全文获取类型
收费全文 | 894篇 |
免费 | 92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 | 515篇 |
金属工艺 | 17篇 |
机械仪表 | 10篇 |
建筑科学 | 19篇 |
矿业工程 | 5篇 |
能源动力 | 30篇 |
轻工业 | 184篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 26篇 |
一般工业技术 | 113篇 |
冶金工业 | 12篇 |
自动化技术 | 43篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 74篇 |
2021年 | 237篇 |
2020年 | 52篇 |
2019年 | 46篇 |
2018年 | 50篇 |
2017年 | 48篇 |
2016年 | 60篇 |
2015年 | 40篇 |
2014年 | 61篇 |
2013年 | 57篇 |
2012年 | 50篇 |
2011年 | 39篇 |
2010年 | 27篇 |
2009年 | 24篇 |
2008年 | 24篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 6篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有987条查询结果,搜索用时 103 毫秒
61.
Aleksandra Mielewczyk-Gryn Katarzyna Gdula-Kasica Bogusław Kusz Maria Gazda 《Ceramics International》2013,39(4):4239-4244
Magnesium doped lanthanum ortho-niobate (La0.98Mg0.02NbO4) was prepared by the molten salt synthesis method. X-ray diffraction and dilatometry methods were used to study high temperature behavior of the ceramic material. Special attention was paid to the phase transition between the monoclinic and tetragonal phases. The values of spontaneous strain on the basis of unit cell parameter, obtained by Rietveld refinement, have been calculated as well as Landau order parameter. The thermal expansion coefficient (TEC) of La0.98Mg0.02NbO4 was determined to be 12×10?6 1/K and 8×10?6 1/K below and above 500 °C, respectively. 相似文献
62.
Michele Leonardi Urszula Skomra Monika Agacka Anna Stochmal Katarzyna E. Ambryszewska Wieslaw Oleszek Guido Flamini Luisa Pistelli 《International Journal of Food Science & Technology》2013,48(8):1770-1774
Polish cultivars of hop (Humulus lupulus L.) are well known as aroma and bitter raw material in the brewing industry. To characterise four popular Polish hop cultivars, Lubelski (Lublin), Marynka, Sybilla and Iunga (also known as Junga), the essential oil profiles were determined by gas chromatography/flame ionisation detector (GC‐FID) and gas chromatography/chemical ionisation mass spectrometry (GC‐CIMS) and the alpha/beta acids amounts by high‐performance liquid chromatography/diode array detector (HPLC‐DAD) analysis. In addition, the multivariate statistical analysis of the volatile profiles was performed. The results obtained evidenced qualitative and quantitative differences between the four cultivars studied and the foreign hops described in the literature. Lubelski and Iunga showed the typical chemical profile of the fine‐aroma and high‐alpha cultivars, respectively. In Marynka and Sybilla, the average amounts of alpha acids were similar to the bitter hops, but with a volatile profile characteristics of the fine‐aroma and aroma cultivars respectively. 相似文献
63.
Different sensitivities to hydrogen embrittlement for the disordered and ordered B2 FeAl alloys have been investigated. The plasticity of annealed alloys (before hydrogenating) has been found to decrease with increasing the long-range order parameter. An intrinsic weakness of FeAl phase grain boundaries revealed at a high degree of ordering. The results of bending tests on specimens annealed and cathodically charged with hydrogen have shown that the influence of hydrogen on the plasticity diminishes with the increase in the degree of FeAl phase ordering. 相似文献
64.
Performance of different estimators describing propagation of electroencephalogram (EEG) activity, namely: Granger causality, directed transfer function (DTF), direct DTF (dDTF), short-time DTF (SDTF), bivariate coherence, and partial directed coherence are compared by means of simulations and on the examples of experimental signals. In particular, the differences between pair-wise and multichannel estimates are studied. The results show unequivocally that in most cases, the pair-wise estimates are incorrect and a complete set of signals involved in a given process has to be used to obtain the correct pattern of EEG flows. Different performance of multivariate estimators of propagation depending on their normalization is discussed. Advantages of multivariate autoregressive model are pointed out. 相似文献
65.
66.
Lead film electrodes (PbFEs) deposited in situ on glassy carbon or carbon paste supports have recently found application in adsorptive stripping voltammetric determination of inorganic ions and organic substances. In this work, the PbFE, prepared in ammonia buffer solutions, was investigated using scanning electron microscopy, atomic force microscopy and various voltammetric techniques. The microscopic images of the lead films deposited on the glassy carbon substrate showed a considerable variability in microstructure and compactness of the deposited layer depending on the selected experimental conditions, such as the concentration of Pb(II) species, the nucleation and deposition potential, and the time applied. The catalytic adsorptive systems of cobalt and nickel in a solution containing 0.1 ammonia buffer, 2.5 × 10−5 M nioxime and 0.25 M NaNO2 were employed to investigate the electrochemical characteristics and utility of the in situ prepared lead films.The optimal parameters, i.e. the lead concentration in the solution, the procedure of film removal, and the time and potential of lead nucleation and film deposition for the adsorptive determination of metal traces, were selected, resulting in the very good reproducibility (RSD = 4.2% for 35 scans) of recorded signals. The voltammetric utility of the lead film electrode was compared to that of glassy carbon, mercury film and bismuth film electrodes, and was subsequently evaluated as superior. 相似文献
67.
N. Bizon 《Applied Energy》2010,87(10):3115-3130
In this paper is proposed an optimization approach, based on optimal utilization of the power harmonics from the probing signal by including a band-pass filter in the feedback loop of the extremum seeking control (ESC) scheme. The ESC is used to track the maximum power point (MMP) of fuel cell power, and presence of the first and second power harmonics in the probing signal assure this tracking capacity. The MPP tracking robustness is improved by including the third power harmonics into the probing signal, given for probing signal amplitude a time adaptive variation depending of third derivate of the fuel cell power. The MPP tracking is demonstrated and the ESC robustness is proved by simulation in case of using a recommended current ripple factor. 相似文献
68.
Aneta Stachowicz Anna Winiewska Katarzyna Ku Magdalena Biaas Magdalena omnicka Justyna Toto-uraska Anna Kiepura Kamila Stachyra Maciej Suski Beata Bujak-Giycka Jacek Jawie Rafa Olszanecki 《International journal of molecular sciences》2021,22(11)
Atherosclerosis and nonalcoholic fatty liver disease are leading causes of morbidity and mortality in the Western countries. The renin–angiotensin system (RAS) with its two main opposing effectors, i.e., angiotensin II (Ang II) and Ang-(1–7), is widely recognized as a major regulator of cardiovascular function and body metabolic processes. Angiotensin-converting enzyme 2 (ACE2) by breaking-down Ang II forms Ang-(1–7) and thus favors Ang-(1–7) actions. Therefore, the aim of our study was to comprehensively evaluate the influence of prolonged treatment with ACE2 activator, diminazene aceturate (DIZE) on the development of atherosclerotic lesions and hepatic steatosis in apoE−/− mice fed a high-fat diet (HFD). We have shown that DIZE stabilized atherosclerotic lesions and attenuated hepatic steatosis in apoE−/− mice fed an HFD. Such effects were associated with decreased total macrophages content and increased α-smooth muscle actin levels in atherosclerotic plaques. Moreover, DIZE changed polarization of macrophages towards increased amount of anti-inflammatory M2 macrophages in the atherosclerotic lesions. Interestingly, the anti-steatotic action of DIZE in the liver was related to the elevated levels of HDL in the plasma, decreased levels of triglycerides, and increased biosynthesis and concentration of taurine in the liver of apoE−/− mice. However, exact molecular mechanisms of both anti-atherosclerotic and anti-steatotic actions of DIZE require further investigations. 相似文献
69.
70.
Anna Gliszczyńska-Świgło Alina Kałużewicz Katarzyna Lemańska Mikołaj Knaflewski Bożena Tyrakowska 《Food chemistry》2007,100(1):241-245
The effect of solar radiation on the quercetin and kaempferol contents in the inflorescence of three broccoli cultivars (‘Lord’, ‘Marathon’ and ‘Fiesta’) was investigated from 1999 to 2001. Great differences in the contents of both flavonols, dependent on growing time and cultivar, were found. Quercetin and kaempferol contents varied from 14.3 to 81.0 mg kg−1 f.w. and from 35.9 to 213 mg kg−1 f.w., respectively. Inflorescences of the cultivar ‘Lord’ were characterised by the highest mean content of quercetin and those of cultivar ‘Fiesta’ of kaempferol. The contents of both flavonols were highly positively correlated with total solar radiation in the period from planting to the harvest of broccoli inflorescences. 相似文献