全文获取类型
收费全文 | 4923篇 |
免费 | 277篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 58篇 |
综合类 | 8篇 |
化学工业 | 969篇 |
金属工艺 | 62篇 |
机械仪表 | 82篇 |
建筑科学 | 183篇 |
矿业工程 | 7篇 |
能源动力 | 165篇 |
轻工业 | 368篇 |
水利工程 | 57篇 |
石油天然气 | 35篇 |
无线电 | 406篇 |
一般工业技术 | 1223篇 |
冶金工业 | 625篇 |
原子能技术 | 14篇 |
自动化技术 | 946篇 |
出版年
2024年 | 13篇 |
2023年 | 60篇 |
2022年 | 98篇 |
2021年 | 145篇 |
2020年 | 116篇 |
2019年 | 123篇 |
2018年 | 126篇 |
2017年 | 137篇 |
2016年 | 163篇 |
2015年 | 135篇 |
2014年 | 188篇 |
2013年 | 341篇 |
2012年 | 321篇 |
2011年 | 397篇 |
2010年 | 301篇 |
2009年 | 291篇 |
2008年 | 323篇 |
2007年 | 255篇 |
2006年 | 223篇 |
2005年 | 195篇 |
2004年 | 158篇 |
2003年 | 144篇 |
2002年 | 136篇 |
2001年 | 70篇 |
2000年 | 63篇 |
1999年 | 62篇 |
1998年 | 56篇 |
1997年 | 56篇 |
1996年 | 50篇 |
1995年 | 46篇 |
1994年 | 46篇 |
1993年 | 39篇 |
1992年 | 39篇 |
1991年 | 23篇 |
1990年 | 28篇 |
1989年 | 19篇 |
1988年 | 16篇 |
1987年 | 31篇 |
1986年 | 17篇 |
1985年 | 30篇 |
1984年 | 17篇 |
1983年 | 6篇 |
1982年 | 14篇 |
1981年 | 22篇 |
1979年 | 5篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 5篇 |
1973年 | 6篇 |
排序方式: 共有5208条查询结果,搜索用时 0 毫秒
121.
122.
123.
Barry Haseltine Tor‐Ulf Weck Lars Meyer Rob van der Pluijm Oliver Dupont Christoph Alfes Wolfram Jaeger John Roberts Jonathan Silver Dirk Martens O. Pfeffermann Bastian Drewes Erhard Gunkler Jan Kubica Nebojsa Mojsilovic Erhard Gunkler Johann Marx Armin Ohler Hipolito Sousa Rui Sousa Romeu S. Vicente J. R. Mendes Silva Roberto Capozucca 《Mauerwerk》2011,15(6):348-361
124.
125.
126.
Jonathan Fikes Seong Jin Park Randall M. German 《Metallurgical and Materials Transactions B》2011,42(1):202-209
The equilibrium state of the liquid–solid structure during liquid-phase sintering (LPS) is pondered with respect to minimum energy geometries. Besides the solid–liquid ratio, several interfacial energies determine the most stable geometric configuration. In this study, we rely on the attributes of the copper or nickel as the liquid, tungsten as the solid, and vapor to solve for terminal configurations that include liquid pools inside the solid grains. Surface evolution is enabled using a stepwise computer program[1] to rearrange and reshape small grain clusters reflective of LPS based on a preset combination of wetting and dihedral angles. The findings show how different interfacial energies, as a result of oxidation or impurity segregation, play a role in determining the final geometry. The specific concern is identification of situations in which a liquid is stable inside the solid, as observed in some LPS materials. 相似文献
127.
Abu Syed H. Kabir Xinjin Cao Javad Gholipour Priti Wanjara Jonathan Cuddy Anand Birur Mamoun Medraj 《Metallurgical and Materials Transactions A》2012,43(11):4171-4184
The effects of postweld heat treatment (PWHT) on 3.2-mm- and 5.1-mm-thick Ti-6Al-4V butt joints welded using a continuous wave (CW) 4-kW Nd:YAG laser welding machine were investigated in terms of microstructural transformations, welding defects, and hardness, as well as global and local tensile properties. Two postweld heat treatments, i.e., stress-relief annealing (SRA) and solution heat treatment followed by aging (STA), were performed and the weld qualities were compared with the as-welded condition. A digital image correlation technique was used to determine the global tensile behavior for the transverse welding samples. The local tensile properties including yield strength and maximum strain were determined, for the first time, for the laser-welded Ti-6Al-4V. The mechanical properties, including hardness and the global and local tensile properties, were correlated to the microstructure and defects in the as-welded, SRA, and STA conditions. 相似文献
128.
129.
Linkenauger Sally A.; Witt Jessica K.; Stefanucci Jeanine K.; Bakdash Jonathan Z.; Proffitt Dennis R. 《Canadian Metallurgical Quarterly》2009,35(6):1649
Previous research has suggested that perceived distances are scaled by the action capabilities of the body. The present studies showed that when “reachability” is constrained due to a difficult grasp required to pick up an object, perceived distance to the object increases. Participants estimated the distances to tools with handle orientations that made them either easy or difficult to grasp with their dominant and nondominant hands. Right-handed participants perceived tools that were more difficult to grasp to be farther away than tools that were easier to grasp. However, perceived distance did not differ in left-handed participants. These studies suggest that, when reaching toward a target, the distance to that target is scaled in terms of how far one can effectively reach, given the type of reaching posture that is executed. Furthermore, this effect is modulated by handedness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
130.
Kanter Jonathan W.; Rusch Laura C.; Landes Sara J.; Holman Gareth I.; Whiteside Ursula; Sedivy Sonja K. 《Canadian Metallurgical Quarterly》2009,46(2):220
To improve cognitive and behavioral therapies (CBT) for depression, several approaches recommend an increased focus on the occurrence of problems as they occur in the therapeutic relationship or in relation to the live therapy process, referred to as present-focused. A lingering question has been the degree to which CBT therapists already engage in present-focused work. This study utilized sessions from recent trials of CBT for depression and, in Phase I, raters identified present-focused interventions on a turn-by-turn basis. Phase II raters used a qualitative analysis to determine categories of present-focused interventions. Results indicated that therapists rarely focused on the therapeutic relationship; when they did, it was often transient and lacking in the elaborations suggested by newer approaches. Therapists more often performed therapy process and emotion focused interventions, but these also tended to lack elaboration. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献