全文获取类型
收费全文 | 161篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 38篇 |
金属工艺 | 1篇 |
机械仪表 | 9篇 |
建筑科学 | 1篇 |
能源动力 | 5篇 |
轻工业 | 27篇 |
无线电 | 36篇 |
一般工业技术 | 44篇 |
冶金工业 | 2篇 |
原子能技术 | 3篇 |
自动化技术 | 8篇 |
出版年
2023年 | 3篇 |
2022年 | 11篇 |
2021年 | 11篇 |
2020年 | 15篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 11篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 15篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 17篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1997年 | 4篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 15 毫秒
1.
2.
The sorption characteristics of various liquids in poly(vinylidene fluoride) (PVDF) were investigated in relation to the Lewis acid–base interaction between the liquids and the polymer. The sorption amount of various liquids and the sorption selectivity of binary mixtures in PVDF were measured and their characteristics were found to be significantly affected by acid–base interaction. The acid–base interaction was evaluated from the Drago constants of PVDF, which were obtained by extending the Fowkes' method observing the shift of stretching frequency of the carbonyl bond of ethylacetate sorbed in PVDF. The partial molar enthalpy change of mixing at infinite dilution was estimated using the Drago constants of PVDF and used as a parameter explaining the sorption characteristics of liquids in PVDF. © 1992 John Wiley & Sons, Inc. 相似文献
3.
Myeong Won Lee Jae Moon Lee 《国际自动化与计算杂志》2007,4(1):25-29
In this paper,we present a framework for the generation and control of an Internet-based 3-dimensionai game virtual environment that allows a character to navigate through the environment.Our framework includes 3-dimensional terrain mesh data processing,a map editor,scene processing,collision processing,and waikthrough control.We also define an environment-specific semantic information editor,which can be applied using specific location obtained from the real world.Users can insert text information related to the characters real position in the real world during navigation in the game virtual environment. 相似文献
4.
Myeong Seong Sim Hye Jeong Kim Sang Hee Jo Chun Kim Il Yup Chung 《International journal of molecular sciences》2022,23(7)
Lysophosphatidylserine (LysoPS) is an amphipathic lysophospholipid that mediates a broad spectrum of inflammatory responses through a poorly characterized mechanism. Because LysoPS levels can rise in a variety of pathological conditions, we sought to investigate LysoPS’s potential role in airway epithelial cells that actively participate in lung homeostasis. Here, we report a previously unappreciated function of LysoPS in production of a mucin component, MUC5AC, in the airway epithelial cells. LysoPS stimulated lung epithelial cells to produce MUC5AC via signaling pathways involving TACE, EGFR, and ERK. Specifically, LysoPS- dependent biphasic activation of ERK resulted in TGF-α secretion and strong EGFR phosphorylation leading to MUC5AC production. Collectively, LysoPS induces the expression of MUC5AC via a feedback loop composed of proligand synthesis and its proteolysis by TACE and following autocrine EGFR activation. To our surprise, we were not able to find a role of GPCRs and TLR2, known LyoPS receptors in LysoPS-induced MUC5AC production in airway epithelial cells, suggesting a potential receptor-independent action of LysoPS during inflammation. This study provides new insight into the potential function and mechanism of LysoPS as an emerging lipid mediator in airway inflammation. 相似文献
5.
Ha Nee Jang Jin Hyun Kim Myeong Hee Jung Taekil Tak Jung Hwa Jung Seunghye Lee Sehyun Jung Se-Ho Chang Hyun-Jung Kim 《International journal of molecular sciences》2022,23(3)
Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) and progression to chronic kidney disease (CKD). However, no effective therapeutic intervention has been established for ischemic AKI. Endothelial progenitor cells (EPCs) have major roles in the maintenance of vascular integrity and the repair of endothelial damage; they also serve as therapeutic agents in various kidney diseases. Thus, we examined whether EPCs have a renoprotective effect in an IRI mouse model. Mice were assigned to sham, EPC, IRI-only, and EPC-treated IRI groups. EPCs originating from human peripheral blood were cultured. The EPCs were administered 5 min before reperfusion, and all mice were killed 72 h after IRI. Blood urea nitrogen, serum creatinine, and tissue injury were significantly increased in IRI mice; EPCs significantly improved the manifestations of IRI. Apoptotic cell death and oxidative stress were significantly reduced in EPC-treated IRI mice. Administration of EPCs decreased the expression levels of NLRP3, cleaved caspase-1, p-NF-κB, and p-p38. Furthermore, the expression levels of F4/80, ICAM-1, RORγt, and IL-17RA were significantly reduced in EPC-treated IRI mice. Finally, the levels of EMT-associated factors (TGF-β, α-SMA, Snail, and Twist) were significantly reduced in EPC-treated IRI mice. This study shows that inflammasome-mediated inflammation accompanied by immune modulation and fibrosis is a potential target of EPCs as a treatment for IRI-induced AKI and the prevention of progression to CKD. 相似文献
6.
Hoo Kun Lee Myeong Soo Jeong Joo Wan Park Hyun Soo Park Jong Hyun Cho 《Korean Journal of Chemical Engineering》1990,7(1):13-17
An absorption efficiency of packed column removing nitrogen oxides with water and NaOH solution under atmospheric pressure
was studied. The efficiency and the acidity produced by absorption of NO, were measured in a packed column. The model developed
that was based on the mass-transfer information for packed column and absorption mechanism accompanying the chemical reaction
was compared with experimental results. Predictions using the model presented by the previous paper (part 1) was shown well
to agree with from the experimental results (part II). The efficiency of NOx, absorption is largely dependent on the height of packing material and the partial pressure of NOx in the feed gas. The efficiency of NOx absorption decreases with the increase of the acidity produced by recycling of water as a scrubber liquid. For the recycle
mode with an aqueous NaOH solution as a scrubber liquid, NOx absorption efficiency is shown to be constant until all of the COH- in the scrubber liquid are converted into CH+. 相似文献
7.
Syndiotactic polystyrene (s‐PS) and atactic polystyrene (a‐PS) were melt‐spun into filaments. The s‐PS filaments exhibited increasing amounts of crystallinity and orientation with increasing drawdown ratio and spinline stress. The a‐PS filaments were amorphous but exhibited birefringence. The birefringence and Hermans orientation factors for a‐PS were proportional to this spinline stress. In ice water and at low drawdown ratios, the s‐PS is glassy or mesomorphic. At higher drawdown ratios and spinline stresses, it crystallized. The crystalline form was the zigzag TTTT hexagonal α‐form. The birefringence and orientation factors of the s‐PS filaments were higher than those of the a‐PS filaments and the difference of the birefringence increased with increasing spinline stress. Mechanical testing results showed that the Young's modulus and tensile strength generally increased with increasing spinline drawdown ratio for both a‐PS and s‐PS filaments. The elongation to break was enhanced for both materials by increased chain orientation. Polym. Eng. Sci. 44:2141–2147, 2004. © 2004 Society of Plastics Engineers. 相似文献
8.
In our study, we extracted the market, finance, and government factors determining R&D investment of individual firms in the IT industry in Korea. We collected the financial data of 515 individual firms belonging to IT and non‐IT industries between 1980 and 1999 from the Korea Investors Service's database and investigated the empirical relationship between the factors using an ordinary regression model, a fixed effects model, and a random effects model. The main findings of our study are as follows: i) The Herfindahl Index variable representing the degree of market concentration is statistically insignificant in explaining R&D expenditures in the IT manufacturing industry. ii) Assets, which is used as a proxy variable for firm size, have a positive and statistically significant coefficient. These two results suggest that the Schumpeterian Hypothesis may be only partially applied to the IT manufacturing industry in Korea. iii) The dividend variable has a negative value and is statistically significant, indicating that a tendency of high dividends can restrict the internal cash flow for R&D investment. iv) The sales variable representing growth potential shows a positive coefficient. v) The subsidy as a proxy variable for governmental R&D promotion policies is positively correlated with R&D expenditure. This suggests that government policy has played a significant role in promoting R&D activities of IT firms in Korea since 1980. vi) Using a dummy variable, we verified that firms reduced their R&D investments to secure sufficient liquidity under the restructuring pressure during Korea's 1998 and 1999 economic crisis. 相似文献
9.
Im Deok Jung Min Kook Cho Kong Myeong Bae Sang Min Lee Phill Gu Jung Ho Kyung Kim Sung Sik Kim Jong Soo Ko 《ETRI Journal》2008,30(5):747-749
We introduce a pixel‐structured scintillator realized on a flexible polymeric substrate and demonstrate its feasibility as an X‐ray converter when it is coupled to photosensitive elements. The sample was prepared by filling Gd2O2S:Tb scintillation material into a square‐pore‐shape cavity array fabricated with polyethylene. For comparison, a sample with the conventional continuous geometry was also prepared. Although the pixelated geometry showed X‐ray sensitivity of about 58% compared with the conventional geometry, the resolving power was improved by about 70% above a spatial frequency of 3 mm?1. The spatial frequency at 10% of the modulation‐transfer function was about 6 mm?1. 相似文献
10.
High impedance fault detection utilizing incremental variance ofnormalized even order harmonic power
Wook Hyun Kwon Gi Wen Lee Young Moon Park Man Chul Yoon Myeong Ho Yoo 《Power Delivery, IEEE Transactions on》1991,6(2):557-564
A novel method for the detection of high-impedance faults is proposed which uses the incremental variance of a normalized even order ratio measure. Staged fault tests were extensively carried out in Korean electric power systems. From the analysis of the staged fault test data, it was found that there exists an intermittent arcing phenomenon in most high-impedance faults and that the waveforms of this arcing fault current have an asymmetrical shape in each cycle. Based on these facts, three criteria, (even-order power, even-order ratio, and even-order incremental variance) for fault detection are presented, all of which are based on the changes of normalized even-order harmonic power in fault currents. These criteria are compared through the analysis of staged fault data and normal switching event data. It is shown that the even-order incremental variance criterion is superior to the other two criteria and that, with this criterion, high-impedance faults can be distinguished from normal switching events, including special loads such as electric furnaces and subways. Microprocessor-based protective relays, which can detect high-impedance faults by using the proposed methods, have been constructed, installed in Korea Electric Power Corporation substations, and tested during the last two years. Details of these field tests are given 相似文献