全文获取类型
收费全文 | 537篇 |
免费 | 29篇 |
学科分类
医药卫生 | 566篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 12篇 |
2020年 | 17篇 |
2019年 | 24篇 |
2018年 | 22篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 18篇 |
2014年 | 26篇 |
2013年 | 27篇 |
2012年 | 46篇 |
2011年 | 47篇 |
2010年 | 24篇 |
2009年 | 22篇 |
2008年 | 35篇 |
2007年 | 46篇 |
2006年 | 45篇 |
2005年 | 29篇 |
2004年 | 31篇 |
2003年 | 19篇 |
2002年 | 17篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有566条查询结果,搜索用时 31 毫秒
11.
目的 研究肝动脉化疗栓塞治疗后肝脏肿瘤内碘油沉积对碳离子放疗剂量的影响。方法 对比纯碘油、纯凝胶和碘油凝胶混合物实际相对水阻止本领(RLSP)和其CT图像转化获得的RLSP。在7例典型有碘油沉积病例的CT图像上制定碳离子放疗计划,然后基于前述分析结果,将碘油沉积区域RLSP修正为正常肝组织,将先前制定碳离子放疗计划在修正后CT图像上重新计算,比较在不同CT图像上等效水深度和剂量分布的差异。结果 依据CT图像HU值,碘油和碘油凝胶混合物转化的RLSP比实际测量值增加4.6%~139.0%。7例临床病例中,原始图像上碘油沉积可致射野路径上的等效水深度平均增加(0.89±0.41)cm,可使靶区远端1 cm区域内平均剂量升高(3.83±1.71)Gy (相对生物剂量)。结论 在肝动脉化疗栓塞治疗后有碘油沉积的CT图像上制定碳离子治疗计划时需将碘油沉积部位的HU值或RLSP修正为正常肝组织。 相似文献
12.
León-Carrión J Martín-Rodríguez JF Damas-López J Pourrezai K Izzetoglu K Barroso y Martin JM Domínguez-Morales MR 《Neuroscience letters》2007,422(3):147-152
This paper introduces a new paradigm in the study of emotional processes through functional neuroimaging. We study whether the valence and arousal of visual stimuli influence neuroimaging of the evoked hemodynamic changes. Using functional near-infrared spectroscopy (fNIRS), we investigate evoked-cerebral blood oxygenation (CBO) changes in dorsolateral prefrontal cortex (DLPFC) during direct exposure to different emotion-eliciting stimuli ('on' period), and during the period directly following stimulus cessation ('off' period). We hypothesize that the evoked-CBO, rather than return to baseline after stimulus cessation, would show either overshoot or undershoot. The study includes 30 healthy subjects and a total of 9 stimuli, which consist of video-clips with different emotional content. The total sample of trials studied (270) is classified according to the valence and arousal ratings given by the subjects. Results show a more robust activation in DLPFC during the 'off' period than during the 'on' period, depending on the subjective degree of arousal given to the stimulus. Our findings provide the first fNIRS evidence showing that an increment in subjective arousal leads to activation in DLPFC which persists after stimulus cessation and this does not occur with non-arousing stimuli. Neuroimaging studies must consider the duration and affective dimensions of the stimulus as well as the duration of the scanning to specify how much of the recorded response is analyzed. Not accounting for this difference may contribute to confusion in the data interpretation. 相似文献
13.
14.
Roberto Sarnari Allison M. Blake Alexander Ruh Muhannad A. Abbasi Ashitha Pathrose Julie Blaisdell Ryan S. Dolan Kambiz Ghafourian Jane E. Wilcox Sadiya S. Khan Esther E. Vorovich Jonathan D. Rich Allen S. Anderson Clyde W. Yancy James C. Carr Michael Markl 《Journal of magnetic resonance imaging : JMRI》2020,52(3):920-929
15.
Angel Fernandez‐Flores Ina Nicklaus‐Wollenteit Dharshini Sathishkumar Vicky Diba Bruce Richard Richard Carr Celia Moss Anita Nagy Malobi Ogboli Isabel Colmenero 《Journal of cutaneous pathology》2017,44(11):954-957
Cutaneous lymphadenoma is an uncommon benign neoplasm often considered to be an adamantinoid variant of trichoblastoma. Lesions present in both sexes, between 14 and 87 years of age, and are mainly located on the head and neck. Cases in children are rare and there is only 1 previous case of a congenital lymphadenoma. An 8‐year‐old Asian girl presented with a congenital lesion on her forehead comprising 4 pink papules, the largest 5 mm in diameter. Microscopy revealed a well‐circumscribed tumor within the dermis and subcutis comprising well‐demarcated epithelial lobules of basaloid and clear cells with subtle peripheral palisading, growing in a collagenous stroma but lacking retraction artefact. A relatively dense accompanying predominantly lymphocytic inflammatory cell infiltrate including both T‐cells (CD3+) and B‐cells (CD20+) permeated the nodules and spilled into the stroma. CD68+ histiocytes and CD1a+ Langerhans cells were moderately numerous. This is the second case of congenital lymphadenoma which—in spite of its rarity in childhood—widens the diagnostic possibilities of cutaneous lymphoepithelial tumors in children. 相似文献
16.
Motamedi K Murphey MD Fetsch JF Furlong MA Vinh TN Laskin WB Sweet DE 《Skeletal radiology》2005,34(4):185-195
Objective To describe the imaging features of spinal pigmented villonodular synovitis (PVNS).Design and patients We retrospectively reviewed 15 cases of pathologically proven spinal PVNS. Patient demographics and clinical presentation were reviewed. Radiologic studies were evaluated by consensus of two musculoskeletal radiologists for spinal location, spinal segments affected, lesion center, detection of facet origin and intrinsic characteristics on radiography (n =11), myelography (n =7), CT (n =6) and MR imaging (n =6).Results Women (64%) were more commonly affected than men (36%) with an average age of 28 years. Clinical symptoms were pain (45%), neurologic (9%) or both (36%). Lesions most frequently affected the cervical spine (53%) followed by the thoracic (27%) and lumbar regions (20%). The majority of lesions (93%) were centered in the posterior elements with frequent involvement of the pedicle (67%), neural foramina (73%), lamina (67%) and facets (93%). No lesions showed calcification. Determination of a facet origin by imaging was dependent on imaging modality and lesion size. A facet origin could be determined in 45% of cases by radiography vs 67% of patients by CT (n=6) and MR (n=6). Large lesions (greater than 3 cm in at least one dimension) obscured the facet origin in all cases with CT and/or MR imaging (44%,n=4). Small lesions (less than 3 cm in any dimension) demonstrated an obvious facet origin in all cases by CT and/or MR imaging (56%,n=5). Low-to-intermediate signal intensity was seen in all cases on T2-weighted MR images resulting from hemosiderin deposition with blooming effect in one case with gradient echo MR images.Conclusions PVNS of the spine is rare. Large lesions obscure the facet origin and simulate an aggressive intraosseous neoplasm. Patient age, a solitary noncystic lesion centered in the posterior elements, lack of mineralization and low-to-intermediate signal intensity on all MR pulse sequences may suggest the diagnosis in these cases. Small lesions demonstrate a facet origin on CT or MR imaging. This limits differential considerations to synovial-based lesions and additional features of a solitary focus, lack of underlying disease or systemic arthropathy, no calcification as well as low-to-intermediate signal intensity on all MR images should allow spinal PVNS to be suggested as the likely diagnosis.The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Departments of the Air Force, Army, Navy or Defense. 相似文献
17.
Ganaha F Ohashi K Do YS Lee J Sugimoto K Minamiguchi H Elkins CJ Sameni D Modanlou S Ali M Kao EY Kay MA Waugh JM Dake MD 《Journal of vascular and interventional radiology : JVIR》2004,15(11):1287-1293
PURPOSE: It is proposed that local elastase inhibition could suppress the extracellular matrix (ECM) degradation and subsequent smooth muscle cell migration and limit subsequent in-stent restenosis. This study evaluated the effect of stent-based controlled elastase inhibition on restenosis after stent implantation in a rabbit model. MATERIALS AND METHODS: Biodegradable microspheres containing the potent elastase inhibitor alpha-1-antitrypsin (AAT) were prepared. Daily release of AAT from the microspheres was confirmed in vitro. The microspheres were loaded into stents with an abluminal polymer reservoir. Implantation of the stent with AAT microspheres and blank microspheres (control) was performed in the abdominal aortae of six rabbits in each group. After stent deployment, all stents were overdilated to 125% diameter. Stent-implanted arteries were harvested after 7 days (n = 3 each) or 28 days (n = 3 each). To assess the effect of local delivery of AAT, elastase activity and elastin content of the stent-implanted aortae were analyzed. As an endpoint, intima-to-media (I/M) ratio was determined in the 7-day and 28-day specimens. RESULTS: Significant inhibition of elastase was confirmed in treated vessels versus controls at 7 days after stent implantation (P < .05). This reduction in elastase activity was sufficient to afford early and late reduction of in-stent neointima. Plaque progression in the 28-day specimens decreased to 67% with elastase inhibition relative to controls (P < .05). CONCLUSION: Stent-based controlled release of elastase inhibitor may significantly reduce ECM degradation and might limit in-stent restenosis. 相似文献
18.
19.
Otero-Garcia JE Youssef E Enamorado II Du W Yoo GH Merati K Kewson D Lonardo F Jacobs JR Kim H 《American journal of otolaryngology》2004,25(4):231-239
OBJECTIVE: To determine the prognostic significance of p53 and fragile histidine triad (FHIT) expression in advanced oropharyngeal squamous cell carcinoma. STUDY DESIGN: A retrospective collection of clinical data was correlated with the protein expression. METHOD: The expression of p53 and FHIT in specimens from patients with previously untreated advanced squamous cell carcinoma of the oropharynx was determined by immunohistochemistry. The expression of p53 and FHIT was statistically correlated with survival outcome. The primary endpoints were overall survival and disease-free survival. RESULTS: Thirty-four patients were analyzed in this study. Overexpression of p53 was observed in 41.2% (14/34) of tumors and was associated with a trend toward an improved overall survival using univariate (P =.1088, risk ratio [RR] = 0.503) and multivariate (P =.1533, RR = 0.470) analyses. Marked reduction or complete absence of FHIT expression was observed in 57.6% (19/33) of tumors. Patients with tumors showing no reduction in FHIT expression had a lower overall survival using univariate (P =.04, RR = 2.27) and multivariate (P =.013, RR = 4.41) analyses. CONCLUSION: Overexpression of p53 predicted a trend toward an improved prognosis, whereas no reduction in FHIT expression predicted a significantly poorer outcome in patients with advanced oropharyngeal cancer. 相似文献
20.
Agumadu CO Yousufi SM Malik IS Nguyen MC Jackson MA Soleymani K Thrower CM Peterman MJ Walters GW Niemtzoff MJ Bartko JJ Postolache TT 《The American journal of psychiatry》2004,161(6):1084-1089
OBJECTIVE: The authors attempted to estimate the occurrence, frequency, and pattern (winter versus summer) of seasonal affective disorder in African American college students. They hypothesized that winter seasonal affective disorder would be more prevalent than summer seasonal affective disorder. METHOD: Undergraduate and graduate college students who identified themselves as African Americans living in the Washington, D.C., metropolitan area were invited to participate in the study. The Seasonal Pattern Assessment Questionnaire was used to calculate a global seasonality score and to estimate the frequency of seasonal affective disorder and subsyndromal seasonal affective disorder. The frequency of the summer versus winter pattern of seasonality of seasonal affective disorder was compared by using multinomial probability distribution tests. The effects of gender and the awareness of seasonal affective disorder were evaluated with a two-way analysis of variance. RESULTS: Of 646 students who were invited to participate, 597 returned the questionnaires, and 537 (83.1%) fully completed them. Winter seasonal affective disorder was significantly more prevalent than summer seasonal affective disorder. The mean global seasonality score was 8.3 (SD=5.3). The majority of the subjects (80%) were not aware of the existence of seasonal affective disorder. CONCLUSIONS: The authors found that the frequency, magnitude, and pattern of seasonality of mood in African American students were similar to those previously reported in the general population at similar latitude, but that awareness of the existence of seasonal affective disorder, a condition with safe and effective treatment options, was lower. 相似文献