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   179篇
  免费   16篇
  国内免费   4篇
儿科学   10篇
基础医学   15篇
口腔科学   2篇
临床医学   16篇
内科学   20篇
皮肤病学   41篇
神经病学   19篇
特种医学   19篇
外科学   10篇
综合类   10篇
预防医学   27篇
眼科学   2篇
药学   5篇
中国医学   1篇
肿瘤学   2篇
  2024年   1篇
  2023年   3篇
  2022年   2篇
  2021年   4篇
  2020年   1篇
  2019年   3篇
  2018年   2篇
  2017年   6篇
  2016年   11篇
  2015年   2篇
  2014年   8篇
  2013年   13篇
  2012年   18篇
  2011年   13篇
  2010年   10篇
  2009年   10篇
  2008年   10篇
  2007年   8篇
  2006年   6篇
  2005年   9篇
  2004年   3篇
  2003年   6篇
  2002年   9篇
  2001年   1篇
  2000年   2篇
  1998年   2篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   7篇
  1991年   4篇
  1990年   5篇
  1989年   3篇
  1988年   1篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1981年   2篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
  1912年   1篇
排序方式: 共有199条查询结果,搜索用时 0 毫秒
21.
Background/aims: Pigmented lesions are often difficult to evaluate clinically. Improvement of diagnostic accuracy by dermatoscopy has attracted much interet. With advanced digital imaging measurement of assymmetry, border irregularity and relative color as well as texture characteristics, lesional depth and changes in lesional area are now possible, the object of this review is to conclude the present status of these techniques and their potential.
Conclusions: Digital imaging of pigmented lesions to this date include acquiring and storing of images, quantification of clinical features including asymmetry, and teledermatology with transfer of images. Predicted uses include malignancy evaluation, delineation of depth of invasion and the development of large collections of pigment lesions observations. The field is rapidly expanding. As of 1994, it is unknown what role digital imaging will ultimately play in clinical dermatology.  相似文献   
22.
本研究旨在探讨齐墩果酸诱导人T淋巴细胞白血病Jurkat细胞株凋亡及对PTEN表达的影响。应用CCK-8法检测细胞增殖抑制率,用Hoechst33258染色观察凋亡细胞形态,Annexin V/PI双染色后流式细胞仪检测细胞凋亡,并应用实时定量RT-PCR和Western blot方法分别检测PTEN基因及其蛋白表达水平。结果表明:齐墩果酸以时间和剂量依赖方式抑制Jurkat细胞增殖,12、24和48小时的半数抑制浓度(IC50)分别约为85.35、53.66和33.18μmol/L。流式细胞术检测显示,齐墩果酸以0、40、80和160μmol/L浓度作用细胞24小时凋亡率分别为6.72%、19.8%、28.72%和30.12%(p<0.05)。80和160μmol/L齐墩果酸分别处理Jurkat细胞24小时后PTEN-mRNA及蛋白表达上调。结论:PTEN基因和蛋白表达上调可能参与齐墩果酸对Jurkat细胞的抑制增殖和诱导凋亡作用。  相似文献   
23.
Aim  General developmental outcome is known to be good in school‐aged children who experienced febrile seizures. We examined cognitive and behavioural outcomes in preschool children with febrile seizures, including language and executive functioning outcomes. Method  This work was performed in the Generation R Study, a population‐based cohort study in Rotterdam from early fetal life onwards. Information about the occurrence of febrile seizures was collected by questionnaires at the ages of 1, 2, and 3 years. At the age of 3 years, behaviour and emotion were assessed using the Child Behavior Checklist. Information on expressive language development was obtained by the Language Development Survey at the age of 2 years 6 months. To assess executive functioning, parents completed the Behaviour Rating Inventory of Executive Function – Preschool Version when their children were 4 years old. Final analyses were based on 3157 children. Results  No associations were found between febrile seizures and the risk of behavioural problems or executive functioning. In contrast to single febrile seizures, recurrent febrile seizures were significantly associated with an increased risk of delayed vocabulary development (odds ratio 3.22, [95% confidence interval 1.30–7.94]). Interpretation  Febrile seizures are not associated with problem behaviour or executive functioning in preschool children, but the results suggest that children with recurrent febrile seizures might be at risk for delayed language development.  相似文献   
24.
电子可读X线探测器的不断改进 ,使数字X线成像技术得以不断的充实和发展。自从电荷耦合技术(chargecouplede vice,CCD)的引入 ,虽使自扫描 ,直接读出数字探测器得以广泛应用 ,但随着设计的更新 ,工艺的进步 ,使具有薄膜晶体管读出机制的大范围平板探测器进入了一个新的阶段。由于X线探测器的改进 ,无论是采用固定的X线设备还是预置的图像质量都超过屏/片或光激励磷光存储计算X线摄影系统。1直接与间接转换电子X线探测器可分为直接转换和间接转换两大类。直接转换是通过探测器中的光导体如无定形硒将X线光…  相似文献   
25.
26.
Considerable variability across individuals has been reported in both the behavioral and fMRI blood oxygen level-dependent (BOLD) response to nicotine. We aimed to investigate (1) whether there is a heterogeneous effect of nicotine on behavioral and BOLD responses across participants and (2) if heterogeneous BOLD responses are associated with behavioral performance measures. In this double-blind, placebo-controlled, cross-over study, 41 healthy participants (19 smokers)—drawn from a larger population-based sample—performed a visual oddball task after acute challenge with 1 mg nasal nicotine. fMRI data and reaction time were recorded during performance of the task. Across the entire group of subjects, we found increased activation in the anterior cingulate cortex, middle frontal gyrus, superior temporal gyrus, post-central gyrus, planum temporal and frontal pole in the nicotine condition compared with the placebo condition. However, follow-up analyses of this difference in activation between the placebo and nicotine conditions revealed that some participants showed an increase in activation while others showed a decrease in BOLD activation from the placebo to the nicotine condition. A reduction of BOLD activation from placebo to nicotine was associated with a decrease in reaction time and reaction time variability and vice versa, suggesting that it is the direction of BOLD response to nicotine which is related to task performance. We conclude that the BOLD response to nicotine is heterogeneous and that the direction of response to nicotine should be taken into account in future pharmaco-fMRI research on the central action of nicotine.  相似文献   
27.
A significant seasonal correlation was recently shown for brown recluse spider activity. Vetter (2011) observed brown recluse spiders were submitted by the general public predominantly during April-October. For patients with suspected brown recluse spider bites (BRSB), we have observed the same seasonality. Among 45 cases with features consistent of a BRSB, 43 (95.6%) occurred during April-October. Both the Vetter study and our study serve to demonstrate seasonal activity for brown recluse spiders.  相似文献   
28.
29.
30.
The purpose of this study was to assess the nutritional status and cognitive performance of women and their 5‐year‐old children using a cross‐sectional design. Cognitive performance of mothers and children was assessed with Raven's Colored Progressive Matrices (CPM) and Kaufman Assessment Battery for Children‐II (KABC‐II). Demographic characteristics, food consumption patterns and anthropometry were also measured. Four rural districts in Sidama, southern Ethiopia served as the setting for this study. Subjects were one hundred women and their 5‐year‐old children. Mean ± standard deviation age of the mothers was 29 ± 6 years and family size was 7.0 ± 2.6. Maternal body mass index (BMI) ranged from 15.3 to 29.0 with 14% of the mothers having BMI < 18.5. Anthropometric assessment of children revealed 29% to be stunted (height‐for‐age z‐score < ?2) and 12% to be underweight (weight‐for‐age z‐score < ?2). Mothers' education significantly contributed to prediction of both mothers' and children's cognitive test scores. There were significant differences in mean cognitive test scores between stunted and non‐stunted, and between underweight and normal‐weight children. Height‐for‐age z‐scores were correlated with scores for short‐term memory (r = 0.42, P < 0.001), and visual processing (r = 0.42, P < 0.001) indices and weight‐for‐age z‐scores were also correlated with scores of short‐term memory (r = 0.41, P < 0.001) and visual processing (r = 0.43, P < 0.001) indices. Malnutrition in the community likely contributed to the cognitive performance of the subjects. Performance on memory and visual processing tasks was significantly lower in children with growth deficits suggesting that efficient and cost effective methods to alleviate malnutrition and food insecurity would impact not only child health but also cognitive function.  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