全文获取类型
收费全文 | 3139篇 |
免费 | 189篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 44篇 |
妇产科学 | 69篇 |
基础医学 | 427篇 |
口腔科学 | 23篇 |
临床医学 | 276篇 |
内科学 | 1003篇 |
皮肤病学 | 65篇 |
神经病学 | 249篇 |
特种医学 | 62篇 |
外科学 | 238篇 |
综合类 | 8篇 |
一般理论 | 1篇 |
预防医学 | 285篇 |
眼科学 | 35篇 |
药学 | 165篇 |
中国医学 | 3篇 |
肿瘤学 | 348篇 |
出版年
2023年 | 12篇 |
2022年 | 54篇 |
2021年 | 108篇 |
2020年 | 56篇 |
2019年 | 109篇 |
2018年 | 86篇 |
2017年 | 74篇 |
2016年 | 61篇 |
2015年 | 67篇 |
2014年 | 112篇 |
2013年 | 144篇 |
2012年 | 242篇 |
2011年 | 258篇 |
2010年 | 146篇 |
2009年 | 139篇 |
2008年 | 211篇 |
2007年 | 206篇 |
2006年 | 205篇 |
2005年 | 174篇 |
2004年 | 175篇 |
2003年 | 140篇 |
2002年 | 166篇 |
2001年 | 42篇 |
2000年 | 26篇 |
1999年 | 44篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 35篇 |
1995年 | 28篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 29篇 |
1991年 | 19篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
排序方式: 共有3338条查询结果,搜索用时 31 毫秒
101.
Torre-Cisneros J Fortún J Aguado JM de la Cámara R Cisneros JM Gavaldá J Gurguí M Lumbreras C Martín C Martín-Dávila P Montejo M Moreno A Muñoz P Pahissa A Pérez JL Rovira M Bernardos A Gil-Vernet S Quijano Y Rábago G Román A Varó E 《Enfermedades infecciosas y microbiología clínica》2005,23(7):424-437
Cytomegalovirus (CMV) infection remains an important complication of transplantation. The last decade has been characterized by improvements to management that has reduced its morbidity and mortality. The advance has been particularly important in the diagnosis and prevention. Several techniques have been developed that allow the increasingly rapid and sensitive diagnosis. The different preventive strategies include use of appropriate blood products, immune globulin, and antiviral agents either as prophylaxis or pre-emptive therapy. The development of effective oral drugs as valganciclovir also represents a new advance. It is necessary to summarize these advances to facilitate the development of local policies reflecting recent changes. The Group of Study of Infections in Transplantation (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) has therefore produced actual recommendations in the management of CMV infection after transplantation. 相似文献
102.
Epidemiology and outcomes of ventilator-associated pneumonia in a large US database 总被引:52,自引:0,他引:52
Rello J Ollendorf DA Oster G Vera-Llonch M Bellm L Redman R Kollef MH;VAP Outcomes Scientific Advisory Group 《Chest》2002,122(6):2115-2121
OBJECTIVES: To evaluate risk factors for ventilator-associated pneumonia (VAP), as well as its influence on in-hospital mortality, resource utilization, and hospital charges. DESIGN: Retrospective matched cohort study using data from a large US inpatient database. PATIENTS: Patients admitted to an ICU between January 1998 and June 1999 who received mechanical ventilation for > 24 h. MEASUREMENTS: Risk factors for VAP were examined using crude and adjusted odds ratios (AORs). Cases of VAP were matched on duration of mechanical ventilation, severity of illness on admission (predicted mortality), type of admission (medical, surgical, trauma), and age with up to three control subjects. Mortality, resource utilization, and billed hospital charges were then compared between cases and control subjects. RESULTS: Of the 9,080 patients meeting study entry criteria, VAP developed in 842 patients (9.3%). The mean interval between intubation, admission to the ICU, hospital admission, and the identification of VAP was 3.3 days, 4.5 days, and 5.4 days, respectively. Identified independent risk factors for the development of VAP were male gender, trauma admission, and intermediate deciles of underlying illness severity (on admission) [AOR, 1.58, 1.75, and 1.47 to 1.70, respectively]. Patients with VAP were matched with 2,243 control subjects without VAP. Hospital mortality did not differ significantly between cases and matched control subjects (30.5% vs 30.4%, p = 0.713). Nevertheless, patients with VAP had a significantly longer duration of mechanical ventilation (14.3 +/- 15.5 days vs 4.7 +/- 7.0 days, p < 0.001), ICU stay (11.7 +/- 11.0 days vs 5.6 +/- 6.1 days, p < 0.001), and hospital stay (25.5 +/- 22.8 days vs 14.0 +/- 14.6 days, p < 0.001). Development of VAP was also associated with an increase of > $40,000 USD in mean hospital charges per patient ($104,983 USD +/- $91,080 USD vs $63,689 USD+/- $75,030 USD, p < 0.001). CONCLUSIONS: This retrospective matched cohort study, the largest of its kind, demonstrates that VAP is a common nosocomial infection that is associated with poor clinical and economic outcomes. While strategies to prevent the occurrence of VAP may not reduce mortality, they may yield other important benefits to patients, their families, and hospital systems. 相似文献
103.
Marc Argente Elisenda Miró Carmina Martí Ana Vilamala Carles Alonso-Tarrés Frederic Ballester Ana Calderón Carmen Gallés Asunción Gasós Beatriz Mirelis Montserrat Morta Montserrat Olsina Goretti Sauca Montserrat Sierra Alba Rivera Ferran Navarro 《Enfermedades infecciosas y microbiología clínica》2019,37(2):82-88
104.
105.
Miquel Gómez Joan Vila Roberto Elosua Lluís Molina Jordi Bruguera Joan Sala Rafel Masià Maria Isabel Covas Jaume Marrugat Montserrat Fitó 《Atherosclerosis》2014
Objectives
To assess 1) the association of lipid oxidation biomarkers with 10-year coronary artery disease (CAD) events and subclinical atherosclerosis, and 2) the reclassification capacity of these biomarkers over Framingham-derived CAD risk functions, in a general population.Methods
Within the framework of the REGICOR study, 4782 individuals aged between 25 and 74 years were recruited in a population-based cohort study. Follow-up of the 4042 who met the eligibility criteria was carried out. Plasma, circulating oxidized low-density lipoprotein (oxLDL) and oxLDL antibodies (OLAB) were measured in a random sample of 2793 participants.End-points included fatal and non-fatal acute myocardial infarction (AMI) and angina. Carotid intima-media thickness (IMT) in the highest quintile and ankle-brachial index <0.9 were considered indicators of subclinical atherosclerosis.Results
Mean age was 50.0 (13.4) years, and 52.4% were women. There were 103 CAD events (34 myocardial infarction, 43 angina, 26 coronary deaths), and 306 subclinical atherosclerosis cases. Oxidized LDL was independently associated with higher incidence of CAD events (HR = 1.70; 95% Confidence Interval: 1.02–2.84), but not with subclinical atherosclerosis. The net classification index of the Framingham-derived CAD risk function was significantly improved when ox-LDL was included (NRI = 14.67% [4.90; 24.45], P = 0.003). No associations were found between OLAB and clinical or subclinical events. The reference values for oxLDL and OLAB are also provided (percentiles).Conclusions
OxLDL was independently associated with 10-year CAD events but not subclinical atherosclerosis in a general population, and improved the reclassification capacity of Framingham-derived CAD risk functions. 相似文献106.
Josep Julve Eva Pardina Montserrat Pérez-Cuéllar Roser Ferrer Joana Rossell Juan Antonio Baena-Fustegueras José Manuel Fort Albert Lecube Francisco Blanco-Vaca José Luis Sánchez-Quesada Julia Peinado-Onsurbe 《Atherosclerosis》2014
Objective
The purpose of this study was to evaluate the effect of weight loss induced in morbidly obese subjects by Roux-en-Y gastric bypass bariatric surgery on the atherogenic features of their plasma lipoproteins.Methods
Twenty-one morbidly obese subjects undergoing bariatric surgery were followed up for up to 1 year after surgery. Plasma and lipoproteins were assayed for chemical composition and lipoprotein-associated phospholipase A2 (Lp-PLA2) activity. Lipoprotein size was assessed by non-denaturing polyacrylamide gradient gel electrophoresis, and oxidised LDL by ELISA. Liver samples were assayed for mRNA abundance of oxidative markers.Results
Lipid profile analysis revealed a reduction in the plasma concentrations of cholesterol and triglycerides, which were mainly associated with a significant reduction in the plasma concentration of circulating apoB-containing lipoproteins rather than with changes in their relative chemical composition. All patients displayed a pattern A phenotype of LDL subfractions and a relative increase in the antiatherogenic plasma HDL-2 subfraction (>2-fold; P < 0.001). The switch towards predominantly larger HDL particles was due to an increase in their relative cholesteryl ester content. Excess weight loss also led to a significant decrease in the plasma concentration of oxidised LDL (∼−25%; P < 0.01) and in the total Lp-PLA2 activity. Interestingly, the decrease in plasma Lp-PLA2 was mainly attributed to a decrease in the apoB-containing lipoprotein-bound Lp-PLA2.Conclusion
Our data indicate that the weight loss induced by bariatric surgery ameliorates the atherogenicity of plasma lipoproteins by reducing the apoB-containing Lp-PLA2 activity and oxidised LDL, as well as increasing the HDL-2 subfraction. 相似文献107.
108.
Diego Alfonso Lpez-Mora Marina Sizova Montserrat Estorch Albert Flotats Valle Camacho Alejandro Fernndez Safae Abouzian Francisco Fuentes-Ocampo Jos Ignacio Prez Garcia Ana Isabel Chico Ballesteros Joan Duch Anna Domnech Antonio Moral Duarte Ignasi Carri 《European journal of nuclear medicine and molecular imaging》2020,47(3):572-578
To compare detectability of hyperfunctioning parathyroid tissue (HPT) by digital and analog 18F-fluorocholine PET/CT in patients with primary hyperparathyroidism and negative/inconclusive 99mTc-MIBI scintigraphy-SPECT/CT. Thirty-three patients with primary hyperparathyroidism and negative/inconclusive 99mTc-MIBI scintigraphy-SPECT/CT were prospectively included. All patients accepted to be scanned by digital and analog PET/CT in the same imaging session after a single injection of 18F-fluorocholine. Three nuclear medicine physicians evaluated the digital and analog PET/CT datasets to assess the detection rate of HPT. Maximum standard uptake values (SUVmax) of HPT and locoregional lymph nodes were measured in both systems. HPT was detected in 30/33 patients by the digital system, whereas it was detected in 22/33 patients by the analog system (p < 0.01). Moreover, in 21 of these 33 patients, both systems detected one focal 18F-fluorocholine uptake, and in one patient the digital system detected two foci. Histopathology demonstrated HPT in 32 patients and it was inconclusive in one patient. The digital PET/CT detected HPT in 29 of the 32 patients, and the analog system in 22 of the 32 (p < 0.01). All HPT suspected lesions resected and detected only by the digital system (n = 8) were < 10 mm (7.5 ± 1.3 mm), while those detected by both systems (n = 22) were > 10 mm (13 ± 3.8 mm). SUVmax of HPT lesions was significantly higher than SUVmax of locoregional lymph node independently of the PET/CT system used (4.5 ± 1.9 vs. 2.9 ± 1.3, p < 0.0001). Digital PET/CT offers superior performance over analog system in patients with suspected HPT and previous negative/inconclusive imaging examinations, particularly in sub-centimeter lesions. SUVmax can help in the differentiation between HTP and locoregional lymph nodes. 相似文献
109.
Maria Tellez-Plaza Wan-yee Tang Yan Shang Jason G. Umans Kevin A. Francesconi Walter Goessler Marta Ledesma Montserrat Leon Martin Laclaustra Jonathan Pollak Eliseo Guallar Shelley A. Cole M. Dani Fallin Ana Navas-Acien 《Environmental health perspectives》2014,122(9):946-954
Background: The association between human blood DNA global methylation and global hydroxymethylation has not been evaluated in population-based studies. No studies have evaluated environmental determinants of global DNA hydroxymethylation, including exposure to metals.Objective: We evaluated the association between global DNA methylation and global DNA hydroxymethylation in 48 Strong Heart Study participants for which selected metals had been measured in urine at baseline and DNA was available from 1989–1991 (visit 1) and 1998–1999 (visit 3).Methods: We measured the percentage of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in samples using capture and detection antibodies followed by colorimetric quantification. We explored the association of participant characteristics (i.e., age, adiposity, smoking, and metal exposure) with both global DNA methylation and global DNA hydroxymethylation.Results: The Spearman’s correlation coefficient for 5-mC and 5-hmC levels was 0.32 (p = 0.03) at visit 1 and 0.54 (p < 0.001) at visit 3. Trends for both epigenetic modifications were consistent across potential determinants. In cross-sectional analyses, the odds ratios of methylated and hydroxymethylated DNA were 1.56 (95% CI: 0.95, 2.57) and 1.76 (95% CI: 1.07, 2.88), respectively, for the comparison of participants above and below the median percentage of dimethylarsinate. The corresponding odds ratios were 1.64 (95% CI: 1.02, 2.65) and 1.16 (95% CI: 0.70, 1.94), respectively, for the comparison of participants above and below the median cadmium level. Arsenic exposure and metabolism were consistently associated with both epigenetic markers in cross-sectional and prospective analyses. The positive correlation of 5-mC and 5-hmC levels was confirmed in an independent study population.Conclusions: Our findings support that both epigenetic measures are related at the population level. The consistent trends in the associations between these two epigenetic modifications and the characteristics evaluated, especially arsenic exposure and metabolism, suggest the need for understanding which of the two measures is a better biomarker for environmental epigenetic effects in future large-scale epidemiologic studies.Citation: Tellez-Plaza M, Tang WY, Shang Y, Umans JG, Francesconi KA, Goessler W, Ledesma M, Leon M, Laclaustra M, Pollak J, Guallar E, Cole SA, Fallin MD, Navas-Acien A. 2014. Association of global DNA methylation and global DNA hydroxymethylation with metals and other exposures in human blood DNA samples. Environ Health Perspect 122:946–954; http://dx.doi.org/10.1289/ehp.1306674 相似文献
110.