全文获取类型
收费全文 | 260篇 |
免费 | 0篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 35篇 |
金属工艺 | 11篇 |
机械仪表 | 1篇 |
建筑科学 | 27篇 |
能源动力 | 6篇 |
轻工业 | 43篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 6篇 |
一般工业技术 | 47篇 |
冶金工业 | 42篇 |
原子能技术 | 3篇 |
自动化技术 | 29篇 |
出版年
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 24篇 |
2012年 | 16篇 |
2011年 | 14篇 |
2010年 | 18篇 |
2009年 | 26篇 |
2008年 | 13篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有260条查询结果,搜索用时 15 毫秒
81.
Research showing the protective qualities of Relational Spirituality, the experience of an ongoing dynamic personal relationship with G-d, against psychopathology in adolescents prompted the current investigation of its developmental correlates. Relational Spirituality in adolescence has been shown to have an unfolding heritable contribution and to be intertwined with a process of spiritual individuation, to which the current study adds the contribution of parents and peers to the developmental process. Participants were 615 adolescents and young adults representing a diverse range of ethnicities and religious affiliations. To measure parenting and friend variables, the Parental Bonding Instrument (PBI), Parental Spiritual Support Scale, and Friends Spiritual Support Scale were utilized. Relational Spirituality was measured using items from several subscales of the Brief Multidimensional Measure of Religiousness/Spirituality to obtain a composite score. Findings of multivariate regression analyses indicated that Maternal Spiritual Support, Paternal Care, and Friends Spiritual Support were significantly positively associated with Relational Spirituality, with Maternal Spiritual Support influencing the selection of peers who offer Friends Spiritual Support. These results underscore the importance of parents and peers in facilitating the development of Relational Spirituality, particularly through maternal openness to discussion about spirituality/religiosity and through paternal affection. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
82.
83.
84.
85.
86.
87.
Modeling the radiation of anisotropically scattering media by coupling Mie theory with finite volume method 总被引:1,自引:0,他引:1
D.N. Trivic T.J. OBrien C.H. Amon 《International Journal of Heat and Mass Transfer》2004,47(26):4343-5780
A new mathematical model and code for radiative heat transfer of particulate media with anisotropic scattering for 2-D rectangular enclosure is developed. The model is based on the coupling of (i) finite volume method for the solution of radiative transfer equation with (ii) Mie equations for the evaluation of scattering phase function. It has not been done before to the authors’ best knowledge. The predictions were compared against the only found results, published 15 years ago. For those results the S-N discrete ordinates method for the solution of radiative transfer equation and the Legendre polynomials expansions for the evaluation of scattering phase function were used. The agreement between the results is very good. The advantages of new model and code are in their straight forward application to any given particles parameters without the need for previously designed analytical expression for scattering phase function. In addition, that analytical expression, with generated expansion coefficients, is restricted and can be used only for that particular case of particle parameters. The new model was applied to the solid particles of several various coals and of an ash and the series of 2-D predictions are performed. The effects of particle size parameter and of scattering albedo on radiative heat flux and on incident radiation were analyzed. It was found that the model developed is reliable and very accurate and thus suitable for extension towards: (i) 3-D geometries, (ii) mixtures of non-gray gases with particles as well as for (iii) incorporation in computational fluid dynamics codes. 相似文献
88.
Life-cycle assessment (LCA) is the preferred methodology to assess carbon footprint per unit of milk. The objective of this case study was to apply an LCA method to compare carbon footprints of high-performance confinement and grass-based dairy farms. Physical performance data from research herds were used to quantify carbon footprints of a high-performance Irish grass-based dairy system and a top-performing United Kingdom (UK) confinement dairy system. For the US confinement dairy system, data from the top 5% of herds of a national database were used. Life-cycle assessment was applied using the same dairy farm greenhouse gas (GHG) model for all dairy systems. The model estimated all on- and off-farm GHG sources associated with dairy production until milk is sold from the farm in kilograms of carbon dioxide equivalents (CO2-eq) and allocated emissions between milk and meat. The carbon footprint of milk was calculated by expressing GHG emissions attributed to milk per tonne of energy-corrected milk (ECM). The comparison showed that when GHG emissions were only attributed to milk, the carbon footprint of milk from the Irish grass-based system (837 kg of CO2-eq/t of ECM) was 5% lower than the UK confinement system (884 kg of CO2-eq/t of ECM) and 7% lower than the US confinement system (898 kg of CO2-eq/t of ECM). However, without grassland carbon sequestration, the grass-based and confinement dairy systems had similar carbon footprints per tonne of ECM. Emission algorithms and allocation of GHG emissions between milk and meat also affected the relative difference and order of dairy system carbon footprints. For instance, depending on the method chosen to allocate emissions between milk and meat, the relative difference between the carbon footprints of grass-based and confinement dairy systems varied by 3 to 22%. This indicates that further harmonization of several aspects of the LCA methodology is required to compare carbon footprints of contrasting dairy systems. In comparison to recent reports that assess the carbon footprint of milk from average Irish, UK, and US dairy systems, this case study indicates that top-performing herds of the respective nations have carbon footprints 27 to 32% lower than average dairy systems. Although differences between studies are partly explained by methodological inconsistency, the comparison suggests that potential exists to reduce the carbon footprint of milk in each of the nations by implementing practices that improve productivity. 相似文献
89.
O. S. Es-Said A. Zeihen M. Ruprich J. Quattrocchi M. Thomas K. H.Shin M. O’Brien D. Johansen W. H. Tijoe D. Ruhl 《Journal of Materials Engineering and Performance》1995,4(3):346-357
Electrical resistivity, superficial hardness, tensile testing, and quantitative metallography techniques were used in this
study. The strip cast type 3004 aluminum alloy received sixteen different thermomechanical treatments before cups were drawn.
The top edges of the drawn cups were not flat. Rather there were high points or ears with valleys between them. The homogenization
temperature varied form 510 to 621 °C at 24 h. Some samples received an additional 426 °C/24 h homogenization anneal. Most
specimens were rolled along the longitudinal direction of the as-cast material, and some were rolled in the transverse direction.
Most samples were recrystallized at 454 °C for 24 h in addition to the homogenization treatment. Some were recrystallized
for 168 h. All samples were subsequently rolled to 0.33 mm for cup drawing and percent earing determination. The percent earing
results of some samples were less than 1.5%, but the mechanical strength was also lowered. The high-temperature recrystallization
anneal of 454 °C was the controlling factor in determining the earing and mechanical strength of the final rolled sheet. 相似文献
90.
ZP Chen A Malapetsa D Marcantonio G Mohr S Brien LC Panasci 《Canadian Metallurgical Quarterly》1996,56(11):2475-2478
We have developed a method to quantitate ERCC-2 gene expression in tumor cell lines. A mutant ERCC-2 DNA fragment (1-bp mutation) is used as a competitive DNA template in a coamplification PCR reaction with cDNA obtained by reverse transcribing DNase-free total RNA from six human tumor cell lines. The PCR products are separated on agarose gel by virtue of their differential banding pattern upon restriction enzyme digestion. Densitometric readings of the PCR products from a negative film of the gel are used to establish a linear regression curve, which in turn is used to quantitate ERCC-2 levels. Beta-actin expression is similarly quantitated. Normalized ERCC-2 gene expression (either to beta-actin or to total RNA) correlates with cytotoxicity of 1,3-bis-(2-chloroethyl)-1-nitrosourea or (2-chloroethyl)-3-sarcosinamide-1-nitrosourea, suggesting that ERCC-2 may play an important role in drug resistance in these cell lines. This method is reliable and can be used to quantitate gene expression in clinical tumor specimens. 相似文献