全文获取类型
收费全文 | 220687篇 |
免费 | 4307篇 |
国内免费 | 168篇 |
专业分类
耳鼻咽喉 | 1821篇 |
儿科学 | 7678篇 |
妇产科学 | 3733篇 |
基础医学 | 22083篇 |
口腔科学 | 2290篇 |
临床医学 | 17485篇 |
内科学 | 39449篇 |
皮肤病学 | 1258篇 |
神经病学 | 20396篇 |
特种医学 | 10680篇 |
外国民族医学 | 2篇 |
外科学 | 36709篇 |
综合类 | 3075篇 |
现状与发展 | 1篇 |
一般理论 | 33篇 |
预防医学 | 21680篇 |
眼科学 | 3717篇 |
药学 | 12911篇 |
1篇 | |
中国医学 | 698篇 |
肿瘤学 | 19462篇 |
出版年
2023年 | 310篇 |
2022年 | 475篇 |
2021年 | 1247篇 |
2020年 | 650篇 |
2019年 | 1224篇 |
2018年 | 23163篇 |
2017年 | 18232篇 |
2016年 | 20400篇 |
2015年 | 2156篇 |
2014年 | 2636篇 |
2013年 | 3104篇 |
2012年 | 10478篇 |
2011年 | 24676篇 |
2010年 | 20761篇 |
2009年 | 13226篇 |
2008年 | 22403篇 |
2007年 | 24905篇 |
2006年 | 3738篇 |
2005年 | 5191篇 |
2004年 | 6022篇 |
2003年 | 6994篇 |
2002年 | 4837篇 |
2001年 | 646篇 |
2000年 | 657篇 |
1999年 | 535篇 |
1998年 | 692篇 |
1997年 | 537篇 |
1996年 | 385篇 |
1995年 | 405篇 |
1994年 | 337篇 |
1993年 | 271篇 |
1992年 | 223篇 |
1991年 | 238篇 |
1990年 | 284篇 |
1989年 | 236篇 |
1988年 | 209篇 |
1987年 | 180篇 |
1986年 | 151篇 |
1985年 | 181篇 |
1984年 | 179篇 |
1983年 | 156篇 |
1982年 | 193篇 |
1981年 | 143篇 |
1980年 | 202篇 |
1979年 | 89篇 |
1978年 | 104篇 |
1977年 | 73篇 |
1976年 | 72篇 |
1975年 | 67篇 |
1974年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Neal G Palmer James R Yacyshyn Herbert C Northcott Brian Nebbe Paul W Major 《American journal of orthodontics and dentofacial orthopedics》2005,128(2):163-167
INTRODUCTION: To plan for future acceptance and implementation of computer-related technology, it is necessary to understand orthodontists' current perceptions and attitudes toward emerging technologies. METHODS: An anonymous, self-administered, mail-out survey of Canadian orthodontists was conducted. The response rate was 45.6% (304/667). RESULTS: Most orthodontists indicated that computer technology could improve current practice efficiency and quality of patient care. Only 15% reported that digital models are quite or very useful; 73.6%, 69.1%, 55%, and 37.4% agreed or strongly agreed with using digital and electronic technology to consult with other dental specialists, other orthodontists, general dentists, and the public, respectively. Cost of the technology was reported as a significant or insurmountable obstacle by 54% of the respondents. Interprovincial legislation, unclear consultation remuneration guidelines, and lack of comfort with the technology were not perceived as significant obstacles. Only 36% reported security or privacy issues as a significant or insurmountable obstacle. CONCLUSIONS: Canadian orthodontists seem to view digital and electronic technology as useful and capable of improving their offices' efficiency and production. Although they are sensitive to some potential obstacles, they are willing to overcome these and incorporate the technology into their practices. 相似文献
52.
Background
Reports on childhood cancer survivors estimated cumulative probability of developing secondary neoplasms vary from 3,3% to 25% at 25 years from diagnosis, and the risk of developing another cancer to several times greater than in the general population. 相似文献53.
54.
55.
Background
The fibromyalgia syndrome (FMS) is suggested to be a manifestation of depression or affective spectrum disorder. We measured the cognitive style of patients with FMS to assess personality styles in 44 patients with fibromyalgia syndrome (FMS) by comparing them with 43 patients with major depressive disorder (MDD) and 41 healthy controls (HC). 相似文献56.
Brian A Haluska Robert Fathi Leanne Jeffriess Rodel Leano Stephane G Carlier Thomas H Marwick 《Journal of the American Society of Echocardiography》2004,17(2):195-202; quiz 203-4
BACKGROUND: Brachial artery reactivity (BAR), carotid intima-media thickness (IMT), and applanation tonometry for evaluation of total arterial compliance may provide information about preclinical vascular disease. We sought to determine whether these tests could be used to identify patients with coronary artery disease (CAD) without being influenced by their ability to identify those at risk for CAD developing. METHODS: We studied 100 patients and compared 3 groups: 35 patients with known CAD; 34 patients with symptoms and risk factors but no CAD identified by stress echocardiography (risk group); and 31 control subjects. BAR and IMT were measured using standard methods, and total arterial compliance was calculated by the pulse-pressure method from simultaneous radial applanation tonometry and pulsed wave Doppler of the left ventricular outflow. Ischemia was identified as a new or worsening wall-motion abnormality induced by stress. RESULTS: In a comparison between the control subjects and patients either at risk for developing CAD or with CAD, the predictors of risk for CAD were: age (P =.01); smoking history (P =.002); hypercholesterolemia (P =.002); and hypertension (P =.004) (model R = 0.82; P =.0001). The independent predictors of CAD were: IMT (P =.001); BAR (P =.04); sex (P =.005); and hypertension (P =.005) (model R = 0.80; P =.0001). CONCLUSION: IMT, BAR, and traditional cardiovascular risk factors appear to identify patients at risk for CAD developing. However, only IMT was significantly different between patients at risk for developing CAD and those with overt CAD. 相似文献
57.
58.
Mozammil Hussain Raghu N. Natarajan Amir H. Fayyazi Brian R. Braaksma Gunnar B.J. Andersson Howard S. An 《The spine journal》2009,9(12):1016-1023
Background contextAnterior corpectomy and reconstruction with bone graft and a rigid screw-plate construct is an established procedure for treatment of cervical neural compression. Despite its reliability in relieving symptoms, there is a high rate of construct failure, especially in multilevel cases.PurposeThere has been no study evaluating the biomechanical effects of screw angulation on construct stability; this study investigates the C4–C7 construct stability and load-sharing properties among varying screw angulations in a rigid plate-screw construct.Study designA finite element model of a two-level cervical corpectomy with static anterior cervical plate.MethodsA three-dimensional finite element (FE) model of an intact C3–T1 segment was developed and validated. From this intact model, a fusion model (two-level [C5, C6] anterior corpectomy) was developed and validated. After corpectomy, allograft interbody fusion with a rigid anterior screw-plate construct was created from C4 to C7. Five additional FE models were developed from the fusion model corresponding to five different combinations of screw angulations within the vertebral bodies (C4, C7): (0°, 0°), (5°, 5°), (10°, 10°), (15°, 15°), and (15°, 0°). The fifth fusion model was termed as a hybrid fusion model.ResultsThe stability of a two-level corpectomy reconstruction is not dependent on the position of the screws. Despite the locked screw-plate interface, some degree of load sharing is transmitted to the graft. The load seen by the graft and the shear stress at the bone-screw junction is dependent on the angle of the screws with respect to the end plate. Higher stresses are seen at more divergent angles, particularly at the lower level of the construct.ConclusionThis study suggests that screw divergence from the end plates not only increases load transmission to the graft but also predisposes the screws to higher shear forces after corpectomy reconstruction. In particular, the inferior screw demonstrated larger stress than the upper-level screws. In the proposed hybrid fusion model, lower stresses on the bone graft, end plates, and bone-screw interface were recorded, inferring lower construct failure (end-plate fractures and screw pullout) potential at the inferior construct end. 相似文献
59.
60.