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   263篇
  免费   24篇
  国内免费   2篇
电工技术   7篇
化学工业   85篇
金属工艺   2篇
机械仪表   10篇
建筑科学   6篇
能源动力   12篇
轻工业   49篇
水利工程   7篇
石油天然气   1篇
无线电   12篇
一般工业技术   56篇
冶金工业   6篇
自动化技术   36篇
  2024年   1篇
  2023年   3篇
  2022年   11篇
  2021年   32篇
  2020年   18篇
  2019年   29篇
  2018年   31篇
  2017年   22篇
  2016年   26篇
  2015年   14篇
  2014年   19篇
  2013年   35篇
  2012年   18篇
  2011年   19篇
  2010年   5篇
  2008年   2篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
排序方式: 共有289条查询结果,搜索用时 10 毫秒
91.
A fish roe protein hydrolysate from rainbow trout (Oncorhynchus mykiss) trout roe protein hydrolysates (TRH) was produced by pepsin and Alcalase. Proximate, amino acid compositions, protein digestibility and molecular mass distribution of the hydrolysates were determined. The degree of hydrolysis was found to be 44.08% and 27.62% (pepsin and Alcalase, respectively). The two hydrolysates contained a high amount of essential amino acids (33.53% Alcalase–29.39% pepsin). The results showed that TRH by different enzymes is a good source of the leucine and lysine amino acids. The pepsin produced a white powder with higher brightness (L* = 89.50). Alcalase hydrolysate was brownish yellow in colour (L* = 52.85, a* = 10.30, b* = 26.25). The hydrolysates represented excellent antioxidant activities in various concentrations. TRHs showed a good foaming and emulsification properties. The results thus revealed that protein hydrolysates from rainbow trout roe could be used as food additives possessing essential amino acids and antioxidant activity.  相似文献   
92.
93.
Sadi  Mahsa H.  Yu  Eric 《Requirements Engineering》2021,26(2):185-236
Requirements Engineering - With the rise in initiatives such as software ecosystems and Internet of Things (IoT), developing web Application Programming Interfaces (web APIs) has become an...  相似文献   
94.
95.
96.
In this paper, the glass composition of (50-x)P2O5-xB2O3-30CuO-20Li2O (x?=?0, 5, 10, 15, and 20?mol%) was prepared and the effect of P2O5 substitution by B2O3 on their structural, optical, switching, and antibacterial characteristics was studied. FT-IR spectra showed that an increase in the B2O3 content leads to gradual erosion of the phosphate characteristic bonds, and the emergence of borate-related ones by creating new linkages between phosphate chains through P–O–B bonds and formation of highly cross-linked P3-O-B4 linkages. The incorporation of boron up to 20?mol%, also leads to an overall increase in glass transition temperature together with a decrease in the molar volume which both, implied improvement of glass stability. Optical studies revealed that all glasses are almost transparent in the UV–Vis region with high band gap energy about 3.83?eV, which experiences a red-shift with increase in the B2O3 concentration to 15?mol%. By calculating the wavelength-dependent optical parameters, however, it was found that the present glass composition with highest concentration of B2O3 shows refractive index near one and very negligible extinction coefficient (and imaginary optical dielectric function) at the visible region. These results support the great potential of the mentioned glass composition as a window layer. The analysis of the high electric field measurements demonstrated a wide range reduction in switching threshold voltage as the B2O3 content increases. This hints at their potential application as electrical-induced sensors. The antibacterial activity of x?=?0 and x?=?5 glass compositions has been examined by zone of inhibition measurements and it was found that they have potential applications as antibacterial agent.  相似文献   
97.
In the present study, a magnetic niosomal nanocarrier for co-delivery of curcumin and letrozole into breast cancer cells has been designed. The magnetic NiCoFe2O4 core was coated by a thin layer of silica, followed by a niosomal structure, allowing us to load letrozole and curcumin into the silica layer and niosomal layer, respectively, and investigate their synergic effects on breast cancer cells. Furthermore, the nanocarriers demonstrated a pH-dependent release due to the niosomal structure at their outer layer, which is a promising behavior for cancer treatment. Additionally, cellular assays revealed that the nanocarriers had low cellular uptake in the case of non-tumorigenic cells (i.e., MCF-10A) and related high viability but high cellular uptake in cancer cell lines (i.e., MDA-MB-231 and SK-BR-3) and related low viability, which is evidenced in their high cytotoxicity against different breast cancer cell lines. The cytotoxicity of the letrozole/curcumin co-loaded nanocarrier is higher than that of the aqueous solutions of both drugs, indicating their enhanced cellular uptake in their encapsulated states. In particular, NiCoFe2O4@L-Silica-L@C-Niosome showed the highest cytotoxicity effects on MDA-MB-231 and SK-BR-3 breast cancer cells. The observed cytotoxicity was due to regulation of the expression levels of the studied genes in breast cancer cells, where downregulation was observed for the Bcl-2, MMP 2, MMP 9, cyclin D, and cyclin E genes while upregulation of the expression of the Bax, caspase-3, and caspase-9 genes was observed. The flow cytometry results also revealed that NiCoFe2O4@L-Silica-L@C-Niosome enhanced the apoptosis rate in both MDA-MB-231 and SK-BR-3 cells compared to the control samples. The findings of our research show the potential of designing magnetic niosomal formulations for simultaneous targeted delivery of both hydrophobic and hydrophilic drugs into cancer cells in order to enhance their synergic chemotherapeutic effects. These results could open new avenues into the future of nanomedicine and the development of theranostic agents.  相似文献   
98.
A new dimethyltin(IV) complex, {[Me2Sn(O2CNC9H6)]2O}2 (1), was prepared by reaction of dimethyltin(IV) dichloride with the quinoline-2-carboxylic acid and characterized by elemental analysis, IR, 1H-, 13C-, 119Sn-NMR spectroscopes. The structure of 1 was determined by single-crystal X-ray diffraction. The results showed that 1 is a tetranuclear, centrosymmetric dimeric, and contains two endo-cyclic five-coordinated and two exo-cyclic six-coordinated tin atoms and a N-atom of the 2-quinaldic carboxylate ligand coordinated to exo-cyclic tin. Complex 1 was utilized as a precursor for SnO2 nanoparticles by direct thermal decomposition at 500 °C in air. The nano-structure of SnO2 was characterized by scanning electron microscopy and X-ray powder diffraction. The SnO2 core showed a band gap of ~4 eV determined from the UV/visible absorption spectrum. The SnO2 nanoparticles show stable photoluminescence (PL) with an emission centered at 557 nm.  相似文献   
99.
Moradi  Parisa  Vafaee  Yavar  Mozafari  Ali Akbar  Tahir  Nawroz Abdul-razzak 《SILICON》2022,14(16):10559-10569
Silicon - Salinity is one of the most crucial abiotic stresses, which is the consequence of an increase in the concentration of NaCl ions, influencing the plant’s growth, development, and...  相似文献   
100.
Meniscus lesions are frequently occurring injuries with poor ability to heal. Typical treatment procedure includes removal of damaged regions, which can lead to sub-optimal knee biomechanics and early onset of osteoarthritis. Some of the drawbacks of current treatment approach present an opportunity for a tissue engineering solution. In this study, gelatin (G)/chitosan (Cs) scaffolds were synthesized via gel casting method and cross-linked with naturally derived cross-linker, genipin, through scaffold cross-linking method. Based on the characteristics of native meniscus tissue microstructure and function, three different layers were chosen to design the macroporous multilayered scaffolds. The multi-layered scaffolds were investigated for their ability to support human-derived meniscus cells by evaluating their morphology and proliferation using MTT assay at various time points. Based on structural, mechanical and cell compatibility considerations, laminated scaffolds composed of G60/Cs40, G80/Cs20 and G40/Cs60 samples, for the first, second and third layers, respectively, could be an appropriate combination for meniscus tissue engineering applications.  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