全文获取类型
收费全文 | 1688篇 |
免费 | 93篇 |
国内免费 | 26篇 |
专业分类
电工技术 | 13篇 |
综合类 | 236篇 |
化学工业 | 78篇 |
金属工艺 | 76篇 |
机械仪表 | 92篇 |
建筑科学 | 743篇 |
矿业工程 | 20篇 |
能源动力 | 39篇 |
轻工业 | 19篇 |
水利工程 | 30篇 |
石油天然气 | 77篇 |
武器工业 | 3篇 |
无线电 | 18篇 |
一般工业技术 | 145篇 |
冶金工业 | 164篇 |
原子能技术 | 6篇 |
自动化技术 | 48篇 |
出版年
2024年 | 6篇 |
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 22篇 |
2020年 | 25篇 |
2019年 | 18篇 |
2018年 | 17篇 |
2017年 | 41篇 |
2016年 | 37篇 |
2015年 | 38篇 |
2014年 | 99篇 |
2013年 | 95篇 |
2012年 | 118篇 |
2011年 | 137篇 |
2010年 | 101篇 |
2009年 | 107篇 |
2008年 | 126篇 |
2007年 | 120篇 |
2006年 | 117篇 |
2005年 | 94篇 |
2004年 | 80篇 |
2003年 | 62篇 |
2002年 | 43篇 |
2001年 | 49篇 |
2000年 | 30篇 |
1999年 | 26篇 |
1998年 | 17篇 |
1997年 | 24篇 |
1996年 | 17篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1985年 | 5篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1966年 | 3篇 |
1964年 | 4篇 |
1960年 | 5篇 |
1959年 | 5篇 |
1957年 | 2篇 |
1956年 | 3篇 |
1955年 | 4篇 |
1954年 | 2篇 |
排序方式: 共有1807条查询结果,搜索用时 125 毫秒
1.
This paper discusses the compressive performance of perforated brick masonry after fire exposure. Compressive strength tests of the mortar, clay perforated brick, and perforated brick masonry specimens were performed in accordance with ISO834 fire tests of different durations. The temperature distribution of the masonry materials and specimens was simulated using the finite element software ABAQUS, with the thermal parameters of masonry materials recommended by European standard Eurocode 6 and related literature. The compressive strength reduction factors of mortar and clay perforated brick exposed to different fire durations were calculated via the layered method suggested by European standard Eurocode 1. In addition, the compressive strength reduction factors after cooldown were obtained from the experimental data of the masonry materials, and by considering further reductions in the compressive strength after cooling from high temperatures. Experimental data of the masonry specimens were compared with the numerical results obtained using the reduction factors proposed in this work. The comparison revealed an overall acceptable approximation. Thus, the method presented in this paper can be used to evaluate the residual capacity of masonry structures after fire. 相似文献
2.
Ph. D. Candidate:Chen Xue-fengState Key Laboratory of Offshore Coastal Engineering Dalian University of Technology Dalian China e-mail: cxfeng @ student dlut. edu.cn 《水动力学研究与进展(B辑)》2003,15(6)
The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data. 相似文献
3.
4.
Steel box sections are usually fabricated from flat plates which are welded at the corners. The welding process can introduce residual stresses and geometric imperfections into the sections which can influence their strength. For some thin-walled sections, large periodic geometric imperfections have been observed in manufactured sections. Subsequent investigations have indicated that the imperfections are in fact buckling deformations i.e. the box section has buckled due to welding residual stresses prior to any application of external load. The welding procedure and the behaviour of the box sections under load has been modelled using a finite element analysis that accounts for both geometric and material non-linearities. Tests have been carried out on box sections with a range of width to thickness ratios for the plate elements. Modelling has been shown to give good correlation with the test results. The conditions for buckling to take place as a result of the welding process have been established. A design method has been proposed. 相似文献
5.
Xue Weichen Lu Zhitao 《常州工学院学报》1993,(2)
本文提出了部分预应力砼构件基于两类极限状态直接控制的设计方法,并给出了具体的设计公式和设计步骤。同时,还对预应力砼超静定结构中的部分预应力砼构件的设计方法进行了说明。本文方法基本属一次性设计且具有较为经济的特点。 相似文献
6.
This article reports research intended to assess and extend a recent theory of peer responses to low-performing team members (J. A. LePine & L. Van Dyne, 2001a). An instrument that assesses 4 types of peer responses to low performers (compensating for, training, motivating, and rejecting) was developed and then cross-validated in a subsequent study. Results of the study supported the validity of the peer responses measure and were generally consistent with the attributional theory of peer responses. Low-performer characteristics influenced the peer responses. These effects were mediated in part by peer attributions, affect, and cognitions, which explained variance in the peer responses over and above the variance explained by respondents' personality characteristics (i.e., The Big Five). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
No authorship indicated 《Canadian Metallurgical Quarterly》1985,40(2):221
The APA Membership Committee announces that the 1,838 persons listed here were elected to initial membership in the American Psychological Association as of January 1, 1985. Of these, 1,392 were elected as Members, and 446 as Associate members. Though not all of them have validated their election by payment of initial dues, all but a few will eventually do so. In addition, in accordance with Article II, Section 8, of the Bylaws, 316 Associate members were transferred to Member status as of January 1, 1985. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
9.
10.
The paper deals with dynamic buckling of thin-walled structures (plates and beam-columns with open cross-section) subjected to compressive rectangular pulse loading. The local, global and interactive dynamic buckling was analysed. Author proposes the new criterion for critical amplitude of pulse loading leading to stability loss. The proposed criterion is a modification of quasi-bifurcation criterion formulated by Kleiber, Kotula and Saran. Results obtained using proposed criterion were compared with other well-known criteria (Volmir (V) and Budiansky–Hutchinson (B–H) criterion). 相似文献