收费全文 | 854篇 |
免费 | 50篇 |
国内免费 | 18篇 |
耳鼻咽喉 | 12篇 |
儿科学 | 23篇 |
妇产科学 | 50篇 |
基础医学 | 115篇 |
口腔科学 | 22篇 |
临床医学 | 103篇 |
内科学 | 120篇 |
皮肤病学 | 8篇 |
神经病学 | 119篇 |
特种医学 | 72篇 |
外科学 | 53篇 |
综合类 | 23篇 |
预防医学 | 90篇 |
眼科学 | 3篇 |
药学 | 56篇 |
肿瘤学 | 53篇 |
2023年 | 7篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 27篇 |
2012年 | 23篇 |
2011年 | 28篇 |
2010年 | 23篇 |
2009年 | 21篇 |
2008年 | 26篇 |
2007年 | 34篇 |
2006年 | 25篇 |
2005年 | 35篇 |
2004年 | 32篇 |
2003年 | 23篇 |
2002年 | 23篇 |
2001年 | 31篇 |
2000年 | 30篇 |
1999年 | 16篇 |
1998年 | 22篇 |
1997年 | 23篇 |
1996年 | 26篇 |
1995年 | 18篇 |
1994年 | 21篇 |
1993年 | 21篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 26篇 |
1989年 | 24篇 |
1988年 | 26篇 |
1987年 | 28篇 |
1986年 | 28篇 |
1985年 | 22篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 18篇 |
1979年 | 4篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1970年 | 3篇 |
Purpose
The objective of this study was to assess the prognostic value of metabolic tumor burden on 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) positron emission tomography (PET)/CT measured with metabolic tumor volume (MTV) and total lesion glycolysis (TLG), independent of Union Internationale Contra la Cancrum (UICC)/American Joint Committee on Cancer (AJCC) tumor, node, and metastasis (TNM) stage, in comparison with that of standardized uptake value (SUV) in nonsurgical patients with non-small cell lung cancer (NSCLC).Methods
This study retrospectively reviewed 169 consecutive nonsurgical patients (78 men, 91 women, median age of 68?years) with newly diagnosed NSCLC who had pretreatment 18F-FDG PET/CT scans. The 18F-FDG PET/CT scans were performed in accordance with National Cancer Institute guidelines. The MTV of whole-body tumor (MTVWB), of primary tumor (MTVT), of nodal metastases (MTVN), and of distant metastases (MTVM); the TLG of whole-body tumor (TLGWB), of primary tumor (TLGT), of nodal metastases (TLGN), and of distant metastases (TLGM); the SUVmax of whole-body tumor (SUVmaxWB), of primary tumor (SUVmaxT), of nodal metastases (SUVmaxN), and of distant metastases (SUVmaxM) as well as the SUVmean of whole-body tumor (SUVmeanWB), of primary tumor (SUVmeanT), of nodal metastases (SUVmeanN), and of distant metastases (SUVmeanM) were measured with the PETedge tool on a MIMvista workstation with manual adjustment. The median follow-up among survivors was 35?months from the PET/CT (range 2?C82?months). Statistical methods included Kaplan-Meier curves, Cox regression, and C-statistics.Results
There were a total of 139 deaths during follow-up. Median overall survival (OS) was 10.9?months [95% confidence interval (CI) 9.0?C13.2?months]. The MTV was statistically associated with OS. The hazard ratios (HR) for 1 unit increase of ln(MTVWB), ??(MTVT), ??(MTVN), and ??(MTVM) before/after adjusting for stage were: 1.47/1.43 (p?0.001/<0.001), 1.06/1.05 (p?0.001/<0.001), 1.11/1.10 (p?0.001/<0.001), and 1.04/1.03 (p?=?0.007/0.043), respectively. TLG had statistically significant associations with OS with the HRs for 1 unit increase in ln(TLGWB), ??(TLGT), ??(TLGN), and ??(TLGM) before/after adjusting for stage being 1.36/1.33 (p?0.001/<0.001), 1.02/1.02 (p?=?0.001/0.002), 1.05/1.04 (p?0.001/<0.001), and 1.02/1.02 (p?=?0.003/0.024), respectively. The ln(SUVmaxWB) and ??(SUVmaxN) were statistically associated with OS with the corresponding HRs for a 1 unit increase before/after adjusting for stage being 1.46/1.43 (p?=?0.013/0.024) and 1.22/1.16 (p?=?0.002/0.040). The ??(SUVmeanN) was statistically associated with OS before and after adjusting for stage with HRs for a 1 unit increase of 1.32 (p?0.001) and 1.24 (p?=?0.015), respectively. The ??(SUVmeanM) and ??(SUVmaxM) were statistically associated with OS before adjusting for stage with HRs for a 1 unit increase of 1.26 (p?=?0.017) and 1.18 (p?=?0.007), respectively, but not after adjusting for stage (p?=?0.127 and 0.056). There was no statistically significant association between OS and ??(SUVmaxT), ln(SUVmeanWB), or ??(SUVmeanT). There was low interobserver variability among three radiologists with intraclass correlation coefficients (ICC) greater than 0.94 for SUVmaxWB, ln(MTVWB), and ln(TLGWB). Interobserver variability was higher for SUVmeanWB with an ICC of 0.806.Conclusion
Baseline metabolic tumor burdens at the level of whole-body tumor, primary tumor, nodal metastasis, and distant metastasis as measured with MTV and TLG on FDG PET are prognostic measures independent of clinical stage with low inter-observer variability and may be used to further stratify nonsurgical patients with NSCLC. This study also suggests MTV and TLG are better prognostic measures than SUVmax and SUVmean. These results will need to be validated in larger cohorts in a prospective study. 相似文献Background:
17β-Oestradiol (E2)-induced reactive oxygen species (ROS) have been implicated in regulating the growth of breast cancer cells. However, the underlying mechanism of this is not clear. Here we show how ROS through a novel redox signalling pathway involving nuclear respiratory factor-1 (NRF-1) and p27 contribute to E2-induced growth of MCF-7 breast cancer cells.Methods:
Chromatin immunoprecipitation, qPCR, mass spectrometry, redox western blot, colony formation, cell proliferation, ROS assay, and immunofluorescence microscopy were used to study the role of NRF-1.Results:
The major novel finding of this study is the demonstration of oxidative modification of phosphatases PTEN and CDC25A by E2-generated ROS along with the subsequent activation of AKT and ERK pathways that culminated in the activation of NRF-1 leading to the upregulation of cell cycle genes. 17β-Oestradiol-induced ROS by influencing nuclear proteins p27 and Jab1 also contributed to the growth of MCF-7 cells.Conclusions:
Taken together, our results present evidence in the support of E2-induced ROS-mediated AKT signalling leading to the activation of NRF-1-regulated cell cycle genes as well as the impairment of p27 activity, which is presumably necessary for the growth of MCF-7 cells. These observations are important because they provide a new paradigm by which oestrogen may contribute to the growth of breast cancer. 相似文献Methods: A cross-sectional study was conducted in two semi-urban communities in Kathmandu, Nepal. Depression was assessed using the 15-item Geriatric Depression Scale in 303 participants, aged 60 years and over. Multivariate logistic regression was then used to assess associations between potential risk factors and depression.
Results: More than half of the participants (n = 175, 60.6%) had significant depressive symptomatology, with 27.7% having scores suggesting mild depression. Illiteracy (aOR = 2.01, 95% CI: 1.08–3.75), physical immobility (aOR = 5.62, 95% CI: 1.76–17.99), the presence of physical health problems (aOR = 1.97, 95% CI: 1.03–3.77), not having any time spent with family members (aOR = 3.55, 95% CI: 1.29–9.76) and not being considered in family decision-making (aOR = 4.02, 95% CI: 2.01–8.04) were significantly associated with depression in older adults.
Conclusion: The prevalence of depression was significant in older adults. There are clear associations of depression with demographic, social support and physical well-being factors in this population. Strategies that increase awareness in the community along with the health and social care interventions are needed to address the likely drivers of depression in older adults. 相似文献