首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   186篇
  免费   11篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   2篇
妇产科学   1篇
基础医学   14篇
口腔科学   4篇
临床医学   10篇
内科学   32篇
神经病学   4篇
特种医学   46篇
外科学   22篇
综合类   8篇
药学   13篇
肿瘤学   41篇
  2024年   1篇
  2023年   2篇
  2022年   3篇
  2021年   4篇
  2020年   3篇
  2019年   8篇
  2018年   15篇
  2017年   3篇
  2016年   2篇
  2015年   7篇
  2014年   19篇
  2013年   20篇
  2012年   11篇
  2011年   16篇
  2010年   9篇
  2009年   17篇
  2008年   16篇
  2007年   18篇
  2006年   4篇
  2005年   5篇
  2004年   3篇
  2003年   4篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1994年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
排序方式: 共有199条查询结果,搜索用时 167 毫秒
101.

Objectives

This study sought to evaluate the incremental value of quantifying the extent and severity of myocardial perfusion and 18F-labeled fluorodeoxyglucose (FDG) abnormalities in predicting adverse outcomes among patients with suspicion for cardiac sarcoidosis (CS).

Background

Positron emission tomography (PET) with FDG is a key component of the noninvasive assessment of patients with suspected CS. However, the optimal method for image interpretation has not been defined.

Methods

A retrospective analysis was performed of 203 patients who underwent perfusion and FDG-PET imaging to evaluate for CS. Imaging findings were scored by conventional 3-category methods (normal perfusion and metabolism, abnormal perfusion or metabolism, abnormal perfusion and metabolism) and by summed scores using the 17-segment model to represent extent and severity of disease. Heterogeneity of metabolism was quantified using the coefficient of variation (SD divided by the mean) of FDG uptake. Multivariable Cox models were developed to assess associations between imaging findings and adverse events (death, heart transplant, or ventricular arrhythmia requiring defibrillation).

Results

The indication for FDG-PET was ventricular arrhythmia in 69 (34%), heart block in 16 (8%), cardiomyopathy in 54 (27%), and other indications in 64 (32%). There were 63 patients who developed adverse events over a mean follow-up of 1.8 years. After robust adjustment, only the summed score in segments with a perfusion–metabolism mismatch and the coefficient of variation were important prognostically (p = 0.029 and p = 0.041, respectively).

Conclusions

Quantitative measures of extent and severity of perfusion–metabolism mismatch and coefficient of variation of FDG uptake provide an incremental prognostic advantage in patients undergoing FDG-PET for CS. These results support the use of a more detailed analysis of imaging findings, as is conventional in coronary artery disease.  相似文献   
102.

Background

Oxidation-specific epitopes (OSEs) are proinflammatory, and elevated levels in plasma predict cardiovascular events.

Objectives

The purpose of this study was to develop novel positron emission tomography (PET) probes to noninvasively image OSE-rich lesions.

Methods

An antigen-binding fragment (Fab) antibody library was constructed from human fetal cord blood. After multiple rounds of screening against malondialdehyde-acetaldehyde (MAA) epitopes, the Fab LA25 containing minimal nontemplated insertions in the CDR3 region was identified and characterized. In mice, pharmacokinetics, biodistribution, and plaque specificity studies were performed with Zirconium-89 (89Zr)-labeled LA25. In rabbits, 89Zr-LA25 was used in combination with an integrated clinical PET/magnetic resonance (MR) system. 18F-fluorodeoxyglucose PET and dynamic contrast-enhanced MR imaging were used to evaluate vessel wall inflammation and plaque neovascularization, respectively. Extensive ex vivo validation was carried out through a combination of gamma counting, near infrared fluorescence, autoradiography, immunohistochemistry, and immunofluorescence.

Results

LA25 bound specifically to MAA epitopes in advanced and ruptured human atherosclerotic plaques with accompanying thrombi and in debris from distal protection devices. PET/MR imaging 24 h after injection of 89Zr-LA25 showed increased uptake in the abdominal aorta of atherosclerotic rabbits compared with nonatherosclerotic control rabbits, confirmed by ex vivo gamma counting and autoradiography. 18F-fluorodeoxyglucose PET, dynamic contrast-enhanced MR imaging, and near-infrared fluorescence signals were also significantly higher in atherosclerotic rabbit aortas compared with control aortas. Enhanced liver uptake was also noted in atherosclerotic animals, confirmed by the presence of MAA epitopes by immunostaining.

Conclusions

89Zr-LA25 is a novel PET radiotracer that may allow noninvasive phenotyping of high-risk OSE-rich lesions.  相似文献   
103.
104.
105.

Objective

To evaluate the prognostic value of volume-based metabolic parameters measured with 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in patients with clinically node-negative (cN0) oral tongue squamous cell carcinoma (OTSCC) as compared with other prognostic factors.

Materials and Methods

In this study, we included a total of 57 patients who had been diagnosed with cN0 tongue cancer by radiologic, 18F-FDG PET/CT, and physical examinations. The maximum standardized uptake value (SUVmax), average SUV (SUVavg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for primary tumors were measured with 18F-FDG PET. The prognostic significances of these parameters and other clinical variables were assessed by Cox proportional hazards regression analysis.

Results

In the univariate analysis, pathological node (pN) stage, American Joint Committee on Cancer (AJCC) stage, SUVmax, SUVavg, MTV, and TLG were significant predictors for survival. On a multivariate analysis, pN stage (hazard ratio = 10.555, p = 0.049), AJCC stage (hazard ratio = 13.220, p = 0.045), and MTV (hazard ratio = 2.698, p = 0.033) were significant prognostic factors in cN0 OTSCC patients. The patients with MTV ≥ 7.78 cm3 showed a worse prognosis than those with MTV < 7.78 cm3 (p = 0.037).

Conclusion

The MTV of primary tumor as a volumetric parameter of 18F-FDG PET, in addition to pN stage and AJCC stage, is an independent prognostic factor for survival in cN0 OTSCC.  相似文献   
106.
107.
108.
109.
Purpose  NK1 receptors have been implicated in various neuropsychiatric and other disorders. R116301 is a selective NK1 receptor antagonist. In this pilot study, [11C]R116301 was evaluated as a potential positron emission tomography (PET) ligand for the NK1 receptor. Procedures  Two dynamic PET studies were performed in three normal volunteers before and after a blocking dose of aprepitant. Data were analyzed using striatum to cerebellum standardized uptake value (SUV) ratios. Results  Baseline SUV ratios at 60–90 min after injection ranged from 1.22 to 1.70. Following aprepitant administration, this specific signal was completely blocked. Aprepitant administration did not significantly affect uptake in cerebellum, confirming the absence of NK1 receptors in cerebellum. Conclusion  These preliminary results indicate that [11C]R116301 has potential as a radioligand for in vivo assessment of NK1 receptors in the human brain.  相似文献   
110.
PET acquisition requires several minutes which can lead to respiratory motion blurring, to increase partial volume effect and SUV under-estimation. To avoid these artifacts, conventional 10-min phase-based respiratory gating (PBRG) can be performed but is time-consuming and difficult with a non-compliant patient. We evaluated an automatic amplitude-based gating method (AABG) which keeps 35% of the counts at the end of expiration to minimize respiratory motion. We estimated the impact of AABG on upper abdominal lesion detectability, quantification and patient management.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号