全文获取类型
收费全文 | 1408篇 |
免费 | 120篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 154篇 |
妇产科学 | 38篇 |
基础医学 | 183篇 |
口腔科学 | 12篇 |
临床医学 | 95篇 |
内科学 | 239篇 |
神经病学 | 72篇 |
特种医学 | 27篇 |
外科学 | 331篇 |
综合类 | 11篇 |
预防医学 | 93篇 |
眼科学 | 2篇 |
药学 | 159篇 |
肿瘤学 | 108篇 |
出版年
2021年 | 25篇 |
2020年 | 11篇 |
2019年 | 20篇 |
2018年 | 23篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 22篇 |
2014年 | 32篇 |
2013年 | 30篇 |
2012年 | 65篇 |
2011年 | 72篇 |
2010年 | 45篇 |
2009年 | 33篇 |
2008年 | 59篇 |
2007年 | 67篇 |
2006年 | 54篇 |
2005年 | 68篇 |
2004年 | 62篇 |
2003年 | 62篇 |
2002年 | 53篇 |
2001年 | 48篇 |
2000年 | 53篇 |
1999年 | 57篇 |
1998年 | 20篇 |
1997年 | 21篇 |
1996年 | 17篇 |
1995年 | 9篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 31篇 |
1991年 | 36篇 |
1990年 | 35篇 |
1989年 | 32篇 |
1988年 | 38篇 |
1987年 | 31篇 |
1986年 | 35篇 |
1985年 | 33篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 10篇 |
1972年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有1531条查询结果,搜索用时 31 毫秒
31.
32.
H. F. Raymond Y.-H. Chen S. L. Syme R. Catalano M. A. Hutson W. McFarland 《AIDS and behavior》2014,18(2):346-356
We examined socioeconomic status and social and sexual network factors and their relationship to HIV acquisition risk among HIV-negative Black MSM (BMSM), White MSM (WMSM) and transfemales (male to female transgenders). Geographic analysis examined residential patterns and neighborhood patterns of HIV prevalence in San Francisco. Factors associated with engaging in more episodes of potentially HIV serodiscordant unprotected receptive anal intercourse were analyzed. Transfemales and BMSM were more likely to live in areas of higher HIV prevalence and lower income compared to WMSM. BMSM and transfemales had lower socioeconomic scores (SES) scores compared to WMSM. BMSM were more likely to report serodiscordant partnerships and higher numbers of potentially serodiscordant unprotected sex acts. Decreasing individual SES did not predict serodiscordant partnerships in any group. Increasing neighborhood HIV prevalence predicted an increase in the number of potentially serodiscordant unprotected sex acts among transfemales and BMSM but only significantly so for transfemales. Prevention interventions must consider neighborhood HIV prevalence, and HIV prevalence in social/sexual networks, in addition to considering individual level behavior change or poverty reduction. 相似文献
33.
34.
35.
36.
Girard F Chaboillez S Cartier A Côté J Hargreave FE Labrecque M Malo JL Tarlo SM Lemière C 《American journal of respiratory and critical care medicine》2004,170(8):845-850
Monitoring airway inflammation by means of induced sputum cell counts seems to improve the management of asthma. We sought to assess whether such monitoring at the end of periods at and away from work combined with the monitoring of PEF could improve the diagnosis of occupational asthma. We enrolled subjects suspected of having occupational asthma. Serial monitoring of PEF was performed during 2 weeks at and away from work. At the end of each period, induced sputum was collected. Specific inhalation challenge was subsequently performed. PEF graphs were interpreted visually by five independent observers. Forty-nine subjects, including 23 with positive specific inhalation challenge, completed the study. The addition of sputum cell counts to the monitoring of PEF increased the specificity of this test, respectively, by 18 (range [r] 13.7-25.5) or 26.8% (r 24.8-30.4) depending if an increase of sputum eosinophils greater than 1 or 2% when at work was considered as significant. The sensitivity increased by 8.2% (r 4.1-13.4) or decreased by 12.3% (r 3.1-24.1) depending on the cutoff value in sputum eosinophils chosen (greater than 1 or 2%, respectively). The addition of sputum cell counts to PEF monitoring is useful to improve the diagnosis of occupational asthma. 相似文献
37.
38.
39.
This article reviews the most significant developments reported between July 2006 and July 2007 in the fields of pediatric cardiology and congenital heart disease, in diagnosis and treatment in particular. In the area of imaging techniques, the increasing clinical roles of magnetic resonance imaging, tissue Doppler imaging and three-dimensional echocardiography are highlighted, as is the application of these techniques to fetal cardiology and its repercussions. The incidence and treatment of arrhythmias in children are also discussed and, with regard to heart failure, there is an assessment of recent findings in epidemiology and diagnosis, new drugs, ventricular assist systems, and the current status of heart transplantation. In the area of interventional cardiology, present-day techniques for the closure of atrial and ventricular septal defects are reviewed and there is an assessment of early results with partially absorbable devices, percutaneous pulmonary valve implantation, and new types of stent (e.g., premounted, coated and absorbable stents). In cardiac surgery, the focus is on studies that evaluate outcome quality, the search for new biocompatible conduits, experience with new techniques for treating complex transpositions (e.g., the Nikaidoh procedure and its variants), the medium- and long-term results of treating aortic valvular disease with pulmonary autografts (i.e., the Ross and Ross-Konno procedures), and current findings on the treatment of pulmonary insufficiency after correction of either the tetralogy of Fallot or a dysfunctional Fontan circuit. 相似文献
40.
D.J. Petite Felipe M.I. Rivera Campos J. San Miguel Espinosa Y. Malo Rubio J.C. Flores Quan M.V. Cuartero Revilla 《Radiologia》2021,63(4):324-333
Background and aimsWe aimed to analyze the relationship between the initial chest X-ray findings in patients with severe acute respiratory syndrome due to infection with SARS-CoV-2 and eventual clinical worsening and to compare three systems of quantifying these findings.Material and methodsThis retrospective study reviewed the clinical and radiological evolution of 265 adult patients with COVID-19 attended at our center between March 2020 and April 2020. We recorded data related to patients’ comorbidities, hospital stay, and clinical worsening (admission to the ICU, intubation, and death). We used three scoring systems taking into consideration 6 or 8 lung fields (designated 6 A, 6 B, and 8) to quantify lung involvement in each patient's initial abnormal chest X-ray and to classify its severity as mild, moderate, or severe, and we compared these three systems. We also recorded the presence of alveolar opacities and linear opacities (fundamentally linear atelectasis) in the first chest X-ray with pathologic findings.ResultsIn the χ2 analysis, moderate or severe involvement in the three classification systems correlated with hospital admission (p = 0.009 in 6 A, p = 0.001 in 6 B, and p = 0.001 in 8) and with death (p = 0.02 in 6 A, p = 0.01 in 6 B, and p = 0.006 in 8). In the regression analysis, the most significant associations were 6 B with alveolar involvement (OR 2.3; 95%CI 1.1.–4.7; p = 0.025;) and 8 with alveolar involvement (OR 2.07; 95% CI 1.01.–4.25; p = 0.046). No differences were observed in the ability of the three systems to predict clinical worsening by classifications of involvement in chest X-rays as moderate or severe.ConclusionModerate/severe extension in the three chest X-ray scoring systems evaluating the extent of involvement over 6 or 8 lung fields and the finding of alveolar opacities in the first abnormal X-ray correlated with mortality and the rate of hospitalization in the patients studied. No significant difference was found in the predictive ability of the three classification systems proposed. 相似文献