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   621篇
  免费   42篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   26篇
妇产科学   19篇
基础医学   82篇
口腔科学   6篇
临床医学   62篇
内科学   167篇
皮肤病学   8篇
神经病学   69篇
特种医学   14篇
外科学   46篇
综合类   3篇
预防医学   47篇
眼科学   5篇
药学   45篇
中国医学   2篇
肿瘤学   62篇
  2024年   1篇
  2023年   11篇
  2022年   10篇
  2021年   11篇
  2020年   18篇
  2019年   16篇
  2018年   20篇
  2017年   7篇
  2016年   18篇
  2015年   20篇
  2014年   20篇
  2013年   34篇
  2012年   47篇
  2011年   52篇
  2010年   25篇
  2009年   24篇
  2008年   34篇
  2007年   34篇
  2006年   38篇
  2005年   45篇
  2004年   46篇
  2003年   34篇
  2002年   30篇
  2001年   2篇
  2000年   4篇
  1999年   4篇
  1998年   5篇
  1997年   5篇
  1996年   5篇
  1995年   6篇
  1994年   5篇
  1993年   3篇
  1992年   2篇
  1991年   5篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   4篇
  1981年   3篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1974年   1篇
  1972年   1篇
排序方式: 共有666条查询结果,搜索用时 21 毫秒
111.
This study investigates glio-vascular interactions in human fetal brain at midgestation, specifically examining the expression and immunolocalization of the CXCL12/CXCR4/CXCR7 ligand-receptor axis and its possible role in the vascular patterning of the developing brain. At midgestation, the telencephalic vesicles are characterized by well developed radial glia cells (RGCs), the first differentiated astrocytes and a basic vascular network mainly built of radial vessels. RGCs have been recognized to contribute to cerebral cortex neuro-vascular architecture and have also been demonstrated to act as a significant source of neural cells (Rakic, Brain Res 33:471–476, 1971; Malatesta et al, Development 127:5253–5263, 2000). According to our hypothesis CXCL12, a potent migration and differentiation chemokine released by RGCs, may act as a linking factor coordinating neuroblast migration with vessel growth and patterning through the activation of different ligand/receptor axes. The obtained results support this hypothesis showing that together with CXCR4/CXCR7-reactive neuroblasts, which migrate in close association with CXCL12 RGCs, layer-specific subsets of CXCL12 RGCs and astrocytes specifically contact the microvessel wall. Moreover, the CXCL12/CXCR4/CXCR7 system appears to be directly involved in microvessel growth, its members being differentially expressed in angiogenically activated microvessels and vascular sprouts.  相似文献   
112.
113.
In previous studies, we investigated a group of subjects who had suffered from a severe non missile traumatic brain injury (nmTBI) without macroscopic focal lesions and we found brain atrophy involving the hippocampus, fornix, corpus callosum, optic chiasm, and optic radiations. Memory test scores correlated mainly with fornix volumes [37,38]. In the present study, we re-examined 11 of these nmTBI subjects approximately 8 yr later. High-spatial resolution T1 weighted magnetic resonance images of the brain (1mm(3)) and standardised memory tests were performed once more in order to compare brain morphology and memory performance originally assessed 3-13 months after head injury (first study) and after 8-10 yr (present study). An overall improvement of memory test performance was demonstrated in the latest assessment, indicating that cognitive recovery in severe nmTBI subjects had not been completed within 3-13 months post-injury. It is notable that the volumes of the fornix and the hippocampus were reduced significantly from normal controls, but these volumes do not differ appreciatively between nmTBI subjects at first (after ~1 yr) and at second (after ~8 yr) scans. On the contrary, a clear reduction in the volume of the corpus callosus can be observed after ~1 yr and a further significant reduction is evident after ~8 yr, indicating that the neural degeneration in severe nmTBI continues long after the head trauma and relates to specific structures and not to the overall brain.  相似文献   
114.
115.
116.
117.
A taste component is implicated in the oro-sensory detection of dietary lipids and free fatty acids seem to be involved in fatty food recognition. Bottarga, the salted and semi-dried ovary product of mullet (Mugil spp.), is a rich-fat food. A comparative sensory assessment of different commercial bottarga samples was performed in insect and human models in relation to their lipid composition. The bottarga attractant effect to Ceratitis capitata was assessed by behavioral tests. The subjective odor and taste perception of bottarga samples was investigated in human determining the rate of pleasantness, familiarity, and intensity dimensions using the 7-points Likert-type scale. Bottarga samples showed similar lipid profiles, but differences emerged in total and free fatty acid levels. Significant differences were observed in the attractant effect/acceptability of samples to medflies, negatively correlated to their total and free fatty acids. Insect female exhibited the ability to select among bottarga samples based on their visual and olfactory properties. In the human model, a potential contribution of free fatty acid amount in the pleasantness and familiarity dimensions of taste of bottarga samples was evidenced. Women exhibited a greater ability than men to select bottarga samples based on their better olfactory perception. Our results increase the knowledge about this outstanding product with nutritional and nutraceutical properties.  相似文献   
118.
Two hundred and forty-nine women suffering from breast problems underwent a complete series of tests including clinical examination, mammography, echography, thermography, and fine-needle aspiration (FNA). Ninety-four of these patients were shown to be positive or to have suspected malignancy. Accordingly, they underwent surgical excision followed by histologic examination, while the remaining patients were re-examined after 12 to 18 mo in order to exclude false negatives. The analysis of specificity and sensitivity of every single procedure showed that FNA describes the best degree of sensitivity and specificity but no procedure allows, by itself, the detection of all carcinomas. When considered in combination, clinical examination, mammography, and fine-needle aspiration have a sensitivity of 100% and a specificity of 49%, and are the best diagnostic tests for a correct assessment of mammary lesions. Thermography and echography showed a low degree of sensitivity and should not be included in the routine diagnostic procedure of breast lesions. Diagn Cytopathol 1994; 11:4–8. © 1994 Wiley-Liss, Inc.  相似文献   
119.

Objectives

To investigate the patient-reported multidimensional gastrointestinal symptoms predictors of generic health-related quality of life (HRQOL) in pediatric patients with functional gastrointestinal disorders (FGIDs).

Methods

The Pediatric Quality of Life Inventory? (PedsQL?) Gastrointestinal Symptoms Scales and PedsQL? 4.0 Generic Core Scales were completed in a 9-site study by 259 pediatric patients with functional constipation, functional abdominal pain (FAP), or irritable bowel syndrome (IBS). Gastrointestinal Symptoms Scales measuring stomach pain, stomach discomfort when eating, food and drink limits, trouble swallowing, heartburn and reflux, nausea and vomiting, gas and bloating, constipation, blood in poop, and diarrhea were identified as clinically important symptom differentiators from healthy controls based on prior findings, and subsequently tested for bivariate and multivariate linear associations with overall HRQOL.

Results

Gastrointestinal symptoms were differentially associated with decreased HRQOL in bivariate analyses for the three FGIDs. In predictive models utilizing hierarchical multiple regression analyses controlling for age, gender, and race/ethnicity, gastrointestinal symptoms differentially accounted for an additional 47, 40, and 60 % of the variance in patient-reported HRQOL for functional constipation, FAP, and IBS, respectively, reflecting large effect sizes. Significant individual gastrointestinal symptoms predictors were identified after controlling for the other gastrointestinal symptoms in the FGID-specific predictive models.

Conclusions

Gastrointestinal symptoms represent potentially modifiable predictors of generic HRQOL in pediatric patients with FGIDs. Identifying the condition-specific gastrointestinal symptoms that are the most important predictors from the patient perspective facilitates a patient-centered approach to targeted interventions designed to ameliorate impaired overall HRQOL.
  相似文献   
120.
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