全文获取类型
收费全文 | 837篇 |
免费 | 49篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 4篇 |
化学工业 | 166篇 |
金属工艺 | 18篇 |
机械仪表 | 7篇 |
建筑科学 | 43篇 |
矿业工程 | 3篇 |
能源动力 | 21篇 |
轻工业 | 74篇 |
水利工程 | 4篇 |
武器工业 | 1篇 |
无线电 | 90篇 |
一般工业技术 | 170篇 |
冶金工业 | 76篇 |
原子能技术 | 10篇 |
自动化技术 | 198篇 |
出版年
2024年 | 4篇 |
2023年 | 15篇 |
2022年 | 18篇 |
2021年 | 27篇 |
2020年 | 20篇 |
2019年 | 34篇 |
2018年 | 33篇 |
2017年 | 21篇 |
2016年 | 42篇 |
2015年 | 33篇 |
2014年 | 41篇 |
2013年 | 48篇 |
2012年 | 47篇 |
2011年 | 71篇 |
2010年 | 44篇 |
2009年 | 44篇 |
2008年 | 55篇 |
2007年 | 45篇 |
2006年 | 43篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 13篇 |
2002年 | 29篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有888条查询结果,搜索用时 31 毫秒
31.
There is a demand for a clean label of ice cream in the food industry. To meet this requirement, alternative surfactants and hydrocolloids without an additive number have to be found. Here, a caseinate hydrolysate with improved interfacial properties was investigated as such an additive. Replacing only the surfactant resulted in ice cream characteristics, comparable to using a commercial emulsifier (INS 472b). Thus, a clean labeling of the surfactant using this hydrolysate is possible. By contrast, replacing the hydrocolloid additionally led to an unfavorable ice cream texture and stability. 相似文献
32.
Reconfiguring flexible machine modules of a PCB assembly line 总被引:2,自引:0,他引:2
Assembly of electronic components to Printed Circuit Boards (PCB) is a complicated manufacturing process and therefore its control is usually divided into several subtasks which are handled separately. We consider the combined task of determining a machine configuration and line balancing for a single assembly line of interconnected, reconfigurable machine modules and one PCB type in production. The modules can be tailored to the needs of each PCB type by suitable assignments for placement heads, nozzles and feeders. Out of these, the component-to-machine assignment appears to be most difficult and we propose five different solution methods for it; brute force, random, greedy, local search and genetic algorithm. The genetic algorithm outperformed the other methods in practical test. 相似文献
33.
PaweJ. Figiel Ahlam Sibaouih Jahir Uddin Ahmad Martin Nieger MinnaT. Risnen Markku Leskel Timo Repo 《Advanced Synthesis \u0026amp; Catalysis》2009,351(16):2625-2632
Novel copper(II) 2‐N‐arylpyrrolecarbaldimine‐based catalysts for the aerobic oxidation of benzylic alcohols mediated by the 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) radical are reported. The catalytic activity for both synthesized and in situ made complexes in alkaline water solutions was studied revealing high efficiency and selectivity (according to GC selectivity always >99%) for both of these catalytic systems. For example, quantitative conversion of benzyl alcohol to benzaldehyde can be achieved with the in situ prepared bis[2‐N‐(4‐fluorophenyl)‐pyrrolylcarbaldimide]copper(II) catalysts in 2 h with atmospheric pressure of O2 at 80 °C. Interestingly, these catalysts can utilize dioxygen as well as air or hydrogen peroxide as the end oxidants, producing water as the only by‐product. 相似文献
34.
The electrochemical reduction of oxygen on thin-film platinum electrodes in 0.1 M HClO4 and 0.05 M H2SO4 solutions has been investigated using the rotating disk electrode (RDE) method. Thin films of Pt (0.25-20 nm thick) were prepared by vacuum evaporation onto glassy carbon substrate. The surface morphology of Pt films was examined by transmission electron microscopy (TEM). The specific activity of O2 reduction was higher in HClO4 and decreased with decreasing film thickness. In H2SO4, the specific activity was lower and appeared to be independent of the Pt loading. The values of Tafel slopes close to −120 mV dec−1 in high current density range and −60 mV dec−1 in low current density range were obtained for all electrodes in both solutions, indicating that the mechanism of O2 reduction is the same for thin-film electrodes as for bulk Pt. The number of electrons transferred per O2 molecule was close to four for all thin Pt films studied. 相似文献
35.
Vamsi Krishna Palukuru Jani Peräntie Mikko Komulainen Timo Tick Heli Jantunen 《Journal of the European Ceramic Society》2010,30(2):389-394
A tunable microwave phase shifter composed of a low-sintering-temperature, screen-printable barium strontium titanate (BST) film and silver metallization was fabricated on an alumina substrate and co-fired at 900 °C for 3 h. The dielectric properties of the films were characterized in a frequency range of 0.8–8 GHz using scattering parameter measurements and a quasi-static coplanar waveguide transmission line model. The temperature dependency of the films was measured through capacitance measurements in a frequency range of 0.5–2.5 GHz. The figure of merit (phase shift/dB of insertion loss) of the phase shifter was found to be 14.6 at 3 GHz with an applied bias field strength of 2.5 V/μm. The performance of the phase shifter is briefly discussed and compared with other phase shifters fabricated by direct screen-printing of BST films. 相似文献
36.
Heikki Käsnänen Mikko J. Myllymäki Anna Minkkilä Antti O. Kataja Susanna M. Saario Dr. Tapio Nevalainen Dr. Ari M. P. Koskinen Prof. Dr. Antti Poso Prof. Dr. 《ChemMedChem》2010,5(2):213-231
Carbamates are a well‐established class of fatty acid amide hydrolase (FAAH) inhibitors. Here we describe the synthesis of meta‐substituted phenolic N‐alkyl/aryl carbamates and their in vitro FAAH inhibitory activities. The most potent compound, 3‐(oxazol‐2yl)phenyl cyclohexylcarbamate ( 2 a ), inhibited FAAH with a sub‐nanomolar IC50 value (IC50=0.74 nM ). Additionally, we developed and validated three‐dimensional quantitative structure–activity relationships (QSAR) models of FAAH inhibition combining the newly disclosed carbamates with our previously published inhibitors to give a total set of 99 compounds. Prior to 3D‐QSAR modeling, the degree of correlation between FAAH inhibition and in silico reactivity was also established. Both 3D‐QSAR methods used, CoMSIA and GRID/GOLPE, produced statistically significant models with coefficient of correlation for external prediction (R2PRED) values of 0.732 and 0.760, respectively. These models could be of high value in further FAAH inhibitor design. 相似文献
37.
Mari Kallioinen Mika Mänttäri Jutta Nuortila-Jokinen Timo Sutela 《Desalination》2010,250(3):1002-1004
The total effluent load of a paper mill can be significantly decreased by recycling of purified clear filtrate (CF) back to paper-making process. The CF treated with membranes can be reused, for instance, as wire section shower water and in the dilution of chemicals. The main requirements for a membrane in CF treatment are high filtration capacity, high retention of turbidity and low fouling tendency. Previous studies have shown that the regenerated cellulose (RC) ultrafiltration (UF) membrane C30F (current trade name UC030T) is especially suitable for the treatment of paper mill process waters. Every paper-making process is, however, different. Thus, filtration experiments are required in order to find the most optimal membrane for the treatment of a certain process water. In this study the best membrane for the treatment of acidic clear filtrate (ACF) was searched. The performance of the C30F membrane was compared with five UF and three microfiltration (MF) membranes. The results revealed that in addition to the C30F membrane, also some other membranes produced high filtration capacity with ACF (approximately 200 L/(m2h bar)). All the tested membranes also retained over 90% of turbidity. The extremely hydrophilic C30F membrane had, however, lower fouling tendency compared to the other tested membranes. Therefore, it was concluded that the C30F membranes were the best possible membrane for the ACF treatment. 相似文献
38.
Dr. Timo Broese Dr. Peter Ehlers Dr. Peter Langer Dr. Jan von Langermann 《Chembiochem : a European journal of chemical biology》2021,22(23):3314-3318
Fluoro-substituted and heteroaromatic compounds are valuable intermediates for a variety of applications in pharma- and agrochemistry and synthetic chemistry. This study investigates the chemoenzymatic preparation of chiral alcohols bearing a heteroaromatic ring with an increasing degree of fluorination in α-position. Starting from readily available picoline derivatives prochiral α-halogenated acyl moieties were introduced with excellent selectivity and 64–95 % yield. The formed carbonyl group was subsequently reduced to the corresponding alcohols using the alcohol dehydrogenase from Lactobacillus kefir, yielding an enantiomeric excess of 95–>99 % and up to 98 % yield. 相似文献
39.
Yoonsang Park Hossein Daneshpajooh Timo Scholehwar Eberhard Hennig Kenji Uchino 《Journal of the European Ceramic Society》2021,41(12):5900-5908
The IEEE standard to determine physical parameters of piezoceramics has been utilized for decades by many researchers, yet it omits presence of important loss factors and possesses serious deficits that restrict accurate parameter determination. To resolve these issues, the partial electrode (PE) method was previously proposed, though the focus has been merely made on development of the method itself. In this study, we provide method simplification and more detailed analysis. The omission of unnecessary samples greatly boosts experiment and analysis process. To prove that the PE method is reliable, possible causes of errors were investigated; it is shown that they were either negligibly small or can be resolved with proper calibration. Furthermore, Applicability of PE method to various types of piezoceramic materials and compatibility with impedance analyzers are shown. Finally, PE method is proved to be reliable and can be alternative to IEEE Standard on Piezoelectricity. 相似文献
40.
Van der Meulen R Camu N Van Vooren T Heymans C De Vuyst L 《International journal of food microbiology》2008,124(1):27-33
The carbohydrate and aromatic amino acid metabolism of several species related to the human colon was investigated into more detail. Therefore, in vitro fermentations were performed, with different carbohydrate sources, during which several aromatic amino acids were added to the fermentation medium. Shifts in end-product formation in response to the available nutrients were observed for all strains tested. The major part of amino acid degradation occurred after depletion of the carbohydrates. Moreover, it was shown that Bifidobacterium strains are capable of degrading aromatic amino acids in the absence of carbohydrates. The excretion of certain intermediates of the aromatic amino acid metabolism was observed for a strain of Clostridium clostridioforme, after which they were metabolized again during a later stage of fermentation. This implies that cross-feeding on degradation products of aromatic amino acids, albeit within the same species, can occur in the human colon. 相似文献