全文获取类型
收费全文 | 539篇 |
免费 | 69篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 609篇 |
出版年
2024年 | 4篇 |
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 24篇 |
2020年 | 14篇 |
2019年 | 24篇 |
2018年 | 32篇 |
2017年 | 36篇 |
2016年 | 40篇 |
2015年 | 29篇 |
2014年 | 27篇 |
2013年 | 41篇 |
2012年 | 35篇 |
2011年 | 28篇 |
2010年 | 11篇 |
2009年 | 26篇 |
2008年 | 21篇 |
2007年 | 27篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 30篇 |
1997年 | 19篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 5篇 |
1974年 | 2篇 |
1968年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1941年 | 2篇 |
1940年 | 2篇 |
1939年 | 2篇 |
1936年 | 2篇 |
1934年 | 1篇 |
排序方式: 共有609条查询结果,搜索用时 109 毫秒
101.
D Ferbus A Fléchon M Muleris Y Li S Hanash B Terris P Hammel L Pibouin B Dutrillaux G Goubin 《Canadian Metallurgical Quarterly》1999,80(3):369-372
The OZF gene encodes a protein consisting of 10 zinc finger motifs and is located on chromosome 19q3.1. We report here the amplification and over-expression of the OZF gene in pancreatic carcinomas. Increased gene copy number was detected in 3 of 12 tumour cell lines and 2 of 12 primary pancreatic carcinomas. Expression was detected in all cell lines, and the gene was over-expressed in cell lines with OZF gene amplification. Five of 8 tumours, including 2 primary tumours with OZF gene amplification, displayed high levels of OZF protein, whereas normal pancreas expressed low levels. Immuno-histochemical analysis showed that expression was restricted to tumour cells. Thus, high-level expression of OZF is frequent in pancreatic carcinomas and may contribute to the development or progression of this tumour. 相似文献
102.
103.
AbstractThe transformation process of biomass through gasification may produce a large amount of solid particles of different granulometry. In order to avoid equipment damage, these particles must be separated from the producer gas before it is utilized in other processes. This separation can be performed through a cyclone separator. This equipment is part of the circulating fluidized bed gasifier and is responsible for particulate separation and producer gas partial cleanup. Cyclone dimensioning requires careful attention and must be done according to the conditions this device is going to be subject. Thus, this work aims to validate and analyze a dimensioning methodology and apply it to a gasifier. Three cyclone geometries were considered (Stairmand, Swift and Lapple) and they were compared in terms of collection efficiency and pressure drop. A parameter sensibility study was performed. Variations of dimension, efficiency and pressure drop for a producer gas volumetric flow range were tested. It was found that an increase of the volumetric flow rate provoked the rise of separation efficiency and pressure drop. From the tested geometries, Swift presented the highest collection efficiency and pressure drop. 相似文献
104.
Reibung und Verschleiss von Präzisionskugellagern können durch Optimierung der Fertigungsqualität, Schmiermittelwahl und geeigneter Beschichtungen verringert werden. Deutliche Standzeiterhöhungen von Präzisionskugellagern lassen sich mit einer Titankarbid‐Beschichtung (TIC) erzielen. Die Keramikschicht bewirkt ein deutlich verbessertes Reibungs‐ und Verschleissverhalten für trockenlaufende und geschmierte Lager. TIC beschichtete Stahlkugeln weisen, im Gegensatz zu Keramikkugeln, einen identischen Ausdehnungskoeffizienten zu den Lagerringen auf und sind daher in vielen Luft‐ und Raumfahrtanwendungen von Vorteil. 相似文献
105.
de Gonçalves AS Davolos MR Nogueira AF 《Journal of nanoscience and nanotechnology》2010,10(10):6432-6438
Well-aligned ZnO nanorod films were grown onto transparent conducting substrates by using an aqueous solution route. The presence of some reflections in the X-ray diffraction pattern of the ZnO films indicates the vertical alignment of the nanorods along the c axis of the wurtzite hexagonal structure. Well-aligned ZnO nanorods were observed by scanning electron microscopy. The presence of top ZnO microflower layers over the ZnO nanorod film was observed for all growth times studied. The ZnO nanorods with ZnO microflower top layers were applied as photoelectrodes in dye-sensitized solar cells. Higher photocurrent densities and photovoltages were observed with longer nanorod growth times. The high performance of the dye-sensitized solar cells might be associated to the combination of ZnO nanorods and microflowers in the same photoelectrode. 相似文献
106.
José Manuel Casado‐Díaz Lucas Martínez‐Bernabéu Francisco Flórez‐Revuelta 《Papers in Regional Science》2017,96(4):859-879
The methods used to define functional regions for public statistics and policy purposes need to establish several parameter values. This is typically achieved using expert knowledge based on qualitative judgements and lengthy consultations with local stakeholders. We propose to support this process by using an optimization algorithm to calibrate any regionalization method by identifying the parameter values that produce the best regionalization for a given quantitative indicator. The approach is exemplified by using a grid search and a genetic algorithm to configure the official methods employed in the UK and Sweden for the definition of their respective official concepts of local labour markets. 相似文献
107.
Effect of Aqueous Extract of the Seaweed Gracilaria domingensis on the Physicochemical,Microbiological, and Textural Features of Fermented Milks 下载免费PDF全文
Adriana Carneiro Tavares Estevam Flávia Carolina Alonso Buriti Tiago Almeida de Oliveira Elainy Virginia dos Santos Pereira Eliane Rolim Florentino Ana Lúcia Figueiredo Porto 《Journal of food science》2016,81(4):C874-C880
The effects of the Gracilaria domingensis seaweed aqueous extract in comparison with gelatin on the physicochemical, microbial, and textural characteristics of fermented milks processed with the mixed culture SAB 440 A, composed of Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium animalis ssp. lactis, were investigated. The addition of G. domingensis aqueous extract did not affect pH, titratable acidity, and microbial viability of fermented milks when compared with the control (with no texture modifier) and the products with added gelatin. Fermented milk with added the seaweed aqueous extract showed firmness, consistency, cohesiveness, and viscosity index at least 10% higher than those observed for the control product (P < 0.05). At 4 h of fermentation, the fermented milks with only G. domingensis extract showed a texture comparable to that observed for products containing only gelatin. At 5 h of fermentation, firmness and consistency increased significantly (P < 0.05) in products with only seaweed extract added, a behavior not observed in products with the full amount of gelatin, probably due to the differences between the interactions of these ingredients with casein during the development of the gel network throughout the acidification of milk. The G. domingensis aqueous extract appears as a promising gelatin alternative to be used as texture modifier in fermented milks and related dairy products. 相似文献
108.
109.
Physicochemical and sensory quality of several commercial Brazilian chocolate milk beverages 下载免费PDF全文
Flávia Della Lucia Juliana Ribeiro Do Carmo Cecília S Nunes Morais Cleiton A Nunes Ana Carla M Pinheiro Eric Batista Ferreira Sandra Maria Pinto Luiz Ronaldo de Abreu Eduardo Valério de Barros Vilas Boas 《International Journal of Dairy Technology》2016,69(3):364-371
Five brands of Brazilian chocolate milk were subjected to physicochemical and acceptability analysis. The moisture content, fat content, pH and soluble solids content varied between 78.35 and 84.27 g/100 mL, 1.68 and 3.08 g/100 mL, 7.11 and 7.44, 14.0 and 19.0° Brix, respectively, while the ash contents and % lactic acid equivalents were similar. Four of the tested brands had acceptable scores in all attributes; however, one had lower acceptability scores and lower values for luminosity, chromaticity, b* and hue angle, which are potential indicators of the sensory quality. Strong chocolate aroma, strong chocolate flavour, strong brown colour, brightness and sandiness may be used as indicators of low acceptability for chocolate milk. 相似文献
110.
Dr. Jaroslaw Iwicki Ivan Pongrac Patrick Gottschalk René Bauer Alexander Schlotter Dr. Michael Flämmich Dr. Ute Bergner 《真空研究与实践》2013,25(2):48-51
Long term stable cold cathode with reliable ignition Cold cathodes gauges have been used in various areas of vacuum technology for decades. Their unique properties make them the method of choice even despite the residual magnetic field, poor ignition characteristics in the UHV‐region and long term stability. In other applications they do not significantly shorten the maintenance intervals. However, especially in the UHV or XHV region these properties lead to an extinguishing of cold cathode discharge. Considering the underlying processes and their correlation in this contribution an improved cold cathode will be presented. The measured data show a residual magnetic field of 1 mT in close vicinity to the gauge and an extended operating pressure range down to the 10?12 mbar region. Furthermore the ignition characteristics were improved to < 60 s at 1×10?9 mbar. 相似文献