全文获取类型
收费全文 | 1002篇 |
免费 | 51篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 2篇 |
化学工业 | 346篇 |
金属工艺 | 12篇 |
机械仪表 | 11篇 |
建筑科学 | 52篇 |
能源动力 | 13篇 |
轻工业 | 203篇 |
水利工程 | 6篇 |
石油天然气 | 2篇 |
无线电 | 51篇 |
一般工业技术 | 153篇 |
冶金工业 | 66篇 |
原子能技术 | 4篇 |
自动化技术 | 130篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 43篇 |
2021年 | 42篇 |
2020年 | 38篇 |
2019年 | 18篇 |
2018年 | 29篇 |
2017年 | 27篇 |
2016年 | 31篇 |
2015年 | 31篇 |
2014年 | 42篇 |
2013年 | 74篇 |
2012年 | 64篇 |
2011年 | 69篇 |
2010年 | 64篇 |
2009年 | 61篇 |
2008年 | 56篇 |
2007年 | 55篇 |
2006年 | 46篇 |
2005年 | 50篇 |
2004年 | 33篇 |
2003年 | 21篇 |
2002年 | 23篇 |
2001年 | 11篇 |
2000年 | 22篇 |
1999年 | 12篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 6篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
1934年 | 3篇 |
排序方式: 共有1055条查询结果,搜索用时 15 毫秒
981.
Fournet Nathalie; Moreaud Olivier; Roulin Jean Luc; Naegele Bernadette; Pellat Jacques 《Canadian Metallurgical Quarterly》2000,14(2):247
Cognitive impairments in Parkinson's disease (PD) could be explained by a central executive (CE) deficit in A. D. Baddeley's (1986) working memory model. To test this hypothesis, verbal, spatial, and double span tasks were given to 12 medicated PD patients and control participants, with varying recall delays. The double span task was assigned to explore the coordinating and integrating function of the CE, and lengthening the recall delay was expected to implicate more attentional resources. PD patients had lower spans relative to controls in all tasks. However, the more specific implication of the CE was difficult to prove. One reason could be that PD patients were on dopaminergic treatment when tested. To control this effect, 12 PD patients on and off medication were studied in a second experiment using the same tasks. PD patients off medication had lower spans only in the double task; this result underlines the role of dopamine on working memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
982.
Combes S González I Déjean S Baccini A Jehl N Juin H Cauquil L Gabinaud B Lebas F Larzul C 《Meat science》2008,80(3):835-841
Meat from rabbits reared either according to a standard (STAND) or a high quality norm (LABEL) or a low growth breeding (RUSSE) system were submitted to a sensory evaluation and to a large set of physicochemical measurements (weight of retail cuts, colour parameters, ultimate pH, femur flexure test, Warner-Bratzler shear test, water holding capacities and cooking losses). STAND rabbit meat exhibited the most juicy meat in back and in leg (p<0.01). Leg tenderness significantly decreased (p<0.001) in the rank order STAND>LABEL>RUSSE. Canonical correlation analysis showed strong correlations between physicochemical and sensory variables (R(2)=0.73 and 0.68 between the two first pairs of canonical variates). Especially, sensory tenderness and WB shear test variables assessed on raw longissimus muscle (LL) were correlated. Fibrous attribute in back was correlated with cooking loss in LL. When analysed separately only RUSSE rabbits exhibited the same relations between variables as those calculated in whole dataset. 相似文献
983.
Nutritional depletion in n‐3 PUFA in apoE knock‐out mice: A new model of endothelial dysfunction associated with fatty liver disease 下载免费PDF全文
984.
Philippe Frederick L.; Vallerand Robert J.; Houlfort Nathalie; Lavigne Geneviève L.; Donahue Eric G. 《Canadian Metallurgical Quarterly》2010,98(6):917
Our purpose in this research was to investigate the role of passion (Vallerand et al., 2003) for a given activity in the quality of interpersonal relationships experienced within the context of that activity in 4 studies. Study 1 demonstrated that a harmonious passion was positively associated with the quality of interpersonal relationships within the context of the passionate activity, whereas an obsessive passion was unrelated to it. Furthermore, in line with the broaden-and-build theory (Fredrickson, 2001), results also showed that positive emotions experienced at work fully mediated the relation between harmonious passion and quality of interpersonal relationships. Obsessive passion was not associated with positive emotions. Study 2 replicated the results from Study 1 while controlling for trait extraversion. Also, in Study 2, we examined the negative mediating role of negative emotions between obsessive passion and quality of interpersonal relationships. Finally, Studies 3 and 4 replicated the results of Study 2 with prospective designs and with objective ratings of interpersonal relationships quality. Implications for the dualistic model of passion and the broaden-and-build theory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
985.
Nathalie Piegay Geneviève Tastevin Pierre-Jean Nacher 《Journal of Low Temperature Physics》2000,121(5-6):785-790
We report on investigations of spin diffusion in isotopic helium liquid mixtures using a multi-echo technique in applied magnetic field gradients. Samples (up to 1 cm
3
in volume) are obtained by liquefaction of optically polarised gas. NMR measurements are performed at saturated vapour pressure in a low magnetic field (2.2 mT). Signal-to-noise ratios stay high down to
3
He concentrations of order a few parts per thousand at 1K for instance. We demonstrate that the experimental accuracy of spin diffusion measurements is substantially improved using optically polarised mixtures. We have observed that the dynamics of the precession of the transverse magnetisation can be altered due to large dipolar fields at high magnetisation densities. Effects on spin-echo signals and implications for the extension of spin diffusion measurements with our technique are discussed. 相似文献
986.
We highlight the fact that hydrodynamic dispersion in shallow microchannels is in most cases controlled by the width of the cross section rather than by the much thinner height of the channel. We identify the relevant time scales that separate the various regimes involved. Using the lubrication approximation, we provide simple formulas that permit a quantitative evaluation of dispersion for most shallow cross-sectional shapes in the "long-time" Taylor regime, which is effectively diffusive. Because of its relevance for microfluidic systems, we also provide results for the short-time "ballistic regime" (for specific initial conditions). The special cases of parabolic and quasi-rectangular shapes are considered due to their frequent use in microsystems. 相似文献
987.
Nathalie Nallet Marlène Bernard Mireille Chiron 《Accident; analysis and prevention》2010,42(4):1302-1309
Goals
The goal was to gain a picture of current driver behaviour, and of the links between committed violations and accident history. It was also to identify how driver behaviour has changed over the last 20 years.Methods
A questionnaire-based cross-sectional study of a sample of 1161 drivers about the frequency of violations and the perception of the dangers and penalties associated with them was used in 2005. Self-reported violations and mental representations were also compared to the results of Biecheler who used similar methods (Biecheler-Fretel, 1983).Results, conclusions
Road traffic violations are frequent in France, particularly among male drivers. Several violations are linked with history of accidents in our sample. Frequently or fairly frequently exceeding the speed limit by 10 km/h (a violation reported by almost 53% of our sample), increases accident occurrence by a factor of 1.4. Progress in drivers’ behaviour has been slow and nonuniform, and appears in part to be related to safety campaigns that have been run (seat belts, alcohol). The results could inform future campaigns. In particular, a campaign on the use of indicators would seem worthwhile. 相似文献988.
Rafael De la Torre Susana De Sola Meritxell Pons Arnaud Duchon María Martínez de Lagran Magí Farré Montserrat Fitó Bessy Benejam Klaus Langohr Joan Rodriguez Mitona Pujadas Jean Charles Bizot Aída Cuenca Nathalie Janel Silvina Catuara Maria Isabel Covas Henri Blehaut Yann Herault Jean Marie Delabar Mara Dierssen 《Molecular nutrition & food research》2014,58(2):278-288
989.
Mathilde Ouattara-Brigaudet Sandrine Berthon-Fabry Christian Beauger Marian Chatenet Nathalie Job Mohamed Sennour Patrick Achard 《International Journal of Hydrogen Energy》2012
Seven carbon aerogels (CAs) with different pore size distributions were synthesized and used as a catalyst support in proton exchange membrane fuel cell (PEMFC) cathodes. The cathodes were tested in 50 cm2 membrane electrode assemblies. The results demonstrate that the CA texture significantly influences performance by impacting gas diffusion and proton transport. Also, the Nafion® loading must be adapted to the CA texture, since its easier penetration into large pores favors their obstruction and results in higher proton resistance and mass-transport voltage losses. Under fixed experimental conditions (notably Nafion®/carbon ratio = 1), the best CA support displays high specific surface area and pore volume, a majority of mesopores with a pore size distribution peak around 25–30 nm and with some macropores. The work confirms that the carbon support structure must be controlled to reduce mass-transport voltage losses. Doing so would lead to reduce PEMFC overall cost per kW. 相似文献
990.
Isabelle Vandekinderen John Van Camp Frank Devlieghere Kim Veramme Nathalie Bernaert Quenten Denon Peter Ragaert Bruno De Meulenaer 《European Food Research and Technology》2009,229(3):443-455
The effect of different decontamination treatments such as washing with sodium hypochlorite (20 and 200 mg/L), peroxyacetic
acid (80 and 250 mg/L), neutral electrolysed oxidising water (4.9 and 31.7 mg/L free chlorine) and contact with 1.55 mg/L
chlorine dioxide gas on the microbial and sensory quality, and the nutrient content of fresh-cut white cabbage was studied.
Only rinsing with 200 mg/L sodium hypochlorite, peroxyacetic acid or contact with gaseous chlorine dioxide resulted in significantly
higher reductions of the total plate count (1.5–2.5 log cfu/g) than the ones achieved by washing with tap water (0.5 log cfu/g).
However, those treatments giving the best results from a microbial point of view induced significant changes in the sensory
quality. Regarding the effects on nutrient content, the mechanical effects caused by water washing already reduced the vitamin
C content by 16–29%. Contrary to washing with neutral electrolysed oxidising water and contact with chlorine dioxide gas,
a supplementary decrease of the vitamin C content ranging between 9 and 28% was observed, when peroxyacetic acid or 200 mg/L
sodium hypochlorite were used. After the use of peroxyacetic acid or gaseous chlorine dioxide, the phenol content also showed
a decreasing trend, although not statistically significant. Apart from the effect of washing with water, the lipophilic nutrients
were well retained after a decontamination step except for the α-tocopherol content, when peroxyacetic acid was used (−43
to 56%), and for the all-trans-β-carotene content (−8%) of cabbage in contact with gaseous chlorine dioxide. Because of its
potential to reduce the initial microbial load without negative effects on the sensory quality, in combination with its limited
effects on nutrient content, a treatment with 80 mg/L peroxyacetic acid is preferable to decontaminate fresh-cut white cabbage. 相似文献