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   152篇
  免费   6篇
教育   124篇
科学研究   12篇
体育   5篇
文化理论   6篇
信息传播   11篇
  2023年   1篇
  2022年   6篇
  2021年   13篇
  2020年   5篇
  2019年   13篇
  2018年   18篇
  2017年   11篇
  2016年   10篇
  2015年   5篇
  2014年   13篇
  2013年   16篇
  2012年   4篇
  2011年   5篇
  2010年   5篇
  2009年   5篇
  2008年   2篇
  2007年   2篇
  2006年   3篇
  2005年   3篇
  2004年   2篇
  2003年   2篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1979年   1篇
排序方式: 共有158条查询结果,搜索用时 31 毫秒
61.
Some errors in the learning of algebra suggest that students might have difficulties giving meaning to algebraic symbolism. In this paper, we use problem posing to analyze the students’ capacity to assign meaning to algebraic symbolism and the difficulties that students encounter in this process, depending on the characteristics of the algebraic statements given. We designed a written questionnaire composed of eight closed algebraic statements expressed symbolically, which was administered to 55 students who had finished their compulsory education and who had some previous experience in problem-posing. In our analysis of the data, we examine both syntactic and semantic structures of the problem posed. We note that in most cases students posed problems with syntactic structures different to those given. They did not include computations within variables, and changed the kinds of relationships connecting variables. Students easily posed problems for statements with additive structures. Other differences in the type of problems posed depend on the characteristics of the given statements.  相似文献   
62.
IntroductionOesophageal varices are routinely diagnosed by esophagogastroduodenoscopy (EGD), and their bleeding has high mortality. We aimed to evaluate diagnostic performance of biochemical tests in comparison to elastography-based approaches, as non-invasive alternatives to EGD, for ruling-out high risk oesophageal varices (HRV).Material and methodsRetrospective analysis of patients (N = 861) who underwent liver stiffness measurement (LSM) by transient elastography (TE) in a single centre over 5-year period, with available results of EGD (within 3 months from LSM). Only patients with suspicion of compensated advanced chronic liver disease (cACLD) defined by LSM ≥ 10 kPa were included comprising the final cohort of 73 subjects. Original and expanded Baveno VI criteria (B6C), controlled attenuation parameter (CAP), platelet count (PLT), aspartate aminotransferase to PLT ratio index (APRI), Fibrosis-4 index (FIB4), model for end stage liver disease (MELD) score were evaluated against the results of EGD that served as the reference method.ResultsAnalysed patients had median age 62 years, 59/73 (0.81) were males, 54/73 (0.74) had alcoholic/non-alcoholic fatty liver disease, and 21/73 (0.29) had HRV. In multivariate logistic regression analysis only LSM and PLT were independently associated with HRV. The best performing tests for ruling-out HRV (% of spared EGD; % of missed HRV) were respectively: LSM < 20 kPa (53.4%; 0%), B6C (38%; 0%), Expanded B6C (47.9%; 4.8%); PLT > 214x109/L (21.9%; 0%); FIB4 ≤ 1.8 (21.4%; 0%), APRI ≤ 0.34 (12.3%; 0%). CAP, MELD = 6 alone or combined with PLT > 150(x109/L) did not show acceptable performance.ConclusionThe best performing biochemical tests for ruling-out HRV in our cohort of patients were PLT and FIB-4, but they were still outperformed by elastography-based approaches.Keyword: portal hypertension, cirrhosis, platelet count, esophageal varices, non-invasive tests  相似文献   
63.
The current study examines costs, measured by educational and general (E&G) spending, and cost efficiency at 252 public master’s institutions in the United States over a nine-year (2004–2012) period. We use a multi-product quadratic cost function and results from a random-effects model with a first-order autoregressive (AR1) disturbance term to calculate economies of scale with regard to undergraduate enrollment, graduate enrollment, and research. We also employ a slightly modified version of Kumbhakar et al. (J Prod Anal 41(2):321–337, 2014) multi-step approach, involving the use of stochastic frontier analysis (SFA) and taking into account spatial interdependency, to decompose cost efficiency into long-term stable (persistent) and short-term (residual) efficiency. The key results of this study include evidence that: (1) regional clustering of costs exists; (2) there are economies of scale in undergraduate education and diseconomies of scale in graduate education; (3) relatively few institutions are cost inefficient; and (4) cost inefficiency tends to be long-term and persistent rather than short-term and residual. This research also identifies public master’s institutions that are the most cost efficient. Our inquiry has implications for future research as it points towards specific institutions, which may be engaged in effective practices to keep costs low, for possible follow-up case studies. Going forward, the techniques used in this study could be applied to examine economies of scale and scope as well as cost efficiency among other types of higher education institutions, such as public or private research universities, baccalaureate institutions, and community colleges.  相似文献   
64.
This paper addresses how educational and cultural contexts incorporate lessons around sexuality, particularly sexual and gender identity, and how these contexts impact on identity construction of gay men in Mexico City. We analyse the experiences of 15 gay men reported through semi-structured in-depth interviews and how they incorporate sexuality through socialisation with primary social institutions in Mexico's contemporary educational political context. The sample was divided into three generations, and was selected through maximum variability. Results show that men incorporate negative meanings around same-sex sexuality, and themselves from institutions such as school and family. Men are able to deconstruct these meanings through interactions with educational tools such as the Internet and interactions with gay friends. These results are discussed using post-structuralist perspectives to understand how identity is fluid and changing constantly, as well as the need to incorporate stigma-free curricular content in educational contexts.  相似文献   
65.
66.
Our department has adopted action research (AR) projects as the culminating task for our master’s degree candidates. This article presents our work on mentoring graduate students towards the completion of their final AR research projects and details the deliberate structures put in place to guide them through the AR process. These structures include a full-semester course, individual meetings with an AR chair, and collaborative faculty–student feedback sessions. These collaborative conversations (between students and faculty) have allowed us to clarify our understandings of AR, set standards and goals for AR, and raise our expectations on the quality of final AR projects. We hope that the discussion in this article will give students assigned AR new insights as they conduct their research. Also, we hope that the guiding principles we have derived through our efforts can inform others who currently use or plan to assign AR to their students.  相似文献   
67.
Guiding inquiry learning has been shown to increase knowledge gains. Yet, little is known about the effect of guidance on attitudes and behaviours, its interaction with student attributes, and transfer of impact once guidance is removed. We address these gaps in the context of an interactive Physics simulation on electric circuits (https://phet.colorado.edu/en/simulation/circuit-construction-kit-dc). 49 students in the Non-Directive condition received a set of goals to focus their inquiry, in addition to implicit support built into the simulation. 48 students in the Directive condition received, in addition to these, also detailed directions and prompts. Log-file analysis found that directive support led to more formal testing and less exploration. Clustering identified two groups of learners: one with higher incoming knowledge (Higher Knowledge), the other with higher incoming perceptions of competence and control (Higher PoCC). Working with the simulation improved knowledge and attitudes across cluster groups, so that prior differences all but disappeared. With regard to guidance, adding directive support improved knowledge gains for the Higher Knowledge group, yet suppressed their attitudinal growth. The same support had no effect on knowledge gains for the Higher PoCC group, yet it boosted their attitudinal growth. A transfer activity, where directive support was no longer available, found that impact on attitudes carried forward, yet impacts on behaviours and knowledge were short-lived. Overall, the study highlights the complex interaction between guidance and student attributes. For some, supporting short-term knowledge gains may inadvertenly lead to longer term negative impact on attitudes towards inquiry.  相似文献   
68.
This study explored longitudinal associations between early shared reading at 2 to 3 years of age and children’s later academic achievement. It examined the mediating role of children’s vocabulary and early academic skills, and the moderating effects of family’s socioeconomic status. Data were drawn from the Longitudinal Study of Australian Children (n = 4,768). Academic achievement was assessed at 8 to 9 years of age via standardized national test scores of literacy and mathematics achievement. Results indicated that early shared reading was associated with children’s academic achievement directly and indirectly through receptive vocabulary and early academic skills. Also, the frequency of early shared reading predicted the outcome measures, over and above other home learning activities. Associations were stronger among low and middle socioeconomic status groups compared to the high socioeconomic status group. We conclude that shared reading offers unique opportunities for adults to teach young children new words and concepts.  相似文献   
69.
A representative sample of counselor educators at U.S. universities were surveyed to identify the kinds of curricula school counselor preparation programs use for preparing students to work with exceptional students (ES). Program courses in exceptional student education (ESE), competencies, field experiences, state certification requirements for ESE courses, the degree of importance accorded by counselor educators to prepare graduates to serve ES, and the educators' level of satisfaction with current program requirements were investigated. Sixty‐two percent of the programs surveyed did not offer a specific ESE course; however, 53% of these programs (N = 146) reported that ESE competencies were incorporated in other program courses.  相似文献   
70.
In this paper, we study the connection between growth and human capital in a convergence regression for the panel of Italian regions. We include measures of average primary, secondary and tertiary education. We find that increased education seems to contribute to growth only in the South. Decomposing total schooling into its three constituent parts, we find that only primary education in the South seems to be important, while tertiary education seems to have a negative impact on regional growth. Our main results are robust to the inclusion of additional variables in the regression analysis and the use of an IV estimator. Overall, this study suggests that Italian growth benefited from the elimination of illiteracy in the South, mainly in the 60s. It also suggests a possible relationship between the level of development of an economy and returns to different levels of education, with Italian regions still far from being able to capture the positive returns from higher levels of education.  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