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The objective of the investigation was to study the application of ultrasound reactor technology (USRT) as a disinfectant for reduction of fungi from sewage effluent. Fungi are carbon heterotrophs that require preformed organic compounds as carbon sources. USRT is an attractive means to improve water quality because of the system simplicity and no production of toxic by-products. An ultrasound reactor produces strong cavitation in aqueous solution causing shock waves and reactive free radicals by the violent collapse of the cavitation bubble. These effects should contribute to the physical disruption of microbial structures and inactivation of organisms. There was significant reduction in fungal growth, with decreased fungal growth with increasing USRT. In this study, ultrasound irradiation at a frequency of 42 kHz was used to expose suspensions of fungi to evaluate the disinfection efficacy of the ultrasound reactor. Also, this study showed that in this system more than 99% reduction of sewage fungi was achieved after 60 min.  相似文献   
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The purpose of the present study was to examine the effects of teaching self- determination skills on the externalizing behaviors of students with emotional and behavioral disorders. The Research method was quasi experimental with pre and post- test and control group. To achieve our goals, thirty students who received high scores in the Child Behavior Checklist (CBCL) were selected and randomly assigned to either the experimental group (N = 15) or the control group (N = 15). Students in the experimental group participated in 16 sessions (1 session per week) receiving Self determination curriculum (Field and Hoffman’s model) intervention, and the control group did not receive any training. The Child Behavior Checklist (CBCL) by participants was completed before and after intervention. MANOVA was used for data analysis. The findings showed that the effects of teaching self- determination skills on decreasing the externalizing behaviors of students with emotional and behavioral disorders was significant. The emerged finding can have clinical applications in prevention and treatment of student’s behavioral disorders. Implications and future directions for research and practice are discussed.  相似文献   
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Implantable drug delivery devices are becoming attractive due to their abilities of targeted and controlled dose release. Currently, two important issues are functional lifetime and non-controlled drug diffusion. In this work, we present a drug delivery device combining an electrolytic pump and a thermo-responsive valve, which are both remotely controlled by an electromagnetic field (40.5 mT and 450 kHz). Our proposed device exhibits a novel operation mechanism for long-term therapeutic treatments using a solid drug in reservoir approach. Our device also prevents undesired drug liquid diffusions. When the electromagnetic field is on, the electrolysis-induced bubble drives the drug liquid towards the Poly (N-Isopropylacrylamide) (PNIPAM) valve that consists of PNIPAM and iron micro-particles. The heat generated by the iron micro-particles causes the PNIPAM to shrink, resulting in an open valve. When the electromagnetic field is turned off, the PNIPAM starts to swell. In the meantime, the bubbles are catalytically recombined into water, reducing the pressure inside the pumping chamber, which leads to the refilling of the fresh liquid from outside the device. A catalytic reformer is included, allowing more liquid refilling during the limited valve''s closing time. The amount of body liquid that refills the drug reservoir can further dissolve the solid drug, forming a reproducible drug solution for the next dose. By repeatedly turning on and off the electromagnetic field, the drug dose can be cyclically released, and the exit port of the device is effectively controlled.  相似文献   
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The purpose of this paper is to propose an operational idea for developing algebraic thinking in the absence of alphanumeric symbols. The paper reports on a design experiment encouraging preschool children to use the associative property algebraically. We describe the theoretical basis of the design, the tasks used, and examples of algebraic thinking in 5–6-year-old children. Theoretically, the paper makes a critical distinction between operational and structural meanings of the notion of equality. We argue that mathematical thinking involving equality among young learners can comprise both an operational and a structural conception and that the operational conception has a side that is productively linked to the structural conception. Using carefully designed hands-on tasks, the crux of the paper is the realization of algebraic thinking (in verbal mathematics) as operationally experienced in the ability to transform one number structure, with a quantity that is subject to change, into another through equality-preserving transformations.  相似文献   
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The study reported in this paper investigated the effectiveness of an Integrated Holistic Teaching Method for teaching grammatical structure, cultural norms and behavior, writing and listening to German language students. The study involved a sample of 24 undergraduate students enrolled in an introductory college-level German course at a large urban community college in Texas. The research utilized a pre- and posttest design to study the instructional effectiveness of the Integrated Holistic Teaching Method. The higher posttest mean scores indicated significant improvement in student learning in the 4 major language skills areas as an artifact of involvement in the Integrated Holistic Teaching Method.  相似文献   
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This article examines the interpretations of high school students from different socioeconomic locations (in terms of socioeconomic class and ethnicity) with regard to the text Brown Morning, used as a didactic tool for antiracism education within the framework of Civics courses. The research findings uncover differences in the students’ interpretations of the text. An in-depth understanding of these differences will be attained through clinical analyses based on the distinctions between metaphor and metonymy made by linguist Roman Jakobson. Among students from low socioeconomic locations, interpretations related to racism were dominated by metonymic characteristics, while that of students from higher socioeconomic locations were predominantly metaphoric. Study findings do not only show the different interpretations among the students, but also the various ways in which metaphorical and metonymic language affect teachers. These analyses will focus on the reasons for these differences and their implications regarding the links between social locations, language, and education.  相似文献   
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  总被引:1,自引:0,他引:1  
Technology firms occupy a central position in modern economies. They drive economic growth, productivity gains and have created new industries and innovative products.Many will agree that technology firms are distinguished from others in their emphasis on technological activities. Since this observation is too general, researchers suggested a variety of specific criteria and definitions. A number of definitions of technology firms appear in the literature but many are arbitrary and simplistic and none gained wide acceptance. Similarly, the number of characteristics suggested is large, reflecting a variety of perspectives and interests. In this case too no agreement exists as to which are the important ones. Also, many seem to be interrelated capturing different aspects of the same underlying concepts.This paper is concerned with the issue of definition and classification of technology firms. We demonstrate the usefulness of a different approach to the definition and classification problem. We rely on executives’ evaluations of their firms’ technology profile and level. An analysis of these evaluations reveals the underlying dimensions the executives used in making their judgments. We regard the dimensions we uncover as capturing the essence of technology firms and use them to classify the firms we study. The specific characteristics the executives used to evaluate their firms were derived from a systematic scan of the literature. Thus, the list represents the set of characteristics early researchers viewed as describing and defining technology firms. The connection to early work enhances our findings’ validity and lends some credence to our belief that the three dimensions we uncover (R&D activities which are closely associated with a set of organizational elements and market conditions, product strategy, and corporate culture) can be used by others to define technology firms and classify firms according to their technology level. In our study we use these three dimensions to classify the firms studied. We show that the commonly used practice of classifying firms as high and low technology according to the industry to which they belong is flawed.Our goal in this study is not to offer a “new” or “better” definition and characterization of technology firms or to offer the “best” approach to the generation of the classification criteria. Rather, we demonstrate here the usefulness of a different approach to the problem. While our approach does suffer from limitations it has important advantages. We hope future studies will confirm not only the usefulness of our approach but also the general applicability of the specific criteria we identify in this study.  相似文献   
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