全文获取类型
| 收费全文 | 2876篇 |
| 免费 | 73篇 |
| 国内免费 | 1篇 |
专业分类
| 电工技术 | 29篇 |
| 综合类 | 1篇 |
| 化学工业 | 674篇 |
| 金属工艺 | 44篇 |
| 机械仪表 | 56篇 |
| 建筑科学 | 80篇 |
| 矿业工程 | 2篇 |
| 能源动力 | 111篇 |
| 轻工业 | 218篇 |
| 水利工程 | 11篇 |
| 石油天然气 | 11篇 |
| 无线电 | 315篇 |
| 一般工业技术 | 558篇 |
| 冶金工业 | 178篇 |
| 原子能技术 | 28篇 |
| 自动化技术 | 634篇 |
出版年
| 2024年 | 24篇 |
| 2023年 | 39篇 |
| 2022年 | 48篇 |
| 2021年 | 75篇 |
| 2020年 | 73篇 |
| 2019年 | 64篇 |
| 2018年 | 74篇 |
| 2017年 | 67篇 |
| 2016年 | 97篇 |
| 2015年 | 68篇 |
| 2014年 | 113篇 |
| 2013年 | 193篇 |
| 2012年 | 202篇 |
| 2011年 | 246篇 |
| 2010年 | 182篇 |
| 2009年 | 159篇 |
| 2008年 | 159篇 |
| 2007年 | 158篇 |
| 2006年 | 111篇 |
| 2005年 | 98篇 |
| 2004年 | 72篇 |
| 2003年 | 58篇 |
| 2002年 | 62篇 |
| 2001年 | 56篇 |
| 2000年 | 37篇 |
| 1999年 | 44篇 |
| 1998年 | 75篇 |
| 1997年 | 51篇 |
| 1996年 | 31篇 |
| 1995年 | 20篇 |
| 1994年 | 24篇 |
| 1993年 | 21篇 |
| 1992年 | 26篇 |
| 1991年 | 12篇 |
| 1990年 | 14篇 |
| 1989年 | 8篇 |
| 1988年 | 6篇 |
| 1987年 | 12篇 |
| 1986年 | 9篇 |
| 1985年 | 5篇 |
| 1984年 | 5篇 |
| 1983年 | 7篇 |
| 1982年 | 6篇 |
| 1980年 | 3篇 |
| 1979年 | 6篇 |
| 1978年 | 4篇 |
| 1977年 | 7篇 |
| 1976年 | 9篇 |
| 1972年 | 2篇 |
| 1966年 | 3篇 |
排序方式： 共有2950条查询结果，搜索用时 0 毫秒
991.
Jonas Schoelynck Olivier Beauchard Sander Jacobs Kris Bal Lúcia Barão Adriaan Smis Jonathan Van Bergen Floor Vandevenne Patrick Meire Tom Van der Spiet Anne Cools Dimitri Van Pelt Martin J. Hodson Eric Struyf 《SILICON》2013,5(1):3-12
Beer is a quintessential part of Belgian heritage. We performed a detailed analysis of factors controlling Si content in Belgian beers as a case study to coincide with the 2011 IBiS meeting in Antwerp (Belgium). Beer is one of the richest dietary sources of Si. Three decades of research have yielded evidence of a role for Si in human physiology: it plays an essential role in bone mineral density and reduces the biological availability of aluminium. We analysed 119 Belgian beers: highest dissolved Si concentrations were found in high fermentation, traditionally brewed ales. Concentrations ranged between 214 and 2,071 μmol L???1. This is probably due to the complexity and length of the brewing procedure: longer, more complicated processing and presence of brewing sediment in the bottle allows more Si to dissolve out of the base products like hop, barley or even rice. As a side effect of fermentation, alcohol content was related to Si content. 相似文献
992.
Grard Cahiez Olivier Gager Alban Moyeux Thomas Delacroix 《Advanced Synthesis u0026amp; Catalysis》2012,354(8):1519-1528
The study presented herein shows that sulfonate/halide exchange can be advantageously performed in THF to avoid several side reactions such as elimination and epimerization when the reaction is performed from a chiral alkyl sulfonate or a substrate having a C H acidic chiral center. The main limitation of this procedure was found to be the conversion of secondary alkyl sulfonates to alkyl chlorides. In this case, the addition of a catalytic amount of manganese chloride clearly accelerates the rate and the efficiency of the reaction. 相似文献
993.
Hoi‐Kuan Lao Estelle Renard Amani El Fagui Valérie Langlois Karine Vallée‐Rehel Isabelle Linossier 《应用聚合物科学杂志》2011,120(1):184-194
We modified hydrophobic poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBHV) films with hydrophilic chains to control their surface properties. We designed and investigated surface‐initiated atom transfer radical polymerization (SI‐ATRP) to modify the PHBHV films by grafting poly(2‐hydroxyethyl methacrylate) (PHEMA) from the surface. This method consisted of two steps. In the first step, amino functions were formed on the surface by aminolysis; this was followed by the immobilization of an atom transfer radical polymerization initiator, 2‐bromoisobutyryl bromide. In the second step, the PHEMA chains were grafted to the substrate by a polymerization process initiated by the surface‐bound initiator. The SI‐ATRP technique was expected to favor a polymerization process with a controlled manner. The experimental results demonstrate that the grafting density was controlled by the reaction conditions in the first step. The grafted films were analyzed by Fourier transform infrared spectroscopy, contact angle testing, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. The results show that grafted chains under the SI‐ATRP method were preferentially located on the surface for surface grafting and in the bulk for conventional free‐radical polymerization initiated by benzoyl peroxide. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
994.
To increase the compatibility between cellulose fibers and polyester matrix an original method for grafting hydrophobic oligoesters onto cellulose was proposed. Two kinds of cellulose substrates were employed as cellulose films and microcrystalline cellulose powder. Different oligoesters containing reactive end groups based on poly(DL ‐lactic acid) PDL‐LA, poly(ε‐caprolactone) PCL and poly(3‐hydroxyalkanoate)s PHA were first prepared and characterized by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC). The carboxylic end groups of the polyesters were activated using thionyl chloride (SOCl2) to increase the esterification reaction with the hydroxyl groups of the cellulose. The esterification was realized in a heterogenous medium without any catalyst by deposition of chloride oligoesters in solution (2–100 g L−1) onto cellulose film at different temperatures (25–105°C) during 1–12 h. The successful grafting on the various substrates was confirmed on the basis of FTIR spectroscopy, contact angle measurement, X‐ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). In particular, it is shown that a small quantity of grafted oligoesters led to a significant increase of the hydrophobic character of the cellulose with a contact angle near 130°. The increase of hydrophobicity of cellulose is independent of the nature and length of grafting oligoesters. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
995.
Marc Comet Alfred Eichhorn Fabien Schnell Olivier Muller Fabrice Ciszek Yannick Boehrer Denis Spitzer 《Propellants, Explosives, Pyrotechnics》2011,36(1):80-87
Thermites prepared from nanoparticles are currently the subject of growing interest due to their increased performances compared to classical micrometer‐sized thermites. Here, we studied the combustion behavior of energetic composite composed of Al and chromium (III) oxide (Cr2O3) as function of the oxide particle size. Homogeneous composites were prepared by mixing Al nanoparticles (Φ≈50 nm) with Cr2O3 micro‐ and nanoparticles (Φ≈20 nm), respectively, in hexane solution. The dried Cr2O3/Al composite powders were ignited by using a CO2 laser beam. The use of nanosized Cr2O3 particles incontestably improves the energetic performances of the Al/Cr2O3 thermite since the ignition delay time was shortened by a factor 3.5 (16±2 vs 54±4 ms) and the combustion rate (340±10 mm s−1) was significantly accelerated in contrast to those reported until now. Interestingly, the sensitivity to friction of the Al‐based thermites formulated from Cr2O3 is two orders of magnitude lower than the thermite prepared from other metal oxide nanoparticles (MnO2, WO3). Finally, our study shows that the decrease of Cr2O3 particle size has an interesting and beneficial effect on the energetic properties of Cr2O3/Al thermites and appears as an alternative to tune the properties of these energetic materials. 相似文献
996.
Anuwat Saetung Adisai Rungvichaniwat Irène Campistron Pairote Klinpituksa Albert Laguerre Pranee Phinyocheep Olivier Doutres Jean‐François Pilard 《应用聚合物科学杂志》2010,117(2):828-837
Novel flexible polyurethane foams were successfully prepared from a renewable source, hydroxytelechelic natural rubber (HTNR) having different molecular weights (1000–3400 g mol?1) and variation of epoxide contents (EHTNR, 0–35% epoxidation) by a one‐shot technique. The chemical and cell structures as well as physico‐mechanical, thermal, and acoustic properties were characterized and compared with commercial polyol analogs. The obtained HTNR based foams are open cell structures with cell dimensions between 0.38 and 0.47 mm. The HTNR1000 based foam exhibits better mechanical properties but lower elongation at break than those of commercial polyol analog. However, the HTNR3400 based foam shows the best elastic properties. In a series of EHTNR based foams, the tensile and compressive strengths show a tendency to increase with increasing epoxide content and amount of 1,4‐butanediol (BD). The HTNR based foams demonstrate better low temperature flexibility than that of the foam based on commercial polyol. Moreover, the HTNR based polyurethane foams was found to be an excellent absorber of acoustics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
997.
Frédéric Addiego Jean Di Martino David Ruch Abdesselam Dahoun Olivier Godard Pascale Lipnik Jean‐Jacques Biebuyck 《Polymer Engineering and Science》2010,50(2):278-289
This paper is focused on the quantitative characterization of cavitation developing in unfilled and nano‐CaCO3 filled high density polyethylene (HDPE) subjected to tensile test. In particular, a methodology to reveal the voids, take into account their localization, and evaluate their characteristics (density and shape), is presented. For this, post‐mortem investigations coupling a cryosectioning method and a pressure‐controlled scanning electron microscope (PC‐SEM) were conducted. In the two materials, whatever the active cavitation mechanism (crazing in neat HDPE or debonding in CaCO3/HDPE system), it was shown that the cavity density and the cavity height/width ratio (shape factor) increase with the deformation state. These two parameters are also influenced by the macroscopic stress triaxiality generated by the necking process. Indeed, when the intensity of the triaxiality is high, the cavity density and the cavity shape factor significantly increase from the skin to the core of the specimen. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
998.
Olivier Morel Robert M Christie Andrew Greaves Keith M Morgan 《Coloration Technology》2008,124(5):301-309
999.
Kun Tao Shuying Yang Jaime C. Grunlan Yeon‐Seok Kim Bachlien Dang Yuanjian Deng Renard L. Thomas Bobby L. Wilson Xin Wei 《应用聚合物科学杂志》2006,102(6):5248-5254
The effects of different grades of carbon nanotubes on the curing of a typical epoxy resin (EPIKOTE? resin 862 and EPIKURE? curing agent W) were examined via differential scanning calorimetry. It was found that nanotubes could initiate cure at lower temperatures, while the overall curing process was slowed as evidenced by lower total heat of reaction and lower glass transition temperatures of the cured nanocomposites compared to neat epoxy. This finding is practically important as it is essential to have a consistent degree of cure when the properties of thermosets with nanoinclusions are compared to neat resins. It was also found that the inclusion of carbon nanotubes might induce the thermal degradation of epoxy composites at lower temperatures. Morphological analysis done with scanning electron microscopy revealed good dispersion of nanotubes within the epoxy matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5248–5254, 2006 相似文献
1000.
James Courmarcel Naouël Mostefaï Sabine Sirol Sabine Choppin Olivier Riant 《Israel journal of chemistry》2001,41(4):231-240
A new copper(II) fluoride–chiral diphosphines catalytic system was developed. This one is very efficient and selective for the hydrosilylation of several substituted or unsubstituted aromatic ketones in so far as moderate to excellent enantioselectivities were obtained. An oxygen acceleration effect was observed that led us to propose a practical protocol with a low amount of catalyst. 相似文献