全文获取类型
| 收费全文 | 2124篇 |
| 免费 | 36篇 |
专业分类
| 电工技术 | 38篇 |
| 综合类 | 3篇 |
| 化学工业 | 471篇 |
| 金属工艺 | 58篇 |
| 机械仪表 | 27篇 |
| 建筑科学 | 76篇 |
| 矿业工程 | 19篇 |
| 能源动力 | 46篇 |
| 轻工业 | 279篇 |
| 水利工程 | 8篇 |
| 石油天然气 | 4篇 |
| 无线电 | 178篇 |
| 一般工业技术 | 392篇 |
| 冶金工业 | 307篇 |
| 原子能技术 | 37篇 |
| 自动化技术 | 217篇 |
出版年
| 2024年 | 17篇 |
| 2023年 | 20篇 |
| 2022年 | 53篇 |
| 2021年 | 85篇 |
| 2020年 | 50篇 |
| 2019年 | 51篇 |
| 2018年 | 51篇 |
| 2017年 | 50篇 |
| 2016年 | 71篇 |
| 2015年 | 46篇 |
| 2014年 | 72篇 |
| 2013年 | 94篇 |
| 2012年 | 99篇 |
| 2011年 | 107篇 |
| 2010年 | 85篇 |
| 2009年 | 85篇 |
| 2008年 | 75篇 |
| 2007年 | 71篇 |
| 2006年 | 54篇 |
| 2005年 | 52篇 |
| 2004年 | 51篇 |
| 2003年 | 42篇 |
| 2002年 | 22篇 |
| 2001年 | 33篇 |
| 2000年 | 34篇 |
| 1999年 | 26篇 |
| 1998年 | 82篇 |
| 1997年 | 52篇 |
| 1996年 | 40篇 |
| 1995年 | 36篇 |
| 1994年 | 28篇 |
| 1993年 | 32篇 |
| 1992年 | 22篇 |
| 1991年 | 19篇 |
| 1990年 | 16篇 |
| 1989年 | 18篇 |
| 1988年 | 14篇 |
| 1987年 | 30篇 |
| 1986年 | 14篇 |
| 1985年 | 26篇 |
| 1984年 | 19篇 |
| 1983年 | 11篇 |
| 1982年 | 19篇 |
| 1981年 | 11篇 |
| 1980年 | 16篇 |
| 1978年 | 13篇 |
| 1977年 | 20篇 |
| 1976年 | 15篇 |
| 1972年 | 9篇 |
| 1970年 | 10篇 |
排序方式： 共有2160条查询结果，搜索用时 0 毫秒
41.
42.
Y.‐S. Hu Y.‐G. Guo R. Dominko M. Gaberscek J. Jamnik J. Maier 《Advanced materials (Deerfield Beach, Fla.)》2007,19(15):1963-1966
43.
44.
A. Lasagni M. Seyler C. Holzapfel W.&#x;F. Maier F. Mücklich 《Advanced materials (Deerfield Beach, Fla.)》2005,17(18):2228-2232
45.
J.P. Nair E. Wachtel I. Lubomirsky J. Fleig J. Maier 《Advanced materials (Deerfield Beach, Fla.)》2003,15(24):2077-2081
46.
47.
It is common practice in the hydropower industry to either shorten the maintenance duration or to postpone maintenance tasks in a hydropower system when there is expected unserved energy based on current water storage levels and forecast storage inflows. It is therefore essential that a maintenance scheduling optimizer can incorporate the options of shortening the maintenance duration and/or deferring maintenance tasks in the search for practical maintenance schedules. In this article, an improved ant colony optimization-power plant maintenance scheduling optimization (ACO-PPMSO) formulation that considers such options in the optimization process is introduced. As a result, both the optimum commencement time and the optimum outage duration are determined for each of the maintenance tasks that need to be scheduled. In addition, a local search strategy is presented in this article to boost the robustness of the algorithm. When tested on a five-station hydropower system problem, the improved formulation is shown to be capable of allowing shortening of maintenance duration in the event of expected demand shortfalls. In addition, the new local search strategy is also shown to have significantly improved the optimization ability of the ACO-PPMSO algorithm. 相似文献
48.
W. Abuzaid A. Oral H. Sehitoglu J. Lambros H. J. Maier 《Fatigue & Fracture of Engineering Materials & Structures》2013,36(8):809-826
In polycrystalline metals, microstructural features such as grain boundaries (GBs) influence fatigue crack initiation. Stress and strain heterogeneities, which arise in the vicinity of GBs, can promote the nucleation of fatigue cracks. Because of variations in grain size and GB types, and consequently variations in the local deformation response, scatter in fatigue life is expected. A deeper quantitative understanding of the early stages of fatigue crack nucleation and the scatter in life requires experimental and modelling work at appropriate length scales. In this work, experiments are conducted on Hastelloy X under fatigue conditions, and observations of fatigue damage are reported in conjunction with measurements of local strains using digital image correlation. We use a recent novel fatigue model based on persistent slip band–GB interaction to investigate the scatter in fatigue lives and shed light into the critical types of GBs that nucleate cracks. Experimental tools and methodologies, utilizing ex situ digital image correlation and electron backscatter diffraction, for high resolution deformation measurements at the grain level are also discussed in this paper and related to the simulations. 相似文献
49.
Artur Ciesielski Artur R. Stefankiewicz Felix Hanke Mats Persson Jean‐Marie Lehn Paolo Samorì 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(3):286-286
Hierarchical self‐assembly of small abiotic molecular modules interacting through noncovalent forces is increasingly being used to generate functional structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H‐bond supramolecular architectures, especially in H‐bonded supramolecular polymers, can be achieved by using conformationally rigid molecular modules undergoing self‐assembly through strong H‐bonds. Their binding strength depends on the multiplicity of the H‐bonds, the nature of donor/acceptor pairs and their secondary attractive/repulsive interactions. Here a functionalized molecular module is described, which is capable of self‐associating through self‐complementary H‐bonding patterns comprising four strong and two medium‐strength H‐bonds to form dimers. The self‐association of these phenylpyrimidine‐based dimers through directional H‐bonding between two lateral pyridin‐2(1H)‐one units of neighboring molecules allows the formation of highly compact 1D supramolecular polymers by self‐assembly on graphite. A concentration‐dependent study by scanning tunneling microscopy at the solid–liquid interface, corroborated by dispersion‐corrected density functional studies, reveals the controlled generation of either linear supramolecular 2D arrays, or long helical supramolecular polymers with a high shape persistence. 相似文献
50.