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排序方式: 共有689条查询结果,搜索用时 15 毫秒
681.
682.
随着“互联网+”时代的到来,移动互联网技术给教育领域带来重大的变革,充分合理地应用互联网技术能更好的推动技工院校课程教学改革。蓝墨云班课作为一种基于互联网技术的移动教学平台,将其应用于《汽车材料》课程教学中,能很好地形成线上和线下一体融合的教学模式,提高学生课堂参与度,打造生动、高效、一体的课程学习环境。 相似文献
683.
传动轴中间轴是传动轴的重要组成部分,主要用来传递发动机扭矩,传动轴中间轴的设计要依照不同设计要求,综合考虑影响设计的各种影响因素,本文主要针对传动轴中间轴现状展开分析,包括分析传动轴的材料,中间轴分类和热加工工艺。 相似文献
684.
随着社会经济的快速发展,环境污染与能源短缺问题愈发突出,对汽车工业未来的发展带来了巨大挑战。汽车工业要想实现可持续发展,首先需要解决的一大问题就是节能减排,而实现节能减排的关键就是汽车轻量化。汽车轻量化的实现途径之一,就是使用轻质金属材料,它不仅可以达到节能减排的目的,部分材料还可以提高车身的安全性与耐久性。基于此,本文主要探究了金属材料在汽车轻量化中的应用与发展,以供大家参考。 相似文献
685.
文章以华东某机场的复合道面工程为例,基于沥青层模量一温度的关系,建立三维有限元模型,得到不同温度下的修正系数,并通过非线性回归分析得到修正系数与温度的关系式,同时采用实测HWD弯沉数据验证了该温度修正模型的正确性。 相似文献
686.
Composite marine propellers improve hydrodynamic efficiency by inducing bend-twist coupling and allowing for passive pitch changes. One critical limitation, however, is the extent to which a composite propeller blade can deform and cause a pitch change without incurring structural failure. Recent numerical studies showed that curvilinear tows could improve the structural response of a composite blade by lowering its deflection or stress and strain required to induce a pitch change, but no experimental validation has been carried out before. The current study, thus, presents the manufacture of composite sandwich hydrofoils made with steered tows using automated fibre placement and validates the curvilinear tow benefits. Two hydrofoils were optimised with straight and curved fibre path layups, respectively and were manufactured for mechanical testing. The manufacturing complications arising from steering curvilinear tows in a three-dimensional convex mould are also discussed in the paper. The study found that significant tow buckling occurred near the tool cavity edge due to excessive steering radius during manufacture. The follow-up structural cantilevered tests showed that the experimental results were consistent with the FE predictions despite the presence of some manufacturing defects. The experiment agreed that the hydrofoil manufactured with curved tows achieved a similar tip twist but a significant reduction in deflection and critical principal strains compared to the hydrofoil made with straight tows. The use of a foam core reduced the overall weight of the sandwich hydrofoils by about 25% compared to that of a fully-carbon composite hydrofoil, and the numerical analysis showed that the core shear failure induced by transverse shear stresses was unlikely to occur. 相似文献
687.
The present study investigates the collapse performance of composite-repaired cylinders with internal metal loss subjected to external pressure. Three groups of intact, thinned, and repaired cylinders were designed, analytically verified, fabricated, geometrically measured, externally tested, and numerically modeled. Each group had three nominally identical cylinders to ensure the repeatability of experiments. The cylinders had the same end closure, effective length, total length, external radius, and intact thickness for an equivalent comparison. The thinned cylinder was considered as the intact cylinder with internal metal loss, whereas the repaired cylinder was considered as the thinned cylinder with composite reinforcement. The results indicated that the external loading capacity of cylinders with internal metal loss could be fully restored and even enhanced by composite reinforcement. Composite-repaired cylinders are much less sensitive to initial geometrical imperfections than intact cylinders. 相似文献
688.
689.
With the rapid growth of the offshore engineering sector, studying the durability of offshore structures becomes primordial. Evaluating experimentally the coupling between mechanical and chemical degradation of the cement-based materials and structures is a challenging task because it requires tracking the evolution of the micro-mechanisms associated with the degradation in real time for long periods. To tackle this issue, a numerical approach is proposed, based on the micromechanics and the coupling between a creep-damage model and a chemical model at the microstructural scale. The seawater chemical effect on cement paste is simulated by considering the penetration fronts of the aggressive water and the attack by layers in the material. The aim of this study is to provide a tool for the rapid mechanical evaluation of the offshore structures and therefore a tool that can be used for the optimization and the development of durable marine constructions. The results highlight the competition between protective and damaged layers formed due to seawater attack, and that the global mechanical behaviour strongly depends on the chemically modified phases in the cement paste. 相似文献