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   3308篇
  免费   174篇
  国内免费   61篇
耳鼻咽喉   43篇
儿科学   138篇
妇产科学   40篇
基础医学   378篇
口腔科学   82篇
临床医学   345篇
内科学   592篇
皮肤病学   72篇
神经病学   179篇
特种医学   117篇
外科学   778篇
综合类   82篇
一般理论   4篇
预防医学   132篇
眼科学   137篇
药学   176篇
中国医学   13篇
肿瘤学   235篇
  2023年   35篇
  2022年   77篇
  2021年   136篇
  2020年   63篇
  2019年   115篇
  2018年   117篇
  2017年   92篇
  2016年   92篇
  2015年   96篇
  2014年   154篇
  2013年   148篇
  2012年   254篇
  2011年   246篇
  2010年   159篇
  2009年   127篇
  2008年   187篇
  2007年   202篇
  2006年   188篇
  2005年   176篇
  2004年   182篇
  2003年   119篇
  2002年   103篇
  2001年   42篇
  2000年   50篇
  1999年   39篇
  1998年   28篇
  1997年   23篇
  1996年   29篇
  1995年   27篇
  1994年   24篇
  1993年   14篇
  1992年   16篇
  1991年   12篇
  1990年   14篇
  1989年   8篇
  1988年   15篇
  1987年   12篇
  1986年   17篇
  1985年   9篇
  1984年   7篇
  1983年   10篇
  1982年   7篇
  1980年   6篇
  1979年   7篇
  1978年   5篇
  1976年   7篇
  1974年   11篇
  1973年   4篇
  1972年   5篇
  1970年   6篇
排序方式: 共有3543条查询结果,搜索用时 15 毫秒
141.

INTRODUCTION

Acute appendicitis is a common condition seen in all surgical units. One rare condition that can mimic acute appendicitis is a nematode infection of the bowel. There have been few reported cases of nematode infection within the appendix and none that have been accompanied by intra-operative pictures.

PRESENTATION OF CASE

A 16-year-old female presented with a 12 h history of right iliac fossa pain and mild pyrexia. Bloods showed a neutrophilia and normal C-reactive protein. Laparoscopy was performed which revealed a non-inflamed appendix. The appendix was dissected and a live nematode was visualised exiting the base of the appendix. Anti-helminthics were given and the infection resolved.

DISCUSSION

Nematode infection is most commonly seen in Africa, Asia and South America. When seen within the United Kingdom (UK), it is seen most commonly within high-risk populations. Testing for these infections is not routine within the UK and when they are performed, the results take a considerable amount of time to return. These tests should be considered within high-risk populations so that unnecessary surgery can be avoided.

CONCLUSION

This case highlights the importance of considering rare causes of right iliac fossa pain including nematode infection in a young patient. The case highlights this by giving intra-operative pictures of live nematodes upon dissection of the appendix.  相似文献   
142.
In everyday conversation, listeners often rely on a speaker's gestures to clarify any ambiguities in the verbal message. Using fMRI during naturalistic story comprehension, we examined which brain regions in the listener are sensitive to speakers' iconic gestures. We focused on iconic gestures that contribute information not found in the speaker's talk, compared with those that convey information redundant with the speaker's talk. We found that three regions—left inferior frontal gyrus triangular (IFGTr) and opercular (IFGOp) portions, and left posterior middle temporal gyrus (MTGp)—responded more strongly when gestures added information to nonspecific language, compared with when they conveyed the same information in more specific language; in other words, when gesture disambiguated speech as opposed to reinforced it. An increased BOLD response was not found in these regions when the nonspecific language was produced without gesture, suggesting that IFGTr, IFGOp, and MTGp are involved in integrating semantic information across gesture and speech. In addition, we found that activity in the posterior superior temporal sulcus (STSp), previously thought to be involved in gesture‐speech integration, was not sensitive to the gesture‐speech relation. Together, these findings clarify the neurobiology of gesture‐speech integration and contribute to an emerging picture of how listeners glean meaning from gestures that accompany speech. Hum Brain Mapp 35:900–917, 2014. © 2012 Wiley Periodicals, Inc.  相似文献   
143.
144.
Vascular calcification (VC) is a risk factor for cardiovascular mortality in the setting of chronic kidney disease (CKD). Pyrophosphate (PPi), an endogenous molecule that inhibits hydroxyapatite crystal formation, has been shown to prevent the development of VC in animal models of CKD. However, the possibility of harmful effects of exogenous administration of PPi on bone requires further investigation. To this end, we examined by histomorphometry the bone of CKD mice after intraperitoneal PPi administration. After CKD creation or sham surgery, 10-week-old female apolipoprotein-E knockout (apoE?/?) mice were randomized to one non-CKD group or 4 CKD groups (n = 10–35/group) treated with placebo or three distinct doses of PPi, and fed with standard diet. Eight weeks later, the animals were killed. Serum and femurs were sampled. Femurs were processed for bone histomorphometry. Placebo-treated CKD mice had significantly higher values of osteoid volume, osteoid surface and bone formation rate than sham-placebo mice with normal renal function. Slightly higher osteoid values were observed in CKD mice in response to very low PPi dose (OV/BV, O.Th and ObS/BS) and, for one parameter measured, to high PPi dose (O.Th), compared to placebo-treated CKD mice. Treatment with PPi did not modify any other structural parameters. Mineral apposition rates, and other parameters of bone formation and resorption were not significantly different among the treated animal groups or control CKD placebo group. In conclusion, PPi does not appear to be deleterious to bone tissue in apoE?/? mice with CKD, although a possible stimulatory PPi effect on osteoid formation may be worth further investigation.  相似文献   
145.
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   
146.
147.
This retrospective study aimed to determine the superior vena cava (SVC) and left innominate vein (INV) normative cross-sectional area in children noninvasively using age as a predictor and also to compare the correlation of the area measured with the diameter on multidetector computed tomography (MDCT). Analysis of the SVC-INV cross-sectional area was performed for 73 consecutive patients. The cross-sectional area of the SVC-INV was manually estimated. A regression analysis was performed for the cross-sectional area and age separately, and regression equations were compared. One-way analysis of variance (ANOVA) was performed to evaluate significant differences in the area means according to age groups. Regression analysis showed that age can be a predictor for the area of the SVC (50.6 mm2 + 1.01 × age), te INV (48.3 mm2 + 0.93 × age), and the left SVC-INV junction (47.2 mm2 + 0.92 × age), with respective R 2 values of 93, 88 and 94 %. The comparative evaluation of the cross-sectional area and the diameter measurement of SVC showed that the cross-sectional area was more closely associated with the increasing age of the cohort (R 2 of 68 vs. 61 %) than the measured diameter. For a cohort of patients without congenital or acquired heart disease, MDCT can be used as a complementary test for a normative cross-sectional normogram area database of SVC-INV using age as a predictor.  相似文献   
148.

Introduction

Temporomandibular joint (TMJ) ankylosis involves the fusion of the mandibular condyle to the glenoid fossa, the skull base. The dilemma with regards to treatment planning whether distraction is done before gap arthroplasty or as a simultaneous procedure or after gap arthroplasty is still a controversy. In an attempt to carry out both the procedures simultaneously there is loss of vector control of the distal segment and the risk of pseudoarthrosis at the osteotomy site. This combined problem could be overcome by the use of total alloplastic joint prosthesis which offers a firm posterior stop for the proximal segment and negates aggressive physiotherapy.

Material and methods

The reference literatures were retrieved from Pub Med and Science Direct database. Three case reports of bilateral recurrent TMJ ankylosis successfully treated with custom made total TMJ by the authors are illustrated.

Conclusion

The purpose of this article is to review the world literature on various alloplastic joints available for TMJ reconstruction and to introduce our indigenous total joint prosthesis in the management of recurrent ankylosis.  相似文献   
149.
Placebo controls play a critical role in the evaluation of any pharmacotherapy. This review surveys the placebo arm in 12 randomized controlled trials (RCTs) investigating burning mouth syndrome (BMS) and documents a positive placebo response in 6 of them. On average, treatment with placebos produced a response that was 72% as large as the response to active drugs. The lack of homogeneity in the use of placebos adds to the difficulty in comparing results and aggregating data. Future RCTs investigating BMS would benefit from larger sample sizes, adequate follow‐up periods, and use of a standard placebo.  相似文献   
150.
Purpose:Intraocular infection in patients with COVID-19 could be different in the presence of treatment with systemic corticosteroid and immunosuppressive agents. We describe the epidemiology and microbiological profile of intraocular infection in COVID-19 patients after their release from the hospital.Methods:We analyzed the clinical and microbiological data of laboratory-confirmed COVID-19 patients from April 2020 to January 2021 presenting with features of endogenous endophthalmitis within 12 weeks of their discharge from the hospital in two neighboring states in South India. The data included demography, systemic comorbidities, COVID-19 treatment details, time interval to visual symptoms, the microbiology of systemic and ocular findings, ophthalmic management, and outcomes.Results:The mean age of 24 patients (33 eyes) was 53.6 ± 13.5 (range: 5–72) years; 17 (70.83%) patients were male. Twenty-two (91.6%) patients had systemic comorbidities, and the median period of hospitalization for COVID-19 treatment was 14.5 ± 0.7 (range: 7–63) days. Infection was bilateral in nine patients. COVID-19 treatment included broad-spectrum systemic antibiotics (all), antiviral drugs (22, 91.66% of patients), systemic corticosteroid (21, 87.5% of patients), supplemental oxygen (18, 75% of patients), low molecular weight heparin (17, 70.8% of patients), admission in intensive care units (16, 66.6% of patients), and interleukin-6 inhibitor (tocilizumab) (14, 58.3% of patients). Five (20.8%) patients died of COVID-19-related complications during treatment for endophthalmitis; one eye progressed to pan ophthalmitis and orbital cellulitis; eight eyes regained vision >20/400. Fourteen of 19 (73.7%) vitreous biopsies were microbiologically positive (culture, PCR, and microscopy), and the majority (11 patients, 78.5%) were fungi.Conclusion:Intraocular infection in COVID-19 patients is predominantly caused by fungi. We suggest a routine eye examination be included as a standard of care of COVID-19.  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