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151.
E. V. Lambert J. A. Hawley J. Goedecke T. D. Noakes S. C. Dennis 《Journal of sports sciences》2013,31(3):315-324
Carbohydrate ingestion before and during endurance exercise delays the onset of fatigue (reduced power output). Therefore, endurance athletes are recommended to ingest diets high in carbohydrate (70% of total energy) during competition and training. However, increasing the availability of plasma free fatty acids has been shown to slow the rate of muscle and liver glycogen depletion by promoting the utilization of fat. Ingested fat, in the form of long-chain (C 16-22 ) triacylglycerols, is largely unavailable during acute exercise, but medium-chain (C 8-10 ) triacylglycerols are rapidly absorbed and oxidized. We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO 2 peak) cycling exercise, and improves 40 km time-trial performance. These data suggest that by combining carbohydrate and medium-chain triacylglycerols as a pre-exercise supplement and as a nutritional supplement during exercise, fat oxidation will be enhanced, and endogenous carbohydrate will be spared. We have also examined the chronic metabolic adaptations and effects on substrate utilization and endurance performance when athletes ingest a diet that is high in fat (> 70% by energy). Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO 2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading. Thus the relative contribution of fuel substrate to prolonged endurance activity may be modified by training, pre-exercise feeding, habitual diet, or by artificially altering the hormonal milieu or the availability of circulating fuels. The time course and dose-response of these effects on maximizing the oxidative contribution of fat for exercise metabolism and in exercise performance have not been systematically studied during moderate- to high-intensity exercise in humans. 相似文献
152.
Jack W. Kostal Paul R. Sackett Nathan R. Kuncel Philip T. Walmsley Melissa S. Stemig 《Educational Measurement》2017,36(1):39-46
Previous research has established that SAT scores and high school grade point average (HSGPA) differ in their predictive power and in the size of mean differences across racial/ethnic groups. However, the SAT is scaled nationally across all test takers while HSGPA is scaled locally within a school. In this study, the researchers propose that this difference in how SAT scores and HSGPA are scaled partially explains differences in validity and subgroup differences. Using a large data set consisting of 170,390 students each of whom matriculated at one of 114 separate colleges, the researchers find that awarding SAT scores by ranking SAT within a high school generally results in substantial reduction in the size of subgroup mean differences for this predictor. However, validity for predicting first‐year GPA is also reduced by a small amount. Conversely, placing HSGPA onto a nationally normed metric through the use of multiple regression procedures results in a moderate increase in the size of subgroup mean differences, while also producing a small increase in validity. Taken together, these findings suggest that differences in predictor scaling can partially explain differences in the size of subgroup mean differences between HSGPA and SAT scores and have implications for predictive power. 相似文献
153.
William T. Allen Jr. 《Roeper Review》2017,39(4):269-283
Much is written at the elementary school level concerning bullying and the socioemotional needs of gifted and talented (GT) students; however, in the last 10 years, little qualitative research exists concerning the early adolescent GT age group. In the social environment of classroom life, early and current research indicates that many of these students experience neurotic perfectionism, overexciteabilities (OEs), developmental asynchrony, and bullying. The formation of autonomous classes (GT-only classes) has afforded some hope concerning the amelioration of such problems; nevertheless, in this study, detailed evidence of classroom bullying in the form of social ostracism and teasing has been found with this GT age group. If left unchecked, psychological autopsies have shown these students suffering emotional difficulties and even committing suicide as a result of school and classroom torment. With such potential for classroom bullying problems, few studies address what veteran teachers of early adolescent GT students do to keep students psychologically safe. Within the social milieu of classroom life, and in comparison to research standards, this study explores three efficacious teacher perspectives and practices. 相似文献
154.
T. Padmanabhan 《Resonance》2009,14(5):499-507
The fact that an accelerated charge radiates energy is considered an elementary textbook result in electromagnetism. Nevertheless,
this process of radiation (and its reaction on the charged particle) raises several conundrums about which technical papers
are written even today. In this installment, we will try to understand why an accelerated charge radiates in a simple, yet
rigorous, manner. 相似文献
155.
Six young deafblind adults took a 1-week course on civic engagement and advocacy, which provided the focus for a participatory action research study with a collective case study design. They selected advocacy topics, were briefed on these policy issues, and were paired with experienced mentors for meetings with legislators in Washington, DC. Eight themes were identified from constant comparative and in vivo analysis of classroom discussion notes, interviews, and journals: (a) defining advocacy and advocate, (b) rights and equality, (c) expectations, (d) role of education in change, (e) deafblind expertise, (f) characteristics of effective change agents, (g) advocacy is teamwork, (h) future advocacy. In the classroom, the participants learned about policy issues, communication considerations, and leadership, then applied this knowledge in the legislative arena. Through the advocacy process, they learned to apply their personal strengths as advocates and experienced the importance of teamwork in advocacy. 相似文献
156.
157.
Esther T. Canrinus Michelle Helms-Lorenz Douwe Beijaard Jaap Buitink Adriaan Hofman 《European Journal of Psychology of Education - EJPE》2012,27(1):115-132
This study investigates how relevant indicators of teachers’ sense of their professional identity (job satisfaction, occupational
commitment, self-efficacy and change in level of motivation) are related. A model is proposed, tested with structural equation
modelling (SEM) and refined using data from 1,214 Dutch teachers working in secondary education. Classroom self-efficacy and
relationship satisfaction play a key influencing role in the relationships between the indicators. Using multiple-group SEM,
the parameters of the overall model are similar for the novice, experienced and senior teachers in a constrained model. This
aspect of similarity across experience groups is in line with findings of previous research on teachers’ professional identity.
The present study contributes to the further development of a solid theory on teachers’ professional identity, which has been
lacking. 相似文献
158.
Irini Dermitzaki Panayiota Stavroussi Denis Vavougios Konstantinos T. Kotsis 《European Journal of Psychology of Education - EJPE》2013,28(3):747-766
The present study aimed at adapting in the Greek language the Students' Motivation Towards Science Learning (SMTSL) questionnaire developed by Tuan, Chin, and Shieh (INT J SCI EDUC 27(6): 639-654, 2005a) into a different cultural context, a different age group, that is, in university students and with a focus on physics learning. Three hundred and fifty Greek student teachers participated in the study. The original instrument consisted of 35 items allocated in six scales: self-efficacy, use of active learning strategies, science learning value, performance goals, achievement goals, and learning environment stimulation. The instrument's internal consistency was acceptable and comparable to previous studies' reports. Confirmatory factor analysis (CFA) was applied on the data in order to test an a priori hypothesis regarding the SMTSL's factorial structure based on previous studies' findings. The results of the study showed that the six-factor conceptual model of students' motivation proposed by the SMTSL applies in this different cultural setting and in this group of university students with reference to physics learning. Along with the six distinct motivational constructs confirmed, students' motivational beliefs were also explained by a general motivational construct assumed to be at their basis. Suggestions for further improvement of the Greek version of the SMTSL are also discussed. 相似文献
159.
160.
O.T. Kibwana Mitiku Haile Laurens vanVeldhuizen Ann Waters‐Bayer 《The Journal of Agricultural Education and Extension》2013,19(3):133-142
Abstract Promoting rural development in Africa involves learning to clap with two hands, that is to say, creating effective interaction between local knowledge and development initiatives, on the one hand, and the knowledge and initiatives of formal agricultural research and extension, on the other. Farmer innovators ‐men and women farmers who take their own initiative to change local agriculture ‐ are key allies in rural development, as shown by the experience of the ISWC programme in Africa. Focusing on Ethiopia and Tanzania, the authors describe how formal research and extension services are made aware of farmers’ innovative work and are encouraged to document the results, promote their spread, and support further development efforts by farmer innovators. A modified Participatory Technology Development (PTD) approach is thus emerging, which starts not with problem analysis but rather by linking up with local problem‐solving initiatives. While the learning process on this approach continues, dialogue has been initiated with policy‐makers with a view to incorporating the approach into regular government extension, research and training activities. 相似文献