全文获取类型
收费全文 | 387篇 |
免费 | 25篇 |
专业分类
化学工业 | 211篇 |
金属工艺 | 8篇 |
机械仪表 | 2篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 14篇 |
轻工业 | 70篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 49篇 |
冶金工业 | 8篇 |
自动化技术 | 27篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 47篇 |
2021年 | 60篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 19篇 |
2016年 | 12篇 |
2015年 | 17篇 |
2014年 | 15篇 |
2013年 | 16篇 |
2012年 | 19篇 |
2011年 | 26篇 |
2010年 | 13篇 |
2009年 | 16篇 |
2008年 | 27篇 |
2007年 | 16篇 |
2006年 | 20篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有412条查询结果,搜索用时 15 毫秒
11.
Mechanism of MxOy nanoparticles/CNTs for catalytic carbonization of polyethylene and application to flame retardancy 下载免费PDF全文
Karolina Wenelska Xuecheng Chen Beata Zielinska Ryszard J. Kaleńczuk Paul K. Chu Tao Tang Ewa Mijowska 《应用聚合物科学杂志》2017,134(34)
Three kinds of metal oxide nanoparticles (Fe3O4, Co3O4, and Ni2O3) are produced on carbon nanotubes (CNTs). The synergistic effects rendered by the CNTs and metal oxide nanoparticles on carbonization of polyethylene (PE) are studied and applications to flame retardancy of PE are investigated systematically. The CNT‐Ni2O3 delivers the best performance and the mechanism pertaining to the enhanced flame retardancy is proposed and discussed. It is found that under the same conditions, the carbonization rate can be a factor to influence the flame retardancy performance. Among Fe, Co, and Ni, Ni has the fastest carbonation rate, which leads to the best flame retardancy performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45233. 相似文献
12.
Beata Tryba Antoni W. Morawski Michio Inagaki Masahiro Toyoda 《Applied catalysis. B, Environmental》2006,63(3-4):215-221
H2O2 used in the photo-Fenton reaction with iron catalyst can accelerate the oxidation of Fe2+ to Fe3+ under UV irradiation and in the dark (in the so called dark Fenton process). It was proved that conversion of phenol under UV irradiation in the presence of H2O2 predominantly produces highly hydrophilic products and catechol, which can accelerate the rate of phenol decomposition. However, while H2O2 under UV irradiation could decompose phenol to highly hydrophilic products and dihydroxybenzenes in a very short time, complete mineralization proceeded rather slowly. When H2O2 is used for phenol decomposition in the presence of TiO2 and Fe–TiO2, decrease of OH radicals formed on the surface of TiO2 and Fe–TiO2 has been observed and photodecomposition of phenol is slowed down. In case of phenol decomposition under UV irradiation on Fe–C–TiO2 photocatalyst in the presence of H2O2, marked acceleration of the decomposition rate is observed due to the photo-Fenton reactions: Fe2+ is likely oxidized to Fe3+, which is then efficiently recycled to Fe2+ by the intermediate products formed during phenol decomposition, such as hydroquinone (HQ) and catechol. 相似文献
13.
14.
Beata Biaobok Janusz Trawczyski Wodzimierz Mita Mirosaw Zawadzki 《Applied catalysis. B, Environmental》2007,72(3-4):395-403
Ce- or Sr-doped LaCoO3 bulk perovskites were prepared by citric acid method as well as 10 wt.% of LaCoO3 was deposited on alumina carrier stabilized with lanthanum. Properties of prepared materials were characterized by determination of surface area, acid-basic properties and XRD, XPS, TPDO2, H2-TPR measurements as well as catalytic activity and selectivity for ethanol combustion was tested. It was found that substitution of La in LaCoO3 with either Sr or Ce has only small effect on its activity in ethanol combustion. Strontium inserted into LaCoO3 structure increases basic character of the perovskite surface as well as selectivity to acetaldehyde (ACA). Substitution of La with cerium has no effect on the concentration of basic sites and does not affect the selectivity to ACA. Activity of LaCoO3-based catalysts in ethanol combustion and their selectivity to ACA formation can be explained on the basis of the presence of both -oxygen species and sites with basic character on the material surface.
Acid-basic properties of supported LaCoO3 are dominated by acidic character of the carrier. Results of XPS and H2-TPR measurements of LaCoO3 supported on La–Al2O3 suggest that perovskite remains in strong interaction with carrier and probably is partially decomposed. Deposition of perovskite on stabilized carrier significantly increases the rate of ethanol combustion. 相似文献
15.
Vitamin D Compounds PRI-2191 and PRI-2205 Enhance Anastrozole Activity in Human Breast Cancer Models
Beata Filip-Psurska Mateusz Psurski Artur Anisiewicz Patrycja Libako Ewa Zbrojewicz Magdalena Maciejewska Micha Chodyski Andrzej Kutner Joanna Wietrzyk 《International journal of molecular sciences》2021,22(5)
1,25-Dihydroxycholecalciferol, the hormonally active vitamin D3 metabolite, is known to exhibit therapeutic effects against breast cancer, mainly by lowering the expression of estrogen receptors and aromatase activity. Previously, the safety of the vitamin D active metabolite (24R)-1,24-dihydroxycholecalciferol (PRI-2191) and 1,25(OH)2D3 analog PRI-2205 was tested, and the in vitro activity of these analogs against different cancer cell lines was studied. We determined the effect of the two vitamin D compounds on anastrozole (An) activity against breast cancer based on antiproliferative activity, ELISA, flow cytometry, enzyme inhibition potency, PCR, and xenograft study. Both the vitamin D active metabolite and synthetic analog regulated the growth of not only estrogen receptor-positive cells (T47D and MCF-7, in vitro and in vivo), but also hormone-independent cancer cells such as SKBR-3 (HER-2-positive) and MDA-MB-231 (triple-negative), despite their relatively low VDR expression. Combined with An, PRI-2191 and PRI-2205 significantly inhibited the tumor growth of MCF-7 cells. Potentiation of the antitumor activity in combined treatment of MCF-7 tumor-bearing mice is related to the reduced activity of aromatase by both An (enzyme inhibition) and vitamin D compounds (switched off/decreased aromatase gene expression, decreased expression of other genes related to estrogen signaling) and by regulation of the expression of the estrogen receptor ERα and VDR. 相似文献
16.
Dora Szabo Zsolt Sarszegi Beata Polgar Eva Saghy Adam Nemeth Dora Reglodi Andras Makkos Aniko Gorbe Zsuzsanna Helyes Peter Ferdinandy Robert Herczeg Attila Gyenesei Attila Cziraki Andrea Tamas 《International journal of molecular sciences》2021,22(6)
Acute myocardial infarction (MI) is one of the most common causes of death worldwide. Pituitary adenylate cyclase activating polypeptide (PACAP) is a cardioprotective neuropeptide expressing its receptors in the cardiovascular system. The aim of our study was to examine tissue PACAP-38 in a translational porcine MI model and plasma PACAP-38 levels in patients with ST-segment elevation myocardial infarction (STEMI). Significantly lower PACAP-38 levels were detected in the non-ischemic region of the left ventricle (LV) in MI heart compared to the ischemic region of MI-LV and also to the Sham-operated LV in porcine MI model. In STEMI patients, plasma PACAP-38 level was significantly higher before percutaneous coronary intervention (PCI) compared to controls, and decreased after PCI. Significant negative correlation was found between plasma PACAP-38 and troponin levels. Furthermore, a significant effect was revealed between plasma PACAP-38, hypertension and HbA1c levels. This was the first study showing significant changes in cardiac tissue PACAP levels in a porcine MI model and plasma PACAP levels in STEMI patients. These results suggest that PACAP, due to its cardioprotective effects, may play a regulatory role in MI and could be a potential biomarker or drug target in MI. 相似文献
17.
Marta Gowacka Sara Lipka Ewelina Mynarska Beata Franczyk Jacek Rysz 《International journal of molecular sciences》2021,22(15)
COVID-19 is mainly considered a respiratory illness, but since SARS-CoV-2 uses the angiotensin converting enzyme 2 receptor (ACE2) to enter human cells, the kidney is also a target of the viral infection. Acute kidney injury (AKI) is the most alarming condition in COVID-19 patients. Recent studies have confirmed the direct entry of SARS-CoV-2 into the renal cells, namely podocytes and proximal tubular cells, but this is not the only pathomechanism of kidney damage. Hypovolemia, cytokine storm and collapsing glomerulopathy also play an important role. An increasing number of papers suggest a strong association between AKI development and higher mortality in COVID-19 patients, hence our interest in the matter. Although knowledge about the role of kidneys in SARS-CoV-2 infection is changing dynamically and is yet to be fully investigated, we present an insight into the possible pathomechanisms of AKI in COVID-19, its clinical features, risk factors, impact on hospitalization and possible ways for its management via renal replacement therapy. 相似文献
18.
Adam Pietras Aleksandra Węglowska Beata Rams Marek Węglowski 《Welding International》2016,30(2):112-118
The article presents the results of research on the use of the new technology of friction welding with a non-wearing tool for welding pipe ends with lids. The pipes and lids were made of aluminium alloy EN AW 2017A, non-weldable by conventional methods. The aim of the study was to verify the possibility of welding the lid to the pipe using the FSW method as well as a new method with a tool with specially profiled friction surface. The article presents the results of structural tests and strength tests of the weld joints obtained using the new technique. 相似文献
19.
Absorption and photoreflectance spectroscopy of zinc phthalocyanine (ZnPc) thin films grown by thermal evaporation 总被引:1,自引:0,他引:1
Optical properties of the as-deposited and annealed ZnPc layers have been investigated using absorption, reflectance and modulated photoreflectance methods. The absorption coefficient of ZnPc layers was directly determined from the transmission and reflection spectra. The absorption spectra were analyzed in terms of the mixed Lorentz–Lorenz model. We found that annealing thin layers at 580 K caused a structural transformation, which results in the decrease of the absorption coefficient and the shifting of all peak position to lower energies except for the peak of the N-band. Photoreflectance spectroscopy confirmed that there exist three transitions in the Q-band region of the studied material. Complex refractive index and dielectric constants of the ZnPc layer were directly found from the spectral data. 相似文献
20.
Wojciech Zalewski Beata Niezgoda-
elasko Marek Litwin 《International Journal of Refrigeration》2000,23(7):553
In the paper the optimization of geometrical and operating parameters for evaporative fluid coolers has been presented. The algorithm of optimizational calculations contains:
- • the mathematical model of heat and mass transfer in evaporative fluid coolers;
- • model of operating costs based, among others, on the Zalewski–Gryglaszewski relations developed by the authors for evaluation of air pressure drops in the heat exchanger;
- • model of evaporative heat exchangers production costs.