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   213篇
  免费   9篇
耳鼻咽喉   2篇
儿科学   9篇
妇产科学   4篇
基础医学   11篇
临床医学   13篇
内科学   59篇
神经病学   24篇
外科学   31篇
综合类   2篇
预防医学   40篇
眼科学   1篇
药学   17篇
中国医学   4篇
肿瘤学   5篇
  2023年   2篇
  2022年   9篇
  2021年   11篇
  2020年   7篇
  2019年   4篇
  2018年   5篇
  2017年   4篇
  2016年   3篇
  2015年   8篇
  2014年   6篇
  2013年   13篇
  2012年   7篇
  2011年   9篇
  2010年   5篇
  2009年   4篇
  2008年   4篇
  2007年   10篇
  2006年   18篇
  2005年   6篇
  2004年   14篇
  2003年   16篇
  2002年   5篇
  2001年   8篇
  2000年   6篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1987年   5篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1982年   3篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1976年   1篇
排序方式: 共有222条查询结果,搜索用时 18 毫秒
81.

Background

Five billion people worldwide lack access to safe surgery. American College of Surgeons (ACS) members have a strong history of humanitarian and volunteer work. Since its founding in 2004, Operation Giving Back (OGB) has served as a volunteer resource portal. This study sought to understand current activities, needs, and barriers to ACS member volunteerism, and to re-assess the role of OGB.

Methods

A 25-question electronic survey was sent to ACS members in August 2015. Utilizing branching logic, those who were involved or interested in volunteerism completed the full survey. Data were assessed using univariable analysis methods.

Results

Three percent (n = 1764) of those e-mailed answered the survey. Respondents were mostly men (82%), ≥50 years of age (61%), and general surgeons (70%). Fifty-three percent (n = 937) reported current or past volunteer activities, and 76.5% (n = 1349) were interested in activities within three years. Approximately 84% were interested in international volunteerism and 55% in domestic volunteerism. Few (5.7%) had both training and experience in emergency and disaster response, and only 17% had institutional salary support. Eighty-two percent wished to work with OGB, and 418 indicated organizations with whom they are involved could benefit from OGB collaboration.

Conclusions

Interest in surgical volunteerism among ACS member survey respondents is high. OGB has the opportunity to meet member needs by developing programmatic activities, identifying volunteer prospects, facilitating multi-institutional consortia, and leading pre-deployment training. By maximizing volunteer efforts, OGB has the potential to foster sustainable and scalable ethical practices to improve basic access to surgical care globally.
  相似文献   
82.
Antigenic reactivity of F.VIII/WF in variants of von Willebrand's disease (vWd) was studied with both fluid-phase and solid-phase immunoradiometric assays. Two different (rabbit and goat) 125I-labeled specific antibodies against purified F.VIII/WF were used in both their divalent (IgG) and their monovalent (Fab fragment) forms. Dose-response curves obtained by reacting a constant amount of antibody with serial dilutions of plasmas from normal or homozygous vWd demonstrated the specificity of the test. The accuracy was significantly higher with 125I-Fab fragments of goat anti-F.VIII/WF antiserum that intact goat IgG or rabbit IgG or Fab fragments. The significant decrease of the slope of the dose-response curves obtained with plasma from variants of vWd has been interpreted as due to the presence of abnormal F.VIII/WF molecules with decreased antigenic reactivity. A similar anomaly was found in cryosupernatant prepared from normal plasma, paralleling similarities demonstrated between variants of vWd and cryosupernatant. Results of experiments performed by reacting constant plasma dilutions from control or variants of confirmed the decreased antigenic reactivity of variant F.VIII/WF.  相似文献   
83.

Background

Within the 52 health districts in South Africa, the family physician is seen as the clinical leader within a multi-professional district health team. Family physicians must be competent to meet 90% of the health needs of the communities in their districts. The eight university departments of Family Medicine have identified five unit standards, broken down into 85 training outcomes, for postgraduate training. The family medicine registrar must prove at the end of training that all the required training outcomes have been attained. District health managers must be assured that the family physician is competent to deliver the expected service. The Colleges of Medicine of South Africa (CMSA) require a portfolio to be submitted as part of the uniform assessment of all registrars applying to write the national fellowship examinations. This study aimed to achieve a consensus on the contents and principles of the first national portfolio for use in family medicine training in South Africa.

Methods

A workshop held at the WONCA Africa Regional Conference in 2009 explored the purpose and broad contents of the portfolio. The 85 training outcomes, ideas from the WONCA workshop, the literature, and existing portfolios in the various universities were used to develop a questionnaire that was tested for content validity by a panel of 31 experts in family medicine in South Africa, via the Delphi technique in four rounds. Eighty five content items (national learning outcomes) and 27 principles were tested. Consensus was defined as 70% agreement. For those items that the panel thought should be included, they were also asked how to provide evidence for the specific item in the portfolio, and how to assess that evidence.

Results

Consensus was reached on 61 of the 85 national learning outcomes. The panel recommended that 50 be assessed by the portfolio and 11 should not be. No consensus could be reached on the remaining 24 outcomes and these were also omitted from the portfolio. The panel recommended that various types of evidence be included in the portfolio. The panel supported 26 of the 27 principles, but could not reach consensus on whether the portfolio should reflect on the relationship between the supervisor and registrar.

Conclusion

A portfolio was developed and distributed to the eight departments of Family Medicine in South Africa, and the CMSA, to be further tested in implementation.  相似文献   
84.
ABSTRACT: BACKGROUND: Chest pain is a common complaint in primary care, with coronary heart disease (CHD) being the most concerning of many potential causes. Systematic reviews on the sensitivity and specificity of symptoms and signs summarize the evidence about which of them are most useful in making a diagnosis. Previous meta-analyses are dominated by studies of patients referred to specialists. Moreover, as the analysis is typically based on study-level data, the statistical analyses in these reviews are limited while meta-analyses based on individual patient data can provide additional information. Our patient-level meta-analysis has three unique aims. First, we strive to determine the diagnostic accuracy of symptoms and signs for myocardial ischemia in primary care. Second, we investigate associations between study- or patient-level characteristics and measures of diagnostic accuracy. Third, we aim to validate existing clinical prediction rules for diagnosing myocardial ischemia in primary care. This article describes the methods of our study and six prospective studies of primary care patients with chest pain. Later articles will describe the main results. METHODS: We will conduct a systematic review and IPD meta-analysis of studies evaluating the diagnostic accuracy of symptoms and signs for diagnosing coronary heart disease in primary care. We will perform bivariate analyses to determine the sensitivity, specificity and likelihood ratios of individual symptoms and signs and multivariate analyses to explore the diagnostic value of an optimal combination of all symptoms and signs based on all data of all studies. We will validate existing clinical prediction rules from each of the included studies by calculating measures of diagnostic accuracy separately by study. DISCUSSION: Our study will face several methodological challenges. First, the number of studies will be limited. Second, the investigators of original studies defined some outcomes and predictors differently. Third, the studies did not collect the same standard clinical data set. Fourth, missing data, varying from partly missing to fully missing, will have to be dealt with. Despite these limitations, we aim to summarize the available evidence regarding the diagnostic accuracy of symptoms and signs for diagnosing CHD in patients presenting with chest pain in primary care. Review registration Centre for Reviews and Dissemination (University of York): CRD42011001170.  相似文献   
85.
ABSTRACT: BACKGROUND: Stigma and discrimination against people living with human immunodeficiency virus (HIV) are obstacles in the way of effective responses to HIV. Understanding the extent of stigma / discrimination and the underlying causes is necessary for developing strategies to reduce them. This study was conducted to explore stigma and discrimination against PLHIV amongst healthcare providers in Jimma zone, Southwest Ethiopia. METHODS: A cross-sectional study, employing quantitative and qualitative methods, was conducted in 18 healthcare institutions of Jimma zone, during March 14 to April 14, 2011. A total of 255 healthcare providers responded to questionnaires asking about sociodemographic characteristics, HIV knowledge, perceived institutional support and HIV-related stigma and discrimination. Factor analysis was employed to create measurement scales for stigma and factor scores were used in one way analysis of variance (ANOVA), T-tests, Pearson's correlation and multiple linear regression analyses. Qualitative data collected using key-informant interviews and Focus Group Discussions (FGDs) were employed to triangulate with the findings from the quantitative survey. RESULTS: Mean stigma scores (as the percentages of maximum scale scores) were: 66.4 for the extra precaution scale, 52.3 for the fear of work-related HIV transmission, 49.4 for the lack of feelings of safety, 39.0 for the value-driven stigma, 37.4 for unethical treatment of PLHIV, 34.4 for discomfort around PLHIV and 31.1 for unofficial disclosure. Testing and disclosing test results without consent, designating HIV clients and unnecessary referral to other healthcare institutions and refusal to treat clients were identified. Having in-depth HIV knowledge, the perception of institutional support, attending training on stigma and discrimination, educational level of degree or higher, high HIV case loads, the presence of ART service in the healthcare facility and claiming to be non-religious were negative predictors of stigma and discrimination as measured by the seven latent factors. CONCLUSIONS: Higher levels of stigma and discrimination against PLHIV were associated with lack of in-depth knowledge on HIV and orientation about policies against stigma and discrimination. Hence, we recommend health managers to ensure institutional support through availing of clear policies and guidelines and the provision of appropriate training on the management of HIV/AIDS. Key words: Stigma and discrimination, healthcare providers, HIV/AIDS.  相似文献   
86.
87.
Cross-sectional studies were conducted to measure soluble viral and immunological markers in plasma in order to determine the prognostic value of these markers for HIV disease progression in Ethiopians and to see their association with cell surface markers in HIV-1-infected and noninfected Ethiopians. Whole blood samples were collected from 52 HIV-1-negative Ethiopians, 32 HIV-1-positive Ethiopians with absolute CD4(+) T-cell count >200/microl whole blood and no AIDS defining conditions, and 39 HIV-positive Ethiopians with CD4(+) T-cell count <200/microl and/or AIDS defining conditions. Plasma levels of b(2)-microglobulin (b(2)m), soluble CD27 (sCD27), soluble tumor necrosis factor alpha receptor type II (sTNFR-II), IgG, IgA, IGE, and IL12 were elevated in HIV-1-infected individuals. The plasma levels of sTNFR-II, sCD27, b(2)m, IL12, and IgG were inversely correlated with numbers of CD4(+) T-cells, the proportion of na?ve (CD45RA(+)CD27(+)) CD8(+) T-cells, and the proportion of CD8(+) T-cells expressing CD28 (CD8(+)CD28(+)) were positively correlated with the proportions of activated (HLA-DR(+)CD38(+)) CD4(+) T-cells, as well as activated (HLA-DR(+)CD38(+)) CD8(+) T-cells. A strong positive correlation was also observed when soluble immune markers were compared to each other. Multivariate regression analyses of soluble markers with numbers of CD4(+) T-cells showed that sCD27 is the best independent marker for CD4(+) T-cell decline in the HIV-1-infected Ethiopians. Our results indicate that measurement of soluble immune markers, which is relatively easy to perform, could be a good alternative to the quantification of T-cell subsets for monitoring HIV-1 disease progression in places where there is no facility for flow cytometric measurements.  相似文献   
88.

Background

Malnutrition has been responsible directly or indirectly for 10.9 million deaths worldwide annually among children under five. Childhood malnutrition is highly related to poor nutritional quality diet in developing countries where there is limited access to animal based foods. Most foods consumed by young children are cereal based which contain high amounts of anti-nutritional factors. Fermentation is thought to significantly lower the content of anti-nutrients in cereal grains. This study therefore, aimed to determine complementary feeding practices and effect of spontaneous fermentation on anti-nutritional factors and mineral contents of selected cereals.

Methods

Cross sectional survey was conducted in Ebinat district to determine complementary feeding practices among 324 lactating mothers. Laboratory analysis was carried out for teff and wheat cereal grains to determine the effect of spontaneous fermentation on anti-nutrients as well as mineral contents.

Results

Prevalence of appropriate complementary feeding practice was 1.5%. Fermentation of the sampled cereals for 12?h significantly (p?<?0.05) reduced total phytate and total tannin. The reduction continued and most of the reduction of phytate and tannin contents occurred during the 72?h of fermentation for both cereal samples. However, the reduction for some fermentation times was not statistically significant. A significant (p?<?0.05) variation was also noticed in the total amounts of calcium, iron and zinc in both sampled cereals within the 72?h of fermentation.

Conclusion

Prevalence of appropriate complementary feeding practice was very low. There were significant reductions of phytate and tannin contents with concomitant increments of minerals after fermentation of cereals. Phytate: mineral ratios were significantly decreased after fermentation for all the parameters examined. It is recommended to ferment cereals while preparing complementary foods for children so as to enhance their micronutrient uptake.
  相似文献   
89.
90.
BackgroundUrinary tract infection (UTI) in the pediatric group may lead to end-stage renal dysfunction later in life. Tracking the type of the isolates and their antimicrobial resistance pattern would impact the management of UTI in these group. The aim of this study was to describe the distribution of bacterial uropathogenes, their antimicrobial susceptibility profile and factors associated with significant bacteriuria (SBU) among pediatric patients at selected facilities in Bahir Dar, Northwest Ethiopia.MethodsA cross-sectional study was conducted from 1st February to 30th June 2020. About 5–10ml of urine samples were collected from pediatrics presumptive for UTI and a urine sample was considered positive for SBU if a single organism was grown at a concentration of ≥104cfu/ml. Antimicrobial sensitivity testing was performed using the Kirby-Bauer disc diffusion technique. Logistic regression was used to identify factors associated with SBU and statistical significance was set at p-value < 0.05.ResultsOf the total 299 study participants, the majority 173 (57.9%) were females. The mean age of the participants was 6.6 years. The proportion of significant bacteriuria was at 49(16.4%). Most, 37 (75.5%) of the isolates were Gram-negative. The most predominant isolate was E. coli, 21(42.9%) followed by P. aeruginosa, 6(12.2%) and coagulase negative staphylococci, 6(12.2%). The level of multi-drug resistance among Gram-positive and Gram-negatives was at 50% and 78.4%, respectively. Participants'' sex, circumcision status, having a flank pain and being malnourished were statistically associated with significant bacteriuria.ConclusionActions to minimize antimicrobial resistance should be strengthened to reduce the impact of UTI among the pediatric group.  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