全文获取类型
收费全文 | 1800篇 |
免费 | 307篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 101篇 |
妇产科学 | 20篇 |
基础医学 | 113篇 |
口腔科学 | 26篇 |
临床医学 | 313篇 |
内科学 | 596篇 |
皮肤病学 | 60篇 |
神经病学 | 193篇 |
特种医学 | 281篇 |
外科学 | 189篇 |
综合类 | 32篇 |
预防医学 | 73篇 |
眼科学 | 19篇 |
药学 | 60篇 |
中国医学 | 1篇 |
肿瘤学 | 55篇 |
出版年
2023年 | 52篇 |
2022年 | 13篇 |
2021年 | 28篇 |
2020年 | 90篇 |
2019年 | 12篇 |
2018年 | 88篇 |
2017年 | 69篇 |
2016年 | 70篇 |
2015年 | 62篇 |
2014年 | 95篇 |
2013年 | 120篇 |
2012年 | 46篇 |
2011年 | 37篇 |
2010年 | 79篇 |
2009年 | 108篇 |
2008年 | 41篇 |
2007年 | 48篇 |
2006年 | 45篇 |
2005年 | 26篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 18篇 |
2001年 | 30篇 |
2000年 | 21篇 |
1999年 | 27篇 |
1998年 | 85篇 |
1997年 | 95篇 |
1996年 | 79篇 |
1995年 | 68篇 |
1994年 | 49篇 |
1993年 | 52篇 |
1992年 | 30篇 |
1991年 | 17篇 |
1990年 | 26篇 |
1989年 | 54篇 |
1988年 | 47篇 |
1987年 | 30篇 |
1986年 | 21篇 |
1985年 | 27篇 |
1984年 | 25篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1977年 | 10篇 |
1976年 | 15篇 |
1975年 | 10篇 |
1971年 | 9篇 |
排序方式: 共有2146条查询结果,搜索用时 31 毫秒
101.
Breast specimen radiography: evaluation of a compression device 总被引:1,自引:0,他引:1
The irregular shape and uneven tissue thickness of excised breast specimens makes radiographic evaluation difficult, especially when calcifications are not present. Xeroradiographs before and after compression of 20 separate excised breast specimens were compared, and 17 of the same specimens were compared after compression combined with immersion in water. Specimen compression improved visibility of the lesion on average in 88% of cases, and visibility was equal in 12%. Combined compression/immersion further improved visibility of the lesion on average in 37% of cases. More significantly, evaluation of the compressed specimen led to a change in interpretation of the radiographs in 45% of cases. Compression of the specimen in specimen radiography is recommended in all cases in which pre-biopsy localization is performed. 相似文献
102.
Speech-controlled generation of radiology reports 总被引:1,自引:0,他引:1
Robbins AH; Horowitz DM; Srinivasan MK; Vincent ME; Shaffer K; Sadowsky NL; Sonnenfeld M 《Radiology》1987,164(2):569-573
Voice entry has been successfully employed to generate radiology reports with a word recognizer with a 1,000-word lexicon capacity. About 50% of reports were able to be dictated with a single 900-word lexicon. This was split into five sections by anatomic or subspecialty application. Each was augmented to 900 words. By switching from one lexicon to another, it was possible to dictate more than 70% of reports. With exclusive use of three lexicons in subspecialty areas (gastrointestinal radiology, neuroradiology, and mammography), and with further modification of the respective vocabulary, it has been possible to employ the system 88% of the time. Twelve percent of cases included wording that was beyond the scope of the lexicon. Computer subsets that allow different translations of some words when used in different contexts have been used. Some of these are used as triggers that will print whole lines, sentences, or even complete reports. Dictation times with voice entry take about 20% longer. Recognition reliability has been greater than 95%. 相似文献
103.
104.
Gordon W. Duncan MRCP Michael J. Firbank PhD John T. O'Brien DM FRCPsych David J. Burn MD FRCP 《Movement disorders》2013,28(4):425-438
Dementia is a frequent and disabling complication of Parkinson's disease (PD). Clinicians and researchers lack a biomarker capable of tracking the structural and functional changes that underlie the evolution of cognitive dysfunction in PD. Magnetic resonance imaging (MRI) has been adopted as a biomarker in natural history and interventional studies of Alzheimer's disease (AD) and amnestic mild cognitive impairment (MCI), but its utility as a biomarker for PD and Parkinson's disease dementia (PDD) is unclear. In this review, the authors summarize the studies that have used MRI to investigate cognitive decline in PD, outline limitations of those studies, and suggest directions for future research. PD dementia is associated with extensive cortical atrophy, which may be quantified with structural MRI. More promisingly, patterns of atrophy may be present in those who have PD with MCI (PD‐MCI). Subcortical white matter tract degeneration is detectable early in the disease with diffusion tensor imaging and may precede changes observed on conventional structural MRI. Although less well studied, other MR techniques, such as functional MRI, MR perfusion imaging with arterial spin labeling, and MR spectroscopy, have demonstrated differences in activation and metabolism between PD and PDD. In this review, the ability to compare studies was limited by the heterogeneity of study populations, cognitive testing methods, and imaging protocols. Future work should adopt agreed scan protocols, should be adequately powered, and should use carefully phenotyped patients to fully maximize the contribution of MRI as a biomarker for PDD. © 2013 Movement Disorder Society 相似文献
105.
106.
107.
108.
109.
110.