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   146篇
  免费   17篇
  国内免费   2篇
儿科学   4篇
妇产科学   3篇
基础医学   27篇
口腔科学   4篇
临床医学   14篇
内科学   46篇
皮肤病学   2篇
神经病学   12篇
特种医学   9篇
外科学   9篇
综合类   1篇
预防医学   18篇
眼科学   5篇
药学   3篇
肿瘤学   8篇
  2023年   3篇
  2022年   10篇
  2021年   19篇
  2020年   5篇
  2019年   7篇
  2018年   9篇
  2017年   1篇
  2016年   4篇
  2015年   6篇
  2014年   7篇
  2013年   11篇
  2012年   14篇
  2011年   14篇
  2010年   5篇
  2009年   3篇
  2008年   4篇
  2007年   2篇
  2006年   5篇
  2005年   2篇
  2004年   5篇
  2003年   4篇
  2002年   3篇
  2000年   1篇
  1997年   2篇
  1996年   2篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1988年   1篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1981年   1篇
  1978年   1篇
  1976年   1篇
排序方式: 共有165条查询结果,搜索用时 12 毫秒
31.
32.
33.
Vitamin D deficiency may exacerbate adverse neurocognitive outcomes in the progression of diseases such as Parkinson's, Alzheimer's, and other dementias. Mild cognitive impairment (MCI) is prodromal for these neurocognitive disorders and neuroimaging studies suggest that, in the elderly, this cognitive impairment is associated with a reduction in hippocampal volume and white matter structural integrity. To test whether vitamin D is associated with neuroanatomical correlates of MCI, we analyzed an existing structural and diffusion MRI dataset of elderly patients with MCI. Based on serum 25‐OHD levels, patients were categorized into serum 25‐OHD deficient (<12 ng/mL, n = 27) or not‐deficient (>12 ng/mL, n = 29). Freesurfer 6.0 was used to parcellate the whole brain into 164 structures and segment the hippocampal subfields. Whole‐brain structural connectomes were generated using probabilistic tractography with MRtrix. The network‐based statistic (NBS) was used to identify subnetworks of connections that significantly differed between the groups. We found a significant reduction in total hippocampal volume in the serum 25‐OHD deficient group especially in the CA1, molecular layer, dentate gyrus, and fimbria. We observed a connection deficit in 13 regions with the right hippocampus at the center of the disrupted network. Our results demonstrate that low vitamin D is associated with reduced volumes of hippocampal subfields and connection deficits in elderly people with MCI, which may exacerbate neurocognitive outcomes. Longitudinal studies are now required to determine if vitamin D can serve as a biomarker for Alzheimer's disease and if intervention can prevent the progression from MCI to major cognitive disorders.  相似文献   
34.

Background/Purpose

The purpose of this study is to examine the association between age and metabolic disorders in the population of Bali.

Method

A cross-sectional study was conducted on metabolic syndrome (MS) as defined on the basis of recommended parameters for diagnosis of the syndrome in the population of seven villages of Bali comprising six villages and one suburban area. At least three of the five parameters must be present for the diagnosis. Three hundred ten elderly people aged 60 years or more, with a male:female ratio of 168:142, of 1840 subjects were recruited in the study. The criteria for obesity were based on the 2000 World Health Organization recommendations for Asia Pacific population, for prediabetes [impaired fasting glycemia (IFG) and impaired glucose tolerance] and diabetes mellitus (DM) by American Diabetes Association (2009), and for MS by a joint statement of International Diabetes Federation, National Heart, Lung, and Blood Institute, American Heart Association, World Heart Federation, International Atherosclerosis Society, and International Association for the Study of Obesity (2009).

Results

The prevalence of IFG and DM were twofold in the elderly as compared with those in the younger-aged groups (21.4 vs. 11.7; 11.7 vs. 4.8, respectively). Blood pressure and fasting blood sugar levels were higher in the elderly than in the younger-aged group (133/81 mmHg vs. 117/76 mmHg; 102.7 mg/dL vs. 93.0 mg/dL, respectively; p < 0.001). There was no statistically significant difference in triglyceride and high-density lipoprotein cholesterol levels between both groups. Waist circumferences were lower among the elderly than among younger-aged groups (75.8 cm vs. 80.9 cm; p < 0.001). The elderly, with lower waist circumference, revealed significantly higher prevalence of MS as compared with the younger-aged group {22.9% vs. 17.3%; p = 0.026; prevalence risk 1.423 [confidence interval (CI) = 1.043G–1.944]}. The subjects who had 1, 2, 3, 4, and 5 components of MS were 34.6%, 23.8%, 13.0%, 4.3%, and 0.9%, respectively. The prevalence risk of each component of MS for the occurrence of MS were: elevated triglyceride [30.2 (CI = 14.5G–63.1)], elevated fasting blood sugar [8.5 (CI = 4.5G–15.8)], increased waist circumference [8.1 (CI = 4.3G–15.0)], reduced high-density lipoprotein cholesterol [4.4 (CI = 2.4G–7.9)], and elevated blood pressure [3.7 (CI = 1.9G–7.2)].

Conclusions

It could be inferred that in comparison with the younger-age group, the elderly had higher (twice) prevalence of IFG and DM, lower prevalence of central obesity, but higher prevalence of MS. Old age (60 years and more) had 1.4-fold risk for MS as compared with that in the younger-aged group, and elevated triglyceride levels appeared to be the most important risk factor for MS.  相似文献   
35.

Objective

To investigate the prevalence of somatic mutations in Indonesian cervical carcinoma patients in the context of histology and human papillomavirus (HPV) type.

Methods

In total 174 somatic hot-spot mutations in 13 genes were analyzed by mass spectrometry in 137 Indonesian cervical carcinomas.

Results

In 66/137 tumors (48%) 95 mutations were identified. PIK3CA was most frequently mutated (24%), followed by FBXW7 (7%), CTNNB1 (6%), and PTEN (6%). In squamous cell carcinomas more often multiple mutations per sample (p = 0.040), and more PIK3CA (p = 0.039) and CTNNB1 (p = 0.038) mutations were detected compared to adenocarcinomas. PIK3CA mutations were associated with HPV 16 positivity, CDKN2A mutations with HPV 52 positivity, and, interestingly, PTEN mutations with HPV negativity. Balinese tumor samples more often carried multiple mutations (p = 0.019), and more CTNNB1, CDKN2A, and NRAS mutations compared to Javanese tumor samples.

Conclusions

Potentially targetable somatic mutations occurred in 48% of Indonesian cervical carcinomas. The landscape of mutations is predominated by mutations concerning the PI3K pathway, and we prompt for more research on developing therapies targeting this pathway, explicitly for the more advanced stage cervical carcinoma patients.  相似文献   
36.
Diffusion tensor microimaging at 16.4 T with 40 μm isotropic voxels was used to investigate anisotropic water diffusion in prostate tissue at spatial resolution approaching the cellular scale. Nine normal glandular tissue samples were collected from the peripheral zone of six formalin fixed radical prostatectomy specimens. Fibromuscular stromal tissue exhibited microscopic diffusion anisotropy (mean fractional anisotropy range 0.47–0.66) significantly higher (P < 0.01, Student's t‐test) than in epithelium‐containing voxels (mean fractional anisotropy range 0.31–0.54) in six of the seven normal tissue samples in which both compartments could be measured. Fiber tracking demonstrated principle stromal fiber directions consistent with myocyte orientation seen on light microscopy of the same sample. Diffusion tensor microimaging may be valuable for investigation of variable results from attempts to measure diffusion anisotropy in the prostate in vivo. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   
37.
The basal ganglia are a group of subpallial nuclei that play an important role in motor, emotional, and cognitive functions. Morphological changes and disrupted afferent/efferent connections in the basal ganglia have been associated with a variety of neurological disorders including psychiatric and movement disorders. While high-resolution magnetic resonance imaging has been used to characterize changes in brain structure in mouse models of these disorders, no systematic method for segmentation of the C57BL/6 J mouse basal ganglia exists. In this study we have used high-resolution MR images of ex vivo C57BL/6 J mouse brain to create a detailed protocol for segmenting the basal ganglia. We created a three-dimensional minimum deformation atlas, which includes the segmentation of 35 striatal, pallidal, and basal ganglia-related structures. In addition, we provide mean volumes, mean T2 contrast intensities and mean FA and ADC values for each structure. This MR atlas is available for download, and enables researchers to perform automated segmentation in genetic models of basal ganglia disorders.  相似文献   
38.
The study explored blind users' mental models and strategies in coping with the Windows environment and investigated the relationship between users' mental models and usability problems they face when using a screen reader. The study found that blind users possess a functional or structural mental model or a combination thereof. Blind users also have a rich and highly procedural strategy for coping with a new Windows environment and application. Users' established mental models developed from using a familiar screen reader were found to contribute to problems in using a new screen reader.  相似文献   
39.
Forty-nine cases of NPC were evaluated histopathologically and the radiation responses of the tumor types were assessed. The overall radiation response were as follows: CR 40.8%, PR 14.3%, NC 42.9%, PD 2.0%. The distribution of tumor types were: Squamous cell carcinoma (WHO type I) 4.08%; Non-keratinizing carcinoma (WHO type II) 4.08%; Undifferentiated carcinoma (WHO type III) 91.84% var. Lympho-epitheliomatous (LE), Anaplastic (A), Spindle cell (SC), Clear cell (CC). 94.38% of the cases were classified as clinical stage II, III and IV (tumor found beyond the nasopharyngeal space). The radiation response rate of the tumor in the lymphnode was reversed to the clinical stage and extent of node involvement, namely the higher stage and node involvement, the less rate of radiation response. Twelve cases received radiation dose of less than 4000 cGy, which comprised 11 NC cases and 1 PD case. Of the 37 cases who got 4000 cGy and over, the response rate was 72.97%. Of these WHO type I was not evaluated because of insufficient radiation dose; WHO type II showed 50% response rate; WHO type III showed 74.29% response rate. Radiation response (as assessed from the cervical lymphnode involvement) of NPC was influenced by tumor burden and histologic type of the tumor, namely the less differentiated tumor responded better than the more differentiated one. No definite conclusion can be drawn yet of the different behaviour (if any) of the variants of undifferentiated carcinoma (WHO type III) toward irradiation.  相似文献   
40.
Laryngeal cancer, clinically as well as pathologically, usually does not pose a difficult problem in diagnosis. The problem lies in the clinical diagnosis of early laryngeal cancer. We began to study and develop the in vivo staining technique for laryngeal lesions in our clinic, using toluidine blue, an acidophilic metachromatic dye. This preliminary study comprised eight cases of laryngeal lesions, five of which were carcinoma. Among these latter cases, besides carcinoma, we were able to detect dysplasia in two cases, carcinoma in situ in one case, and a false-positive area in one case. Noncarcinoma cases consisted of dysplasia, dysplasia in postradiation for carcinoma, and carcinoma in situ. In two cases of carcinoma, the tumor margin was accurately defined by positive staining area. This experience suggests that in vivo staining may be a useful method for early detection of laryngeal cancer used as an adjunct to microlaryngoscopy.  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