全文获取类型
收费全文 | 467篇 |
免费 | 42篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 10篇 |
综合类 | 2篇 |
化学工业 | 112篇 |
金属工艺 | 4篇 |
机械仪表 | 20篇 |
建筑科学 | 30篇 |
矿业工程 | 3篇 |
能源动力 | 12篇 |
轻工业 | 26篇 |
水利工程 | 36篇 |
石油天然气 | 1篇 |
无线电 | 29篇 |
一般工业技术 | 94篇 |
冶金工业 | 57篇 |
原子能技术 | 1篇 |
自动化技术 | 73篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 10篇 |
2019年 | 22篇 |
2018年 | 19篇 |
2017年 | 24篇 |
2016年 | 21篇 |
2015年 | 16篇 |
2014年 | 17篇 |
2013年 | 34篇 |
2012年 | 43篇 |
2011年 | 47篇 |
2010年 | 31篇 |
2009年 | 20篇 |
2008年 | 37篇 |
2007年 | 31篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有510条查询结果,搜索用时 31 毫秒
121.
122.
123.
Jared Sponzilli John Sponzilli 《Journal of Materials Engineering and Performance》2013,22(7):1923-1928
The very nature of global sourcing means that components must carry clear and detailed specifications for material, heat treatment, and test methods. Qualified global heat treat facilities can achieve good control of not only the common features such as surface and gradient hardness, but also of microstructure, core hardness, residual stress, and other critical metallurgical parameters. This paper will discuss a new concept for material specifications and more detailed heat treatment specifications for the global marketplace. 相似文献
124.
Defife Jared A.; Conklin Carolyn Z.; Smith Janna M.; Poole James 《Canadian Metallurgical Quarterly》2010,47(3):413
Patients who frequently miss or do not show for their scheduled psychotherapy appointments create administrative and clinical difficulties, and may not be receiving effective treatment. Prior research has predominately focused on either identifying demographic and administrative factors related to patient no-show rates or evaluating the effectiveness of administrative procedures for reducing no-shows. This paper attempts to identify rates of missed appointments in clinical practice and explore more specific clinical process factors related to patient no-shows. Psychotherapists (N = 24) and their patients (N = 542) in the outpatient department of a public safety-net hospital were surveyed to examine how frequently patients missed scheduled psychotherapy appointments and for what reasons. Findings indicate that the majority of missed appointments were accounted for by patients with occasional absences (approx. 1 per month), while only a small percentage of patients missed appointments with high frequency. Patients missed their psychotherapy appointments for a number of reasons, including clinical symptoms, practical matters, motivational concerns, and negative treatment reactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
125.
The effect of solidification direction with respect to gravity on ice-templated TiO2 microstructures
Kristen L. Scotti Lauren G. Kearney Jared Burns Matthew Ocana Lucas Duros Aaron Shelhamer David C. Dunand 《Journal of the European Ceramic Society》2019,39(10):3180-3193
Unidirectional ice-templating produces materials with aligned, elongated pores via: (i) directional solidification of particle suspensions wherein suspended particles are rejected and incorporated between aligned dendrites, (ii) sublimation of the solidified fluid, and (iii) sintering of the particles into elongated walls which are templated by the ice dendrites. Most ice-templating studies utilize upward solidification techniques, where solid ice is located at the bottom of the solidification mold (closest to the cold source), the liquid suspension is above the ice, and the solidification front advances upward, against gravity. Liquid water reaches its maximum density at 4 °C; thus, liquid nearest the solid/liquid interface, at 0ºC, is less dense than warmer liquid above (up to 4 °C, above which, a density inversion occurs, and liquid density decreases with increasing temperature). The lower density liquid nearest the solidification front is thus expected to rise due to buoyancy, promoting convective fluid motion in the liquid during solidification. Here, we investigate the effect of solidification direction with respect to the direction of gravity on ice-templated microstructures to study the role of buoyancy-driven fluid motion during solidification. We hypothesize that, for upward solidification, the convective fluid motion that results from the liquid density gradient occurs near the solidification front. For downward solidification, we expect that this fluid motion occurs farther away from the solidification front. Aqueous suspensions of TiO2 nanoparticles (10–30 nm in size, 10, 15, and 21 vol.%) are solidified upward (against gravity, with ice on bottom and water on top), downward (water on bottom, ice on top), and horizontally (perpendicular to gravity). Microstructural investigation of sintered samples shows evidence of buoyancy-driven, convective fluid flow during solidification for samples solidified upwards (against gravity), including (i) tilting of the wall (and pore) orientation with respect to the induced temperature gradient, (ii) ice lens defects (cracks oriented perpendicular to the freezing direction), and (iii) radial macrosegregation. These features are not observed for downward nor horizontal solidification configurations, consistent with the hypothesis that convective fluid motion does not interact directly with the solidification front for downward solidification. 相似文献
126.
Fama Rosemary; Sullivan Edith V.; Shear Paula K.; Cahn-Weiner Deborah A.; Marsh Laura; Lim Kelvin O.; Yesavage Jerome A.; Tinklenberg Jared R.; Pfefferbaum Adolf 《Canadian Metallurgical Quarterly》2000,14(1):29
This study examined the relationships between regional brain volumes and semantic, phonological, and nonverbal fluency in 32 participants with Alzheimer's disease (AD). Object but not animal semantic fluency correlated with frontal and temporal gray matter volumes. Phonological fluency was not significantly associated with any brain volume examined. Nonverbal fluency was selectively associated with bilateral frontal gray matter volumes. Hippocampal volumes, although markedly reduced in these patients, were not related to any of the fluency measures. Results lend evidence to the importance of the frontal lobes in the directed generation of nonverbal and verbal exemplars by AD patients. Furthermore, both left and right-hemisphere regions contribute to the generation of verbal and nonverbal exemplars. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
127.
Slobodan Vujic Borislav Zajic Igor Miljanovic Aleksandar Petrovski 《Journal of Mining Science》2008,44(4):402-406
Application of GPS in mining and geology has proved to be of ever increasing importance since recently. GPS is used for positioning
both researching and exploitation drill holes, mining facilities, equipment, machines, when monitoring slopes and falls, mining
facilities dimensioning, navigation of machines, roads tracing, etc. The paper presents a pilot system for surveillance and
monitoring of energetic and technological parameters at open pit mines, developed at the “Jazovnik” open pit mine for experimental
purposes.
__________
Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 90–94, July–August, 2008. 相似文献
128.
Research findings on reading acquisition in early French immersion programs are reviewed. Findings on general reading outcomes, in English and French, are reviewed first, followed by a review of reading outcomes for students who are at risk for reading difficulty because of below-average levels of academic ability, poor first language abilities, disadvantaged socioeconomic backgrounds, and minority language status. There follows a review of studies on individual differences in reading outcomes, including research on students with or at risk for reading difficulties, and on interventions to support students with reading difficulties in immersion. Conclusions along with suggestions for future research are offered. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
129.
130.
The mountain pine beetle epidemic is destroying an extensive volume of the lodgepole pine forests being one of the most commercially harvested trees in British Columbia. The purpose of this study was to test the permeability of wood of four different classes regarding the time of the beetle attack. The experiments used the ‘‘falling water’’ unsteady-steady method of measuring superficial air permeability. The results showed that the specific permeability is not significantly different between the infested classes tested. The same conclusion could be reached for comparisons of uninfected and infested wood. 相似文献