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   26篇
  免费   0篇
管理学   2篇
民族学   1篇
人口学   2篇
社会学   3篇
统计学   18篇
  2020年   2篇
  2019年   1篇
  2018年   2篇
  2017年   2篇
  2016年   1篇
  2014年   1篇
  2013年   11篇
  2011年   1篇
  2003年   1篇
  1992年   1篇
  1985年   1篇
  1983年   1篇
  1981年   1篇
排序方式: 共有26条查询结果,搜索用时 390 毫秒
1.
For two-level factorials, we consider designs in N=2 (mod 4) runs as obtained by adding two runs, with a certain coincidence pattern, to an orthogonal array of strength two. These designs are known to be optimal main effect plans in a very broad sense in the absence of interactions. Among them, we explore the ones having minimum aberration, with a view to ensuring maximum model robustness even when interactions are possibly present. This is done by sequentially minimizing a measure of the bias caused by interactions of successively higher orders.  相似文献   
2.

Problem

There is lack of data on the rate of episiotomy in Lebanon and the study’s hospital.

Background

Only a few studies have addressed episiotomy practice in Lebanon and the Middle East and they show varying rates.

Aim

To identify the rate, and change in rate, of episiotomy practice over the years at a teaching hospital in Lebanon and to assess whether maternal age, parity, fetal weight, woman’s hospital admission class, and physician’s gender were associated with episiotomy. We also tested the association between episiotomy and postpartum hemorrhage and/or high degree perineal tears.

Methods

A retrospective observational study was conducted on 1756 records for women having a normal vaginal birth at a single centre from January 2009 to January 2014.

Findings

The rate of episiotomy at the hospital was very high, with 97.4% of women receiving an episiotomy in 2009. A major decrease in the rate was identified with a decline from 97.4% in 2009 to 73.3% in January 2014. Episiotomy was found to be associated with parity, maternal age, and with high degree perineal tears.

Discussion

The episiotomy rate at this centre remains higher than the 10% rate recommended by the World Health Organization, although there has been a significant reduction after a call for restrictive rather than liberal use.

Conclusion

Raising awareness among providers appeared to play a significant role in reducing this rate, although more efforts remain warranted. Other strategies – such as raising awareness of women about potential risks of episiotomy – are also worth exploring.  相似文献   
3.
In the midst of the current economic crisis, there is renewed interest in transforming vacant lots into food-producing gardens. This study analyzed whether vacant lots are suitable for food production, by comparing the soil nematode food webs and nutrient pools of vacant lots and community gardens in two post-industrial U.S. cities, Akron and Cleveland, Ohio. Twelve vacant lots and 12 community gardens were examined in the two cities. All six Akron community gardens were established just prior to the initiation of this study, whereas the six in Cleveland were 15–30 years old. Soil pH, texture, moisture, organic matter, mineral nitrogen content, microbial biomass, and nematode communities were measured in both cities. Soil decomposition rate was also measured in Cleveland. Results show that the soils of vacant lots surpassed those of the newly-established Akron gardens and were equal to the soils of the well-established Cleveland gardens in the amount of ammonium-nitrogen, total nematode population, genus diversity, and maturity and structure indices. The soils of the vacant lots were lower than the community gardens in the amounts of soil moisture, organic matter, and nitrate-nitrogen, which we associate with the addition of water, compost, fertilizer, and tilling in the gardens. No significant difference was found between community gardens and vacant lots in microbial biomass, decomposition rate, or nematode enrichment index, which seems to indicate that vacant lots are equal to community gardens in nutrient availability and nutrient cycling. We conclude that barring any contamination, the soil in vacant lots maybe suitable for the establishment of food gardens, which can provide many desirable ecosystem services and enhance human well-being. We also find that the disturbance associated with tillage and conversion of a vacant lot into a community garden has short-term ramifications for both nematode food webs and mineral-nitrogen content.  相似文献   
4.
This study evaluates the effects of the implementation of resident-oriented care on the job characteristics (job autonomy, job demands and social support) of nursing caregivers in three Dutch nursing homes. In a quasi-experimental design, experimental and control groups in both general and psychogeriatric wards were followed for up to 22 months, using a pre-test and two post-tests by means of written questionnaires and semi-structured interviews. The results showed that the intervention appeared to be partly successful. Last post-test regression analyses revealed significant increases in a number of design characteristics of resident-oriented care. Significant increases were noticed on resident assignment, the two variables measuring the nursing process and, in the psychogeriatric experimental group, on resident-oriented tasks (p≤.01). The effects on job characteristics were limited. An indicative increase was shown in contextual job autonomy in the experimental group (p≤.05). The qualitative data derived from the interviews showed that there was still a partly task-oriented division of labour. Further, the delegation of co-ordination tasks to nursing caregivers had not yet been properly achieved. The study concludes with some theoretical and methodological reflections in the light of the findings.  相似文献   
5.
The paper examines hypotheses that certain aspects of status of married women such as (i) decision-making power; (ii) employment status and (iii) educational status, are positively associated with use of contraception and inversely related to fertility performance. The study is based on 1,130 women of reproductive age (15-49) who are currently married and living with their husbands and reported to be fecund. The data are drawn from a cross-section of working and non-working women of Dacca City. The hypothesis that each of the above status variables is related to fertility behaviour (measured as current use of contraception and number of children ever-born) is confirmed, with the sole exception of the relationship between female employment status and fertility behaviour. Female participation in the labour force has little or no effect on use of contraception, particularly among those who belong to higher education and income groups. However, in the lower education and income groups, fertility and use of contraception vary with work experience. The findings clearly point out the need to improve the status of women in order to achieve a breakthrough in the use of contraception and a reduction in fertility.  相似文献   
6.
Design of experiments is considered for the situation where estimation of the slopes of a response surface is the main interest. Under the D-minimax criterion, the objective is to minimize the generalized variance of the estimated axial slopes at a point maximized over all points in the region of interest in the factor space. For the third-order model over spherical regions, the D-minimax designs are derived in two and three dimensions. The efficiencies of some two- and three-dimensional designs available in the literature are also investigated.  相似文献   
7.
Minimization of the maximum and average variance of the difference between estimated responses are taken as design criteria for univariate polynomial regression models. An optimal design under the first criterion is derived for the second-order model and a class of designs nearly optimal under the second criterion is obtained for the general polynomial models.  相似文献   
8.
Minimization of the variance of the estimated slope of a response surface maximized over all points in the factor space is taken as the design criterion. Optimal designs under the criterion are derived for second-order polynomial regression over hypercubic regions.  相似文献   
9.
The D-minimax criterion for estimating slopes of a response surface involving k factors is considered for situations where the experimental region χ and the region of interest ? are co-centered cubes but not necessarily identical. Taking χ = [ ? 1, 1]k and ? = [ ? R, R]k, optimal designs under the criterion for the full second-order model are derived for various values of R and their relative performances investigated. The asymptotically optimal design as R → ∞ is also derived and investigated. In addition, the optimal designs within the class of product designs are obtained. In the asymptotic case it is found that the optimal product design is given by a solution of a cubic equation that reduces to a quadratic equation for k = 3?and?6. Relative performances of various designs obtained are examined. In particular, the optimal asymptotic product design and the traditional D-optimal design are compared and it is found that the former performs very well.  相似文献   
10.
This study evaluates the effects of the implementation of resident-oriented care on the job characteristics (job autonomy, job demands and social support) of nursing caregivers in three Dutch nursing homes. In a quasi-experimental design, experimental and control groups in both general and psychogeriatric wards were followed for up to 22 months, using a pre-test and two post-tests by means of written questionnaires and semi-structured interviews. The results showed that the intervention appeared to be partly successful. Last post-test regression analyses revealed significant increases in a number of design characteristics of resident-oriented care. Significant increases were noticed on resident assignment, the two variables measuring the nursing process and, in the psychogeriatric experimental group, on resident-oriented tasks (p≤.01). The effects on job characteristics were limited. An indicative increase was shown in contextual job autonomy in the experimental group (p≤.05). The qualitative data derived from the interviews showed that there was still a partly task-oriented division of labour. Further, the delegation of co-ordination tasks to nursing caregivers had not yet been properly achieved. The study concludes with some theoretical and methodological reflections in the light of the findings.  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