全文获取类型
收费全文 | 1237篇 |
免费 | 102篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 16篇 |
综合类 | 2篇 |
化学工业 | 367篇 |
金属工艺 | 21篇 |
机械仪表 | 24篇 |
建筑科学 | 30篇 |
能源动力 | 55篇 |
轻工业 | 206篇 |
水利工程 | 5篇 |
石油天然气 | 1篇 |
无线电 | 108篇 |
一般工业技术 | 221篇 |
冶金工业 | 37篇 |
原子能技术 | 4篇 |
自动化技术 | 246篇 |
出版年
2024年 | 2篇 |
2023年 | 32篇 |
2022年 | 90篇 |
2021年 | 113篇 |
2020年 | 46篇 |
2019年 | 44篇 |
2018年 | 72篇 |
2017年 | 61篇 |
2016年 | 69篇 |
2015年 | 58篇 |
2014年 | 56篇 |
2013年 | 107篇 |
2012年 | 92篇 |
2011年 | 103篇 |
2010年 | 70篇 |
2009年 | 74篇 |
2008年 | 62篇 |
2007年 | 47篇 |
2006年 | 35篇 |
2005年 | 21篇 |
2004年 | 22篇 |
2003年 | 15篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
排序方式: 共有1343条查询结果,搜索用时 15 毫秒
61.
Rahul Sasidharan Pillai Matteo Frasnelli Vincenzo M. Sglavo 《Ceramics International》2018,44(2):1328-1333
The present work focuses on the fabrication of βTCP (β-tricalcium phosphate) and HA/βTCP (hydroxyapatite/β-tricalcium phosphate) composite coatings by plasma spraying. The starting powders were produced via solid-state method using 2 wt% MgO to stabilize βTCP phase. The synthesized powders were preliminarily granulated to be used by the plasma spray process. Coatings obtained on titanium substrates are uniform and well adherent but due to the high temperature and cooling rate typical for plasma spraying process, βTCP phase is almost totally transformed into the α allotrope. Thermal treatment at 800 °C allows the reconversion of the phase αTCP→ βTCP. It is therefore possible to produce coatings with tuneable dissolution properties by selecting the proper initial powder mixture and the specific thermal treatment. 相似文献
62.
63.
64.
A simple top-down fabrication technique that involves scanning probe lithography on Si is presented. The writing procedure consists of a chemically selective patterning in mesitylene. Operating in an organic media is possible to perform local oxidation or solvent decomposition during the same pass by tuning the applied bias. The layer deposited with a positively biased tip with sub-100-nm lateral resolution consists of nanocrystalline graphite, as verified by Raman spectroscopy. The oxide pattern obtained in opposite polarization is later used as a mask for dry etching, showing a remarkable selectivity in SF6 plasma, to produce Si nanofeatured molds. 相似文献
65.
The influence of drying air temperature on the physical properties of dried and rehydrated eggplant 总被引:1,自引:0,他引:1
Paola Russo Giuseppina Adiletta Marisa Di Matteo 《Food and Bioproducts Processing》2013,91(3):249-256
Drying processes generally cause volume and surface change of foodstuffs. Information on the porous structure and the mechanical properties of dried food products is needed for determining food quality, process design and estimating properties such as density and moisture diffusivity.In this work we investigated the structural changes induced in eggplant by convective air drying at four different temperatures (40, 50, 60 and 70 °C) and their effect on the subsequent rehydration process. Drying and rehydration kinetic curves were also measured.The changes in physical properties, such as porosity, pore-size distribution and bulk density were determined by Hg porosimetry, scanning electron microscopy and optical microscopy while their effect on the textural characteristics by dynamometric measurements.As expected, the increase of the drying air temperature causes shorter drying times. The drying temperature influences strongly the microstructure of dried samples: the porosity increases with the air temperature, but the structure is better preserved at intermediate temperature (60 °C) as confirmed by the lower firmness values with respect to the other dehydrated samples (40, 50 and 70 °C). In these latter, the longer drying time and the higher temperature, respectively, causes the development of a wrinkled structure. In particular, at 70 °C the structure of dehydrated samples appears totally broken with a consequent faster water uptake during rehydration. 相似文献
66.
Matteo Bergami Stefano Protti Davide Ravelli Maurizio Fagnoni 《Advanced Synthesis \u0026amp; Catalysis》2016,358(7):1164-1172
A convenient photochemical flow protocol for the formation of aryl‐carbon bonds via photogenerated phenyl cations has been developed. A wide range of phenylated products, including biaryls, allylarenes, 2‐arylacetals and benzyl γ‐lactones, was smoothly synthesized in satisfactory yields under metal‐free conditions. The adoption of a flow reactor often allowed us to adopt higher concentrations of substrates and shorter irradiation times compared to those usually employed in batch systems.
67.
Chiara Paolini Silvia Agarbati Devis Benfaremo Matteo Mozzicafreddo Silvia Svegliati Gianluca Moroncini 《International journal of molecular sciences》2022,23(7)
Systemic sclerosis (SSc) is a clinically heterogeneous disorder of the connective tissue characterized by vascular alterations, immune/inflammatory manifestations, and organ fibrosis. SSc pathogenesis is complex and still poorly understood. Therefore, effective therapies are lacking and remain nonspecific and limited to disease symptoms. In the last few years, many molecular and cellular mediators of SSc fibrosis have been described, providing new potential options for targeted therapies. In this review: (i) we focused on the PDGF/PDGFR pathway as key signaling molecules in the development of tissue fibrosis; (ii) we highlighted the possible role of stimulatory anti-PDGFRα autoantibodies in the pathogenesis of SSc; (iii) we reported the most promising PDGF/PDGFR targeting therapies. 相似文献
68.
Anna Angela Barba Matteo dAmore Sara Cascone Gaetano Lamberti Giuseppe Titomanlio 《Chemical Engineering and Processing: Process Intensification》2009,48(10):1477-1483
In this work ultrasonic atomization process is applied to produce biopolymer microparticles with potential applications in pharmaceutical and nutraceutical fields. Natural polymer (alginate)/water solution is atomized by ultrasonic assisted process and the droplets spray is reticulated using a solution of copper sulfate, where the Cu2+ ions cause the formation of a network structure (hard porous gel). Several operating parameters (solution concentration, flow rate, atomization power) are changed to study their effects on the produced microparticles. Literature correlations able to predict the features of the droplets as functions of process parameters are optimized using a statistical approach. Furthermore, the energy requirement for the drops production is compared with the energy required by traditional techniques to evaluate the intensification effect of the ultrasonic on the atomization process. 相似文献
69.
Georgios D. Stefanidis Dionisios G. Vlachos Niket S. Kaisare Matteo Maestri 《American Institute of Chemical Engineers》2009,55(1):180-191
The potential of methane steam reforming at microscale is theoretically explored. To this end, a multifunctional catalytic plate microreactor, comprising of a propane combustion channel and a methane steam reforming channel, separated by a solid wall, is simulated with a pseudo 2‐D (two‐dimensional) reactor model. Newly developed lumped kinetic rate expressions for both processes, obtained from a posteriori reduction of detailed microkinetic models, are used. It is shown that the steam reforming at millisecond contact times is feasible at microscale, and in agreement with a recent experimental report. Furthermore, the attainable operating regions delimited from the materials stability limit, the breakthrough limit, and the maximum power output limit are mapped out. A simple operation strategy is presented for obtaining variable power output along the breakthrough line (a nearly iso‐flow rate ratio line), while ensuring good overlap of reaction zones, and provide guidelines for reactor sizing. Finally, it is shown that the choice of the wall material depends on the targeted operating regime. Low‐conductivity materials increase the methane conversion and power output at the expense of higher wall temperatures and steeper temperature gradients along the wall. For operation close to the breakthrough limit, intermediate conductivity materials, such as stainless steel, offer a good compromise between methane conversion and wall temperature. Even without recuperative heat exchange, the thermal efficiency of the multifunctional device and the reformer approaches ~65% and ~85%, respectively. © 2008 American Institute of Chemical Engineers AIChE J, 2009 相似文献
70.
Anna Di Gianni Giovanna Colucci Aldo Priola Lucia Conzatti Matteo Alessi Paola Stagnaro 《大分子材料与工程》2009,294(10):705-710
The preparation of new rubber based nanocomposites by using properly modified organophilic clays is described. A commercial organophilic montmorillonite containing a hydroxylated ammonium ion is reacted with LPBs. The reaction causes a decrease of the polarity of the clay and a great increase of the interlayer distance. The modified organoclays are successfully dispersed into rubber matrices (SBR or BR) by melt blending in an internal batch mixer. SAXS analyses and TEM micrographs revealed the formation of highly exfoliated nanocomposites containing intercalated stacks made of few lamellae.