全文获取类型
收费全文 | 1382篇 |
免费 | 88篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 442篇 |
金属工艺 | 57篇 |
机械仪表 | 60篇 |
建筑科学 | 51篇 |
矿业工程 | 13篇 |
能源动力 | 46篇 |
轻工业 | 102篇 |
水利工程 | 5篇 |
石油天然气 | 9篇 |
无线电 | 87篇 |
一般工业技术 | 268篇 |
冶金工业 | 106篇 |
原子能技术 | 7篇 |
自动化技术 | 209篇 |
出版年
2023年 | 11篇 |
2022年 | 76篇 |
2021年 | 137篇 |
2020年 | 43篇 |
2019年 | 45篇 |
2018年 | 67篇 |
2017年 | 50篇 |
2016年 | 84篇 |
2015年 | 64篇 |
2014年 | 69篇 |
2013年 | 108篇 |
2012年 | 79篇 |
2011年 | 99篇 |
2010年 | 57篇 |
2009年 | 53篇 |
2008年 | 62篇 |
2007年 | 40篇 |
2006年 | 32篇 |
2005年 | 35篇 |
2004年 | 27篇 |
2003年 | 25篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 24篇 |
1997年 | 24篇 |
1996年 | 22篇 |
1995年 | 13篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 1篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有1474条查询结果,搜索用时 15 毫秒
151.
Branislaw Jariczuk Wieslaw Wojcik Tomasz Bialopiotrowicz 《Petroleum Science and Technology》2013,31(7):969-987
Abstract Contact angle measurements were carried out in coal / n-alkanes film - air bubble - water systems. Then theoretical an analysis of the equilibrium state of that system was carried out on the basis of the components of the surface free energy of coal of various ranks. The contact angles were measured for four ranks of Polish coal which surfaces were covered with n-alkanes film in the homological series from n-hexane to n-hexadecane. On the basis of the studies and calculations carried out we have concluded that the values of the contact angle depend on the rank of coal, a thickness of n-alkane film and its structure and the presence of water film under the air bubble. It was also found that the changes of the- values of the contact angles measured in the mentioned sytems as a function of the number of contacted air bubbles were similar to those calculated on the basis of the solution of Young equation in function of the surface free energy of coals precovered with n-alkane film. 相似文献
152.
M Sadowski HM Wisniewski M Tarnawski PB Kozlowski B Lach J Wegiel 《Canadian Metallurgical Quarterly》1999,97(2):156-164
OBJECTIVE: To examine directly the extent to which ICD-10 hyperkinetic disorder and DSM-IV attention-deficit/hyperactivity disorder (ADHD) identify the same children with the same difficulties. METHOD: Participants were children referred for symptoms of overactivity, inattention, and impulsivity, and a normal control group. Diagnostic criteria for ICD-10 hyperkinetic disorder and DSM-IV ADHD were applied retrospectively. Four groups were identified: hyperkinetic disorder and ADHD (n = 21), ADHD only (n = 22), clinic control (n = 15), and normal control (n = 19). The groups were compared on measures reflecting the central characteristics of ADHD, neurodevelopmental functioning, academic and cognitive functioning, and the presence of conduct problems. RESULTS: There is some evidence of increased symptom severity in the combined diagnostic group. Few differences emerged on measures of neurodevelopmental, academic, and cognitive functioning. Rates of conduct disturbance were similar in both ADHD groups. CONCLUSIONS: DSM-IV criteria identify a broader group of children than those identified by ICD-10. However, there is substantial overlap between the groups formed with these different criteria. 相似文献
153.
Marcin Wierszycki Krzysztof Szajek Tomasz Łodygowski Michał Nowak 《Computational Mechanics》2014,54(2):287-298
In this paper the numerical implementation of two-scale modelling of bone microstructure is presented. The study is a part of long-term project on bone remodelling which drives bone microstructure change based directly on trabeculae surface energy. The proposed approach is based on a first-order computational homogenization technique. The coincidence of macro- and micro-model kinematics is done with the use of uniform displacement and traction boundary conditions. The computational homogenization procedure is driven by a self-prepared manager which is coded in Python. The computation on real bone structure (a piece of female Wistar rat bone) is performed as well. 相似文献
154.
155.
An investigation of the through-thickness properties of carbon fibre prepreg laminates, Non-Crimp Fabric laminates and non-crimp 3D orthogonal woven composites by pull-through testing was performed. Influence of matrix system and curing temperature on the performance of the 3D woven composites was investigated. 相似文献
156.
157.
158.
159.
160.
Nuri Ersoy Tomasz Garstka Kevin Potter Michael R. Wisnom David Porter Graeme Stringer 《Composites Part A》2010,41(3):410-418
In this study, a simple two step finite element model is developed to predict the spring-in of C-sections parts made of AS4/8552 composite. The development of resin properties throughout the MRCC were derived using Group Interaction Modelling and the mechanical properties of the composite predicted by using micromechanical models. Important mechanisms during manufacturing that are effective in the formation of residual stresses and shape distortions are defined. The finite element method implemented is composed of two steps before and after the vitrification of the resin. Vitrification is treated as a point at which the material suddenly changes from the rubbery to glassy state with constant properties in each state. The spring-in angles predicted by the finite element analysis are compared to the angles measured on C-section specimens of various lay-ups and thicknesses. The correlation is good showing the validity of the assumptions adopted. 相似文献