全文获取类型
收费全文 | 1724篇 |
免费 | 116篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 405篇 |
金属工艺 | 36篇 |
机械仪表 | 30篇 |
建筑科学 | 65篇 |
矿业工程 | 2篇 |
能源动力 | 53篇 |
轻工业 | 148篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 206篇 |
一般工业技术 | 354篇 |
冶金工业 | 93篇 |
原子能技术 | 23篇 |
自动化技术 | 404篇 |
出版年
2023年 | 21篇 |
2022年 | 19篇 |
2021年 | 37篇 |
2020年 | 50篇 |
2019年 | 51篇 |
2018年 | 55篇 |
2017年 | 66篇 |
2016年 | 66篇 |
2015年 | 53篇 |
2014年 | 64篇 |
2013年 | 125篇 |
2012年 | 110篇 |
2011年 | 151篇 |
2010年 | 99篇 |
2009年 | 98篇 |
2008年 | 111篇 |
2007年 | 87篇 |
2006年 | 87篇 |
2005年 | 72篇 |
2004年 | 58篇 |
2003年 | 47篇 |
2002年 | 39篇 |
2001年 | 15篇 |
2000年 | 15篇 |
1999年 | 25篇 |
1998年 | 24篇 |
1997年 | 35篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 18篇 |
1993年 | 18篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1841条查询结果,搜索用时 937 毫秒
101.
Alexandre Garcia Jérôme Polesel‐Maris Pascal Viel Serge Palacin Thomas Berthelot 《Advanced functional materials》2011,21(11):2096-2102
The “ligand induced electroless plating (LIEP) process” is a simple process to obtain localized metal plating onto flexible polymers such as poly(ethylene terephtalate) and polyvinylidene fluoride sheets. This generic and cost‐effective process, efficient on any common polymer surface, is based on the covalent grafting by the GraftFast process of a thin chelating polymer film, such as poly(acrylic acid), which can complex copper ions. The entrapped copper ions are then chemically reduced in situ and the resulting Cu0 species act as a seed layer for the electroless copper growth which, thus, starts inside the host polymer. The present work focuses on the application of the LIEP process to the patterning of localized metallic tracks via two simple lithographic methods. The first is based on a standard photolithography process using a positive photoresist masking to prevent the covalent grafting of PAA in designated areas of the polymer substrate. In the second, the patterning is performed by direct printing of the mask with a commercial laser printer. In both cases, the mask was lifted off before the copper electroless plating step, which provides ecological benefits, since only the amount of copper necessary for the metallic patterning is used. 相似文献
102.
This study addresses heat and mass transfer during the vaporization of a liquid in a heated square cross-section mini-channel. A theoretical model is developed in steady state using the radius of curvature as a variable. One-dimensional simulations have been performed. An analysis of this model reveals that heat and mass transfer is governed by two main groups of non-dimensional numbers (i.e., Reynolds × Boiling and Weber × Boiling2 numbers). Maps of heat transfer performance are thus proposed according to these non-dimensional numbers. A reduced model is finally derived, allowing the main parameters to be expressed (such as the extended meniscus length) analytically. 相似文献
103.
Mohamed Kamel Hadj-Kali Vincent Gerbaud Patrick Lovera Olivier Baudouin Pascal Floquet Xavier Joulia Jean-Marc Borgard Philippe Carles 《International Journal of Hydrogen Energy》2009
A model for the Bunsen section of the Sulfur–Iodine thermo-chemical cycle is proposed, where sulfur dioxide reacts with excess water and iodine to produce two demixing liquid aqueous phases (H2SO4 rich and HI rich) in equilibrium. Considering the mild temperature and pressure conditions, the UNIQUAC activity coefficient model combined with Engels' solvation model is used. The complete model is discussed, with HI solvation by water and by iodine as well as H2SO4 solvation by water, leading to a very high complexity with almost hundred parameters to be estimated from experimental data. Taking into account the water excess, a successful reduced model with only 15 parameters is proposed after defining new apparent species. Acids total dissociation and total H+ solvation by water are the main assumptions. Results show a good agreement with published experimental data between 25 °C and 120 °C. 相似文献
104.
105.
Christian Schmaltz Pascal Gwosdek Andrs Bruhn Joachim Weickert 《Computer Graphics Forum》2010,29(8):2313-2327
We introduce a new global approach for image dithering, stippling, screening and sampling. It is inspired by the physical principles of electrostatics. Repelling forces between equally charged particles create a homogeneous distribution in flat areas, while attracting forces from the image brightness values ensure a high approximation quality. Our model is transparent and uses only two intuitive parameters: One steers the granularity of our halftoning approach, and the other its regularity. We evaluate two versions of our algorithm: A discrete version for dithering that ties points to grid positions, as well as a continuous one which does not have this restriction, and can thus be used for stippling or sampling density functions. Our methods create very few visual artefacts, reveal favourable blue‐noise behaviour in the frequency domain, and have a lower approximation error under Gaussian convolution than state‐of‐the‐art methods. 相似文献
106.
Carlos A. Montoya Jean-Paul Lallès Stephen Beebe Pascal Leterme 《Food research international (Ottawa, Ont.)》2010,43(2):443-449
This article proposes a new way to improve the protein quality of the common bean (Phaseolus vulgaris). It is based on the natural variability found in the different types of phaseolin, its main storage protein (40–50% of the total protein). Despite the fact that it is deficient in methionine content, phaseolin still represents the main source of that amino acid in the seed. More than 40 genetic variants, differing in subunit number (2–6) and molecular weight (40–54 kDa) have been analyzed. The similarity of the amino acid composition among phaseolins, suggests that a nutritional improvement cannot be expected from that side. Conversely, important variation in phaseolin susceptibility to proteolysis (ranging from 57% to 96% after cooking) has been observed, increasing the theoretical availability of methionine by up to 37%. Therefore, breeding programs based on highly-digestible phaseolin types could lead to the production of beans with higher protein quality. 相似文献
107.
Mr. Alain Froment Mr. Pascal Gautier Mr. Alexandre Nussbaumer Mr. Alec Griffiths 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2011,6(2):277-281
Some mycotoxins are produced by several Fusarium species during cultivation and are found in wheat and maize grain. Since 2000, Syngenta has organised a large field survey. Agronomic and climatic data and grain samples have been collected for mycotoxin analysis in France and Belgium. The importance of the agroclimatic factors and their interactions on the mycotoxin levels in grain has been estimated. The climate around flowering stage is the major factor for deoxynivalenol (DON) in wheat. The main agronomic criteria are residue management and the variety sensitivity to this mycotoxin. For DON, zearalenone and fumonisins in maize, the climate from flowering stage until harvest is the major factor. Then, according to each mycotoxin, the main agronomic criteria are the harvest condition (date and grain moisture), the corn borer infestation and the variety sensitivity to these mycotoxins. Over the years, the database has been used to define models to predict the mycotoxin risk before harvesting. Grain purchasers enter the required agronomic data via the Syngenta Internet site and define their grain purchasing areas. They also define the flowering period for wheat and corn borer infestation for maize. After calculation which integrates climatic data, the purchasers receive reports with forecasts of mycotoxin levels. Prediction is based on different agro-climatic statistical models specifically configured according to the different regions of production in France and Belgium. This approach is called Qualimètre? and was the first service in France and Belgium to forecast the grain mycotoxin level for wheat in 2004 and maize in 2006. 相似文献
108.
109.
110.