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21.
Taking the online teaching of "inorganic chemistry" course at Dezhou University as an example, the "six steps before class, six steps in class, six steps after class" online course teaching model based on "Rain Class + Dingding Live" and an online "short class" were constructed. The main content and implementation methods of teaching design, teaching process, teaching effect, teaching reflection, teaching evaluation in online course teaching were discussed. It has been proved in practice that this model can effectively improve students' learning interest and enhance teaching effects. 相似文献
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Recent progress concerning experimental and numerical methods for practical investigations of vehicle soiling are reviewed in this paper. Wind tunnel tests and available measurement techniques are analyzed and compared with respect to their possible applications and to the results they may deliver. Different computational models for liquid films generated by spray impingement on vehicle surfaces are then considered. Models relying either on a dispersed or on a continuous approach are compared, resulting advantages and shortcomings are discussed. It is finally shown that, in spite of considerable progress during the last years, substantial work remains to be done in order to capture the complexity of real film flow dynamics for an accurate representation of wetting processes, film separation and break-up interacting with turbulent flows. 相似文献
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Rain–wind induced vibration is an aeroelastic phenomenon that occurs on the inclined cables of cable-stayed bridges and arises due to the interaction between the unsteady wind loading and the formation of water rivulets on the cable surface. A new numerical method has been developed at the University of Strathclyde to simulate the influence of the external flow field on the rivulet dynamics and vice versa. The approach is to couple a Discrete Vortex Method solver to determine the external flow field and unsteady aerodynamic loading, and a pseudo-spectral solver based on lubrication theory to model the evolution and growth of the water rivulets on the cable surface under external loading. Results of this coupled model are presented, to provide detailed information on the development of water rivulets and their interaction with the aerodynamic field. In particular, the effect of the initial water film thickness and the angle of attack in plane on the resulting rivulets are investigated. The results are consistent with previous full scale and experimental observations with rivulets forming on the upper surface of the cable only in configurations where rain–wind induced vibration has been observed. Additionally, the thickness of the lower rivulet is found to be self-limiting in all configurations. The results demonstrate that the model can be used to enhance the understanding of the underlying physical mechanisms of rain–wind-induced vibration. 相似文献
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Ning Han 《Applied Acoustics》2008,69(11):945-950
Optimal classroom acoustical design can directly enhance students’ learning efficiency. Effective acoustical designs are important and necessary to achieve a high degree of speech intelligibility for listeners. A speech intelligibility metric, U50, at different receiver positions in a classroom of 10 m × 8 m × 6 m was obtained by numerical simulations based on the mirror image model, with and without the uniform surface absorption coefficient. Comparisons show that increasing the absorption coefficient at the back wall can increase the speech intelligibility metric U50 to the largest extent in the classroom. A numerical case study was then conducted in a typical classroom of 10 m × 10 m × 3.5 m, and the speech intelligibility was assessed through a third-order polynomial of Wonyoung and Murray [Wonyoung Y, Murray H. Auralization study of optimal reverberation times for speech intelligibility for normal and hearing-impaired listeners in classrooms with diffuse sound field. J Acoust Soc Am 2006;120(2):801-7]. 相似文献
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以"碳的结构与性能及其应用"为例说明元素化学课堂教学中的方法,引导学生在复习碳元素的结构与性质的基础上,组织学生开展课堂讨论,引导学生对不断涌现的新型碳材料的关注和兴趣。同时,分组讨论碳氧化物的结构与化学性质之间关系及其有效利用,即模拟光合作用实现CO2的光催化还原和基于费托合成实现CO为原料制备燃料,鼓励和推进学生开展碳材料及其应用的本科生科研训练,实现课堂知识与科学研究衔接。 相似文献
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Considerable and significant research1 has been conducted focusing on what students know about fraction ideas.2 However, much of the research looks at student understanding following some instruction. The research3 reported in this paper differs from other studies in three significant ways: (1) the students were 9- and 10-year-old fourth graders; (2) they had not yet had an introduction to operational rules and definitions about fractions; and (3) the research design emphasized a student-centered approach. The research is based on the view that given particular conditions in which students are invited to work together and conduct thoughtful investigations with appropriate materials, they can build fundamental mathematical ideas. 相似文献
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Nitrate-selective ion-sensitive field effect transistors (ISFETs) were prepared by dip-coating the silica gate insulator surface with an ion exchanger based on bis(bathocuproin)-copper(I) nitrate in a molten mixture of docosan 1-ol and Triphenylphosphate. This sensor showed a linear response from 10−1 mol dm−3 to at least 10−5 mol dm−3 and maintained its response characteristics for as long as 5 weeks. The selectivity sequence for common anions such as Cl0−4 and Cl− followed the conventional Hofmeister series. This sensor was applied to rain water analysis. 相似文献