全文获取类型
收费全文 | 2213篇 |
免费 | 178篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 888篇 |
金属工艺 | 25篇 |
机械仪表 | 43篇 |
建筑科学 | 79篇 |
矿业工程 | 5篇 |
能源动力 | 41篇 |
轻工业 | 581篇 |
水利工程 | 16篇 |
石油天然气 | 7篇 |
无线电 | 84篇 |
一般工业技术 | 295篇 |
冶金工业 | 73篇 |
原子能技术 | 6篇 |
自动化技术 | 242篇 |
出版年
2024年 | 5篇 |
2023年 | 30篇 |
2022年 | 111篇 |
2021年 | 309篇 |
2020年 | 84篇 |
2019年 | 74篇 |
2018年 | 89篇 |
2017年 | 86篇 |
2016年 | 100篇 |
2015年 | 76篇 |
2014年 | 97篇 |
2013年 | 161篇 |
2012年 | 138篇 |
2011年 | 164篇 |
2010年 | 115篇 |
2009年 | 117篇 |
2008年 | 94篇 |
2007年 | 93篇 |
2006年 | 76篇 |
2005年 | 66篇 |
2004年 | 55篇 |
2003年 | 42篇 |
2002年 | 29篇 |
2001年 | 25篇 |
2000年 | 17篇 |
1999年 | 8篇 |
1998年 | 19篇 |
1997年 | 17篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 4篇 |
1973年 | 4篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1965年 | 1篇 |
1934年 | 1篇 |
1933年 | 1篇 |
1932年 | 2篇 |
排序方式: 共有2392条查询结果,搜索用时 15 毫秒
951.
952.
Fibroblast Growth Factor-21 and the Beneficial Effects of Long-Chain n-3 Polyunsaturated Fatty Acids
Joan Villarroya Pavel Flachs Ibon Redondo-Angulo Marta Giralt Dasa Medrikova Francesc Villarroya Jan Kopecky Anna Planavila 《Lipids》2014,49(11):1081-1089
Long‐chain n‐3 polyunsaturated fatty acids (LC n‐3 PUFA) in the diet protect against insulin resistance and obesity. Fibroblast growth factor‐21 (Fgf21) is a hormonal factor released mainly by the liver that has powerful anti‐diabetic effects. Here, we tested whether the beneficial metabolic effects of LC n‐3 PUFA involve the induction of Fgf21. C57BL/6 J mice were exposed to an obesogenic, corn‐oil‐based, high‐fat diet (cHF), or a diet in which corn oil was replaced with a fish‐derived LC n‐3 PUFA concentrate (cHF + F) using two experimental settings: short‐term (3 weeks) and long‐term treatment (8 weeks). CHF + F reduced body weight gain, insulinemia, and triglyceridemia compared to cHF. cHF increased plasma Fgf21 levels and hepatic Fgf21 gene expression compared with controls, but these effects were less pronounced or absent in cHF + F‐fed mice. In contrast, hepatic expression of peroxisome proliferator‐activated receptor (PPAR)‐α target genes were more strongly induced by cHF + F than cHF, especially in the short‐term treatment setting. The expression of genes encoding Fgf21, its receptors, and Fgf21 targets was unaltered by short‐term LC n‐3 PUFA treatment, with the exception of Ucp1 (uncoupling protein 1) and adiponectin genes, which were specifically up‐regulated in white fat. In the long‐term treatment setting, the expression of Fgf21 target genes and receptors was not differentially affected by LC n‐3 PUFA. Collectively, our findings indicate that increased Fgf21 levels do not appear to be a major mechanism through which LC n‐3 PUFA ameliorates high‐fat‐diet‐associated metabolic disorders. 相似文献
953.
954.
955.
Vivoda Prodan Martina Mileusnić Marta Mihalić Arbanas Snježana Arbanas Željko 《Bulletin of Engineering Geology and the Environment》2017,76(2):695-711
Bulletin of Engineering Geology and the Environment - Weathering processes cause significant changes in the engineering properties of rocks. Slope instability in flysch rock formations along the... 相似文献
956.
957.
Effects of fat replacement and fibre addition on the texture,sensory acceptance and structure of sucrose‐free chocolate 下载免费PDF全文
Natália V. Rezende Marta T. Benassi Fernanda Z. Vissotto Pedro P. C. Augusto Maria V. E. Grossmann 《International Journal of Food Science & Technology》2015,50(6):1413-1420
Dietary fibre has been employed as a sucrose and fat replacement in chocolates and can influence the physical and sensory characteristics of the resulting product. Formulations of sucrose‐free chocolates were developed with the addition of inulin and β‐glucan concentrate as partial substitutes for cocoa butter using a mixture design. The effects of the combinations of the three ingredients provided for the design on the texture, microstructure and sensory acceptance of the chocolates were investigated. The substitution of cocoa butter for inulin or β‐glucan concentrate decreased the hardness of the chocolates. It was possible to replace 10 g of cocoa butter in a 100‐g control formulation with inulin and still maintain good acceptance, while this same substitution with β‐glucan resulted in less acceptable chocolate, with a mean score of 6.4 on a scale from 0 to 10. Scanning electron microscopy (SEM) was used to investigate the effects of fibre addition by observing the developed microstructure. 相似文献
958.
P Ardenghi D Barros LA Izquierdo L Bevilaqua N Schr?der J Quevedo C Rodrigues M Madruga JH Medina I Izquierdo 《Canadian Metallurgical Quarterly》1997,8(8):745-751
Rats implanted bilaterally with cannulae in the entorhinal or posterior parietal cortex or in the amygdaloid nucleus were trained in one-trial step-down inhibitory (passive) avoidance using a 0.3 mA footshock. At 0, 3, 6 or 9 h after training, they received localized 0.5 microliter infusions into these areas of a vehicle, or of 8-Br-cAMP, forskolin (adenylyl cyclase activator), KT5720 (protein kinase A inhibitor), SKF38393 (dopamine D1 receptor agonist), SCH23390 (D1 antagonist), norepinephrine hydrochloride, timolol hydrochloride (beta blocker), 8-HO-DPAT (5-HT1A receptor agonist) or NAN-190 (5-HT1A antagonist) dissolved in 20% dimethylsulfoxide (DMSO) in saline (vehicle). Rats were tested for retention 24 h after training. 8-Br-cAMP, forskolin, SKF 38393 and norepinephrine caused memory facilitation and KT5720, SCH23390, timolol and 8-HO-DPAT caused retrograde amnesia when given into the entorhinal cortex 0, 3 or 6 h but not 9 h after training. When given into the posterior parietal cortex 0, 3 or 6 but not 9 h after training, KT5720 was amnestic. When given into this structure 3 or 6 h but not 0 or 9 h after training 8-Br-cAMP, forskolin and norepinephrine caused memory facilitation and KT5720, SCH23390 and timolol caused retrograde amnesia. All treatments given into the amygdala 0, 3 or 6 h after training were ineffective except for norepinephrine given at 0 h, which caused facilitation. The data point to a role of cAMP/protein kinase A-dependent mechanisms in memory formation in the entorhinal and parietal cortex, but not the amygdala, from 0 to 6 h after training, and to a strong modulation of these mechanisms by dopaminergic D1, beta-noradrenergic and 5-HT1A receptors. The lack of effect of NAN-190 but not 8-HO-DPAT in both cortical regions suggests that 5-HT1A receptors do not play a physiological role but can be activated pharmacologically. The fact that SCH23390 was amnestic but SKF38393 had no effect when given into the parietal cortex suggests that D1 receptors may play a maintenance rather than a stimulant role in this area. 相似文献
959.
960.
Challenges to Manage the Risk of Water Scarcity and Climate Change in the Mediterranean 总被引:6,自引:3,他引:3
Ana Iglesias Luis Garrote Francisco Flores Marta Moneo 《Water Resources Management》2007,21(5):775-788
The Mediterranean region is undergoing rapid local and global social and environmental changes. All indicators point to an
increase in environmental and water scarcity problems with negative implications towards current and future sustainability.
Water management in Mediterranean countries is challenged these pressures and needs to evolve to reach the target of increasing
population with reliable access to freshwater established by the Millennium Development Goals. This paper first reviews and
evaluates current and future social and environmental pressures on water resources, including climate change. The results
show that pressures are not homogeneous across the region and sectors of water use. Second the paper evaluates the adaptation
strategies to cope with water scarcity, including technology, use of strategic groundwater, and management. Finally, the paper
proposes a framework for managing the risk of water scarcity based on preparedness rather than a crisis approach. The importance
of local management at the basin level is emphasized, but the potential benefits depend on the appropriate multi-institutional
and multi-stakeholder coordination. 相似文献