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391.
ABSTRACT

Previous research on remediation has examined course placement practices, but little is known about first responders and how their beliefs about proper course placements help maintain patterns in course access. This study examined how taken-for-granted racial beliefs were used as legitimate knowledge by community college counselors. Haney López’s (2000) race as commonsense theoretical perspective was used to analyze interview data from 34 counselors in 2 southern California community colleges. Data showed that counselors recreated race categories and racial hierarchy, and they did so by reinforcing beliefs about white students as intelligent and deserving higher placements and Latina/o students as comparatively lower in ability and deserving remediation. The results suggest that counselors begin institutionalizing racial sorting immediately as first-time students begin to enroll. The findings highlight the importance of racial mindfulness in policy, practice, and research.  相似文献   
392.
In this work a procedure for obtaining polytopic λ-contractive sets for Takagi–Sugeno fuzzy systems is presented, adapting well-known algorithms from literature on discrete-time linear difference inclusions (LDI) to multi-dimensional summations. As a complexity parameter increases, these sets tend to the maximal invariant set of the system when no information on the shape of the membership functions is available. λ-contractive sets are naturally associated to level sets of polyhedral Lyapunov functions proving a decay-rate of λ. The paper proves that the proposed algorithm obtains better results than a class of Lyapunov methods for the same complexity degree: if such a Lyapunov function exists, the proposed algorithm converges in a finite number of steps and proves a larger λ-contractive set.  相似文献   
393.
Chaurey V  Polanco C  Chou CF  Swami NS 《Biomicrofluidics》2012,6(1):12806-1280614
We present an electrokinetic framework for designing insulator constriction-based dielectrophoresis devices with enhanced ability to trap nanoscale biomolecules in physiological media of high conductivity, through coupling short-range dielectrophoresis forces with long-range electrothermal flow. While a 500-fold constriction enables field focusing sufficient to trap nanoscale biomolecules by dielectrophoresis, the extent of this high-field region is enhanced through coupling the constriction to an electrically floating sensor electrode at the constriction floor. However, the enhanced localized fields due to the constriction and enhanced current within saline media of high conductivity (1 S/m) cause a rise in temperature due to Joule heating, resulting in a hotspot region midway within the channel depth at the constriction center, with temperatures of ∼8°–10°K above the ambient. While the resulting vortices from electrothermal flow are directed away from the hotspot region to oppose dielectrophoretic trapping, they also cause a downward and inward flow towards the electrode edges at the constriction floor. This assists biomolecular trapping at the sensor electrode through enabling long-range fluid sampling as well as through localized stirring by fluid circulation in its vicinity.  相似文献   
394.
Science learning in virtual environments: a descriptive study   总被引:3,自引:0,他引:3  
Usually, students learn more if the method of instruction matches their learning style. Since Physics and Chemistry deal with three–dimensional (3–D) objects, the ability to visualize and mentally manipulate shapes is very helpful in their learning. In fact, much of what Physics and Chemistry students know takes the form of images. However, little attention has been given to the pedagogical effectiveness of visual stimuli in those disciplines. Computers are being increasingly used as teaching tools. The new approaches include simulations, multimedia presentations and, more recently, virtual environments. Computer–based worlds are useful to visualize physical and chemical processes allowing for better conceptual understanding. Since 3–D virtual environments need to be explored and evaluated in science education, we have created a virtual environment ( Virtual Water ) for studying phases of matter, phase transitions and atomic orbitals at the final year of high school and first year of university levels. Based on that work, we discuss the implications of visual learning in designing strategies to cater for differences in learning modes. Our study indicates that 3–D virtual environments may help students with high spatial aptitude to acquire better conceptual understandings. However, only some parameters (interactivity, navigation and 3–D perception) have shown to be relevant and only for some topics. On the other hand, stereoscopic visualizations do not seem to be relevant, with the exception of crystalline structures.  相似文献   
395.
When translating word problems into equations, a common error consists of using the same letter to refer to two different quantities. This error, called multiple referents for the unknown, can be connected to the existence of deictic or indexical expressions within the problem statement. This paper aims to analyse the influence of indexical expressions on the incidence of the multiple referents for the unknown error. Results from a quantitative study with 117 Spanish secondary students show a significantly higher number of such type of error when the problem statement contains indexical expressions. The analysis of students’ performances in subsequent interviews indicates that this error may be due to the fragmented reading of statements.  相似文献   
396.
Technology is modifying the way companies do business all over the world. The education sector is no exception; virtual education has emerged as a basic tool to satisfy the changing needs of traditional and newly incorporated students, as well as meet the new requirements of educational institutions. This article therefore tries to achieve a double objective: to analyze what drives the development of online education within the Universities of the European Union and to design a theoretical framework that permits to obtain responses to que question of why students continue their estudies at the same educational institution. Thus, first, the analysis of external factors identifies social, political and technological capacity as issues that explain the rise of e-learning within the field of European higher education. Second, the empirical work shows the design of a cause-effect model with relationships between different variables in which market orientation of Universities and usability play an important role in the future intentions of use for students.  相似文献   
397.
Resumen

En el presente trabajo se analiza la relación existente entre el concepto de estrategias de aprendizaje y de habilidades metacognitivas en el marco de un modelo explicativo basado en la mediación cognitiva. Posteriormente se revisan los métodos instruccionales que se han mostrado más eficaces en la instauración de macroestrategias entre los estudiantes, y se describe de manera pormenorizada un sistema de autointerrogación metacognitiva, el procedimiento metacognitive de enseñanza-aprendizaje (promete-a). La aplicación de promete-a, en un estudio piloto, a 16 profesores de distintos niveles educativos no-universitarios, ha demostrado tener una incidencia positiva en la planificación, monitorización y evaluación de los procesos cognitivos implicados en la tarea ae preparation de sesiones de clase.  相似文献   
398.

Dr. Ahnell examines several tenets of perceptual psychology and makes specific suggestions for their application by supervising teachers. All supervising teachers could benefit from reading this article.  相似文献   
399.
This paper compares the efficiency of calculus classes. Two kinds of classes are evaluated: the traditional ones and others that use computational methods in teaching. This experiment was performed at Fluminense Federal University, Niterói, Brazil, from 1998 to 2000. The emphasis of this paper is on the quantitative evaluation using two operational research tools: multicriteria decision aid methods (mainly using the MACBETH approach) and data envelopment analysis. The evaluating variables are the level at which students enter the university and the performance of the students after studying calculus.  相似文献   
400.
In a randomised controlled trial design, effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players. Young (age 21.1 ± 2.7 years) players with similar training load and competitive background were assigned to training (women, n = 19; men, n = 21) and control (women, n = 19; men, n = 21) groups. Players were evaluated for lower- and upper-body maximal-intensity exercise, 30 m sprint, change of direction speed and endurance performance before and after 6 weeks of training. After intervention, the control groups did not change, whereas both training groups improved jumps (effect size (ES) = 0.35–1.76), throwing (ES = 0.62–0.78), sprint (ES = 0.86–1.44), change of direction speed (ES = 0.46–0.85) and endurance performance (ES = 0.42–0.62). There were no differences in performance improvements between the plyometric training groups. Both plyometric groups improved more in all performance tests than the controls. The results suggest that adaptations to plyometric training do not differ between men and women.  相似文献   
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