全文获取类型
收费全文 | 2119143篇 |
免费 | 162837篇 |
国内免费 | 8292篇 |
专业分类
耳鼻咽喉 | 28124篇 |
儿科学 | 68302篇 |
妇产科学 | 58624篇 |
基础医学 | 293949篇 |
口腔科学 | 58146篇 |
临床医学 | 186328篇 |
内科学 | 431055篇 |
皮肤病学 | 48248篇 |
神经病学 | 173297篇 |
特种医学 | 86295篇 |
外国民族医学 | 614篇 |
外科学 | 330712篇 |
综合类 | 48490篇 |
现状与发展 | 2篇 |
一般理论 | 678篇 |
预防医学 | 163729篇 |
眼科学 | 46025篇 |
药学 | 150851篇 |
8篇 | |
中国医学 | 4171篇 |
肿瘤学 | 112624篇 |
出版年
2018年 | 21971篇 |
2017年 | 17381篇 |
2016年 | 19843篇 |
2015年 | 22483篇 |
2014年 | 31576篇 |
2013年 | 47714篇 |
2012年 | 60586篇 |
2011年 | 64671篇 |
2010年 | 40156篇 |
2009年 | 38635篇 |
2008年 | 60808篇 |
2007年 | 64802篇 |
2006年 | 65654篇 |
2005年 | 63934篇 |
2004年 | 61452篇 |
2003年 | 59835篇 |
2002年 | 57671篇 |
2001年 | 98645篇 |
2000年 | 101522篇 |
1999年 | 85296篇 |
1998年 | 25307篇 |
1997年 | 22708篇 |
1996年 | 23344篇 |
1995年 | 22943篇 |
1994年 | 21545篇 |
1993年 | 20178篇 |
1992年 | 69218篇 |
1991年 | 66921篇 |
1990年 | 64766篇 |
1989年 | 61867篇 |
1988年 | 57439篇 |
1987年 | 56312篇 |
1986年 | 53538篇 |
1985年 | 51442篇 |
1984年 | 39039篇 |
1983年 | 33064篇 |
1982年 | 20438篇 |
1981年 | 18186篇 |
1980年 | 17208篇 |
1979年 | 35383篇 |
1978年 | 25374篇 |
1977年 | 21444篇 |
1976年 | 19874篇 |
1975年 | 21223篇 |
1974年 | 25161篇 |
1973年 | 24003篇 |
1972年 | 22530篇 |
1971年 | 20755篇 |
1970年 | 19252篇 |
1969年 | 18147篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
D F du Toit 《SADJ》2003,58(9):375-6, 380-3
The tongue (L. lingua; G. glossa) functions as a digestive organ by facilitating the movement of food during mastication and assisting swallowing. Other important functions include speech and taste. The tongue consists of striated muscle and occupies the floor of the mouth. The dorsal mucosal surface consists of stratified squamous epithelium, with numerous papillae and taste buds. The tongue, a voluntary muscular structure, is attached by a fold, called the frenulum, to the floor of the mouth. Typically, between 8 and 12 circumvallate papillae are arranged in an inverted V-shape towards the base of the tongue. This anatomical review focuses on structure, function relationships and diseases affecting the tongue. From a primary oral health care perspective, this overview will facilitate the process of differential diagnosis in persons presenting with vesiculo-bullous, ulcerative, atrophic and cystic disorders of the tongue. Suspicious lesions should be biopsied to rule out carcinoma. 相似文献
113.
Bifid mandibular canal. 总被引:1,自引:0,他引:1
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women. 相似文献
114.
Contour defects resulting in deformity caused by lack of tissue can be improved by conventional surgery using autologous tissue, but there is always a donor site morbidity. Integra has been available since the early 1980's for use in acute burns and more recently in reconstruction. It has been shown histologically to act as a tissue regeneration template. The regenerated dermis is buried under an autologous thin split-skin graft. In this study, the principle of burying Integra (without the silicone layer) has been applied to deep tissue defects in 12 reconstructive cases. Such regenerated tissues survive at least 3 years after burying. Modification to the technique to avoid visible edges are being developed. 相似文献
115.
A Trakic F Liu H Sanchez Lopez H Wang S Crozier 《Magnetic resonance in medicine》2007,57(6):1119-1130
The switching of magnetic field gradient coils in magnetic resonance imaging (MRI) inevitably induces transient eddy currents in conducting system components, such as the cryostat vessel. These secondary currents degrade the spatial and temporal performance of the gradient coils, and compensation methods are commonly employed to correct for these distortions. This theoretical study shows that by incorporating the eddy currents into the coil optimization process, it is possible to modify a gradient coil design so that the fields created by the coil and the eddy currents combine together to generate a spatially homogeneous gradient that follows the input pulse. Shielded and unshielded longitudinal gradient coils are used to exemplify this novel approach. To assist in the evaluation of transient eddy currents induced within a realistic cryostat vessel, a low-frequency finite-difference time-domain (FDTD) method using the total-field scattered-field (TFSF) scheme was performed. The simulations demonstrate the effectiveness of the proposed method for optimizing longitudinal gradient fields while taking into account the spatial and temporal behavior of the eddy currents. 相似文献
116.
Michele D. Mignogna Stefano Fedele Lucio Lo Russo Lorenzo Lo Muzio 《Journal of oral pathology & medicine》2003,32(4):200-205
BACKGROUND: The recurrent chronic orofacial swelling caused by orofacial granulomatosis (OFG) can cause significant cosmetic and functional problems but can be prevented if the disease is diagnosed early and promptly treated. Although the enlargement of the lips is described to be the most common presenting complaint, the clinical onset of OFG may be characterized by minor associated mucosal and neurological manifestations, making early diagnosis very difficult or, sometimes, merely presumable. PATIENTS AND METHODS: We retrospectively analyzed the clinical manifestations of 19 patients with OFG, who were examined at our institution between 1998 and 2002, in order to determine their initial manifestations and presenting symptoms. RESULTS: A total of 10 patients showed classical recurrent enlargement of the lips (six lower; four upper) as presenting symptom. In the other nine patients, OFG onset was characterized by transient unilateral facial nerve palsy (two cases), intraoral manifestations (two cases), recurrent swelling of the periorbital area (two cases), of the chin (one case), of the zygomatic area (one case), and of the cheeks (one case). CONCLUSION: Our data underlined that OFG onset could be frequently characterized by widely variable, multiform, and temporary clinical findings. Involvement of atypical sites of the orofacial region and presence of single minor manifestations may occur as presenting symptoms, often preceding the development of traditional clinical findings. 相似文献
117.
118.
O Schouten J H H van Laanen E Boersma R Vidakovic H H H Feringa M Dunkelgrün J J Bax J Koning H van Urk D Poldermans 《European journal of vascular and endovascular surgery》2006,32(1):21-26
OBJECTIVE: To evaluate the effect of statins on aneurysm growth in a group of consecutive patients under surveillance for infrarenal aortic aneurysms (AAA). MATERIALS AND METHODS: All patients (59 statin users, 91 non-users) under surveillance between January 2002 and August 2005 with a follow-up for aneurysm growth of at least 12 months and a minimum of three diameter evaluations were retrospectively included in the analysis. Multiple regression analysis, weighted with the number of observations, was performed to test the influence of statins on AAA growth rate. RESULTS: During a median period of 3.1 (1.1-13.1) years the overall mean aneurysm growth rate was 2.95+/-2.8 mm/year. Statin users had a 1.16 mm/year lower AAA growth rate compared to non-users (95% CI 0.33-1.99 mm/year). Increased age was associated with a slower growth (-0.09 mm/year per year, p = 0.003). Female gender (+1.82 mm/year, p = 0.008) and aneurysm diameter (+0.06 mm/year per mm, p = 0.049) were associated with increased AAA growth. The use of non-steroidal anti-inflammatory drugs, chronic lung disease, or other cardiovascular risk factors were not independently associated with AAA growth. CONCLUSIONS: Statins appear to be associated with attenuation of AAA growth, irrespective of other known factors influencing aneurysm growth. 相似文献
119.
目的:通过16例经内窥镜及病理证实为Barrett食管的钡餐检查表现,初步探讨Barrett食管及其并发症放射学检查的意义。方法:回顾性分析16例Barrett食管的内窥镜和气钡检查的记录及表现,着重探讨气钡检查的X线表现。结果:食管内窥镜和组织学检查全部病例均有炎症改变,其他可见胃食管反流、食管溃疡和食管腺癌。放射学钡餐检查结果:Barrett食管炎4例,Barrett食管溃疡7例,Barrett食管癌5例。结论:Barrett食管及其并发症至今无明确放射学征象,改进对“Z”线的检查技术和方法,有可能提高其发现率。钡餐发现胃食管反流、食管裂孔疝同时并发食管炎、食管溃疡及食管癌者均应考虑到本症的可能。 相似文献
120.