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941.
The pressurized reservoir is a closed hydraulic tank which plays a significant role in enhancing the capabilities of hydraulic driven robotics. The spring pressurized reservoir adopted in this paper requires comprehensive performance, such as weight, size, fluid volume, and pressure, which is hard to balance. A novel interactive multi-objective optimization approach, the feasible space tightening method, is proposed, which is efficient in solving complicated engineering design problems where multiple objectives are determined by multiple design variables. This method provides sufficient information to the designer by visualizing the performance trends within the feasible space as well as its relationship with the design variables. A step towards the final solution could be made by raising the threshold on performance indicators interactively, so that the feasible space is reduced and the remaining solutions are more preferred by the designer. With the help of this new method, the preferred solution of a spring pressurized reservoir is found. Practicability and efficiency are demonstrated in the optimal design process, where the solution is determined within four rounds of interaction between the designer and the optimization program. Tests on the designed prototype show good results. 相似文献
942.
DAVID M. SHOEMAKER 《Journal of Educational Measurement》1970,7(4):255-262
Selected parameters for a negatively skewed and a normally distributed normative distribution were estimated in a post mortem item-examinee sampling investigation. Manipulated systematically were number of subtests, number of items per subtest, and number of examinees responding to each sub-test. Each item-examinee sampling procedure was replicated five times. Defining one observation as the score received by one examinee on one item, the results of this investigation support the conclusion that, in estimating parameters by item-examinee sampling, the variable of importance is not the item-examinee sampling procedure but is instead the number of observations obtained by that procedure. Degree of skewness in the normative distribution and failure to distribute all items among subtests were found to be relatively unimportant variables. 相似文献
943.
Visual signals convey emotions and intentions between individuals. Darwin underlined that human facial expressions represent a shared heritage between our species and many other social mammals. Social play is a fertile field to examine the role and the potential communicative function of facial expressions. The relaxed open-mouth (or play face) is a context-specific playful expression, which is widespread in human and non-human mammals. Here, we focus on playful communication by applying Tinbergen’s four areas of inquiry: proximate causation, ontogeny, function, and evolution. First of all we explore mimicry by focusing on its neural substrates and factors of modulation within playful and non-playful context (proximate causation). Play face is one of the earliest facial expressions to appear and be mimicked in neonates. The motor resonance between infants and their caregivers is essential later in life when individuals begin to engage in increasingly complex social interactions, including play (ontogeny). The success of a playful session can be evaluated by its duration in time. Mirroring facial expressions prolongs the session by favoring individuals to fine-tune their own motor sequences accordingly (function). Finally, through a comparative approach we also demonstrate that the elements constituting play communication and mimicry are sensitive to the quality of interindividual relationships of a species, thus reflecting the nature of its social network and style (evolution). In conclusion, our goal is to integrate Tinbergen’s four areas of ethological inquiry to provide a broader framework regarding the importance of communication and mimicry in the play domain of humans and other social mammals. 相似文献
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Konstantinos Stouraitis Despina Potari Jeppe Skott 《Educational Studies in Mathematics》2017,95(2):203-217
The study reported in this paper concerns the tensions and conflicts that teachers experience while they enact a new set of reform-oriented curricular materials into their classrooms. Our focus is οn the interactions developed in two groups of teachers in two schools for a period of a school year. We use Activity Theory to study emerging contradictions and we elaborate on the construct of dialectical opposition to understand the nature of these contradictions and their potential for teacher learning. We provide evidence that discussions about contradictions and their dialectical character in the two groups support teachers to engage differently in mathematics teaching and learning and carry potentials for shifts in the practices that evolve in their classrooms. Our study addresses empirically in the context of mathematics teaching the philosophical claim about the role of contradictions as a driving force for any dynamic system. 相似文献
947.
Jeroen Lavrijsen Ides Nicaise 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2017,63(2):257-280
An important issue in the design of secondary-level education is the balance between conveying general and occupation-specific (vocational) skills. On the one hand, vocationally oriented programmes, providing occupation-specific skills with immediate labour market relevance, have repeatedly been shown to secure safe pathways into employment. On the other hand, these programmes tend to put less emphasis on developing general knowledge, skills and competencies, including numeracy and literacy, which are foundational to lifelong learning. Hence, when the needs of the labour market change, employees who opted for a vocational track when they were at secondary school risk being less flexible in adapting to such changes later in their career. The authors of this article examine whether this results in a trade-off between short-term gains and long-term losses by considering differences in the labour market careers of vocationally and generally educated respondents in the 2012 Programme for the International Assessment of Adult Competencies (PIAAC). Their results suggest that early labour market benefits of vocational specialisation decrease over time; the authors relate this to its lower ability to equip secondary school students – future employees – with skills for lifelong learning. 相似文献
948.
We investigated differences between field-study classrooms and traditional science classrooms in terms of the learning environment and students’ attitudes to science, as well as the differential effectiveness of field-study classrooms for students differing in sex and English proficiency. A modified version of selected scales from the What Is Happening In this Class? questionnaire was used to assess the learning environment, whereas students’ attitudes were assessed with a shortened version of a scale from the Test of Science Related Attitudes. A sample of 765 grade 5 students from 17 schools responded to the learning environment and attitude scales in terms of both their traditional science classrooms and classrooms at a field-study centre in Florida. Large effect sizes supported the effectiveness of the field-studies classroom in terms of both the learning environment and student attitudes. Relative to the home school science class, the field-study class was considerably more effective for students with limited English proficiency than for native English speakers. 相似文献
949.
This study examined the similarities and differences in experienced secondary science teachers' planning, teaching, and reflecting on their teaching, when teaching in their science area of certification and when teaching in another science area. The study also focused on the influence of these teachers' content knowledge, pedagogical knowledge, and pedagogical content knowledge on their planning, teaching, and reflecting. Experienced teachers were observed and interviewed while teaching classes in their science area of certification, and in another science area they were teaching for the first or second time. Both similarities and differences in teaching were found in the two areas for all three teachers. For example, their planning and postlesson reflections were similar in both areas. In the interactive phase of teaching more differences were observed. Many aspects of their teaching resembled that of expert teachers in other studies. In the unfamiliar science area, the teachers sometimes acted like novice teachers. However, they were able to draw upon their pedagogical knowledge to provide a framework for their teaching in both science areas. Their wealth of pedagogical knowledge, and pedagogical content knowledge for general science topics, seemed to sustain them in whatever content they were teaching. Recommendations for further study and implications for teacher education are discussed. 相似文献
950.