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   319篇
  免费   18篇
  国内免费   32篇
耳鼻咽喉   2篇
儿科学   25篇
妇产科学   4篇
基础医学   31篇
口腔科学   8篇
临床医学   61篇
内科学   71篇
皮肤病学   19篇
神经病学   6篇
特种医学   58篇
外科学   12篇
综合类   13篇
预防医学   3篇
眼科学   8篇
药学   27篇
中国医学   2篇
肿瘤学   19篇
  2022年   4篇
  2020年   2篇
  2019年   1篇
  2018年   6篇
  2017年   3篇
  2016年   8篇
  2015年   6篇
  2014年   8篇
  2013年   10篇
  2012年   7篇
  2011年   8篇
  2010年   11篇
  2009年   22篇
  2008年   9篇
  2007年   33篇
  2006年   12篇
  2005年   1篇
  2004年   9篇
  2003年   6篇
  2002年   7篇
  2001年   9篇
  2000年   2篇
  1999年   5篇
  1998年   16篇
  1997年   19篇
  1996年   24篇
  1995年   12篇
  1994年   23篇
  1993年   5篇
  1992年   2篇
  1991年   6篇
  1990年   7篇
  1989年   9篇
  1988年   7篇
  1987年   5篇
  1986年   8篇
  1985年   5篇
  1984年   4篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1977年   12篇
  1976年   2篇
  1975年   1篇
  1970年   1篇
排序方式: 共有369条查询结果,搜索用时 15 毫秒
11.
The sequential algorithm for fibrosis evaluation (SAFE) and the Bordeaux algorithm (BA), which cross-check FibroTest with the aspartate aminotransferase-to-platelet ratio index (APRI) or FibroScan, are very accurate but provide only a binary diagnosis of significant fibrosis (SAFE or BA for Metavir F ≥ 2) or cirrhosis (SAFE or BA for F4). Therefore, in clinical practice, physicians have to apply the algorithm for F ≥ 2, and then, when needed, the algorithm for F4 ("successive algorithms"). We aimed to evaluate successive SAFE, successive BA, and a new, noninvasive, detailed classification of fibrosis. The study included 1785 patients with chronic hepatitis C, liver biopsy, blood fibrosis tests, and FibroScan (the latter in 729 patients). The most accurate synchronous combination of FibroScan with a blood test (FibroMeter) provided a new detailed (six classes) classification (FM+FS). Successive SAFE had a significantly (P < 10(-3) ) lower diagnostic accuracy (87.3%) than individual SAFE for F ≥ 2 (94.6%) or SAFE for F4 (89.5%), and required significantly more biopsies (70.8% versus 64.0% or 6.4%, respectively, P < 10(-3) ). Similarly, successive BA had significantly (P ≤ 10(-3) ) lower diagnostic accuracy (84.7%) than individual BA for F ≥ 2 (88.3%) or BA for F4 (94.2%), and required significantly more biopsies (49.8% versus 34.6% or 24.6%, respectively, P < 10(-3) ). The diagnostic accuracy of the FM+FS classification (86.7%) was not significantly different from those of successive SAFE or BA. However, this new classification required no biopsy. CONCLUSION: SAFE and BA for significant fibrosis or cirrhosis are very accurate. However, their successive use induces a significant decrease in diagnostic accuracy and a significant increase in required liver biopsy. A new fibrosis classification that synchronously combines two fibrosis tests was as accurate as successive SAFE or BA, while providing an entirely noninvasive (0% liver biopsy) and more precise (six versus two or three fibrosis classes) fibrosis diagnosis.  相似文献   
12.

Background

The increased reports of ESBL dissemination from various centres in south western, Nigeria and the recent emergence of carbapenem resistant bacteria prompted the conception of this study.

Objectives

To demonstrate the relationship between high molecular weight plasmids and the expression of antibiotic multi-resistance including ESBL and carbapenemase.

Methods

We investigated 97 isolates of selected organisms consisting of 67 E. coli and 30 Klebseilla spp for the presence of plasmids expressing ESBL including carbapenem-hydrolysing enzymes. Beta-lactamase was determined using acidometric method, while ESBL and carbapenemase activity was determined using the double-disk diffusion test as well as the Modified Hodge test (MHT). Plasmid profiles of ESBL and carbapenemase positive isolates were determined according to standard protocols.

Results

An ESBL prevalence rate of 21.6% and carbapenem- resistance rate of 9.3% was recorded. Antibiotic susceptibility profile of ESBL isolates showed 100.0% resistance against Amoxicillin, Cotrimoxazole and Erythromycin. Moderate susceptibility was recorded against the Quinolone class of antibiotics; Meropenem remained the most active antibiotic against ESBL isolates with 62.5% against E. coli and 60% against K. pneumoniae. The plasmid profiles of our study isolates ranged from 11.8kbp to 35.5kbp.

Conclusion

Due to the relationship between high molecular weight plasmids and multi-drug resistance, we hereby recommend regular molecular surveillance of this form in our study setting.  相似文献   
13.
Using the CD40 system, in vitro proliferation of hairy cell leukemia (HCL) was examined in 43 patients. In this culture system, cells were stimulated by interleukin-4 (IL-4) and anti-CD40 monoclonal antibodies (MoAbs) that were added in soluble form or were cross-linked via their Fc part using Fc gamma RII-transfected mouse fibroblast cells. Proliferation was induced and confirmed by 3H-thymidine incorporation in 14 cases and by the presence of metaphases in 42 cases. 3H-thymidine incorporation showed a heterogeneous pattern: cross-linking of anti- CD40 gave the highest proliferation in 8 cases; in 11 cases, stimulation with anti-CD40 MoAbs alone, without cross-linking also resulted in proliferation; the addition of IL-4 further enhanced 3H- thymidine incorporation in 5 cases, but suppressed this phenomenon in 5 other cases. The CD40 system proved to be very effective in obtaining cytogenetic data. With a success rate of 42 of 43 patients tested, we found clonal abnormalities in 8 cases (19%) and nonclonal abnormalities with involvement of one or two abnormal metaphases in another 7 cases. The chromosomes most frequently involved in the abnormal karyotypes, both structurally and numerically, were chromosomes 5, 7, and 14. By fluorescence-activated cell-sorting analysis of the cultured cells, and by immunophenotypic analysis of metaphase spreads, T-cell growth could be excluded and the HCL-lineage confirmed. Stimulation via the CD40 antigen is an excellent tool for growing hairy cell leukemia cells.  相似文献   
14.
Kim  SH; Chang  KH; Song  IC; Han  MH; Kim  HC; Kang  HS; Han  MC 《Radiology》1997,204(1):239
  相似文献   
15.
16.
Yeh  HC; Rabinowitz  JG 《Radiology》1982,144(4):859-863
Twenty-four patients with inflammatory lesions of the abdominal wall were examined by ultrasonography. Nine of these patients underwent computed tomographic (CT) scanning as well. Both ultrasonography and CT clearly delineated the exact location and extent of abdominal wall abscesses. Abscesses were easily differentiated from cellulitis or phlegmon with ultrasound. The peritoneal line was more clearly delineated on ultrasonograms than on CT scans; abscesses were also more distinct on the ultrasonograms because of their low echogenicity compared with the surrounding structures. Gas bubbles, fat density with specific low attenuation values, and underlying inflamed bowel loops in obese patients with Crohn's disease were better delineated by CT.  相似文献   
17.
18.
19.
Phenylalanine and tyrosine constitute the two initial steps in the biosynthesis of dopamine, which, in its turn, is the metabolic precursor of noradrenaline and adrenaline. The extracellular phenylalanine concentration influences brain function in phenylalanine deficiency (PHD) by decreased dopamine synthesis. It has been shown to induce EEG slowing, and prolonged the performance time on neuropsychological tests. The tyrosine concentration in the CNS is reduced in PHD, possibly implying insufficient substrate (= tyrosine) for catecholamine synthesis due to competition inhibition, for instance across the blood brain barrier. In experimental studies it has been shown that the synthesis and release of dopamine can be influenced by an increase in the availability of tyrosine. In PHD an extra dietary intake of three doses of tyrosine (160mg/kg/24h) induced a shortsning of reaction time and decreased variability, and in a double-blind crossover study a similar dose has been reported to induce an improvement on psychological tests. In a study with lower doses of tyrosine (110mg/kg/24h) no effect was found on reaction time tests. These findings need to be substantiated, and more detailed information should be obtained.  相似文献   
20.

Background  

Increasing activity levels in adolescents with obesity requires the development of exercise programs that are both attractive to adolescents and easily reproducible. The aim of this study was to develop a modular aerobic training program for adolescents with severe obesity, with a focus on variety, individual targets and acquiring physical skills. We report here the effects on aerobic fitness from a pilot study. Furthermore, we examined the feasibility of the modified shuttle test (MST) as an outcome parameter for aerobic fitness in adolescents with severe obesity.  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