including recurrent VTE and pulmonary embolism. METHODS: In an open, multicenter clinical trial, 720 consecutive patients with acute symptomatic VTE, including 119 noncritically ill patients (16.5%) with pulmonary embolism and 102 (14.2%) with recurrent VTE, were randomly assigned to treatment with subcutaneous UFH with dose adjusted by activated partial thromboplastin time by means of a weight-based algorithm (preceded by an intravenous loading dose), or fixed-dose (adjusted only to body weight) subcutaneous nadroparin calcium. Oral anticoagulant therapy was started concomitantly and continued for at least 3 months. We recorded the incidence of major bleeding during the initial heparin treatment and that of recurrent VTE and death during 3 months of follow-up. RESULTS: Fifteen (4.2%) of the 360 patients assigned to UFH had recurrent thromboembolic events, as compared with 14 (3.9%) of the 360 patients assigned to nadroparin (absolute difference between rates, 0.3%; 95% confidence interval, -2.5% to 3.1%). Four patients assigned to UFH (1.1%) and 3 patients assigned to nadroparin (0.8%) had episodes of major bleeding (absolute difference between rates, 0.3%; 95% confidence interval, -1.2% to 1.7%). Overall mortality was 3.3% in each group. CONCLUSIONS: Subcutaneous UFH with dose adjusted by activated partial thromboplastin time by means of a weight-based algorithm is as effective and safe as fixed-dose nadroparin for the initial treatment of patients with VTE, including those with pulmonary embolism and recurrent VTE. 相似文献
147.
Diosque P Padilla AM Cimino RO Cardozo RM Negrette OS Marco JD Zacca R Meza C Juarez A Rojo H Rey R Corrales RM Nasser JR Basombrío MA 《The American journal of tropical medicine and hygiene》2004,71(5):590-593
We studied the seroprevalence of antibodies against Trypanosoma cruzi in the human population along with domiciliary infestation by triatomine bugs in an area endemic for Chagas disease in the Chaco Province of Argentina. In addition, we carried out parasitologic surveys in patients, dogs, wild mammals, and vectors. The mean seroprevalence in humans was 27.81% (109 of 392) and 24.14% (63 of 261) in 1-15-year-old children. The minimum domiciliary infestation rate was 13.33%, with certain areas reaching 53.85%. The prevalence was 15.09% (16 of 106) in dogs and 35.71% (10 of 28) in opossums. Infection with T. cruzi was detected in 30.10% (59 of 196) of the Triatoma infestans tested. Compared with nationwide studies, our data suggest that 1) there are zones requiring immediate sanitary action, and 2) nationwide estimates are based on very heterogeneous epidemiologic situations. This heterogeneity emphasizes the importance of in-depth studies of restricted areas to provide additional information for a better understanding of the present status of Chagas disease in Argentina. 相似文献
148.
Effect of erythromycin on gallbladder emptying in diabetic patients with and without autonomic neuropathy and high levels of motilin 总被引:4,自引:0,他引:4
Stefano Fiorucci MD Luciano Scionti MD Rachele Bosso MD Antonio Desando MD Paolo Bottini MD Cecilia Marino MD Prof. Antonio Morelli MD 《Digestive diseases and sciences》1992,37(11):1671-1677
A reduction of gallbladder emptying in response to neural or hormonal stimulation has been reported in patients with diabetes mellitus. Decreased gallbladder emptying may be a key factor in the pathogenesis of gallbladder stones. Few drugs, if any, are able to stimulate gallbladder emptying. However, in a previous study we demonstrated that erythromycin, a macrolide antibiotic, stimulates gallbladder emptying and motilin release in healthy human subjects by an atropine-sensitive pathway. Therefore, the present study was designed to evaluate the effect of erythromycin on gallbladder emptying and motilin release in diabetic patients with or without cardiac autonomic neuropathy (AN). Thirteen diabetic patients, six with AN, and 10 healthy subjects were enrolled in the study protocol. Gallbladder emptying was determined by sonography after ingestion of a standard meal and during infusion of erythromycin alone or together with 6 g/kg/hr atropine. We found that 100 mg/hr erythromycin caused a significant reduction in gallbladder volume in both healthy subjects and diabetic patients. The ejection fraction (mean ±se) of 45.3±8.2% and 37.3±5.0% was similar. The presence of AN had no influence on gallbladder emptying induced by erythromycin. Basal motilin plasma levels were 111.5±14.5 pmol/liter in diabetic patients and 63.3 ±6.0 pmol/liter in healthy subjects (P<0.01). However, patients with AN had higher (130.0 ±11.9 pmol/liter) motilin plasma levels than patients without (74.0±9.4 pmol/liter,P<0.01). Erythromycin administration caused an approximately twofold increase in plasma motilin concentrations in healthy subject and patients withou AN, but did not stimulate motilin release in neuropathic patients. A negative correlation (r=–0.75,P<0.01) was found between basal plasma levels of motilin and peak of gallbladder emptying induced by erythromycin. Atropine completely inhibited the effects of erythromycin on gallbladder emptying and motilin release (P<0.001 by ANOVA). A negative correlation (r=–0.52,P<0.05) was also found between plasma glucose concentrations and peak of gallbladder emptying. Present results demonstrate that erythromycin could be used for treating alterations of gallbladder emptying in diabetic patients with or without AN. 相似文献
149.
Brewer HB Remaley AT Neufeld EB Basso F Joyce C 《Arteriosclerosis, thrombosis, and vascular biology》2004,24(10):1755-1760
High-density lipoproteins (HDL) protect against cardiovascular disease. HDL removes and transports excess cholesterol from peripheral cells to the liver for removal from the body. HDL also protects low-density lipoproteins (LDL) from oxidation and inhibits expression of adhesion molecules in endothelial cells, preventing monocyte movement into the vessel wall. The ABCA1 transporter regulates intracellular cholesterol levels in the liver and in peripheral cells by effluxing excess cholesterol to lipid-poor apoA-I to form nascent HDL, which is converted to mature alpha-HDL by esterification of cholesterol to cholesteryl esters (CE) by lecithin cholesterol acyltransferase. The hepatic ABCA1 transporter and apoA-I are major determinants of levels of plasma alpha-HDL cholesterol as well as poorly lipidated apoA-I, which interact with ABCA1 transporters on peripheral cells in the process of reverse cholesterol transport. Cholesterol in HDL is transported directly back to the liver by HDL or after transfer of CE by the cholesteryl ester transfer protein (CETP) by the apoB lipoproteins. Current approaches to increasing HDL to determine the efficacy of HDL in reducing atherosclerosis involve acute HDL therapy with infusions of apoA-I or apoA-I mimetic peptides and chronic long-term therapy with selective agents to increase HDL, including CETP inhibitors. 相似文献
150.
Rizzi N Liu N Napolitano C Nori A Turcato F Colombi B Bicciato S Arcelli D Spedito A Scelsi M Villani L Esposito G Boncompagni S Protasi F Volpe P Priori SG 《Circulation research》2008,103(3):298-306
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disorder characterized by life threatening arrhythmias elicited by physical and emotional stress in young individuals. The recessive form of CPVT is associated with mutation in the cardiac calsequestrin gene (CASQ2). We engineered and characterized a homozygous CASQ2(R33Q/R33Q) mouse model that closely mimics the clinical phenotype of CPVT patients. CASQ2(R33Q/R33Q) mice develop bidirectional VT on exposure to environmental stress whereas CASQ2(R33Q/R33Q) myocytes show reduction of the sarcoplasmic reticulum (SR) calcium content, adrenergically mediated delayed (DADs) and early (EADs) afterdepolarizations leading to triggered activity. Furthermore triadin, junctin, and CASQ2-R33Q proteins are significantly decreased in knock-in mice despite normal levels of mRNA, whereas the ryanodine receptor (RyR2), calreticulin, phospholamban, and SERCA2a-ATPase are not changed. Trypsin digestion studies show increased susceptibility to proteolysis of mutant CASQ2. Despite normal histology, CASQ2(R33Q/R33Q) hearts display ultrastructural changes such as disarray of junctional electron-dense material, referable to CASQ2 polymers, dilatation of junctional SR, yet normal total SR volume. Based on the foregoings, we propose that the phenotype of the CASQ2(R33Q/R33Q) CPVT mouse model is portrayed by an unexpected set of abnormalities including (1) reduced CASQ2 content, possibly attributable to increased degradation of CASQ2-R33Q, (2) reduction of SR calcium content, (3) dilatation of junctional SR, and (4) impaired clustering of mutant CASQ2. 相似文献