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   448篇
  免费   29篇
  国内免费   4篇
耳鼻咽喉   3篇
儿科学   38篇
妇产科学   9篇
基础医学   38篇
口腔科学   10篇
临床医学   40篇
内科学   70篇
皮肤病学   7篇
神经病学   7篇
特种医学   90篇
外科学   33篇
综合类   61篇
预防医学   15篇
眼科学   11篇
药学   22篇
肿瘤学   27篇
  2022年   6篇
  2021年   4篇
  2020年   5篇
  2019年   2篇
  2018年   8篇
  2017年   6篇
  2016年   7篇
  2015年   16篇
  2014年   4篇
  2013年   7篇
  2012年   12篇
  2011年   15篇
  2010年   23篇
  2009年   15篇
  2008年   14篇
  2007年   13篇
  2006年   20篇
  2005年   21篇
  2004年   8篇
  2003年   8篇
  2002年   15篇
  2001年   11篇
  2000年   7篇
  1999年   13篇
  1998年   29篇
  1997年   23篇
  1996年   18篇
  1995年   15篇
  1994年   13篇
  1993年   9篇
  1992年   4篇
  1990年   4篇
  1989年   15篇
  1988年   11篇
  1987年   17篇
  1986年   11篇
  1985年   5篇
  1984年   5篇
  1983年   6篇
  1982年   5篇
  1981年   5篇
  1980年   6篇
  1978年   3篇
  1977年   1篇
  1976年   3篇
  1975年   8篇
  1969年   1篇
  1967年   1篇
  1966年   1篇
  1965年   1篇
排序方式: 共有481条查询结果,搜索用时 4 毫秒
71.
Microglandular adenosis (MGA) and atypical MGA (AMGA) are unusual lesions of the breast. They were once regarded as benign proliferative lesions and innocent bystanders. Several lines of evidence suggested that they could be neoplastic, clonal lesions and a non‐obligate precursor for triple‐negative breast cancers (TNBC). Recent work published in The Journal of Pathology by Guerini‐Rocco and colleagues provided further evidence regarding the precursor–product relationship between MGA/AMGA and TNBC. Using a massively parallel sequencing approach, they demonstrated that MGA/AMGA, particularly those associated with TNBC, could be clonal neoplastic lesions showing clonal non‐synonymous mutations, but none in pure MGA. Importantly, those alterations were observed in the associated TNBC. They were also able to identify recurrent alterations in TP53 in those MGA/AMGA cases as well as their associated TNBC. The findings, in conjunction with others, underscore the significance for MGA in clinical diagnosis. The potential of a benign lesion to progress into an aggressive malignant tumour implies that modification of the current management approach may be necessary. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
72.
73.

Background

The relationship between bone mineral density (BMD) and type 2 diabetes mellitus (T2DM) has been controversial. Recent studies have revealed adverse impact of antidiabetic drugs on BMD in type 2 diabetic patients. However, the influence of various antihyperglycaemic agents on BMD has not been well studied.

Method

A total of 200 patients with T2DM were screened initially for the study. Finally 67 patients (M:34, F:33) who satisfied the requirement of having been on one year of prescribed therapy were included for analysis.

Results

Bone mineral density was lower in diabetic patients as compared to controls (hip 0.962 ± 0.167 g/cm2 vs 1.013 ± 0.184 g/cm2, P = 0.05; spine 0.929 ± 0.214 g/cm2 vs 1.113 ± 0.186 g/cm2, P < 0.00001). In males BMD was significantly lower at spine (P < 0.00001) and in females BMD was significantly lower in both at the spine (P < 0.00001) and hip (P < 0.032). On multivariate analysis significant positive correlation was found between spine BMD and body mass index (BMI) (r = 0.372, P = 0.002), total cholesterol (r = 0.272, P = 0.026), low-density lipoprotein (r = 0.242, P = 0.047), and triglycerides (r = 0.282, P = 0.021). There was no correlation between BMD and glycosylated haemoglobin (r = 0.158, P = 0.265). A significant decrease in BMD at spine and hip was seen with the use of glitazones and metformin while increase was noted with sulphonylurea and its combination.

Conclusion

Men and women with T2DM have lower BMD. Bone mineral density did not have correlation to glycaemic control. Glitazones, metformin, and insulin are associated with decrease in BMD at spine, and hip, while sulphonylureas are associated with increase in BMD.Key Words: antihyperglycaemic drugs, bone mineral density, type 2 diabetes mellitus  相似文献   
74.
The high-molecular-weight sulfated or sulfonated polysaccharides or polymers cellulose sulfate, dextran sulfate, and polystyrene sulfonate were tested for microbicidal activity against bovine papillomavirus type 1 (BPV-1) and human papillomavirus type 11 (HPV-11) and type 40 (HPV-40). In vitro assays included the BPV-1-induced focus-forming assay and transient infection of human A431 cells with HPVs. The compounds were tested for microbicidal activity directly by preincubation with virus prior to addition to cell cultures and indirectly by addition of virus to compound-treated cells and to virus-coated cells to test inactivation of the virus after virus-cell binding. The data indicated that all three compounds showed direct microbicidal activity with 50% effective concentrations between 10 to 100 microg/ml. These concentrations were nontoxic to cell cultures for both assays. When a clone of C127 cells was tested for microbicidal activity, approximately 10-fold-less compound was required to achieve a 50% reduction in BPV-1-induced foci than for the uncloned parental C127 cells. Pretreatment of cells with compound prior to addition of virus also demonstrated strong microbicidal activity with dextran sulfate and polystyrene sulfonate, but cellulose sulfate required several orders of magnitude more compound for virus inactivation. Polystyrene sulfonate prevented subsequent infection of HPV-11 after virus-cell binding, and this inactivation was observed up to 4 h after addition of virus. These data indicate that the polysulfated and polysulfonated compounds may be useful nontoxic microbicidal compounds that are active against a variety of sexually transmitted disease agents including papillomaviruses.  相似文献   
75.
76.
77.
Iliopsoas impingement is a commonly recognised source of groin pain following total hip replacement. When conservative measures fail, open or arthroscopic iliopsoas tendon release can reliably alleviate pain and improve function. This article describes an alternative ultrasound‐guided percutaneous technique, achieving iliopsoas tenotomy utilising a modified 18G coaxial needle and thus minimising the morbidity and cost associated with an open or arthroscopic procedure. This method proved successful with resultant complete resolution of patient symptoms. To the knowledge of the authors, this is the first case of ultrasound‐guided percutaneous iliopsoas tenotomy for iliopsoas impingement post total hip replacement.  相似文献   
78.
79.
Mutations in the PEX gene at Xp22.1 (phosphate-regulating gene with homologies to endopeptidases, on the X-chromosome), are responsible for X-linked hypophosphataemic rickets (HYP). Homology of PEX to the M13 family of Zn2+ metallopeptidases which include neprilysin (NEP) as prototype, has raised important questions regarding PEX function at the molecular level. The aim of this study was to analyse 99 HYP families for PEX gene mutations, and to correlate predicted changes in the protein structure with Zn2+ metallopeptidase gene function. Primers flanking 22 characterised exons were used to amplify DNA by PCR, and SSCP was then used to screen for mutations. Deletions, insertions, nonsense mutations, stop codons and splice mutations occurred in 83% of families screened for in all 22 exons, and 51% of a separate set of families screened in 17 PEX gene exons. Missense mutations in four regions of the gene were informative regarding function, with one mutation in the Zn2+-binding site predicted to alter substrate enzyme interaction and catalysis. Computer analysis of the remaining mutations predicted changes in secondary structure, N-glycosylation, protein phosphorylation and catalytic site molecular structure. The wide range of mutations that align with regions required for protease activity in NEP suggests that PEX also functions as a protease, and may act by processing factor(s) involved in bone mineral metabolism.   相似文献   
80.
Speech-controlled generation of radiology reports   总被引:1,自引:0,他引:1  
Voice entry has been successfully employed to generate radiology reports with a word recognizer with a 1,000-word lexicon capacity. About 50% of reports were able to be dictated with a single 900-word lexicon. This was split into five sections by anatomic or subspecialty application. Each was augmented to 900 words. By switching from one lexicon to another, it was possible to dictate more than 70% of reports. With exclusive use of three lexicons in subspecialty areas (gastrointestinal radiology, neuroradiology, and mammography), and with further modification of the respective vocabulary, it has been possible to employ the system 88% of the time. Twelve percent of cases included wording that was beyond the scope of the lexicon. Computer subsets that allow different translations of some words when used in different contexts have been used. Some of these are used as triggers that will print whole lines, sentences, or even complete reports. Dictation times with voice entry take about 20% longer. Recognition reliability has been greater than 95%.  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