全文获取类型
收费全文 | 694篇 |
免费 | 39篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 277篇 |
金属工艺 | 9篇 |
机械仪表 | 13篇 |
建筑科学 | 15篇 |
能源动力 | 28篇 |
轻工业 | 83篇 |
水利工程 | 3篇 |
石油天然气 | 4篇 |
无线电 | 57篇 |
一般工业技术 | 93篇 |
冶金工业 | 17篇 |
原子能技术 | 3篇 |
自动化技术 | 127篇 |
出版年
2023年 | 6篇 |
2022年 | 38篇 |
2021年 | 58篇 |
2020年 | 30篇 |
2019年 | 25篇 |
2018年 | 27篇 |
2017年 | 21篇 |
2016年 | 36篇 |
2015年 | 22篇 |
2014年 | 39篇 |
2013年 | 47篇 |
2012年 | 49篇 |
2011年 | 42篇 |
2010年 | 38篇 |
2009年 | 36篇 |
2008年 | 25篇 |
2007年 | 25篇 |
2006年 | 18篇 |
2005年 | 15篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1971年 | 3篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1939年 | 1篇 |
1937年 | 1篇 |
1933年 | 2篇 |
1916年 | 2篇 |
排序方式: 共有733条查询结果,搜索用时 9 毫秒
41.
Ana C.F. Ribeiro Susana M.N. Simões Victor M.M. Lobo Artur J.M. Valente M.A. Esteso 《Food chemistry》2010
A Taylor dispersion method is used to measure ternary mutual diffusion coefficients (D11, D22, D12 and D21) for aqueous solutions of CuCl2 (1) + caffeine (2) + H2O-(3) at 25 °C and 37 °C at carrier concentrations from (0.000 to 0.020 mol dm−3), for each solute, respectively. The results are compared with these obtained for the binary systems, that is, CuCl2 (1) + H2O (2) and caffeine (1) + H2O (2), also reported here. From these data it is possible to make conclusions about the influence of the caffeine solutes in diffusion of copper chloride. 相似文献
42.
Joanna Mastalska‐Popawska Piotr Izak ukasz Wjcik Agata Stempkowska Zuzanna Gral Artur T. Krzyak Iwona Habina 《Polymer Engineering and Science》2019,59(6):1279-1287
Transparent and intumescent polymer‐silicate hydrogels were synthesized by free‐radical polymerization, in the presence of the redox initiators system (potassium persulphate/sodium thiosulphate) and cross‐linking monomer (N,N′‐methylenebisacrylamide). Hydrogels obtained in such a manner were rheologically tested and it was found that the same sample with a different sodium acrylate concentration polymerized faster when its content was lower. The spectroscopic and thermal analysis proved that the polymer combines with sodium silicate by hydrogen bonds and during thermal degradation only small polymer fragments and water molecules were released. NMR studies have shown that the content of water glass causes shorter relaxation times. Conducted fire tests showed that glass panes systems filled with the tested hydrogels meet the relevant construction standards and what is their big advantage, a thin 1 mm layer of polymer‐silicate gel is sufficient for this purpose. We believe that these results will contribute to the development of intumescent hydrogels with enhanced fire‐retardant properties. POLYM. ENG. SCI., 59:1279–1287 2019. © 2019 Society of Plastics Engineers 相似文献
43.
Małgorzata Misiak Michał Skowicki Tomasz Lipiński Agnieszka Kowalczyk Katarzyna Prorok Sebastian Arabasz Artur Bednarkiewicz 《Nano Research》2017,10(10):3333-3345
Versatile optimization of the synthesis method and composition of Yb3+ and Tm3+ co-doped CaF2 nanoparticles as well as a novel biofunctionalization method were developed and evaluated.Through multistep synthesis,the luminescence intensity of the Tm3+ activator was enhanced by more than 10-fold compared to standard one-step synthesis.The proposed methods were used to homogenously distribute the doping ions within the nanoparticle's volume and thus reduce luminescence quenching.Optimization of dopant ions concentration led to the selection of the most efficient visible and near-infrared up-converting nanoparticles,which were CaF2 doped with 10% Yb3+ 0.05% Tm3+ and 20% Yb3+ 0.5% Tm3+,respectively.To illustrate the suitability of the synthesized nanoparticles as bio-labels,a dedicated biofunctionalization method was used,and the nanoparticles were applied for labeling and imaging of Candida albicans cells.This method shows great promise because of extremely low background and high specificity because of the presence of the attached molecules. 相似文献
44.
Paulo Romano Cruz Correia Ingrid Graça Ramos Arão Cardoso Viana Artur José Santos Mascarenhas Antônio Euzébio Goulart Sant'ana Henrique Fonseca Goulart Janice Izabel Druzian 《应用聚合物科学杂志》2018,135(5)
Composite membranes consisting of biodegradable poly(butylene adipate‐co‐terephthalate (PBAT) and zeolite Y (0–10 wt %) were produced by extrusion. Zeolite Y is well dispersed in the membrane up to 5 wt %, but tends to agglomerate at higher contents. The presence of zeolite Y in the composite resulted in an improvement of the thermal stability, mechanical properties, and increased the barrier properties. The interaction of the composite membranes with rhynchophorol was investigated by different techniques, showing that the semiochemical progressively lixiviates PBAT monomers, causing thermal and mechanical properties to decrease. However, no interaction seemed to occur between the rhynchophorol and the zeolite. Studies of diffusion of pheromone through membranes have shown that the addition of the zeolite Y has not contributed significantly to a decrease in the release rate of rhynchophorol, but the presence of the zeolite Y helps to increase chemical, mechanical, and thermal stabilities of the membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45757. 相似文献
45.
Lydia Saidi Dr. Djenisa H. A. Rocha Dr. Oualid Talhi Dr. Yamina Bentarzi Prof. Dr. Bellara Nedjar-Kolli Dr. Khaldoun Bachari Dr. Filipe A. Almeida Paz Dr. Luisa A. Helguero Prof. Dr. Artur M. S. Silva 《ChemMedChem》2019,14(10):1041-1048
Breast and prostate cancers are frequently treated with chemotherapy. Several novel chemicals are being reported for this purpose, particularly synthetic and natural benzophenones. This work reports the synthesis of substituted 2-hydroxybenzophenones through 1,4-conjugate addition/intramolecular cycloaddition/dehydration of nitromethane on key intermediate chromones. Structures were extensively studied by means of 2D NMR spectroscopy and single-crystal XRD. Their cytotoxicity was evaluated in vitro in two breast cancer cell lines (MDA-MB-231 and T47-D) and one prostate cancer cell line (PC3). The most potent compound exhibited good cytotoxic effects against the three cancer cell lines (IC50 values ranging from 12.09 to 26.49 μm ) and induced cell-cycle retardation only on prostate cancer cells, which suggested that it might exert cell-type-specific effects. 相似文献
46.
Shaping Luminescent Properties of Yb3+ and Ho3+ Co‐Doped Upconverting Core–Shell β‐NaYF4 Nanoparticles by Dopant Distribution and Spacing 下载免费PDF全文
Aleksandra Pilch Christian Würth Martin Kaiser Dominika Wawrzyńczyk Michalina Kurnatowska Sebastian Arabasz Katarzyna Prorok Marek Samoć Wiesław Strek Ute Resch‐Genger Artur Bednarkiewicz 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
At the core of luminescence color and lifetime tuning of rare earth doped upconverting nanoparticles (UCNPs), is the understanding of the impact of the particle architecture for commonly used sensitizer (S) and activator (A) ions. In this respect, a series of core@shell NaYF4 UCNPs doped with Yb3+ and Ho3+ ions are presented here, where the same dopant concentrations are distributed in different particle architectures following the scheme: YbHo core and YbHo@…, …@YbHo, Yb@Ho, Ho@Yb, YbHo@Yb, and Yb@YbHo core–shell NPs. As revealed by quantitative steady‐state and time‐resolved luminescence studies, the relative spatial distribution of the A and S ions in the UCNPs and their protection from surface quenching has a critical impact on their luminescence characteristics. Although the increased amount of Yb3+ ions boosts UCNP performance by amplifying the absorption, the Yb3+ ions can also efficiently dissipate the energy stored in the material through energy migration to the surface, thereby reducing the overall energy transfer efficiency to the activator ions. The results provide yet another proof that UC phosphor chemistry combined with materials engineering through intentional core@shell structures may help to fine‐tune the luminescence features of UCNPs for their specific future applications in biosensing, bioimaging, photovoltaics, and display technologies. 相似文献
47.
Artur Mielcarek Wojciech Janczukowicz Kamila Ostrowska Tomasz Jóźwiak Izabella Kłodowska Joanna Rodziewicz Marcin Zieliński 《Journal of the Institute of Brewing》2013,119(4):242-250
This study reports results of respirometric measurements of activated sludge biodegrading the substrate in wastewater originating from the following brewery plant production departments: malt house, brewhouse, fermentation house and racking house. The process was conducted at two temperatures: 10 and 20°C with activated sludge adapted to brewery wastewaters. The loading of activated sludge reached 0.25 g chemical oxygen demand per gram dry matter per day, which assured complete degradation of organic matter. The physicochemical characteristics of the wastewaters are provided. The study demonstrates a correlation between the site of wastewater generation, the specific character of a unitary technological process and the quality of the wastewater discharged to the sewage system, including biodegradability. Despite significant differences in the quality of the wastewaters, they were characterized by high biodegradability at a temperature of 10 and 20°C and by the C:N:P ratio being beneficial for biological treatment, irrespective of their source of origin. Copyright © 2013 The Institute of Brewing & Distilling 相似文献
48.
49.
50.
The market success of a new product critically depends on the marketing strategy that is adopted during the introductory phase of its life cycle. The decision theoretic marketing literature provides useful insights to this problem through the application of new product diffusion models. While most of the diffusion models incorporate only marketing variables such as price or advertising into the adoption rates of the new product, we introduce the issue of financial decision making and argue that the success of a new product not only depends on an optimal marketing mix strategy but also on the financial decisions of a firm. We adopt a simple diffusion model and show that in case with demand uncertainty and limited liability more leverage (a higher debt equity ratio) causes the firm to be more aggressive in the product market, i.e., to reduce the price of the product. Our findings suggest that marketing decisions should not be taken in isolation but should be coordinated with financial variables. 相似文献