全文获取类型
收费全文 | 2089篇 |
免费 | 131篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 68篇 |
妇产科学 | 34篇 |
基础医学 | 308篇 |
口腔科学 | 17篇 |
临床医学 | 274篇 |
内科学 | 494篇 |
皮肤病学 | 79篇 |
神经病学 | 215篇 |
特种医学 | 42篇 |
外科学 | 199篇 |
综合类 | 13篇 |
一般理论 | 1篇 |
预防医学 | 165篇 |
眼科学 | 24篇 |
药学 | 132篇 |
中国医学 | 5篇 |
肿瘤学 | 142篇 |
出版年
2023年 | 16篇 |
2022年 | 30篇 |
2021年 | 52篇 |
2020年 | 39篇 |
2019年 | 49篇 |
2018年 | 45篇 |
2017年 | 28篇 |
2016年 | 46篇 |
2015年 | 43篇 |
2014年 | 66篇 |
2013年 | 110篇 |
2012年 | 162篇 |
2011年 | 119篇 |
2010年 | 79篇 |
2009年 | 89篇 |
2008年 | 158篇 |
2007年 | 153篇 |
2006年 | 150篇 |
2005年 | 119篇 |
2004年 | 107篇 |
2003年 | 117篇 |
2002年 | 108篇 |
2001年 | 31篇 |
2000年 | 19篇 |
1999年 | 24篇 |
1998年 | 27篇 |
1997年 | 25篇 |
1996年 | 13篇 |
1995年 | 11篇 |
1994年 | 16篇 |
1993年 | 16篇 |
1992年 | 16篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1977年 | 6篇 |
1970年 | 3篇 |
1968年 | 3篇 |
1965年 | 3篇 |
1964年 | 3篇 |
1923年 | 3篇 |
1922年 | 3篇 |
排序方式: 共有2233条查询结果,搜索用时 31 毫秒
1.
BackgroundEpidemiological studies on peptic ulcer disease (PUD) have shown a recent decrease in hospital admissions in Western countries.ObjectiveThis paper aimed to study the current status and risk factors of PUD in a Nigerian metropolis.MethodsA cross-sectional study of symptomatic patients at upper gastrointestinal (GI) endoscopy diagnosed with PUD from February 2014 to September 2019 at a referral endoscopy facility in Port Harcourt, Niger delta region of Nigeria. The variables studied included demographics, symptoms and duration, blood group, chronic non-steroidal anti-inflammatory (NSAID) use, smoking, endoscopic and histology findings. Statistical analysis was performed using SPSS version 20.ResultsA total of 434 upper GI endoscopies were performed during the study period with thirty-one diagnosis of PUD made. The mean age of gastric ulcer (GU) and duodenal ulcer (DU) cases were 54.4 ± 20.2yrs and 48.1 ± 14.5yrs respectively (p = 0.367). GU to DU ratio was 1.4:1. H. pylori infection, chronic NSAID use and blood group O were seen in 7(22.5%), 8(25.8%) and 18(72.0%) respectively. Major indication in 21(67.7%) cases was gastrointestinal bleeding.ConclusionThere is a low diagnostic rate of PUD (6.7%) with pre-pyloric antral gastric ulcers as most common type and multifactorial aetiology. 相似文献
2.
Evaluation of training nurses to perform semi‐automated three‐dimensional left ventricular ejection fraction using a customised workstation‐based training protocol 下载免费PDF全文
3.
4.
Nursing in the health care system of the postmodern world: crossroads, paradoxes and complexity 总被引:1,自引:0,他引:1
Ada Spitzer RN PhD 《Journal of advanced nursing》1998,28(1):164-171
Entering the postmodern world in which society is confronting crossroads, paradoxes, and complexity, the health care system is encountering a transformation more comprehensive and revolutionary than has ever been seen before. Analysis of the state of nursing vis a vis these transformations indicates that the current paradigm does not ensure the existence of the profession in the postmodern health care system. That is because of increased difficulties in consolidating the economic and quality issues into the core of nursing, and in understanding the complexity inherent in health related situations. 相似文献
5.
6.
Simona Ben-Haim Ela Kupzov Ada Tamir Alex Frenkel Ora Israel 《Journal of nuclear cardiology》2006,13(6):791-800
BACKGROUND: Fluorine 18 fluorodeoxyglucose (FDG) uptake may be increased in atherosclerotic plaques in asymptomatic patients. Repeat positron emission tomography (PET)/computed tomography (CT) studies were assessed for changes in patterns of FDG uptake and CT calcifications. METHODS AND RESULTS: Fifty consecutive cancer patients (mean age, 68 +/- 8 years) had repeat PET/CT studies 8 to 26 months apart. PET, CT, and PET/CT images were retrospectively evaluated for vascular wall abnormalities and for interval changes in the thoracic and abdominal aortas, as well as in carotid and iliac arteries, classified as PET+/CT+, PET+/CT-, and PET-/CT+. There were 485 abnormal sites in the first study and 495 in the second. CT calcifications were found in 46 patients (92%) in the first study and in 47 (94%) in the second. Vascular wall FDG uptake was found in both studies in 37 patients (74%). The pattern changed in 57 of 119 PET+ sites (48%) in the second study compared with 15 of 366 PET- sites (4%) (P < .0001). In the second study new PET+ sites were observed in 36 of 111 sites (32%) versus new PET-/CT+ sites in 19 of 384 sites (5%) (P < .0001). CONCLUSIONS: Changes in vascular FDG activity and CT calcifications can be assessed by repeat PET/CT. FDG-avid foci may represent a dynamic process, transient inflammation, whereas CT calcifications may indicate stable atherosclerosis. These preliminary results support the need for further research. 相似文献
7.
8.
9.
Antigen in tissues: IV. The effect of antibody on the retention and localization of antigen in rat lymph nodes* 总被引:5,自引:1,他引:5
A study has been made of the role of specific antibody in causing increased retention and specific localization of a weak antigen, human serum albumin (HSA), in the popliteal and aortic lymph nodes of rats. The antigen was labelled with 125I prior to mixing with antibody. HSA mixed with excess homologous antibody was trapped to the greatest extent in these nodes after footpad injection of the antigen. Injection of HSA with antibody caused increased uptake of HSA into the medulla but retention was poor as autoradiographs showed the area to be essentially free of antigen 4–5 days after injection. By contrast, antigen injected with antibody localized strongly in lymphoid follicles and persisted at this site. Both IgM and IgG antibody were found to cause follicular localization of HSA in rats. Heterologous, isologous and homologous antibody also caused follicular localization of the antigen. Purified homologous γ-globulin was found to localize in the follicles. A moderate increase in the net negative charge of the γ-globulin by acetylation did not appreciably affect the ability of the globulin to localize in the follicles. Detectable formation of antibody did not occur in the rats after injection of antigen—antibody complexes, owing possibly to the inhibitory effect of free antibody on the primary response. 相似文献