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   241篇
  免费   16篇
电工技术   3篇
化学工业   50篇
金属工艺   6篇
机械仪表   12篇
建筑科学   13篇
能源动力   30篇
轻工业   12篇
水利工程   1篇
石油天然气   1篇
无线电   25篇
一般工业技术   62篇
冶金工业   8篇
原子能技术   3篇
自动化技术   31篇
  2023年   8篇
  2022年   2篇
  2021年   7篇
  2020年   4篇
  2019年   5篇
  2018年   11篇
  2017年   8篇
  2016年   9篇
  2015年   13篇
  2014年   15篇
  2013年   20篇
  2012年   16篇
  2011年   26篇
  2010年   22篇
  2009年   15篇
  2008年   13篇
  2007年   15篇
  2006年   15篇
  2005年   9篇
  2004年   5篇
  2003年   6篇
  2002年   1篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1989年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
排序方式: 共有257条查询结果,搜索用时 15 毫秒
1.
2.
The main scope of this comprehensive study is to investigate the effects of poly(p-benzophenoneoxycarbonylphenyl acrylate), poly(BPOCPA), which presenting as only graft units or both graft and ungrafted units in the matrix, on the fundamental features of isotactic polypropylene (IPP). The graft copolymerization of BPOCPA onto IPP was performed with the aid of bulk melt polymerization at varying monomer content levels ranging from 5% to 40%. The thermal behavior, crystal quality, mechanical performance, and surface morphology of the samples were investigated by means of differential scanning calorimeter, X-ray diffractometer (XRD), universal mechanical test, and scanning electron microscope (SEM) techniques. Thermal analyses depicted that there existed the noteworthy enhancements in both crystalline melting temperatures and percent crystallinities of matrix polymers. Furthermore, according to XRD results, a and b parameters increased significantly at low percentages of the graft units, while the parameter c decreased in all products in consistence with the content. As for the mechanical characterization, the grafting led to remarkable improvements in modulus, tensile and impact strength of the products. SEM micrographs indicated that the samples were completely homogeneous without any phase separation and the products exhibited brittle nature with some ductility.  相似文献   
3.
Journal of Materials Science: Materials in Electronics - In this study, zinc oxide (ZnO) nanowires (NWs) were successfully produced on Zn plates through electrochemical anodization in potassium...  相似文献   
4.

A solar-blind ultraviolet photodetector based on Ti-doped Ga2O3/Si p–n heterojunction is demonstrated for the first time. It is found that the heterojunction quality forming between Ga2O3 and Si becomes better after Ti incorporation in Ga2O3. The current–voltage and temporal response measurements show that the detector based on Ti-doped Ga2O3/Si p–n heterojunction has a responsivity of 0.382 A/W and a fast rise time of 73 ms as well, which are much better than those undoped Ga2O3/Si p–n heterojunction analogues.

  相似文献   
5.
6.
Polyacrylonitrile/polyurethane/poly(m-anthranilic acid) nanofibers were fabricated by electrospinning. Tyrosinase immobilization was performed by EDC/N-hydroxyl succinimide activation. Covalent binding of tyrosinase onto nanofibers was confirmed by Fourier transform infrared-attenuated total reflectance, and bicinchoninic acid assay revealed the amount of enzyme. Nanofiber morphology and composition were characterized by scanning electron microscopy/energy-dispersive X-ray spectroscopy (EDX). Nanofibers became smoother and thicker after tyrosinase immobilization. Effects of enzyme on nanofibers were investigated by electrochemical impedance spectroscopy and the data were fitted to equivalent electrical circuit model. EDX-mapping showed uniform distribution of enzyme. The solution resistance and charge transfer resistance of nanofibers decreased after enzyme immobilization.  相似文献   
7.
8.
Circulating nucleic acids (CNAs) are under investigation as a liquid biopsy in cancer as potential non-invasive biomarkers, as stable structure in circulation nucleosomes could be valuable sources for detection of cancer-specific alterations in histone modifications. Our interest is in histone methylation marks with a focus on colorectal cancer, one of the leading cancers respective the incidence and mortality. Our previous work included the analysis of trimethylations of lysine 9 on histone 3 (H3K9me3) and of lysine 20 on histone 4 (H4K20me3) by chromatin immuno- precipitation-related PCR in circulating nucleosomes. Here we asked whether global immunologic measurement of histone marks in circulation could be a suitable approach to show their potential as biomarkers. In addition to H3K9me3 and H4K20me3 we also measured H3K27me3 in plasma samples from CRC patients (n = 63) and cancer free individuals (n = 40) by ELISA-based methylation assays. Our results show that of three marks, the amounts of H3K27me3 (p = 0.04) and H4K20me3 (p < 0.001) were significantly lower in CRC patients than in healthy controls. For H3K9me3 similar amounts were measured in both groups. Areas under the curve (AUC) in receiver operating characteristic (ROC) curves indicating the power of CRC detection were 0.620 for H3K27me3, 0.715 for H4K20me3 and 0.769 for the combination of both markers. In conclusion, findings of this preliminary study reveal the potential of blood-based detection of CRC by quantification of histone methylation marks and the additive effect of the marker combination.  相似文献   
9.
10.
The lower heating value is an important parameter to conduct the modeling of any fuel processing system. In this study, the relationship between the physical composition of municipal solid waste and its lower heating values was investigated using a Bayesian regularized artificial neural network (ANN) as an artificial intelligence approach. A new nonlinear regression model was also developed in this study. The artificial intelligence approach was compared using the developed and published correlations. The approach offers a high degree of correlation, and as a result, the ANN provides a useful tool for designing any thermolysis process for municipal solid waste.  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