全文获取类型
收费全文 | 358篇 |
免费 | 32篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 7篇 |
综合类 | 85篇 |
化学工业 | 18篇 |
金属工艺 | 6篇 |
机械仪表 | 11篇 |
建筑科学 | 143篇 |
矿业工程 | 4篇 |
能源动力 | 8篇 |
轻工业 | 11篇 |
水利工程 | 10篇 |
石油天然气 | 9篇 |
武器工业 | 2篇 |
无线电 | 3篇 |
一般工业技术 | 60篇 |
冶金工业 | 1篇 |
原子能技术 | 1篇 |
自动化技术 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 15篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 27篇 |
2013年 | 33篇 |
2012年 | 39篇 |
2011年 | 30篇 |
2010年 | 28篇 |
2009年 | 18篇 |
2008年 | 23篇 |
2007年 | 31篇 |
2006年 | 23篇 |
2005年 | 16篇 |
2004年 | 9篇 |
2003年 | 2篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有404条查询结果,搜索用时 15 毫秒
31.
32.
设纵肋钢箱混凝土轴压短柱试验研究 总被引:1,自引:0,他引:1
为研究钢箱内填混凝土、含钢率以及钢箱内纵向加劲肋是否开孔等对钢箱混凝土轴压短柱力学性能的影响,进行了3个钢箱混凝土和1个钢箱轴压短柱的模型试验。试验结果表明:钢箱内填混凝土可有效提高试件的轴压刚度和承载力;纵肋可充分参与构件整体受力,其中纵肋开孔试件变形能力更强,延性更好。与设纵肋薄壁钢管混凝土短柱现有试验数据对比表明:随含钢率的提高,混凝土强度提高系数有所增大。建议设纵肋钢箱混凝土轴压短柱承载力可按叠加原理进行计算,其中钢箱截面积可计入纵肋的面积。 相似文献
33.
对欧洲规范Eurocode 3的组件法进行改进,考虑了带加劲肋的外伸端板与柱翼缘之间的拉伸刚度组件,使之可用于计算门式刚架结构中最常见的设置了加劲肋外伸端板连接节点的初始转动刚度,同时给出了该类节点的初始转动刚度的简化分析模型以及详细计算步骤,并通过试验进行了验证.结果表明:所提出的方法计算结果与试验结果吻合较好,可用... 相似文献
34.
Du Baisong Ge Yaojun Zhou Zheng 《Frontiers of Architecture and Civil Engineering in China》2007,1(3):293-297
In this paper, an analytical method is proposed for calculating torsional constants for complicated thin-walled cross-sections
with arbitrary closed or open rib stiffeners. This method uses the free torsional theory and the principle of virtual work
to build governing equilibrium equations involving unknown shear flows and twisting rate. After changing the form of the equations
and combining these two unknowns into one, torsional function, which is a function of shear flow, shear modulus, and twisting
rate, is included in the governing equations as only one of the unknowns. All the torsional functions can be easily obtained
from these homogeneous linear equations, and torsional constants can be easily obtained from the torsional functions. The
advantage of this method is that we can easily and directly obtain torsional constants from the torsional functions, rather
than the more sophisticated shear flow and twisting rate calculations. Finally, a complicated thin-walled cross-section is
given as a valid numerical example to verify the analytical method, which is much more accurate and simpler than the traditional
finite element method.
__________
Translated from Journal of Tongji University (Natural Science), 2006, 34(9): 1 170–1 174 [译自: 同济大学学报 (自然科学版)] 相似文献
35.
The nonsingular H-matrices play an important role in the study of the matrix theory and the iterative method of systems of linear equations, etc. It has always been searched how to verify nonsingular H-matrices. In this paper, nonsingular H-matrices is studies by applying diagonally dominant matrices, irreducible diagonally dominant matrices and comparison matrices and several practical criteria for identifying nonsingular H-matrices are obtained. 相似文献
36.
In this research, the free vibration analysis of cylindrical shells with circumferential stiffeners, i.e. rings with non-uniform stiffeners eccentricity and unequal stiffeners spacing is investigated using analytical, experimental and finite elements (FE) methods. Ritz method is applied in analytical solution while stiffeners treated as discrete elements. The polynomial functions are used for Ritz functions and natural frequency results for simply supported stiffened cylindrical shell with equal rings spacing and constant eccentricity is compared with other's analytical and experimental results, which showed good agreement. Also, a stiffened shell with unequal rings spacing and non-uniform eccentricity with free–free boundary condition is considered using analytical, experimental and FE methods. In experimental method, modal testing is performed to obtain modal parameters, including natural frequencies, mode shapes and damping in each mode. In FE method, two types of modeling, including shell and beam elements and solid element are used, applying ANSYS software. The analytical and the FE results are compared with the experimental one, showing good agreements. Because of insufficient experimental modal data for non-uniformly stiffeners distribution, the results of modal testing obtained in this study could be as useful reference for validating the accuracy of other analytical and numerical methods for free vibration analysis. 相似文献
37.
许醇义 《苏州科技学院学报(工程技术版)》1994,(3)
本文利用能量原理研究了具有加劲肋的四边简支矩形板的稳定性,比较了横向与纵向设置加劲肋对板稳定性的作用。 相似文献
38.
设A=(aij)∈Cn×n,若α∈(0,1),使i∈N+,有|aii|≥Riα(A)S1i-α(A)成立,则称A为Ostrowski对角占优矩阵;推广Ostrowski对角占优矩阵的概念到广义Ostrowski对角占优矩阵;得到了判别非奇异H-矩阵的一个判定方法.进一步丰富和完善了Ostrowski对角占优矩阵和非奇异H-矩阵的理论. 相似文献
39.
Buckling-restrained braced frames (BRBFs) are used as lateral-load resisting systems in seismic design. The braces in BRBFs are connected to beams and columns by gusset plate connections, and can yield in both tension and compression instead of buckling. Although tests of buckling-restrained braces (BRBs) have demonstrated their ability to withstand significant inelastic axial deformation, large-scale BRBF tests have exhibited central gusset plate buckling before BRBs develop the ultimate compressive strength. To extend and better understand the experimental work, this paper presents an analytical study of the compressive behavior for BRBF central gusset plate connections using the finite element computer program ABAQUS. A model of a previously tested BRBF is conducted to predict experimental buckling load of the central gusset plate and verify the accuracy of a simple model of a central gusset plate connection including a beam and part of the BRB. The out-of-plane deformation of the central gusset plate resembles the buckled shape of a gusset plate with low bending rigidity provided by the BRB end. The experimental buckling load of the central gusset plate cannot be predicted based on the AISC-LRFD approach with an effective column length factor of 1.2. Therefore, a parametric study on the compressive strength of BRBF central gusset plate connections is conducted with various gusset plate dimensions and free-edge stiffeners. An inelastic plate buckling equation together with coefficient charts is proposed to predict ultimate load. For gusset plates with sufficient free-edge stiffener rigidity, the yield load can be developed and increased to the post-yield strength level. A required free-edge stiffener size is also recommended for BRBF central gusset plates to develop compressive yield load. 相似文献
40.