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1.
This article attempts to characterize the general problem of selecting methods for decision-making. The traditional rational approach to choice is from economics, which offers expected-value maximization. The task environment of decision method selection, however, does not seem to provide the data necessary for carrying out the expected-value calculations. Our approach uses methods from the field of cognitive science. We develop the notion of domain size in fields such as chess, borrowing the concept of a chunk from human memory. We then develop a heuristic rule for choiceamongmethods. We propose this rule as one of many possible rules.  相似文献   
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Selecting the correct method for routine analysis by ‘method evaluation’ is an important component of quality assurance. It is a step-wise procedure that evaluates various analytical parameters like accuracy, precision etc of the given method. Finally reference intervals are established for selected population. We evaluated an enzymatic method for serum creatinine. The results show that it is an acceptable method based on the above mentioned criteria.  相似文献   
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In this paper, a theoretical analysis of diversity incorporated Variable Energy Adaptation (VEA) in an Asynchronous Code Division Multiple Access (A-CDMA) system is discussed for Rayleigh, Rician and Nakagami slow fading channels. The adaptation is accomplished by providing the receiver with the capability of measuring the signal energy-to-noise ratio, and controlling the transmitted signal energy by means of a noise-free feedback loop. System parameters such as fading margin, maximum signal-to-noise ratio, and mean transmitter energy gain are derived and plotted for fading channels as a function of the probability of error specification and the probability of unsatisfactory operation. The mean and median probabilities of error are plotted as a function of energy-to-noise ratios for different fading channels. Error probability distribution and density functions are derived and plotted for various signal-fading distributions.  相似文献   
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In the first part we discussed Tammes’ problem and its higher dimensional analogues. In this part we shall see how harmonic analysis and the theory of orthogonal polynomials can be used to settle some of the most interesting instances of this problem.  相似文献   
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Tuberculosis remains major health problem in India and developing countries Immunodiagnosis has important role in screening, diagnosis and management of tuberculosis. SEVA TB ES-31 antigen has shown potential in detecting tuberculous IgG antibody in earlier studies from our laboratory. In the present study we have analysedSEVA TB ES-31 antigen specific immunoglobulinsIgM, IgA and IgG in clinically and bacteriologically confirmed pulmonary tuberculosis cases to determine the usefulness of specific immunoglobulin class in the diagnosis of patients attending the hospital. Of the 30 cases of pulmonary tuberculosis 25 (83.3%) were positive for IgG, 19 (63.3%) for IgM and 16 (53.3%) for IgA. On combining IgG and IgM positivity, sensitivity was increased to 93.3%. While combining IgG and IgA positivity, sensitivity increased to 90%. However specificity was decreased to 66.6% and 70% for both of these combinations respectively. It could be envisaged from this study that IgG antibody detection against ES-31 antigen showed acceptable sensitivity (83.3%) and specificity (86.6%) compared to IgM or IgA alone or in combination. When immune responses were analysed according to degree of sputum positivity, IgG response was observed to be predominant in all grades, compared to IgM or IgA antibody. The addition of IgM or IgA as an adjunct test increases the sensitivity but at the cost of specificity. Hence the detection of IgG alone is more useful compared to IgM or IgA assay, in detecting tuberculosis disease cases coming to the hospital.  相似文献   
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Mathematics is full of innocent looking problems which, when pursued, soon grow to majestic proportions and begin to impinge upon the frontiers of research. One such problem is the subject of this two-part article — the problem of packing spherical caps on the surface of a sphere.  相似文献   
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This study draws upon a qualitative case study to investigate the impact of the high-stakes test environment on an elementary teacher’s identities and the influence of identity maintenance on science teaching. Drawing from social identity theory, I argue that we can gain deep insight into how and why urban elementary science teachers engage in defining and negotiating their identities in practice. In addition, we can further understand how and why science teachers of poor urban students engage in teaching decisions that accommodate school demands and students’ needs to succeed in high-stakes tests. This paper presents in-depth experiences of one elementary teacher as she negotiates her identities and teaching science in school settings that emphasize high-stakes testing. I found that a teacher’s identities generate tensions while teaching science when: (a) schools prioritize high-stakes tests as the benchmark of teacher success and student success; (b) activity-based and participatory science teaching is deemphasized; (c) science teacher of minority students identity is threatened or questioned; and (d) a teacher perceives a threat to one’s identities in the context of high stakes testing. Further, the results suggest that stronger links to identities generate more positive values in teachers, and greater possibilities for positive actions in science classrooms that support minority students’ success in science.
Bhaskar UpadhyayEmail:

Bhaskar Upadhyay   is an assistant professor of science education at the University of Minnesota, Twin Cities. His research focuses on equity and social justice issues in science education; sociocultural influences on teaching and learning of science; and issues of teaching and learning science to immigrant children and parents. He teaches courses concerning equity, diversity, social justice, and multicultural education issues in science teaching and learning.  相似文献   
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