全文获取类型
收费全文 | 587篇 |
免费 | 34篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 173篇 |
金属工艺 | 2篇 |
机械仪表 | 13篇 |
建筑科学 | 24篇 |
矿业工程 | 1篇 |
能源动力 | 27篇 |
轻工业 | 210篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 8篇 |
一般工业技术 | 61篇 |
冶金工业 | 12篇 |
原子能技术 | 2篇 |
自动化技术 | 82篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 15篇 |
2021年 | 24篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 10篇 |
2017年 | 23篇 |
2016年 | 15篇 |
2015年 | 16篇 |
2014年 | 27篇 |
2013年 | 41篇 |
2012年 | 31篇 |
2011年 | 51篇 |
2010年 | 37篇 |
2009年 | 32篇 |
2008年 | 54篇 |
2007年 | 35篇 |
2006年 | 28篇 |
2005年 | 29篇 |
2004年 | 18篇 |
2003年 | 21篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有621条查询结果,搜索用时 15 毫秒
531.
Yolanda wu 《中国服装(北京)》2008,(19)
“我们是一个很谨慎的家族.(对香奈儿)我们从来不说什么。香奈儿是关于可可·夏奈尔的,是关于卡尔的,是关于每一个在香奈儿工作、创作的人的.而不是关于维德摩尔家族的。” 相似文献
532.
Martín López-Nores Yolanda Blanco-Fernández José J. Pazos-Arias Ana Fernández-Vilas Manuel Ramos-Cabrer 《Expert systems with applications》2011,38(10):12691-12698
Digital TV (DTV) bears much potential for e-commerce, but most of it remains underexploited due to the lack of systematic approaches to the provision of interactive applications. Working on top of an existing recommender system, this paper presents mechanisms to automatically compose applications that provide personalized commercial functionalities to the users. The proposal addresses specific concerns of DTV environments, with special attention to achieving good personalization quality and furnishing useful interactions when there is no return channel permanently available for bidirectional communication. Preliminary experiments reveal good acceptance of the concept among real users. 相似文献
533.
Olga Bergadà Pilar Salagre Yolanda Cesteros Francisco Medina Jesús E. Sueiras 《Catalysis Letters》2008,122(3-4):259-266
The addition of basic solutions to the reaction medium in the catalytic hydrogenation of styrene oxide improves the selectivity
to 2-phenylethanol (used in perfumery) but also can favour condensation reactions. To study the influence of different basic
sites on the reaction products, we prepared several catalysts by mixing a commercial magnesia (MgO), and other previously
rehydrated (MgOr), with different amounts of NiO followed by reduction (NiMgO, 4NiMgO, NiMgOr, 4NiMgOr), and by mixing directly
MgO with Ni (NiMgOa, 4NiMgOa). Ni–MgO catalysts showed the best conversion and selectivity to 2-phenylethanol values, arriving
to 100% when increasing the MgO content. Interestingly, CO2-TPD study of catalyst NiMgO indicates that metallic nickel covers the weakest basic sites of magnesia. On the other hand,
CO2-TPD profiles of Ni–MgOr and Ni–MgOa catalysts, which present low catalytic activity, showed an important amount of available
basic sites that favour the formation of higher amounts of condensation products, which are responsible for the catalyst deactivation. 相似文献
534.
Response of Epilachna paenulata to Two Flavonoids, Pinocembrin and Quercetin, in a Comparative Study
Georgina N. Diaz Napal Maria T. Defagó Graciela R. Valladares Sara M. Palacios 《Journal of chemical ecology》2010,36(8):898-904
We examined the effects of the flavonoids pinocembrin and quercetin on the feeding behavior, survival, and development of the Cucurbitaceae pest Epilachna paenulata (Coleoptera: Coccinellidae). In no-choice experiments, 48 hr-consumption of Cucurbita maxima Duch. leaves treated with pinocembrin at 1, 5, and 50 μg/cm2 was less than one third of that for leaves treated with 0.1 μg/cm2 of pinocembrin or untreated leaves. Larvae stopped feeding after 9 days of high doses of pinocembrin (5 and 50 μg/cm2), and larval weight and survival were negatively affected by pinocembrin at 1–50 μg/cm2. Delayed mortality in comparison to food-deprived larvae suggests that the mechanism of action for pinocembrin is chronic intoxication, rather than simple starvation from antifeedant effects. In contrast, leaf consumption and larval weight were not significantly affected by quercetin (at 0.1, 1, 5, and 50 μg/cm2) while mortality rates were only slightly increased. The response of E. paenulata larvae in a choice-test to combinations of pinocembrin at antifeedant doses (5 and 50 μg/cm2) and quercetin at phagostimulant doses (0.01 and 0.1 μg/cm2) indicated that the feeding deterrent activity of the former completely overshadowed the stimulant activity of the latter. These results demonstrate the different responses of one insect species to two widely distributed plant flavonoids. Pinocembrin strongly affected survival of E. paenulata while quercetin had only a weak effect without major consequences on the insect life-cycle. 相似文献
535.
Graciela C. Abuin Patrick Nonjola Esteban A. Franceschini Federico H. Izraelevitch Mkhulu K. Mathe Horacio R. Corti 《International Journal of Hydrogen Energy》2010
Ammonium quaternized polymers such as poly (arylene ether sulfones) are being developed and studied as candidates of ionomeric materials for application in alkaline fuel cells, due to their low cost and promising electrochemical properties. In this work, a quaternary ammonium polymer was synthesized by chloromethylation of a commercial polysulfone followed by amination process. 相似文献
536.
José A. Marazza Mónica A. Nazareno Graciela Savoy de Giori Marisa S. Garro 《International Journal of Food Science & Technology》2013,48(12):2480-2489
Bioconversion of isoflavone glucosides and antioxidant activity by probiotic strain (Bifidobacterium longum) during soymilk fermentation was investigated, as well as partial characterisation of the produced enzyme β‐glucosidase. The enzyme has higher affinity for genistin than for other substrates assayed. Maximum activity occurred at 42 °C and at pH 6.0; keeping 70–80% of activity for 60 days stored at low temperatures. Bifidobacterium longum grew well in soymilk (8.26 log CFU mL?1 and pH of 3.9 at 24 h) and were produced in good quantities of organic acids. High hydrolysis degree of isoflavone glucosides (81.2%) was observed at 24 h. Enhancements in bioactivity were assessed in fermented soymilk by monitoring the radical‐scavenging activity, antioxidant activity and DNA protective action. The use of probiotic Bifidobacterium strain as β‐glucosidase producer increased bioactive isoflavone content and demonstrated that this enzyme plays a key role in the bioavailability of soymilk isoflavones, reducing the bioconversion time compared to other studies. 相似文献
537.
Rubén D. Piacentini Graciela M. Salum Naum Fraidenraich Chigueru Tiba 《Renewable Energy》2011,36(1):409-412
Extraterrestrial total solar irradiance, usually called Solar Constant, is attenuated by the atmosphere in different proportions, depending mainly on solar zenith angle and altitude of the measurement point. In this work, it is presented very high and extreme horizontal plane measurements of global solar irradiance that in some days overpassed the Solar Constant corrected by the actual Sun–Earth distance (CSC). They were obtained at sea level of the intertropical Atlantic coast, in the city of Recife, Brazil, in the period February 2008–January 2009. Extreme total solar irradiance values larger than CSC were measured during 3.4% of the days of the total registered period. This percentage increases to 7.4% for global solar irradiance within 95.1–100% of the CSC and to 15.3% within 90.1–95% of the CSC. The largest extreme total solar irradiance value, 1477 ± 30 W/m2, was registered the 28th of March 2008 at 11:34 local time (UT – 3h). It overpassed by 7.9% the CSC value for this day (1369.4 W/m2) and by 42.3% the estimated value of the clear sky Iqbal C radiation model (1037.7 W/m2). The observation of extreme values should be taken into account in the study of solar radiation effects related to materials exposed to the outside, UV index and biological effects, among others. Also, the detailed knowledge of this interesting effect may contribute significantly to clarify physical aspects about the interaction of global solar radiation with the ecosystem and climate change. 相似文献
538.
Vanesa Benítez Esperanza MolláMaría A. Martín-Cabrejas Yolanda AguileraFrancisco J. López-Andréu Rosa M. Esteban 《Food chemistry》2011
Food industries are forced to develop productions without secondary residues. Therefore, there is a considerable emphasis on the recovery, recycling and upgrading of wastes. The possibility has been suggested for the conversion of onion waste into food ingredients, but with a stabilisation treatment being necessary. The objective of this work was to study the effect of sterilisation on fibre fractions, fibre composition and physicochemical properties of onion by-products to evaluate the use of sterilised onion by-products as a source of fibre. 相似文献
539.
Shimrit Bar-El Dadon Cristina Yolanda Pascual Dani Eshel Paula Teper-Bamnolker María Dolores Paloma Ibáñez Ram Reifen 《Food chemistry》2013
IgE-mediated reactions to food allergens constitute a major health problem in industrialized countries. Chickpea is consumed in Mediterranean countries, and reportedly associated with IgE-mediated hypersensitivity reactions. However, the nature of allergic reactions to chickpea has not been characterized. 相似文献
540.
Vanesa Benítez Sara Cantera Yolanda Aguilera Esperanza Mollá Rosa M. Esteban María Felicia Díaz María A. Martín-Cabrejas 《Food research international (Ottawa, Ont.)》2013,50(1):64-69
The objective of this study was to evaluate the impact of germination on dietary fiber composition, starch availability and physicochemical properties in four non-conventional legumes (Vigna unguiculata, Canavalia ensiformis, Stizolobium niveum, Lablab purpureus) in order to improve the carbohydrate supply and to optimize native products of developing countries. Germination promoted a significant decrease of resistant starch along with an increase of available starch percentage. Total dietary fiber contents increased during germination and improved insoluble/soluble dietary fiber ratio. This process produced an increase of total sugar content, mainly due to the rise of cellulosic glucose from metabolic reaction undergone during germination. Moreover, physicochemical properties of germinated legume flours were modified, improving oil holding, water holding, water absorption and gelation capacities, whereas decreases of emulsifying and foaming capacities were detected. In conclusion, germination provides non-conventional legume flours with higher nutritional quality and better physicochemical properties than the raw flours. 相似文献