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   354篇
  免费   28篇
  国内免费   3篇
儿科学   30篇
妇产科学   1篇
基础医学   42篇
口腔科学   14篇
临床医学   18篇
内科学   60篇
皮肤病学   3篇
神经病学   7篇
特种医学   71篇
外科学   35篇
综合类   11篇
预防医学   53篇
眼科学   2篇
药学   30篇
中国医学   3篇
肿瘤学   5篇
  2023年   2篇
  2022年   1篇
  2021年   2篇
  2020年   7篇
  2019年   6篇
  2018年   8篇
  2017年   4篇
  2016年   2篇
  2015年   12篇
  2014年   5篇
  2013年   10篇
  2012年   15篇
  2011年   11篇
  2010年   17篇
  2009年   19篇
  2008年   13篇
  2007年   7篇
  2006年   9篇
  2005年   13篇
  2004年   7篇
  2003年   8篇
  2002年   10篇
  2001年   4篇
  2000年   6篇
  1999年   9篇
  1998年   15篇
  1997年   10篇
  1996年   17篇
  1995年   13篇
  1994年   14篇
  1993年   13篇
  1992年   6篇
  1991年   3篇
  1990年   5篇
  1989年   7篇
  1988年   8篇
  1987年   5篇
  1986年   4篇
  1985年   9篇
  1984年   6篇
  1983年   2篇
  1982年   6篇
  1981年   6篇
  1980年   3篇
  1979年   1篇
  1978年   2篇
  1977年   6篇
  1976年   9篇
  1975年   6篇
  1973年   2篇
排序方式: 共有385条查询结果,搜索用时 46 毫秒
31.
32.
Aim:   A short vaccination protocol against hepatitis B was compared to the standard approach in patients under haemodialysis who were primarily non-responsive to the vaccine.
Methods:   This randomized, controlled open trial included 51 chronic haemodialysis subjects previously vaccinated against hepatitis B and with anti-HBs levels of less than 10 IU/mol/L. Twenty-six patients received 20 µg i.m. once a week for 8 weeks (short protocol) and 25 subjects three doses of 40 µg i.m. at months 0, 1 and 6 (standard protocol). Clinical and laboratory data were compared between responders and non-responders. A logistic regression model included selected parameters to assess risk factors for non-seroconversion.
Results:   Seroconversion rates to vaccine at 2 months were 80% and 78% in the short and standard protocol groups, respectively ( P  = 0.99). Median of anti-HBs levels were similar up to 6 months of follow up, but patients in the standard protocol showed a trend to higher anti-HBs in month 3 and a more steady decline in antibody titres. Non-responders were older, had longer duration of dialysis and a higher prevalence of a prior renal transplant and hepatitis C. In multivariate analysis, only advanced age and hepatitis C remained independently associated with non-responsiveness to vaccination.
Conclusion:   In haemodialysis patients, a short vaccination protocol against hepatitis B did not provide any benefit compared to the standard approach with respect to peak anti-HBs titres or a higher rate of seroprotection at the end of follow up. Other strategies to increase seroconversion rates should be explored, especially in the elderly and in patients with hepatitis C.  相似文献   
33.
High‐resolution gas chromatography/mass spectrometry (HRGC/MS) is the standard method for analysing dioxin, furan and polybrominated retardants in hazardous waste. Determination of dioxin‐like compounds using in vitro bioassays such as ethoxyresorufin‐O‐deethylase (EROD) is an important tool to evaluate their Ah receptor‐mediated toxic effects, because it detects all arylhydrocarbon receptor ligands in a variety of sample matrices. In the present work, we compared RTG‐2 cell line EROD bioassay with HRGC/MS for assessing waste samples (liquid and solid) contaminated with polychlorinated dibenzo‐p‐dioxins and dibenzofurans, polychlorinated biphenyls (dioxin‐like PCBs) and other xenobiotics. For liquid samples, HRGC/MS‐toxic equivalent (HRGC/MS‐TEQ) values ranged from 273.26 to 5.84 ng TEQ l?1 and correlated well (correlation coefficient 0.99) with values obtained by EROD‐TEQ, which ranged from 128 to 2.5 ng TEQ l?1. For solid samples, HRGC/MS‐TEQ values ranged from 3.44 to 0.49 ng TEQ g?1 and correlated less well than liquid samples (correlation coefficient 0.64) with values obtained by EROD‐TEQ ranging from 2.27 to 0.93 ng TEQ g?1. The overestimation of RTG‐2 EROD‐TEQ (1.2 ± 0.92 of values established by HRGC/MS) and the absence of false‐negative results may limit analytical costs by eliminating the need for follow‐up GC/MS analysis on the negative samples. We suggest that RTG‐2 EROD bioassay is an inexpensive means for preliminary dioxin and furan positive screenings of waste samples. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
34.
35.
Objective To describe the genetic diversity of Plasmodium vivax isolates from different areas in the Brazilian Amazon using 11 polymorphic microsatellites and to evaluate the correlation between microsatellite variation and repeat array length. Methods Microsatellites with variable repeat units and array lengths were selected using in silico search of the P. vivax genome. We designed primers and amplified the selected loci in DNA obtained from patients with P. vivax acute infections. Results Positive correlation between repeat array length and microsatellite variation was detected independently of the size of repeat unit (di, tri, or tetranucleotide). We used these markers to describe the genetic variability of P. vivax isolates from four geographic regions of the Brazilian Amazon. Substantial variability was observed among P. vivax isolates within populations, concurrent with high levels of multiple‐clone infections and high linkage disequilibrium. Overall, structured populations were observed with moderate to high genetic differentiation. Conclusion The markers studied are useful tools for assessing population structure of P. vivax, as demonstrated for Brazilian populations and for searching for evidence of recent selection events associated with different phenotypes, such as drug resistance.  相似文献   
36.

Introduction

Breast gangrene has been reported as a complication following puerperal sepsis, breast surgery, nipple piercings, warfarin toxicity, etc. We report a case of primary breast gangrene in an HIV-positive individual which, to the best of our knowledge, is the first of its kind.

Case report

A 40-year-old previously healthy woman presented with fulminating left breast gangrene. She was detected to be HIV positive. Mastectomy was performed. The detailed management of the condition is discussed.

Conclusion

Severe necrotising infections may be initial manifestations of HIV infection and patients with such infections should be screened for HIV.  相似文献   
37.
Aim:   Coronary artery calcification (CAC) has been associated with higher mortality in chronic renal disease. The purpose of this study was to assess coronary artery calcium score (CaCs) in haemodialysis patients and to correlate calcium scores with clinical parameters and mortality.
Methods:   A cross-sectional study was conducted in 59 haemodialysis patients. CaCs was assessed by multidetector-row computed tomography and stratified as: CaCs of less than 10 Agatston units (U), no calcification; CaCs of 10–400 U, mild-to-moderate; and CaCs of more than 400 U, severe calcification. The effects of age, haemodialysis duration and biochemical and inflammatory markers on CaCs logarithm were evaluated by multiple linear regression analysis. Cox regression analysis was used to measure the impact of CaCs of more than 400 on 2-year mortality.
Results:   Coronary calcifications were detected in 64.5% of patients, and the median of CaCs was 31.7 U (0–589.7) with a range of 0–5790.0 U. Twenty-one (35.5%) patients had mild-to-moderate and 17 (29%) severe CaCs. Patients with severe CaCs were older and showed a higher prevalence of ischaemic heart disease and a higher body mass index ( P  = 0.04). A trend towards higher C-reactive protein levels was found in patients with severe CaCs. Advanced age was the only variable that influenced CaCs logarithm independently. The effect of severe CaCs on 2-year mortality did not persist after adjustment for other covariates.
Conclusion:   Coronary calcification was highly prevalent in these uraemic patients on chronic haemodialysis. A correlation was evidenced between CaCs and advanced age, but severity of the CAC score did not have an impact on 2-year mortality of this cohort.  相似文献   
38.
BACKGROUND: Tubulointerstitial damage plays an important role in chronic kidney disease (CKD) with proteinuria. Urinary kidney injury molecule 1 (KIM-1) reflects tubular KIM-1 and is considered a sensitive biomarker for early tubular damage. We hypothesized that a decrease in proteinuria by using therapeutic interventions is associated with decreased urinary KIM-1 levels. STUDY DESIGN: Post hoc analysis of a randomized, double-blind, placebo-controlled, crossover trial. SETTING & PARTICIPANTS: 34 proteinuric patients without diabetes from our outpatient renal clinic. INTERVENTION: Stepwise 6-week interventions of losartan, sodium restriction (low-sodium [LS] diet), their combination, losartan plus hydrochlorothiazide (HCT), and the latter plus an LS diet. OUTCOMES & MEASUREMENTS: Urinary excretion of KIM-1, total protein, and N-acetyl-beta-d-glucosaminidase (NAG) as a positive control for tubular injury. RESULTS: Mean baseline urine protein level was 3.8 +/- 0.4 (SE) g/d, and KIM-1 level was 1,706 +/- 498 ng/d (increased compared with healthy controls; 74 ng/d). KIM-1 level was decreased by using placebo/LS (1,201 +/- 388 ng/d; P = 0.04), losartan/high sodium (1,184 +/- 296 ng/d; P = 0.09), losartan/LS (921 +/- 176 ng/d; P = 0.008), losartan/high sodium plus HCT (862 +/- 151 ng/d; P = 0.008) and losartan/LS plus HCT (743 +/- 170 ng/d; P = 0.001). The decrease in urinary KIM-1 levels paralleled the decrease in proteinuria (R = 0.523; P < 0.001), but not blood pressure or creatinine clearance. 16 patients reached target proteinuria with protein less than 1 g/d, whereas KIM-1 levels normalized in only 2 patients. Urinary NAG level was increased at baseline and significantly decreased during the treatment periods of combined losartan plus HCT only. The decrease in urinary NAG levels was not closely related to proteinuria. LIMITATIONS: Post hoc analysis. CONCLUSIONS: Urinary KIM-1 level was increased in patients with nondiabetic CKD with proteinuria and decreased in parallel with proteinuria by using losartan, sodium restriction, their combination, losartan plus HCT, and the latter plus sodium restriction. These results are consistent with the hypothesis of amelioration of proteinuria-induced tubular damage. Long-term studies are warranted to evaluate whether targeting treatment on KIM-1 can improve outcomes in patients with CKD with proteinuria.  相似文献   
39.
Pulmonary nocardiosis: risk factors and outcomes   总被引:1,自引:0,他引:1  
BACKGROUND AND OBJECTIVES: Pulmonary nocardiosis (PN) is an infrequent but severe infection caused by Nocardia spp., which can behave either as opportunistic or primary pathogens. The present study identifies the risk factors for PN, clinical symptoms and radiographic features and the factors that affect its prognosis. METHODS: An observational study of all the patients diagnosed with PN over a 13-year period at the authors' institution. RESULTS: Thirty-one adult patients were identified with PN, 11 of whom had disseminated nocardiosis. The predisposing conditions were COPD (23%), transplantation (29%), HIV infection (19%), alcoholism (6.5%) and treatment with steroids (64.5%). Respiratory tract sampling using non-invasive techniques had a diagnostic yield of 77%, while specimens from invasive methods had a yield of 47%. Mean time to diagnosis was 42 days. Dissemination to the central nervous system was related to alcoholism. The mortality rates were 41% for PN and 64% for disseminated nocardiosis; when Nocardia disseminated to the central nervous system, the mortality was 100%. CONCLUSION: Specific risk factors were found in 94% of patients, with the most common being corticosteroid treatment and immunosuppressive therapy. The time to reach diagnosis and to prescribe specific treatment was considerable and mandatory assessment for nocardia in high-risk patients is required. The mortality rate of PN is high and early diagnosis and treatment are needed. Medications other than co-trimoxazole may be required.  相似文献   
40.

Background  

To present an episodic random utility model that unifies time trade-off and discrete choice approaches in health state valuation.  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