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   663篇
  免费   38篇
  国内免费   1篇
耳鼻咽喉   7篇
儿科学   8篇
妇产科学   13篇
基础医学   74篇
口腔科学   12篇
临床医学   65篇
内科学   188篇
皮肤病学   15篇
神经病学   61篇
特种医学   13篇
外科学   82篇
综合类   7篇
预防医学   34篇
眼科学   17篇
药学   53篇
中国医学   5篇
肿瘤学   48篇
  2024年   2篇
  2023年   10篇
  2022年   22篇
  2021年   41篇
  2020年   17篇
  2019年   42篇
  2018年   23篇
  2017年   25篇
  2016年   14篇
  2015年   21篇
  2014年   23篇
  2013年   38篇
  2012年   63篇
  2011年   50篇
  2010年   21篇
  2009年   10篇
  2008年   31篇
  2007年   28篇
  2006年   26篇
  2005年   33篇
  2004年   25篇
  2003年   32篇
  2002年   30篇
  2001年   5篇
  2000年   4篇
  1999年   8篇
  1998年   3篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   3篇
  1989年   6篇
  1988年   4篇
  1987年   3篇
  1986年   3篇
  1985年   1篇
  1984年   4篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   3篇
  1978年   2篇
  1975年   1篇
  1974年   3篇
  1972年   2篇
  1967年   2篇
排序方式: 共有702条查询结果,搜索用时 15 毫秒
21.
22.

Background

The urban low income has often been assumed to have the greatest dental treatment needs compared to the general population. However, no studies have been carried out to verify these assumptions. This study was conducted to assess whether there was any difference between the treatment needs of an urban poor population as compared to the general population in order to design an intervention programme for this community.

Methods

A random sampling of living quarters (households) in the selected areas was done. 586 adults over 19 years old living in these households were clinically examined using World Health Organization (WHO) Oral Health Survey criteria 4th edition (1997).

Results

The overall prevalence of dental caries, periodontal disease, denture wearers and temporomandibular joint problems were 70.5%, 97.1%, 16.7% and 26%, respectively. The majority (80.5%) needed some form of dental treatment. The highest treatment needs were found in the oldest age group while the lowest were in the youngest group (19-29 years) (p = 0.000). The most prevalent periodontal problem was calculus; regardless of gender, ethnicity and age. Significantly more females (20.5%) wore prosthesis than males (11.1%) (p = 0.003). Prosthetic status and need significantly increased with age (p = 0.000). About one in four adults had Temporo-Mandibular Joint (TMJ) problems. Overall, it was surprising to note that the oral disease burden related to caries, prosthetic status and treatment need were lower in this population as compared to the national average (NOHSA, 2010). However, their periodontal disease status and treatment needs were higher compared to the national average indicating a poor oral hygiene standard.

Conclusions

The evidence does not show that the overall oral disease burden and treatment needs in this urban disadvantaged adult population as higher than the national average, except for periodontal disease. The older age groups and elderly were identified as the most in need for oral health intervention and promotion. An integrated health intervention programme through a multisectoral common risk factor approach in collaboration with the Faculties of Medicine, Dentistry and other agencies is needed for the identified target group.
  相似文献   
23.

INTRODUCTION

Open surgical release for carpal tunnel syndrome is not devoid of complications and its quantitative assessment with the Boston questionnaire in a developing country had not been conducted, where, lack of facilities and surgical technique can influence the outcome.

PRESENTATION OF CASE

This was a prospective study in which all cases of carpal tunnel syndrome undergoing open release between June 2007 and June 2012 and who returned for follow up were included. Each patient was requested to fill out the Boston questionnaire twice both pre and post op at 3 months. All complications were recorded as well as bio-data of patients and co morbidities. Follow up was at 2 weeks and at 3 months. Those reporting complications at 3 months were further followed up until 6 months. 373 patients were included in the study. Twenty four patients developed complications. Of these, 12 experienced pain resulting from reflex sympathetic dystrophy. Three patients developed wound dehiscence, 2 cases acquired infections, 4 patients developed immediate post-operative haemorrhage and in 3 patients there was late recurrence of median nerve compression. The symptom severity score pre-operatively was 3.30 (±0.60) and it improved to 1.65 (±0.75) post-operatively indicating a significant change (p < 0.0001). The preoperative functional status score was 2.58 (±0.75) and post-op it became 1.60 (±0.80) again implying a good improvement with an effect size of 1.3.

DISCUSSION

All of the complications produced were well managed. The complication incidence was low. The open release procedure produced good improvement in hand function and in decreasing the symptom severity.

CONCLUSION

Conducting open release for carpal tunnel syndrome in a tertiary referral centre in a developing country offers a good outcome.  相似文献   
24.
Glaucoma is a progressive and deteriorating optic neuropathy that leads to visual field defects. The damage occurs as glaucoma is irreversible, so early and timely diagnosis is of significant importance. The proposed system employs the convolution neural network (CNN) for automatic segmentation of the retinal layers. The inner limiting membrane (ILM) and retinal pigmented epithelium (RPE) are used to calculate cup-to-disc ratio (CDR) for glaucoma diagnosis. The proposed system uses structure tensors to extract candidate layer pixels, and a patch across each candidate layer pixel is extracted, which is classified using CNN. The proposed framework is based upon VGG-16 architecture for feature extraction and classification of retinal layer pixels. The output feature map is merged into SoftMax layer for classification and produces probability map for central pixel of each patch and decides whether it is ILM, RPE, or background pixels. Graph search theory refines the extracted layers by interpolating the missing points, and these extracted ILM and RPE are finally used to compute CDR value and diagnose glaucoma. The proposed system is validated using a local dataset of optical coherence tomography images from 196 patients, including normal and glaucoma subjects. The dataset contains manually annotated ILM and RPE layers; manually extracted patches for ILM, RPE, and background pixels; CDR values; and eventually final finding related to glaucoma. The proposed system is able to extract ILM and RPE with a small absolute mean error of 6.03 and 5.56, respectively, and it finds CDR value within average range of ± 0.09 as compared with glaucoma expert. The proposed system achieves average sensitivity, specificity, and accuracies of 94.6, 94.07, and 94.68, respectively.  相似文献   
25.
The present study was designed to evaluate the effects of chlorpyriphos, lead acetate and vitamin C alone and in combinations, on various haematological parameters in Wistar rats. Rats of 150–200 g body weight were divided into eight groups of six animals each and were subjected to various daily oral treatment regimes for 98 days. Group C served as control receiving only corn oil, group CP received chlorpyriphos at 5.5 mg/kg in corn oil and group L received lead acetate at100?ppm in water, whereas animals in group CP + L received a combination of chlorpyriphos at 5.5 mg/kg in corn oil and lead acetate at 100 ppm in water. Group VC received vitamin C at 100 mg/kg in water; group CP + VC received a combination of chlorpyriphos at 5.5 mg/kg and vitamin C at 100 mg/kg; group L + VC received lead acetate at 100 ppm in water and vitamin C at 100 mg/kg and group CP + L + VC received chlorpyriphos at 5.5 mg/kg, lead acetate at 100 ppm in water and vitamin C at 100 mg/kg. Blood samples were collected on days 0, 30, 60 and 98 post exposure and analysed for packed cell volume (PCV), total erythrocyte count (TEC), haemoglobin (Hb), erythrocyte sedimentation rate (ESR), total leucocyte count (TLC) and differential leucocyte count. A significant decrease in TEC, PCV and Hb and a significant increase in ESR values were observed. However, lead acetate caused an increase in TLC while chlorpyriphos resulted in a decrease in TLC. Both of these toxicants potentiated toxicity of each other. The study demonstrated that treatment of chlorpyriphos- and lead-treated rats with vitamin C significantly altered some of the important haematological parameters revealing the protective effect of this vitamin against haematological alterations induced by chlorpyriphos and lead.  相似文献   
26.
27.
28.
Sahi H  Karnak D  Meli YM  Machuzak M  Gildea TR  Mehta AC 《COPD》2008,5(2):125-131
Chronic obstructive pulmonary disease (COPD) is a highly prevalent condition that has frequent morbidity and mortality, with associated costs of US $ 2.5 billion annually and nearly 14,000 deaths each year. In the most advanced stages it causes debilitating breathlessness which is not improved despite maximal medical therapy including smoking cessation, bronchodilators, steroids and supplemental oxygen. Limitations of medical therapy led to the development of several surgical techniques to improve quality of life. However, surgical techniques still carry substantial morbidity even if the mortality is low at centers with larger experience; hence investigators are vigorously pursuing research into innovative, alternative methods for achieving lung volume reduction (LVR), in recent years. Endoscopic techniques for LVR are proposed, based on two main approaches, either closing of anatomical airway passages into destroyed lobe/segment of the lung to affect a collapse and reduction in volume or opening extra-anatomical airway passages, aimed at improving expiratory collateral flow from hyper-inflated areas bypassing the flow limited segments of the emphysematous airways. This article reviews the available endoscopic devises and the evidence supporting their use in the treatment of COPD.  相似文献   
29.
Vitamin D co-regulates cell proliferation, differentiation and apoptosis, the processes that are disturbed in cancer tissues. It acts through the vitamin D nuclear receptor (VDR) that binds to DNA in the regulatory sequences of the target genes. As the kidney is one of the key organs for vitamin D metabolism and action, we analyzed VDR expression and its DNA binding activity in human renal clear cell cancer. 24 tumors, 24 controls that were excised from the opposite pole of the same kidney and 7 controls originating from kidneys without cancer were examined. Independently of tumor grading neither Northern blots nor immunoblotting demonstrated statistically significant differences of the mean VDR mRNA and protein amounts, respectively, in the cancer as compared to both control types. In contrast, the amount of VDR-DNA complexes was lower in 52.2% of the tumors in comparison to their corresponding controls. After normalization against VDR receptor protein amount in 34.8% of the tumors VDR-DNA binding was at least 3-4 times weaker than in the controls. However, the expression of vitamin D-dependent P21 gene on the mRNA level was not decreased in these cancers. It remains to be elucidated if altered VDR function due to its impaired binding to DNA contributes to the process of tumorigenesis, and what potential vitamin D-dependent mechanisms are involved in this process.  相似文献   
30.
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