全文获取类型
收费全文 | 292篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 64篇 |
金属工艺 | 9篇 |
机械仪表 | 8篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 20篇 |
轻工业 | 30篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 18篇 |
一般工业技术 | 61篇 |
冶金工业 | 32篇 |
自动化技术 | 41篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 25篇 |
2012年 | 27篇 |
2011年 | 15篇 |
2010年 | 14篇 |
2009年 | 17篇 |
2008年 | 16篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 13篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有298条查询结果,搜索用时 15 毫秒
161.
162.
Sergey A. Menzikov Danila M. Zaichenko Aleksey A. Moskovtsev Sergey G. Morozov Aslan A. Kubatiev 《International journal of molecular sciences》2022,23(10)
γ-Aminobutyric acid type A receptors (GABAARs) mediate primarily inhibitory synaptic transmission in the central nervous system. Following fast-paced activation, which provides the selective flow of mainly chloride (Cl−) and less bicarbonate (HCO3−) ions via the pore, these receptors undergo desensitization that is paradoxically prevented by the process of their recovery, referred to as resensitization. To clarify the mechanism of resensitization, we used the cortical synaptoneurosomes from the rat brain and HEK 293FT cells. Here, we describe the effect of γ-phosphate analogues (γPAs) that mimic various states of ATP hydrolysis on GABAAR-mediated Cl− and HCO3− fluxes in response to the first and repeated application of the agonist. We found that depending on the presence of bicarbonate, opened and desensitized states of the wild or chimeric GABAARs had different sensitivities to γPAs. This study presents the evidence that recovery of neuronal Cl− and HCO3− concentrations after desensitization is accompanied by a change in the intracellular ATP concentration via ATPase performance. The transition between the desensitization and resensitization states was linked to changes in both conformation and phosphorylation. In addition, the chimeric β3 isoform did not exhibit the desensitization of the GABAAR-mediated Cl− influx but only the resensitization. These observations lend a new physiological significance to the β3 subunit in the manifestation of GABAAR resensitization. 相似文献
163.
Semantic heterogeneity resolution in federated databases by metadata implantation and stepwise evolution 总被引:3,自引:0,他引:3
Goksel Aslan Dennis McLeod 《The VLDB Journal The International Journal on Very Large Data Bases》1999,8(2):120-132
A key aspect of interoperation among data-intensive systems involves the mediation of metadata and ontologies across database
boundaries. One way to achieve such mediation between a local database and a remote database is to fold remote metadata into
the local metadata, thereby creating a common platform through which information sharing and exchange becomes possible. Schema
implantation and semantic evolution, our approach to the metadata folding problem, is a partial database integration scheme
in which remote and local (meta)data are integrated in a stepwise manner over time. We introduce metadata implantation and
stepwise evolution techniques to interrelate database elements in different databases, and to resolve conflicts on the structure
and semantics of database elements (classes, attributes, and individual instances). We employ a semantically rich canonical
data model, and an incremental integration and semantic heterogeneity resolution scheme. In our approach, relationships between
local and remote information units are determined whenever enough knowledge about their semantics is acquired. The metadata
folding problem is solved by implanting remote database elements into the local database, a process that imports remote database
elements into the local database environment, hypothesizes the relevance of local and remote classes, and customizes the organization
of remote metadata. We have implemented a prototype system and demonstrated its use in an experimental neuroscience environment.
Received June 19, 1998 / Accepted April 20, 1999 相似文献
164.
Ibrahim Aslan Resitoglu Ali Keskin 《International Journal of Hydrogen Energy》2017,42(36):23389-23394
Diesel engines have been considered as a major source in nitrogen oxide (NOx) formation worldwide. The widespread use of diesel engines in consequence of their low fuel consumption, high durability and efficiency increases NOx emissions day by day. NOx emissions from diesel engines cause unavoidable damage on environment and people health. Although so many technologies such as exhaust gas recirculation (EGR), lean burn combustion, electronic controlling fuel injection systems, etc. have been developed to control NOx emissions from diesel engines, they couldn't meet the desired reduction in NOx emissions. In any case, Selective Catalytic Reduction (SCR) as one of the most promising aftertreatment-emission control technologies is an effective solution in restriction of NOx emissions. The use of SCR systems especially in heavy-duty diesel powered vehicles has been increasing nowadays. In these systems, to use of hydrogen (H2) as a reductant or promoter have been improved the conversion efficiency especially at low exhaust temperatures. Many researchers have been focused on the use of H2 in SCR systems for controlling NOx emissions.In this study, the applications of H2 in SCR of NOx have been discussed. The studies on use of H2 in SCR of NOx emissions were examined and the effects on NOx conversions were determined. Consequently, it is confirmed that H2 is a promising and alternative reductant in SCR of NOx and it has been kept as an attracting subject for many researchers. 相似文献
165.
Airflow rate to a cell is one of the main operating variables in flotation. In many plants, if measurements are available at all, they are typically made on a line common to several cells with valves to distribute as determined by the operator. In this study, air distribution throughout zinc cleaner circuit of CBI was adjusted to three different profiles. These are “as found” which was the original profile adjusted by operators, “decreasing” and “increasing” profiles which were adjusted for test. It was seen that air distribution profile significantly affected flotation selectivity. Selectivity between both sphalerite–pyrite and sphalerite–chalcopyrite increased with “increasing” profile. The effect of air distribution profile on flotation selectivity was also studied at mini pilot plant (MPP). Zinc rougher concentrate was taken as feed of MPP. Air distribution profile was adjusted and controlled by airflow meters of each cell. Three different air profiles; “balanced”, “decreasing” and “increasing”, were tested. The results of MPP tests also confirmed that “increasing” air distribution profile improved selectivity at zinc cleaner circuit. 相似文献
166.
Robust adaptive unscented Kalman filter for attitude estimation of pico satellites 总被引:1,自引:0,他引:1 下载免费PDF全文
Chingiz Hajiyev Halil Ersin Soken 《International Journal of Adaptive Control and Signal Processing》2014,28(2):107-120
Unscented Kalman filter (UKF) is a filtering algorithm that gives sufficiently good estimation results for the estimation problems of nonlinear systems even when high nonlinearity is in question. However, in case of system uncertainty or measurement malfunctions, the UKF becomes inaccurate and diverges by time. This study introduces a fault‐tolerant attitude estimation algorithm for pico satellites. The algorithm uses a robust adaptive UKF, which performs correction for the process noise covariance (Q‐adaptation) or measurement noise covariance (R‐adaptation) depending on the type of the fault. By the use of a newly proposed adaptation scheme for the conventional UKF algorithm, the fault is detected and isolated, and the essential adaptation procedure is followed in accordance with the fault type. The proposed algorithm is tested as a part of the attitude estimation algorithm of a pico satellite. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
167.
Ay?e Aslan 《Journal of power sources》2009,191(2):442-447
The fabrication, thermal and proton conducting properties of complex polymer electrolytes based on poly(vinylphosphonic acid) (VPA) and poly(1-vinyl-1,2,4-triazole) (PVTri) were investigated throughout this work. The membrane materials were produced by complexation of PVPA with PVTri at various concentrations to get PVTriP(VPA)x where x designates the molar ratio of the polymer repeating units and varied from 0.25 to 4. The complexed structure of the polymers was confirmed by FT-IR spectroscopy. The TGA results verified that the presence of PVTri in the complex polymer electrolytes suppressed the formation of phosphonic acid anhydrides up to 150 °C. The DSC and SEM results demonstrated the homogeneity of the materials. Proton conductivity, activation energy and water/methanol uptake of these membranes were also measured. PVTriP(VPA)2 showed a proton conductivity of 2.5 × 10−5 S cm−1 at 180 °C in the anhydrous state. After humidification (RH = 50%), PVTri-P(VPA)4 and PVTri-P(VPA)2 showed respective proton conductivities of 0.008 and 0.022 S cm−1 at 100 °C, where the conductivity of the latter is close to Nafion 117 at the same humidity level. 相似文献
168.
The aim of the study is to lay bare the impact behavior of filled composite plates experimentally. The woven glass/polyester‐matrix composite plates filled with 0% (unfilled), 10%, and 20% SiCp ceramic particles were manufactured by hand lay‐up method. The low velocity drop impact testing is conducted to the composite samples subjected to increasing impact energies that were ranged from approximately 2.5 to 22.5 J. With this use of increasing impact energies, it was possible to examine the impact response and damage mechanism until perforation of the composite plates. An energy profiling method was used in order to identify the perforation thresholds of composites. It is concluded that addition of particles to resin, until a certain ratio, increases the perforation thresholds of the woven glass/polyester. The perforation threshold of 10% filled composite is about 37% higher than that of the 20% filled composite and 6% higher than ones of the unfilled composite. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
169.
Oktay Celep A. Deniz Bas Ersin Y. Yazici İbrahim Alp Haci Deveci 《Mineral Processing and Extractive Metallurgy Review》2013,34(4):227-236
Ultrafine grinding (UFG) was proposed as a pretreatment method prior to cyanide leaching of old plant tailings of a refractory silver ore. Direct cyanidation of the as-received tailings (d80: 100 µm) led to a low silver extraction of only ≤43% over 24 h. A size-based diagnostic study has demonstrated that the refractoriness of the tailings is essentially physical in character. Therefore, effects of particle size/UFG (d99: 5–75 µm), concentrations of NaCN (0.75–2.25 g/L) and Pb(NO3)2 (0–500 g/t) on the extraction of silver were investigated using a Box–Behnken design. The statistical analysis of the experimental data (%Ag extraction at 1 h) revealed that particle size/UFG was the most significant parameter for the extraction of silver, which was substantially improved after UFG. A positive effect of increasing the concentration of NaCN was also observed particularly at finer particle sizes while the effect of concentration of Pb(NO3)2 was insignificant. Almost complete extraction for silver (i.e., ≥99%) was demonstrated to be possible at even higher concentrations of cyanide (>2.25 g/L NaCN) when using the finest material (d99: 5 µm) over only 1 h of leaching. Albeit, the consumption of cyanide tended to increase with UFG or increasing the initial concentration of cyanide. The findings showed that UFG can be used as a suitable and environmentally sound pretreatment method to improve the extraction of silver from the refractory silver ore tailings. The diagnostic approach adopted in the current study has proved to be a useful analytical tool to determine the amenability of the ore to ultrafine-grinding as a pretreatment process. 相似文献
170.
We demonstrate high speed force-distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force-distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force-distance measurements. The method is demonstrated on self-assembled peptidic nanofibers. 相似文献