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   563篇
  免费   26篇
  国内免费   5篇
耳鼻咽喉   3篇
儿科学   33篇
妇产科学   7篇
基础医学   58篇
口腔科学   16篇
临床医学   83篇
内科学   117篇
皮肤病学   32篇
神经病学   16篇
特种医学   123篇
外科学   17篇
综合类   22篇
预防医学   23篇
眼科学   5篇
药学   15篇
  1篇
肿瘤学   23篇
  2023年   2篇
  2022年   3篇
  2021年   4篇
  2020年   2篇
  2019年   4篇
  2018年   9篇
  2017年   2篇
  2016年   8篇
  2015年   10篇
  2014年   11篇
  2013年   15篇
  2012年   7篇
  2011年   11篇
  2010年   27篇
  2009年   28篇
  2008年   10篇
  2007年   22篇
  2006年   16篇
  2005年   15篇
  2004年   8篇
  2003年   4篇
  2002年   8篇
  2001年   6篇
  2000年   4篇
  1999年   6篇
  1998年   37篇
  1997年   45篇
  1996年   38篇
  1995年   19篇
  1994年   29篇
  1993年   22篇
  1992年   9篇
  1991年   9篇
  1990年   11篇
  1989年   22篇
  1988年   20篇
  1987年   9篇
  1986年   8篇
  1985年   5篇
  1984年   14篇
  1983年   14篇
  1982年   12篇
  1981年   11篇
  1980年   7篇
  1979年   1篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1969年   1篇
排序方式: 共有594条查询结果,搜索用时 31 毫秒
101.
102.
NTRODUCTIONPolygonumcuspidatumSieb.etZucc.(Polygonaceae)isatraditionalChineseherbaldrug,withbitertasteandcoldnature.Itmainly...  相似文献   
103.
104.
Cushing syndrome (CS) is the classic condition of cortisol dysregulation, and cortisol dysregulation is the prototypic finding in Major Depressive Disorder (MDD). We hypothesized that subjects with active CS would show dysfunction in frontal and limbic structures relevant to affective networks, and also manifest poorer facial affect identification accuracy, a finding reported in MDD. Twenty-one patients with confirmed CS (20 ACTH-dependent and 1 ACTH-independent) were compared to 21 healthy control subjects. Identification of affective facial expressions (Facial Emotion Perception Test) was conducted in a 3 Tesla GE fMRI scanner using BOLD fMRI signal. The impact of disease (illness duration, current hormone elevation and degree of disruption of circadian rhythm), performance, and comorbid conditions secondary to hypercortisolemia were evaluated. CS patients made more errors in categorizing facial expressions and had less activation in left anterior superior temporal gyrus, a region important in emotion processing. CS patients showed higher activation in frontal, medial, and subcortical regions relative to controls. Two regions of elevated activation in CS, left middle frontal and lateral posterior/pulvinar areas, were positively correlated with accuracy in emotion identification in the CS group, reflecting compensatory recruitment. In addition, within the CS group, greater activation in left dorsal anterior cingulate was related to greater severity of hormone dysregulation. In conclusion, cortisol dysregulation in CS patients is associated with problems in accuracy of affective discrimination and altered activation of brain structures relevant to emotion perception, processing and regulation, similar to the performance decrements and brain regions shown to be dysfunctional in MDD. This article is part of a Special Issue entitled 'Anxiety and Depression'.  相似文献   
105.

Background:

Fluorosis is one of the common but major emerging areas of research in the tropics. It is considered endemic in 17 states of India. However, the Cuddalore district of Tamil Nadu is categorised as a fluorosis non-endemic area. But clinical cases of dental fluorosis were reported in the field practice area of Department of Community Medicine, Rajah Muthiah Medical College, Annamalai University, Chidambaram. Since dental fluorosis has been described as a biomarker of exposure to fluoride, we assessed the prevalence and severity of dental fluorosis among primary school children in the service area.

Materials and Methods:

Children studying in six primary schools of six villages in the field practice area of Rural Health Centre of Faculty of Medicine, Annamalai University, Chidambaram, were surveyed. Every child was clinically examined at the school by calibrated examiners with Dean''s fluorosis index recommended by WHO (1997). Chi-square test, Chi-square trend test and Spearman''s rank correlation coefficient test were used for statistical analysis.

Results:

Five hundred and twenty-five 5- to 12-year-old school children (255 boys and 270 girls) were surveyed. The overall dental fluorosis prevalence was found to be 31.4% in our study sample. Dental fluorosis increased with age P < 0.001, whereas gender difference was not statistically significant. Aesthetically objectionable dental fluorosis was found in 2.1% of the sample. Villages Senjicherry, Keezhaperambai and Kanagarapattu revealed a community fluorosis index (CFI) score of 0.43, 0.54 and 0.54 with 5.6%, 4.8% and 1.4% of objectionable dental fluorosis, respectively. Correlation between water fluoride content and CFI values in four villages was noted to be positively significant.

Conclusion:

Three out of six villages studied were in ‘borderline’ public health significance (CFI score 0.4-0.6). A well-designed epidemiological investigation can be undertaken to evaluate the risk factors associated with the condition in the study region.  相似文献   
106.
Objectives: To evaluate the clinical utility of the City University of New York sentence test in a cohort of post-lingually deafened cochlear implants recipients over time.

Methods: 117 post-lingually deafened, Australian English-speaking CI recipients aged between 23 and 98 years (M?=?66 years; SD?=?15.09) were recruited. CUNY sentence test scores in quiet were collated and analysed at two cut-offs, 95% and 100%, as ceiling scores.

Results: CUNY sentence scores ranged from 4% to 100% (M?=?86.75; SD?=?20.65), with 38.8% of participants scoring 95% and 16.5% of participants reaching the 100% scores. The percentage of participants reaching the 95% and 100% ceiling scores increased over time (6 and 12 months post-implantation).

The distribution of all post-operative CUNY test scores skewed to the right with 82% of test scores reaching above 90%.

Discussion: This study demonstrates that the CUNY test cannot be used as a valid tool to measure the speech perception skills of post-lingually deafened CI recipients over time. This may be overcome by using adaptive test protocols or linguistically, cognitively or contextually demanding test materials.

Conclusion: The high percentage of CI recipients achieving ceiling scores for the CUNY sentence test in quiet at 3 months post-implantation, questions the validity of using CUNY in CI assessment test battery and limits its application for use in longitudinal studies evaluating CI outcomes. Further studies are required to examine different methods to overcome this problem.  相似文献   
107.
108.
Objective:  Determination of the microflora present on the tongue dorsum of subjects with and without halitosis using conventional microbiological culture methods.
Methods:  Twenty-one halitosis and 20 control patients were recruited using a strict clinical protocol. Samples were collected from the posterior dorsum of the tongue using a sterile brush. Each sample was vortex mixed for 30 s and serial 10-fold dilutions to 10−7 were carried out. Samples were plated onto fastidious anaerobe agar (FAA) and FAA enriched with vancomycin. These were incubated under anaerobic conditions for 10 days at 37°C. Strict anaerobes were identified by metronidazole sensitivity and bacteria were identified to genus level by a combination of colony morphology, Gram staining and biochemical and enzymatic tests (rapid ID 32 A).
Results:  The predominant species in test and control groups were Veillonella sp. and Prevotella sp. Greater species diversity was found in the halitosis samples compared with controls. The halitosis samples contained an increased incidence of unidentifiable Gram-negative rods, Gram-positive rods and Gram-negative coccobacilli.
Conclusions:  There was no obvious association between halitosis and any specific bacterial genus. The increased species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. The role of uncultivable bacteria may also be important in contributing to this process.  相似文献   
109.
110.

Objectives:

Childhood obesity and poor lifestyle practices are emerging as major public health challenges in the Caribbean. Given the fact that a significant part of childhood is spent at school, curriculum-based interventions aimed at improving good dietary and physical activity patterns may provide a useful vehicle for mass inculcation of long-term healthy lifestyle practices. In this study, we evaluated the long-term impact of a brief curriculum based intervention on dietary behaviour, physical activity and knowledge level of primary schoolchildren.

Methods:

The study was a randomized, controlled, school-based nutrition education and physical activity intervention. One hundred students each were then randomly assigned to the intervention (IVG) and non-intervention (NIVG) groups and followed-up for 18 months. Participants in the IVG group were exposed to a curriculum consisting of six one-hour modules followed by school-based activities geared at fostering healthy behaviours. Students in the non-intervention group did not receive any modules and were subject to the information available at school on a regular basis.

Results:

In multivariate regression equations controlling for age, gender, body mass index (BMI) and baseline values, intervention was associated with lower intake of fried foods and sodas (p < 0.05) and higher knowledge scores (p < 0.01) 18 months later but not significantly associated with improved physical activity or lower BMI.

Conclusions:

In this study, participants in the intervention group reported significantly lower intakes of fried foods and sodas and higher knowledge scores than participants in the control group some 18 months post-intervention independent of age, gender, BMI, ethnicity and the intakes at baseline.  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