全文获取类型
收费全文 | 12945篇 |
免费 | 785篇 |
专业分类
公路运输 | 4443篇 |
综合类 | 3875篇 |
水路运输 | 3044篇 |
铁路运输 | 1891篇 |
综合运输 | 477篇 |
出版年
2024年 | 49篇 |
2023年 | 107篇 |
2022年 | 210篇 |
2021年 | 376篇 |
2020年 | 412篇 |
2019年 | 291篇 |
2018年 | 227篇 |
2017年 | 297篇 |
2016年 | 268篇 |
2015年 | 470篇 |
2014年 | 981篇 |
2013年 | 743篇 |
2012年 | 1133篇 |
2011年 | 1236篇 |
2010年 | 949篇 |
2009年 | 849篇 |
2008年 | 862篇 |
2007年 | 1171篇 |
2006年 | 992篇 |
2005年 | 615篇 |
2004年 | 376篇 |
2003年 | 228篇 |
2002年 | 173篇 |
2001年 | 160篇 |
2000年 | 120篇 |
1999年 | 56篇 |
1998年 | 42篇 |
1997年 | 54篇 |
1996年 | 39篇 |
1995年 | 32篇 |
1994年 | 40篇 |
1993年 | 24篇 |
1992年 | 25篇 |
1991年 | 20篇 |
1990年 | 21篇 |
1989年 | 29篇 |
1988年 | 12篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 14篇 |
1984年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
191.
������ѩ�ڳ��е�·��ͨ��ͻ���¹�Ԥ�� 总被引:1,自引:0,他引:1
�����£��̹����������ԣ���¶¶ 《交通运输系统工程与信息》2016,16(6):216-221
192.
To ensure the safety of navigating ship, working loads and structural load-carrying capacity are two important aspects. In the present paper, a total simulation system combing load calculation and structural collapse analysis is applied to simulate progressive collapse behaviour of a single-hull Kamsarmax type bulk carrier. A three dimensional singularity distribution method is adopted to calculate pressure distribution with time history. A mixed structural model, collapse part simulated by ISUM elements and remaining part by elastic FEM elements with relative coarse mesh, is proposed for collapse analysis. Progressive collapse behaviour obtained by ISUM is good agreement with that by nonlinear software package, MARC. However, the calculation time of ISUM analysis is about 1/70 of MARC analysis. The applicability to structure system, high accuracy and sufficient efficiency of ISUM had been demonstrated. 相似文献
193.
哈大客专运粮河特大桥跨既有线连续梁采用平转法施工,为确保转体顺利进行,转体前进行了T构不平衡重试验分析,文中介绍了一种转体构件不平衡重的测试方法和应用过程。结果表明,方法有效可行,可供同类工程借鉴。 相似文献
194.
This paper studies the assignment of long-distance passenger traffic on a highway corridor network. First, we propose a traditional model for the long-distance traffic assignment considering interactions with local commuter traffic. It addresses the effect of local networks on highway corridors. An iterative algorithm is developed to solve for the exact solution. Then, to address the potential computational issues that arise therein, a decomposition method is proposed by introducing a new concept of corridor elasticity. An assignment procedure for long-distance passenger traffic is developed accordingly. Numerical tests show that the proposed decomposition method makes significant improvements in computational performance at a small loss of optimality. This decomposition method well approximates the exact assignment from the traditional formulation, especially when the highway corridors are near-saturation. The proposed decomposition method appears practical for application. 相似文献
195.
Catenary risers have an interaction zone with the seabed, usually referenced as flowline. Movements in this region can be induced by sea currents and large offsets in floating unit, leading to touchdown position changes and affecting internal loads along riser length. In this work the contact flowline-seabed is modeled including sliding and rolling friction. Case studies involving large offsets in floating unit and lateral sea currents are solved to better understand the consequences of possible rolling and large sliding. The riser is modeled using a geometrically-exact finite element beam model. The contact is addressed with a new technique to include rotation movements from underlying beam models. This leads to global riser models including complex kinematics, being able to represent scenarios with alternating sliding/rolling and its consequences on internal loads of riser structure. A parametric study is performed to measure the influence of the friction coefficient in tension and torsion along typical flexible pipe and steel pipe catenary risers. 相似文献
196.
文章结合某连续刚构桥,通过分析应力波反射法的检测原理,试将该检测方法用于桥梁竖向预应力筋波纹管注浆效果的评价,结果表明采用该方法检测桥梁单根预应力筋管道注浆密实度是一种高效、便捷、经济的检测方法。 相似文献
197.
198.
软弱富水地层浅埋暗挖隧道地表沉降和支护结构受力的模型试验 总被引:1,自引:1,他引:0
张杰 《铁道标准设计通讯》2018,(3):107-113
以莞惠城际轨道交通工程项目GZH-5标段中DK32+300~DK32+927.303段为背景,通过2组模型试验,其中一组无超前注浆,另一组进行超前注浆,研究软弱富水地层浅埋暗挖隧道地表沉降和支护结构受力规律及超前注浆对其受力变形造成的影响,最后,针对软弱富水地层浅埋暗挖隧道施工,提出几点隧道工程设计和施工的相关建议。 相似文献
199.
以青岛蓝色硅谷城际轨道交通高架桥预制U形梁为工程背景,运用有限元方法对比分析先张法和后张法预制U形梁内力、应力状态及变形3方面的力学性能。对先张法和后张法U形梁进行静载试验,详细分析试验荷载下U形梁的刚度及抗裂性等指标。结果表明,先张法预应力U形梁力学性能优越,具有推广应用潜力。 相似文献
200.
本文介绍了ISO 9943-2009国际标准和GBT 20846-2007中国国家标准中对船用厨房和具有烹调设备的配餐室的通风计算及空气处理中提出的送风量的计算方法,提出另一种更易于大家理解和接受的简易计算方法和空气处理过程,供工程技术及设计研究人员参考。 相似文献