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   1097篇
  免费   84篇
  国内免费   7篇
耳鼻咽喉   8篇
儿科学   21篇
妇产科学   28篇
基础医学   161篇
口腔科学   17篇
临床医学   100篇
内科学   327篇
皮肤病学   44篇
神经病学   81篇
特种医学   37篇
外科学   120篇
综合类   1篇
预防医学   64篇
眼科学   5篇
药学   61篇
中国医学   1篇
肿瘤学   112篇
  2024年   3篇
  2023年   17篇
  2022年   41篇
  2021年   43篇
  2020年   18篇
  2019年   33篇
  2018年   48篇
  2017年   26篇
  2016年   43篇
  2015年   37篇
  2014年   51篇
  2013年   61篇
  2012年   88篇
  2011年   86篇
  2010年   46篇
  2009年   54篇
  2008年   75篇
  2007年   73篇
  2006年   54篇
  2005年   59篇
  2004年   59篇
  2003年   51篇
  2002年   40篇
  2001年   4篇
  2000年   3篇
  1999年   4篇
  1998年   9篇
  1997年   5篇
  1996年   8篇
  1995年   3篇
  1994年   8篇
  1993年   9篇
  1992年   5篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   5篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1980年   1篇
  1977年   1篇
排序方式: 共有1188条查询结果,搜索用时 15 毫秒
11.
12.
Metabolomics is the analysis of the concentration profiles of low molecular weight compounds present in biological fluids. Metabolites are nonpeptide molecules representing the end products of cellular activity. Therefore, changes in metabolite concentrations reveal the range of biochemical effects induced by a disease or its therapeutic intervention. Metabolomics has recently become feasible with the accessibility of new technologies, including mass spectrometry and high-resolution proton nuclear magnetic resonance, and has already been applied to several disorders. Indeed, it has the advantage of being a nontargeted approach for identifying potential biomarkers, which means that it does not require a preliminary knowledge of the substances to be studied. In this review, we summarize the main studies in which metabolomic approach was used in some allergic (asthma, atopic dermatitis) and rheumatic diseases (rheumatoid arthritis, systemic lupus erythematosus) to explore the feasibility of this technique as a novel diagnostic tool in these complex disorders.  相似文献   
13.
14.
ABSTRACT: We present the case of a 15-year-old boy who presented to our emergency department because of a soft lesion growing on the back of his tongue. On examination, a vegetant mass on the posteromidline lingual part of the body of the tongue was noticed: it was not painful, even if the boy reported discomfort because of its size; there was no bleeding or signs of infection. The magnetic resonance imaging showed the lesion as trilobated and capsulated, but was not diriment to define a diagnosis; excisional biopsy was performed under general anesthesia, and the mass was identified as a schwannoma.Schwannoma, or neurilemmoma, is a benign tumor originating from Schwann cells of the nerve sheath surrounding peripheral nerves. It is slow-growing, usually solitary, and encapsulated. Intraoral schwannomas are rare and account for 1% of lesions of the head and neck region. There is no sex predilection. The symptoms depend on size and location of the tumor. Recurrence is rare after complete surgical resection.The present study aimed to retrospectively describe our experience with a case of neurilemmoma of the tongue presenting in childhood, the diagnostic methods used, the surgical decision, and the treatment outcome and to analyze the data and review the literature available on this type of tumor. The etiology, clinical presentation, differential diagnosis, and management are discussed.  相似文献   
15.
16.
17.

Background

Chronic lymphocytic leukemia B cells display prolonged survival in vivo, but when cultured in vitro rapidly undergo spontaneous apoptosis. We hypothesize that interactions with endothelial cells in infiltrated tissues and during recirculation may have a pathogenic role in chronic lymphocytic leukemia.

Design and Methods

We evaluated apoptosis of leukemic cells after co-culture on a monolayer of human umbilical vein endothelial cells with addition of fludarabine and antibodies that block adhesion. Then, we compared microarray-based gene expression profiles between leukemic cells at baseline and after co-culture.

Results

We found that the endothelial layer protected leukemic cells from apoptosis inducing a 2-fold mean decrement in apoptotic cells after 2 days of co-culture. Moreover, the endothelial layer decreased the sensitivity of chronic lymphocytic leukemia B cells to fludarabine-induced apoptosis. Physical contact with endothelium mediated by both β1- and β2- integrins is essential for the survival advantage of leukemic cells. In particular, blocking CD106 on endothelial cells or CD18 on leukemic B cells led to the almost complete abrogation of the survival advantage (>70% inhibition of viability). However, a reduction of apoptosis was also measured in leukemic cells cultured in conditioned medium collected after 2 days of co-culture, implying that survival is partially mediated by soluble factors. Overall, the contact with endothelial cells modulated 1,944 genes in chronic lymphocytic leukemia B cells, establishing a peculiar gene expression profile: up-regulation of angiogenesis-related genes, an increase of genes involved in TGFβ and Wnt signaling pathways, secretion of cytokines recruiting stromal cells and macrophages and up-regulation of anti-apoptotic molecules such as Bcl2 and Survivin.

Conclusions

Our study supports the notion that endothelial cells are major players in the chronic lymphocytic leukemia microenvironment. Adhesion to endothelium strongly supports survival, protects from drug-induced apoptosis and extensively modifies the gene expression profile of leukemic cells.  相似文献   
18.
19.
Despite current guidelines, variability exists in the workup of hypertensive children due to physician preferences. The study evaluates primary vs secondary hypertension diagnosis from investigations routinely performed in hypertensive children. This retrospective study included children 5 to 19 years with primary and secondary hypertension. The proportions of abnormal laboratory and imaging tests were compared between primary and secondary hypertension groups. Risk factors for primary vs secondary hypertension were evaluated by logistic regression and likelihood function analysis. Patients with secondary hypertension were younger (5-12 years) and had a higher proportion of abnormal creatinine, renal ultrasound, and echocardiogram findings. There was no significant difference in abnormal results of thyroid function, urine catecholamines, plasma renin, and aldosterone. Abnormal renal ultrasound findings and age were predictors of secondary hypertension by regression and likelihood function analysis. Children aged 5 to 12 years with abnormal renal ultrasound findings and high diastolic blood pressures are at higher risk for secondary hypertension that requires detailed evaluation.  相似文献   
20.
BackgroundNF-κB expression has been shown to be responsible for resistance to antineoplastic agents.AimsThe aim of our study was to investigate the importance of NF-κB expression as prognostic factor in locally advanced rectal cancer patients receiving neoadjuvant radiochemotherapy.MethodsWe retrospectively analysed the immunoreactivity for NF-κB in patients with locally advanced rectal cancer who underwent neoadjuvant treatment (chemotherapy and/or radiotherapy) in our Institution between March 2003 and June 2006.ResultsSeventy-four consecutive patients were enrolled into this study. Immunohistochemistry analysis for NF-κB was performed both in biopsies and in primary tumour samples. NF-κB was considered positive when at least 1% of the tumour cells showed nuclear positivity. A significant correlation between a positive NF-κB nuclear expression, both in biopsies and in tumour samples, and a worse overall survival was observed.Moreover, median time to progression was significantly shorter in the NF-κB-positive subgroup of patients.ConclusionGlobally, our findings seem to suggest that NF-κB could represent an important parameter able to predict the outcome in patients receiving neoadjuvant treatment for rectal cancer. It also could be useful in order to select patients to receive adjuvant chemotherapy, intensifying the adjuvant therapy and, in the next future, obviating the use of drugs involving NF-κB system in their mechanism of action in NF-κB-positive patients.  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