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Objective

To characterize PubMed usage over a typical day and compare it to previous studies of user behavior on Web search engines.

Design

We performed a lexical and semantic analysis of 2,689,166 queries issued on PubMed over 24 consecutive hours on a typical day.

Measurements

We measured the number of queries, number of distinct users, queries per user, terms per query, common terms, Boolean operator use, common phrases, result set size, MeSH categories, used semantic measurements to group queries into sessions, and studied the addition and removal of terms from consecutive queries to gauge search strategies.

Results

The size of the result sets from a sample of queries showed a bimodal distribution, with peaks at approximately 3 and 100 results, suggesting that a large group of queries was tightly focused and another was broad. Like Web search engine sessions, most PubMed sessions consisted of a single query. However, PubMed queries contained more terms.

Conclusion

PubMed’s usage profile should be considered when educating users, building user interfaces, and developing future biomedical information retrieval systems.  相似文献   

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In order to study risk factors and their association with birth defects,data were collected from 329 cases and 329 controls in 38 hospitals in Guangdong Province of China in 1988.Information was obtained from the same questionnaire(23 risk factors listed)of cases and controls.We used a multivariate logistic model,which described variables significantly increased risk of birth defects.The risk factors included maternal educa-tional levels,medicine taken during pregnancy and antenatal care.It was suggested to strengthen antenatal care was the main preventive measure against birth defects.  相似文献   

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Background:

Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease characterized by destruction of the interlobular bile ducts and a striking female predominance. The aim of this study was to identify associations between estrogen receptor (ESR) gene polymorphisms with the risk of developing PBC and abnormal serum liver tests in a Chinese population.

Methods:

Thirty-six patients with PBC (case group) and 35 healthy individuals (control group) from the First Hospital of Jilin University were studied. Whole genomic DNA was extracted from all the participants. Three single-nucleotide polymorphisms (rs2234693, rs2228480, and rs3798577) from ESR1 and two (rs1256030 and rs1048315) from ESR2 were analyzed by a pyrosequencing method. Demographic data and liver biochemical data were collected.

Results:

Subjects with the T allele at ESR2 rs1256030 had 1.5 times higher risk of developing PBC than those with the C allele (odds ratio [OR] = 2.1277, 95% confidence interval [CI] = 1.1872–4.5517). Haplotypes TGC of ESR1 rs2234693, rs2228480, and rs3798577 were risk factors for having PBC. The C allele at ESR1 rs2234693 was associated with abnormal alkaline phosphatase (OR = 5.2469, 95% CI = 1.3704–20.0895) and gamma-glutamyl transferase (OR = 3.4286, 95% CI = 1.0083–13.6578) levels in PBC patients.

Conclusions:

ESR2 rs1256030 T allele may be a significant risk factor for the development of PBC. Screening for patients with gene polymorphisms may help to make early diagnoses in patients with PBC.  相似文献   

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Objective: To systematically evaluate the effectiveness and safety of Sodium Tanshinone ⅡA Sulfonate Injection(STS) as one adjuvant therapy for treating unstable angina pectoris(UAP). Methods: Randomized controlled trials(RCTs) of UAP treated by STS were searched in the China National Knowledge Infrastructure Database(CNKI), VIP Database for Chinese Technical Periodicals(VIP), Wanfang Database, the Chinese Biomedical Literature Database(CBM), Web of Science, the Cochrane Library, Embase, and Pub Med, which from inception to January, 2016. The Cochrane Risk Assessment Tool was used to evaluate the methodological quality of the RCTs. The Review Manager 5.3 software was used to conduct the metaanalysis. Results: The results showed that 17 RCTs involving 1,372 patients were included. The meta-analysis indicated that the combined use of STS and Western medicine(WM) in the treatment of UAP can obviously improve the total effective rate [risk ratio(RR)=1.31, 95% confidence interval(CI)(1.24,1.39), P0.0001], and the total effective rate of electrocardiogram [RR=1.43, 95% CI(1.30,1.56), P0.0001], decrease the level of CRP [mean difference(MD)=–3.06, 95%CI(–3.85, –2.27), P0.00001], fibrinogen [MD=–1.03, 95% CI(–1.16, –0.89), P0.00001], and whole blood high shear viscosity [MD=–0.70, 95% CI(–0.92, –0.49), P0.00001]. Additionally, the occurrence of adverse drug reaction of the experimental group was significantly higher than that of the control group [RR=3.57, 95% CI(1.28, 9.94), P0.05]. Conclusions: Compared with WM, the combined use of STS was more effective.  相似文献   

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Developing countries face a number of unique problems related to the hazards of chemicals. The WHO International Program on Chemical Safety may play a useful role by working jointly with Member Nations and such international organizations as FAO, UNEP. and ILO. (c)1990 Academic Press. Inc.  相似文献   

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Background  The expression of genes encoding a number of pathogenetic pathways involved in colorectal cancer could potentially act as prognostic markers. Large prospective studies are required to establish their relevance to disease prognosis.

Methods  We investigated the relevance of 19 markers in 790 patients enrolled in a large randomised trial of 5-fluorouracil using immunohistochemistry and chromogenic in situ hybridisation. The relationship between overall 10-year survival and marker status was assessed.

Results  Minichromosome maintenance complex component 2 (MCM2) and cyclin A were significantly associated with overall survival. Elevated MCM2 expression was associated with a better prognosis (HR=0.63, 95%CI: 0.46–0.86). Cyclin A expression above the median predicted an improved patient prognosis (HR=0.71, 95%CI: 0.53–0.95). For mismatch repair deficiency and transforming growth factor β receptor type II (TGFBRII) overexpression there was a borderline association with a poorer prognosis (HR=0.69, 95%CI: 0.46–1.04 and HR=2.11, 95%CI: 1.02–4.40, respectively). No apparent associations were found for other markers.

Conclusion  This study identified cell proliferation and cyclin A expression as prognostic indicators of patient outcome in colorectal cancer.

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Background Diagnosis and treatment of respiratory symptoms (RSs) of gastroesophageal reflux disease (GERD) are more difficult than for common esophageal symptoms. The goal of this study was to evaluate the efficacy and safety of RF treatment for RSs of GERD in a preliminary 12-month follow-up observation. Methods From April 2006 to October 2008, 505 GERD patients with mainly respiratory presentations such as wheezing, chronic cough or hoarseness, were treated by endoscopic RF. A questionnaire was completed before and after treatment, using a six-point scale ranging from 0 to 5 to assess symptom severity and frequency. The symptom scores was the sum of frequency and severity. Results A significant improvement in symptom scores at the end of the follow-up period. The mean heartburn score decreased from 5.31 to 1.79. The mean regurgitation score decreased from 5.02 to 1.64; mean cough score decreased from 6.77 to 2.85; mean wheezing score decreased from 7.83 to 3.07; and mean hoarseness score decreased from 5.13 to 1.81 (P<0.01). No major complications or deaths occurred. Minor complications included temporary post-procedural retrosternal unease or pain (n=106; 21%), mild fever (n=86; 17%), transient nausea/vomiting (n=97; 19.2%), and transient dysphagia (n=42; 9.3%). Thirty-five (6.9%) patients had recurrence of symptoms, and endoscopic RF treatment was repeated in six patients, and laparoscopic fundoplication was performed in seven. Conclusions The outcome of this study indicates that endoscopic RF is an effective and safe means to treat RSs in patients with GERD.  相似文献   

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I read with great interest the article by Collaborating Research Group for NoninvasiveMechanical Ventilation of Chinese Respiratory Society. 1 Based on the concept mentioned in this paper, I have found that it is really an encouraging new finding in the field of clinical application of mechanical ventilation and treatment of acute respiratory failure (ARF) of chronic obstructive pulmonary disease (COPD).  相似文献   

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Objective: To assess the effects of Shenfu Injection(参附注射液, SFI) on blood lactate, and secondarily its effect on the lactate clearance(LC) in patients with post cardiac arrest syndrome(PCAS). Methods: The present study is a post hoc study of a randomized, assessor-blinded, controlled trial. Patients experienced in-hospital cardiac arrest between 2012 and 2015 were included in the predefined post hoc analyses. Of 1,022 patients enrolled, a total of 978 patients were allocated to the control group...  相似文献   

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Background: Given the general unavailability, common adverse effects, and complicated administration of tetracycline, the clinical application of classic bismuth quadruple therapy (BQT) is greatly limited. Whether minocycline can replace tetracycline forHelicobacter pylori (H.pylori) eradication is unknown. We aimed to compare the eradication rate, safety, and compliance between minocycline- and tetracycline-containing BQT as first-line regimens.Methods: This randomized controlled trial was cond...  相似文献   

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Background Several clinical trials have shown that rapamycin-eluting stents significantly reduce the risk of restenosis after percutaneous coronary intervention (PCI). The Firebird stent and the Excel stent (coated with bioabsorbable polymer) are two different types of rapamycin-eluting stents made in China, both have been recently approved for clinical use in China by State Food and Drug Administration. However, it is unclear whether there are differences in safety and efficacy between the two types of stents in daily practice. Methods In the month of June 2006, a total of 190 consecutive patients were treated exclusively with Firebird stents (n=93, Firebird group) or Excel stents (n=97, Excel group) in our center and were included in this study. The frequency of major adverse cardiac events (MACE, a composite of death, myocardial infarction or target lesion revascularization), binary restenosis, and late lumen loss and stent thrombosis during a six-month follow-up period were compared between the two groups.Results Patient and lesion characteristics were comparable between the groups. Major adverse cardiac event rates were low in hospital and at 6 months (2.1% in the Excel group and 0% in the Firebird group, P﹥0.05). The 6-month angiographic in-stent restenosis rate was 0% in both groups, with an associated late loss of (0.15 ± 0.21) mm versus (0.14 ± 0.20) mm (P=0.858) and the in-segment restenosis rate was also 0% for the Excel group and the Firebird group. There was no definite stent thrombosis identified in either group during the six-month follow-up period and only one patient in the Excel group had probable stent thrombosis in hospital. Conclusions Results from this mid-term, single-center study showed that both of the Firebird and the Excel rapamycin eluting stent had similar effects on reducing the incidence of MACE and the risk of restenosis (both in-stent and in-segment binary restenosis) after PCI in daily practice.  相似文献   

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Background: Pneumonia-like primary pulmonary lymphoma (PPL) was commonly misdiagnosed as infectious pneumonia, leading to delayed treatment. The purpose of this study was to establish a computed tomography (CT)-based radiomics model to differentiate pneumonia-like PPL from infectious pneumonia.Methods: In this retrospective study, 79 patients with pneumonia-like PPL and 176 patients with infectious pneumonia from 12 medical centers were enrolled. Patients from center 1 to center 7 were assigned ...  相似文献   

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