全文获取类型
收费全文 | 1774篇 |
免费 | 201篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 25篇 |
综合类 | 1篇 |
化学工业 | 460篇 |
金属工艺 | 24篇 |
机械仪表 | 86篇 |
建筑科学 | 58篇 |
矿业工程 | 6篇 |
能源动力 | 61篇 |
轻工业 | 524篇 |
水利工程 | 16篇 |
石油天然气 | 8篇 |
无线电 | 80篇 |
一般工业技术 | 235篇 |
冶金工业 | 28篇 |
原子能技术 | 9篇 |
自动化技术 | 355篇 |
出版年
2024年 | 10篇 |
2023年 | 19篇 |
2022年 | 73篇 |
2021年 | 120篇 |
2020年 | 78篇 |
2019年 | 93篇 |
2018年 | 110篇 |
2017年 | 99篇 |
2016年 | 96篇 |
2015年 | 97篇 |
2014年 | 102篇 |
2013年 | 254篇 |
2012年 | 138篇 |
2011年 | 165篇 |
2010年 | 135篇 |
2009年 | 111篇 |
2008年 | 76篇 |
2007年 | 38篇 |
2006年 | 34篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 18篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1966年 | 1篇 |
1965年 | 2篇 |
1964年 | 1篇 |
1963年 | 2篇 |
1938年 | 2篇 |
排序方式: 共有1976条查询结果,搜索用时 15 毫秒
111.
María Del Carmen Flores‐Álvarez Erika F. Molina‐Hernández José Concepción Hernández‐Raya María Elena Sosa‐Morales 《Journal of food science》2012,77(11):C1136-C1143
Abstract: Oil that is reused multiple times for deep frying goes through changes in chemical composition and physical characteristics, affecting the quality of the fried foods. In this study, the effect of the food type (fish nuggets or French fries) on the degradation of an oil blend during the deep‐fat frying of each food at 180°C during 12 days was determined, and the characteristics of the fried products were evaluated. The degradation of oil during repeated use was relatively faster when fish nuggets were fried than when French fries were fried, as higher values of total polar compounds were obtained. Practical Application: The results are useful for producers of French fries and fish nuggets, such as restaurants or fast foods sellers, providing them with practical guidelines within the permitted values established by the regulatory authorities. The studied foods have high economic importance and are different in their composition. Under the studied conditions, the tested oil blend may be used during 4 d (4 h per day) with a daily replenishment, without discarding the oil when frying fish nuggets, and must be discarded after 8 d when French fries are processed. This suggestion allows preparing safe fried foods for consumers. 相似文献
112.
T. ZIKMUND L. KVASNICA M. TÝČ A. KŘÍŽOVÁ J. ČOLLÁKOVÁ R. CHMELÍK 《Journal of microscopy》2014,256(2):117-125
Transmitted light holographic microscopy is particularly used for quantitative phase imaging of transparent microscopic objects such as living cells. The study of the cell is based on extraction of the dynamic data on cell behaviour from the time‐lapse sequence of the phase images. However, the phase images are affected by the phase aberrations that make the analysis particularly difficult. This is because the phase deformation is prone to change during long‐term experiments. Here, we present a novel algorithm for sequential processing of living cells phase images in a time‐lapse sequence. The algorithm compensates for the deformation of a phase image using weighted least‐squares surface fitting. Moreover, it identifies and segments the individual cells in the phase image. All these procedures are performed automatically and applied immediately after obtaining every single phase image. This property of the algorithm is important for real‐time cell quantitative phase imaging and instantaneous control of the course of the experiment by playback of the recorded sequence up to actual time. Such operator's intervention is a forerunner of process automation derived from image analysis. The efficiency of the propounded algorithm is demonstrated on images of rat fibrosarcoma cells using an off‐axis holographic microscope. 相似文献
113.
Carlos Adelantado Ángel Ríos 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(9):1755-1766
A simple and rapid microextraction procedure is reported on the use of ionic liquid in combination with magnetic nanocellulose hybrid nanoparticles. The procedure is ultrasound-assisted and applicable to selective preconcentration of neonicotinoid insecticides from milk samples, prior to being analysed by liquid chromatography-mass spectrometry. The extraction procedure uses small volume of organic solvents (<1 mL), and there is no need for centrifugation. In the experimental approach the ionic liquid was quickly disrupted by an ultrasonic probe and dispersed in milk samples in a cloudy form. At this stage, neonicotinoid insecticides were extracted into the fine droplets of ionic liquid. Then small amounts of magnetic nanocellulose hybrid nanoparticles were dispersed into the sample solutions to adsorb the ionic liquid containing the analytes and phase separation was completed. The ionic liquid allowed the microextraction of the analytes and a small volume of acetonitrile was used for elution. Magnetic nanocellulose favoured the adsorption of the ionic liquid with the analytes and improved the final recovery with respect to the use of simple magnetic nanoparticles as a sorbent material. Under the optimum conditions, decision capabilities were achieved in the 0.02–0.06 mg kg?1 range, with recoveries between 91.0% and 109.5%. 相似文献
114.
115.
Dr. Patricia García‐Domínguez Mélanie Weiss Ilaria Lepore Prof. Dr. Rosana Álvarez Prof. Dr. Lucia Altucci Prof. Dr. Hinrich Gronemeyer Prof. Dr. Ángel R. de Lera 《ChemMedChem》2012,7(12):2101-2112
A novel epigenetic modulator that displays a DNMT1 inhibition and DNMT3A activation profile was characterized (compound 8 ). This compound is a derivative of palmitic acid that incorporates the putative reactive functional group (diynone) of the peyssonenyne natural products. Other analogues containing the diynone or an acetoxyenediyne did not show the same biological profile. In U937 human leukemia cells, diynone 8 induced cell differentiation and apoptosis, which correlated with the expression of Fas protein. Very surprisingly, diynone 8 was toxic to normal human fibroblasts (BJ) and mouse embryo fibroblasts (MEF), but not to immortalized human fibroblasts (BJEL); this unique effect was not observed with the classical DNMT inhibitor 5‐azacytidine. Therefore, compound 8 interferes in a very specific manner with signaling pathways, the activities of which differ between normal and immortalized cell types. This toxicity is reminiscent of the effects of Dnmt1 ablation on mouse fibroblasts. In fact, some of the genes deregulated by the loss of Dnmt1 are similarly deregulated by 8 , but not by the DNMT inhibitor SGI‐1027. 相似文献
116.
Sándor Németh Balázs Feil Péter Árva 《Polymer-Plastics Technology and Engineering》2013,52(12):1301-1306
The aim of this paper is to analyze how different catalyst activity profiles influence the operating strategies of industrial polymerization reactors. Since the catalyst activity profiles may change considerably in the range of the residence-time of the reactor, the properties of the produced polymer powder are the averages of ones produced by catalyst particles with various activities. Hence, the residence-time distribution of the polymer phase has an effect on the product properties as well. Based on these phenomena a new method is proposed to transform information from laboratory reactor into a form which can be used to estimate the operation condition of industrial reactor. The whole approach is demonstrated in case of the production of high-density polyethylene. 相似文献
117.
Andres Fullana ngel A Carbonell‐Barrachina Sukh Sidhu 《Journal of the science of food and agriculture》2004,84(15):2015-2021
Low molecular weight aldehydes (LMWAs) formed during the heating of frying media (triglycerides) were adsorbed onto tenax and analyzed by GC‐MS after thermal desorption. Six alkanals (C5 to C10), seven 2‐alkenals (C5 to C11) and 3 alkadienals (C7, C9 and C10) were found in the fumes of canola oil (control), extra virgin olive oil, and refined olive oil, heated at 180 and 240 °C. The emission rates of these aldehydes depended on the heating temperature. Frying in any type of olive oil, independently of its commercial category, will effectively decrease the emission of volatile aldehydes at temperatures below the smoking point. Thus, using the cheaper olive oil for deep‐frying purposes will not affect aldehyde emissions. This is important since olive oil is usually used for deep‐frying operations while extra virgin olive oil is used as salad dressing in Spain. The mixture of refined olive oil with some virgin olive oil is the most acceptable type of olive oil in non‐Mediterranean countries due to its milder flavor. However, if higher temperatures are needed the use of canola oil is more advisable due to its higher smoke point. Copyright © 2004 Society of Chemical Industry 相似文献
118.
Gonzalo Ricardo Ríos-Muoz Francisco Fernndez-Avils ngel Arenal 《International journal of molecular sciences》2022,23(8)
The maintaining and initiating mechanisms of atrial fibrillation (AF) remain controversial. Deep learning is emerging as a powerful tool to better understand AF and improve its treatment, which remains suboptimal. This paper aims to provide a solution to automatically identify rotational activity drivers in endocardial electrograms (EGMs) with convolutional recurrent neural networks (CRNNs). The CRNN model was compared with two other state-of-the-art methods (SimpleCNN and attention-based time-incremental convolutional neural network (ATI-CNN)) for different input signals (unipolar EGMs, bipolar EGMs, and unipolar local activation times), sampling frequencies, and signal lengths. The proposed CRNN obtained a detection score based on the Matthews correlation coefficient of 0.680, an ATI-CNN score of 0.401, and a SimpleCNN score of 0.118, with bipolar EGMs as input signals exhibiting better overall performance. In terms of signal length and sampling frequency, no significant differences were found. The proposed architecture opens the way for new ablation strategies and driver detection methods to better understand the AF problem and its treatment. 相似文献
119.
Andrea Snchez-Navarro Miguel ngel Martínez-Rojas Adrin Albarrn-Godinez Rosalba Prez-Villalva Johan Auwerx Abigail de la Cruz Lilia G. Noriega Florencia Rosetti Norma A. Bobadilla 《International journal of molecular sciences》2022,23(5)
Acute kidney injury (AKI) is a public health problem worldwide. Sirtuins are a family of seven NAD+-dependent deacylases, Overexpression of Sirtuin 1, 3, and 5 protect against AKI. However, the role of Sirtuin 7 (Sirt7) in AKI is not known. Here, we analyzed how Sirt7 deficient mice (KO-Sirt7) were affected by AKI. As expected, wild-type and Sirt7 heterozygotes mice that underwent renal ischemia/reperfusion (IR) exhibited the characteristic hallmarks of AKI: renal dysfunction, tubular damage, albuminuria, increased oxidative stress, and renal inflammation. In contrast, the KO-Sirt7+IR mice were protected from AKI, exhibiting lesser albuminuria and reduction in urinary biomarkers of tubular damage, despite similar renal dysfunction. The renoprotection in the Sirt7-KO+IR group was associated with reduced kidney weight, minor expression of inflammatory cytokines and less renal infiltration of inflammatory cells. This anti-inflammatory effect was related to diminished p65 expression and in its active phosphorylation, as well as by a reduction in p65 nuclear translocation. Sirt7 deficient mice are protected from AKI, suggesting that this histone deacetylase promotes tubular damage and renal inflammation. Therefore, our findings indicate that Sirt7 inhibitors may be an attractive therapeutic target to reduce NFκB signaling. 相似文献
120.