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   61篇
  免费   5篇
教育   45篇
科学研究   15篇
各国文化   3篇
文化理论   1篇
信息传播   2篇
  2022年   1篇
  2021年   6篇
  2020年   3篇
  2019年   2篇
  2018年   9篇
  2017年   3篇
  2016年   5篇
  2015年   1篇
  2014年   6篇
  2013年   6篇
  2011年   4篇
  2010年   2篇
  2008年   2篇
  2007年   5篇
  2006年   1篇
  2003年   1篇
  2002年   2篇
  2000年   3篇
  1993年   1篇
  1990年   1篇
  1989年   2篇
排序方式: 共有66条查询结果,搜索用时 625 毫秒
1.
Genetic variation in the angiotensin II type 1 receptor (AT1R) has an important effect on the outcome of acute coronary syndrome (ACS) initiated treatment with captopril. This study aims to investigate the impact of genetic polymorphism of AT1R (rs5186 and rs275651) on the ACS outcome in Iraqi patients treated with captopril. A total of 250 Iraqi individuals with ACS were included in this case—control study and they were divided into two study groups; Study group 1 included 125 participants who were prescribed captopril, 25 mg twice daily and study group 2 included 125 participants who received no captopril as part of their ACS treatment (control study). The AT1R gene (rs5186) CC genotype was found to be associated with ST-elevation myocardial infarction (STEMI) (Odd’s ratio (O.R) = 1.2, P = 0.7), while AC was associated with Non-ST-elevation myocardial infarction (NSTEMI) and unstable angina (UA) (O.R = 1.2, P = 0.8). AC genotype is more prone to have Percutaneous coronary intervention (PCI) after ACS attack (O.R = 1.2, P = 0.6). CC genotype had a risk to get less improvement (O.R = 1.6, P = 0.5), so might require higher doses of captopril during acute coronary insult. The AT1R gene (rs275651) AA genotype was associated with UA (O.R = 1.3, P = 0.9). AA and AT genotypes were more prone to have PCI after ACS attack (O.R = 3.9 P = 0.2, O.R = 3.5, P = 0.3 respectively) and thus requiring higher doses of captopril. We conclude that the AT1R rs5186, rs275651 genetic polymorphisms might partially affect the clinical outcome of ACS patients treated with captopril and might have captopril resistance which requires higher doses.  相似文献   
2.
Having found hidden hyperchaos in a 5D self-exciting homopolar disc dynamo, we study the existence of a Hopf bifurcation, which leads to unstable limit cycles bifurcating from a stable equilibrium. Hidden chaos with only stable equilibria can be observed from the Hopf bifurcation: a typical way to enable hidden attractors to be located. We then provide a new fuzzy controller, and a fast fuzzy disturbance observer, based on terminal sliding mode control for synchronization of the hyperchaotic system. Fuzzy inference is considered to weaken the chattering phenomena. Using Lyapunov stability theory, the stability of the closed-loop system is proved. Finally, simulations of synchronization are illustrated to show the efficient performance of the designed control method via external disturbances and dynamic uncertainties.  相似文献   
3.
Demand for and productivity analysis of Turkish public theater   总被引:1,自引:0,他引:1  
We estimate a demand function for live theater provided by the General Directorate of State Theaters in Turkey. We show that demand is more elastic in less developed cities, that attendance is not significantly affected by various qualitative variables, and that the government's practice of offering free passes to government officials is an ineffective way of increasing paid attendance. Comedies and musicals both show significantly higher attendance. Having a Turkish author does not significantly affect attendance. Having a known author significantly increases attendance for more developed cities but not for less developed cities. Being the opening season significantly reduces attendance in less developed cities but has no effect in more developed cities. We also present evidence of inefficiency in state theaters in Turkey through a performance of plays equation in which we evaluate the determinants of the number of performances per play.  相似文献   
4.
5.
This study (a) assessed the influence of three history of science (HOS) courses on college students' and preservice science teachers' conceptions of nature of science (NOS), (b) examined whether participants who entered the investigated courses with a conceptual framework consistent with contemporary NOS views achieved more elaborate NOS understandings, and (c) explored the aspects of the participant HOS courses that rendered them more “effective” in influencing students' views. Participants were 166 undergraduate and graduate students and 15 preservice secondary science teachers. An open‐ended questionnaire in conjunction with individual interviews, was used to assess participants' pre‐ and postinstruction NOS views. Almost all participants held inadequate views of several NOS aspects at the outset of the study. Very few and limited changes in participants' views were evident at the conclusion of the courses. Change was evident in the views of relatively more participants, especially preservice science teachers, who entered the HOS courses with frameworks that were somewhat consistent with current NOS views. Moreover, explicitly addressing certain NOS aspects rendered the HOS courses relatively more effective in enhancing participants' NOS views. The results of this study do not lend empirical support to the intuitively appealing assumption held by many science educators that coursework in HOS will necessarily enhance students' and preservice science teachers' NOS views. However, explicitly addressing specific NOS aspects might enhance the effectiveness of HOS courses in this regard. Moreover, the study suggests that exposing preservice science teachers to explicit NOS instruction in science methods courses prior to their enrollment in HOS courses might increase the likelihood that their NOS views will be changed or enriched as a result of their experiences with HOS. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 1057–1095, 2000  相似文献   
6.
Owing to the higher amount and the better quality of power transferred, three-phase multilevel inverters have strengthened their presence in low-power photovoltaic (PV) applications. However, the existing topologies investigated for low-power PV systems are basically meant for medium- and high-power applications, thus making them underutilized for low-power range. In order to address this shortcoming, this paper proposes a three-phase multilevel inverter with a switch-sharing capability and its control solution. It combines the characteristics of the two-level full-bridge topology and the diode-clamped multilevel structure. As a result, the inverter can be used with full capacity and without being underutilized, and significantly improves the output quality. A control strategy that is able to maximize the full potential of the inverter is developed. A digital proportional-integral (PI) controller with a new tuning algorithm is designed to effectively deal with the load changes. The result reveals that the load current is always retained at the intended quality level despite the variations in load. The performance of the inverter is validated from the experimental work conducted on a laboratory prototype under closed-loop conditions.  相似文献   
7.
This paper uses Tight (High Educ Res Dev 23(4):395–411, 2004; High Educ Res Dev 31(5):723–740, 2012; High Educ Res Dev 32(1):136–151, 2013)’s journal analysis and review framework to review a sample of 497 journal articles on researches concerning international students over the past 30 years. It was found that a majority of the articles focus on the students’ in-campus, academic and social experience. Even with different conceptualisation of the terms “international student” and “international student mobility”, international students undergo similar challenges throughout their sojourn duration, and much of the responsibilities in managing international students fall on universities and respective faculty members within the institutions. It might seem as if we are going in circles in terms of the issues and concerns in managing international students, but the silver lining out of this observation is the increased ethnical awareness among countries and higher education institutions in hosting and safeguarding the students throughout their international higher education experience, albeit rather slowly. The analysis brings to attention how much have we achieved in internationalisation of higher education in general and international student-related research in particular, and the potential for greater expansion and focus on managing the student population within a comprehensive “life cycle” approach.  相似文献   
8.
Solid oxide fuel cells(SOFCs) offer high energy conversion,low noise,low pollutant emission,and low processing cost.Despite many advantages,SOFCs face a major challenge in competing with other types of fuel cells because of their high operating temperature.The necessity to reduce the operational temperature of SOFCs has led to the development of research into the materials and fabrication technology of fuel cells.The use of composite cathodes significantly reduces the cathode polarization resistance and expands the triple phase boundary area available for oxygen reduction.Powder preparation and composite cathode fabrication also affect the overall performance of composite cathodes and fuel cells.Among many types of cathode materials,lanthanum-based materials such as lanthanum strontium cobalt ferrite(La1-xSrxCo1-yFeyO3- have recently been discovered to offer great compatibility with ceria-based electrolytes in performing as composite cathode materials for intermediate-to low-temperature SOFCs(IT-LTSOFCs).This paper reviews various ceria-based composite cathodes for IT-LTSOFCs and focuses on the aspects of progress and challenges in materials technology.  相似文献   
9.
10.
The pun is a tricky use of a word or phrase which has very different meanings that are closely interrelated, or of words with the same sound but different meanings. The Pun is a term with a dual meaning: “close” using obvious reference, and “far” using obscure reference. The hidden is usually meant. The close meaning is the sooner that comes to the listener’s mind. However, the speaker targets at the far one yet use the close to hide it. Translating the Quran text always raises several serious challenges in translation; these challenges are due to the different translations of puns and the misinterpretations between the intended meanings of a pun with their basic concepts, which could result in a certain amount of ambiguity. The study examines the Quranic corpus and its three versions of English translations. The study utilizes the typology of Delabastita?s for horizontal puns, Nida’s techniques of dynamic and formal equivalent and Newmark’s translation methods. This research attempts to investigate the semantic meaning of puns in the Quran translation and to define the translation techniques applied in translating the Quranic puns from Arabic into English.  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