首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   293篇
  免费   23篇
电工技术   3篇
化学工业   169篇
金属工艺   3篇
机械仪表   5篇
建筑科学   7篇
能源动力   5篇
轻工业   49篇
水利工程   1篇
无线电   8篇
一般工业技术   27篇
冶金工业   9篇
原子能技术   3篇
自动化技术   27篇
  2023年   2篇
  2022年   40篇
  2021年   51篇
  2020年   15篇
  2019年   6篇
  2018年   13篇
  2017年   10篇
  2016年   9篇
  2015年   10篇
  2014年   12篇
  2013年   23篇
  2012年   19篇
  2011年   21篇
  2010年   10篇
  2009年   15篇
  2008年   16篇
  2007年   10篇
  2006年   11篇
  2005年   1篇
  2004年   5篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1997年   1篇
  1996年   3篇
  1994年   1篇
  1993年   1篇
  1989年   1篇
排序方式: 共有316条查询结果,搜索用时 31 毫秒
301.
The present editorial aims to summarise the six scientific papers that have contributed to this Special Issue, focusing on different aspects of molecular and translational research on colorectal cancer. We believe that the present Special Issue might contribute to the expansion of the current knowledge concerning potential molecular predictive and/or prognostic biomarkers in CRC, as well as new targets for anticancer treatment. This may help in identifying new strategies to improve diagnostic and therapeutic approaches.  相似文献   
302.
303.
Stable gold nanoparticles stabilized by different mono and bi-functional arenethiols, namely, benzylthiol and 1,4-benzenedimethanethiol, have been prepared by using a modified Brust's two-phase synthesis. The size, shape, and crystalline structure of the gold nanoparticles have been determined by high-resolution electron microscopy and full-pattern X-ray powder diffraction analyses. Nanocrystals diameters have been tuned in the range 2 ÷ 9 nm by a proper variation of Au/S molar ratio. The chemical composition of gold nanoparticles and their interaction with thiols have been investigated by X-ray photoelectron spectroscopy. In particular, the formation of networks has been observed with interconnected gold nanoparticles containing 1,4-benzenedimethanethiol as ligand.  相似文献   
304.
In this research work organic/inorganic nano composites were synthesized from poly-2-hydroxyethylmethacrylate and properly modified silica nanoparticles by in situ polymerization. In particular, fumed nanosilica was functionalized with methacryloylpropyltrimetoxy silane (MPTMS) in order to obtain a more homogeneous, reliable and mechanically performing nano composite. For comparison, nano composites with non functionalised silica were also prepared. Scanning electron microscopy was performed in order to visualize the effects of functionalization on the mode and state of dispersion. This analysis demonstrated that MPTMS grafted onto silica surface acts as an effective coupling agent and assures a good dispersion and distribution of nanoparticles as well as a strong nano particle/matrix interfacial adhesion. As a result of strong interactions occurring between phases, a pronounced increase of the glass transition temperature and mechanical parameters were recorded. Finally, these novel nano composites were seeded with murine fibroblast and human mesenchymal stem cells, and observed in time-lapse experiments proving an effective biological response.  相似文献   
305.
306.
We show that thin films of silica loaded with 22 wt% of carbon nanotubes (CNTs) can be deposited on cellulose substrate via the sol–gel route by a well-controlled process. The high loadings are obtained by airbrush spraying of a diluted sol solution (which contained a much smaller concentration of CNTs) followed by drying at 200 °C. The films are nearly continuous despite the fibrous structure of the substrate. The high degree of connectivity of the stranded structure of the CNTs yields a specific electrical conductivity of 3 × 103 Ω−1 m−1. In contrast, films made with high loadings of carbon black have poor electrical conductivity. Results from mechanical tensile tests of samples are also reported. This economical method of producing CNT dispersed thin films could find application in catalysis, as electrodes in fuel cells and batteries, and in sensor technologies.  相似文献   
307.
BACKGROUND: Contamination by mycotoxins is a major concern to the maize industry in north‐east Italy where maize grain is often spoiled by Fusarium spp. In this work, fumonisins, deoxynivalenol and zearalenone were determined and an artificial neural network (ANN) model suitable for predicting mycotoxin contamination of maize at harvest time was developed. RESULTS: The occurrence of deoxynivalenol and zearalenone was very limited, while fumonisins concentration ranged from 163 and to 3663 µg kg?1 in 2007, and from 333 to 11473 µg kg?1 in 2008. Statistical data analysis of factors affecting fumonisins concentration revealed that irrigation, chemical treatment against the European corn borer and harvest date significantly affected the level of contamination (P < 0.05), although the relevance of the factors was different in 2007 and 2008. The neural network approach showed a significant correlation between ascertained values and predictions based on agronomic data. CONCLUSION: This is the first time that an artificial neural network has been used to predict fumonisin accumulation in maize: the prediction has been shown to have the potential for the development of a new approach for the rapid cataloging of grain lots. Copyright © 2012 Society of Chemical Industry  相似文献   
308.
Sn, Sn-Sb, Ti, Zr, Fe, Ce and In oxides are prepared as nanometric powders by the hydrolytic route, starting from their ordinary salts or alkoxides, in the presence of 5% w/v starch as a non-ionic stabilizer of crystallization nuclei versus coalescence and flocculation. The starch can be degraded by a-amylase to soluble glucosidic oligomers, which may further be degraded by yeast to CO2 and ethanol. The nanoparticle features of prepared oxides result from experimental evidence based on X-ray diffractometry, transmission electron microscopy, differential thermal analysis/thermogravimetry coupled to mass spectrometry, specific surface area and porosity of samples obtained by curing in the 80-600 degrees C interval.  相似文献   
309.
Tadalafil is a selective phosphodiesterase type-5 (PDE5) inhibitor that is approved for the treatment of men with erectile dysfunction (ED) and/or benign prostate hyperplasia (BPH) -associated symptoms. Besides its classical actions on PDE5 within the genitourinary tract, where the specific enzyme expression is maximal, it may exert different systemic effects. This is mainly due to the pleiotropic distribution of PDE5 enzyme throughout the human (and animal) body, where it can exert protective effects in different clinical conditions. Recently, it has been demonstrated that tadalafil may display novel actions on androgen receptor (AR) expression and activity and cytochrome P19a1 (Cyp19a1) and estrogen receptor β (ERβ) expression in different in vitro systems, such as adipose, bone and prostate cancer cells, where it can act as a selective modulator of steroid hormone production. This may determine novel potential mechanism(s) of control in pathophysiologic pathways. In this review, we summarize basic research and translational results applicable to the use of tadalafil in the treatment of obesity, bone loss and prostate cancer.  相似文献   
310.
The effect of the addition of different concentration of inulin fibre to durum wheat pasta was evaluated in terms of structure, texture and morphological characteristics. Inulin fibre fraction was incorporated into pasta at 5%, 10% and 15% inclusion rates. Changes to pasta quality were observed with inulin fibre fraction addition by scanning electron microscopy, X-ray diffraction and Raman spectroscopy methods. Investigation of pasta microstructure indicate a lowering in crystallinity increasing the inulin content and characterisation of starch gelatinisation events indicated that a combination of changes to the starch–protein matrix and the high water-binding capacity of inulin alters the physico-chemical properties and then the digestibility of the pastas.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号