全文获取类型
收费全文 | 1535篇 |
免费 | 76篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 345篇 |
金属工艺 | 30篇 |
机械仪表 | 27篇 |
建筑科学 | 54篇 |
矿业工程 | 1篇 |
能源动力 | 47篇 |
轻工业 | 231篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 102篇 |
一般工业技术 | 219篇 |
冶金工业 | 342篇 |
原子能技术 | 16篇 |
自动化技术 | 182篇 |
出版年
2023年 | 6篇 |
2022年 | 25篇 |
2021年 | 32篇 |
2020年 | 23篇 |
2019年 | 35篇 |
2018年 | 42篇 |
2017年 | 22篇 |
2016年 | 38篇 |
2015年 | 28篇 |
2014年 | 51篇 |
2013年 | 96篇 |
2012年 | 63篇 |
2011年 | 72篇 |
2010年 | 72篇 |
2009年 | 83篇 |
2008年 | 80篇 |
2007年 | 72篇 |
2006年 | 62篇 |
2005年 | 60篇 |
2004年 | 43篇 |
2003年 | 49篇 |
2002年 | 37篇 |
2001年 | 31篇 |
2000年 | 27篇 |
1999年 | 31篇 |
1998年 | 115篇 |
1997年 | 71篇 |
1996年 | 57篇 |
1995年 | 34篇 |
1994年 | 28篇 |
1993年 | 28篇 |
1992年 | 12篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 12篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1983年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 14篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有1615条查询结果,搜索用时 31 毫秒
61.
62.
63.
José Luis Ochoa Rafael Valencia-García Alonso Perez-Soltero Mario Barceló-Valenzuela 《Expert systems with applications》2013,40(6):2058-2068
Currently, most of the information available in the Web is adapted primarily for human consumption, but there is so much information that can no longer be processed by a person in a reasonable time, either in digital or physical formats. To solve this problem, the idea of the Semantic Web arose. The Semantic Web deals with adding machine-readable information to Web pages. Ontologies represent a very important element of this web, as they provide a valid and robust structure to represent knowledge based on concepts, relations, axioms, etc. The need for overcoming the bottleneck provoked by the manual construction of ontologies has generated several studies and research on obtaining semiautomatic methods to learn ontologies. In this sense, this paper proposes a new ontology learning methodology based on semantic role labeling from digital Spanish documents. The method makes it possible to represent multiple semantic relations specially taxonomic and partonomic ones in the standardized OWL 2.0. A set of experiments has been performed with the approach implemented in educational domain that show promising results. 相似文献
64.
Amanda Alonso Xavier Muñoz‐Berbel Núria Vigués Rosalía Rodríguez‐Rodríguez Jorge Macanás Maria Muñoz Jordi Mas Dmitri N. Muraviev 《Advanced functional materials》2013,23(19):2450-2458
Cation exchange polymeric matrices are widely used in water treatment protocols to reduce the mineral content of hard waters, even for human consumption. However, they are not antibacterial and flowing bacteria can be trapped in their structures and proliferate, thus acting as microbial contamination sources. Here, Ag@Co‐nanoparticles (Ag@Co‐NPs) with a low‐cost superparamagnetic Co0‐core and an antibacterial Ag‐shell are synthesized on granulated cation exchange polymeric matrices under soft reaction conditions. The presence of these NPs provides the final nanocomposite (NC) with additional functionalities (superparamagnetism and antibacterial activity) making it ideal for water purification applications. Ag@Co‐NPs are synthesized in situ on four cation exchange polymeric matrices containing either strong (sulfonic) or weak (carboxylic) acid functional groups homogeneously distributed (C‐type) or concentrated on an external shell (SST‐type) by the intermatrix synthesis (IMS) method. The NCs are characterized (metal content, NP size and distribution, metal oxidative state, and metal release) and evaluated for water purification applications. 相似文献
65.
Ana Carolina Rodríguez-Negrette María José Rodríguez-Batiller Victor Alonso García-Londoño Virginia Borroni Roberto Jorge Candal María Lidia Herrera 《Journal of the American Oil Chemists' Society》2020,97(11):1215-1228
Physical chemical properties of cupuassu fat were modified by dry fractionation. Stearin and olein fractions were obtained at 29, 26, and 24 °C. Polymorphic behavior of unfractionated cupuassu fat (UCF) and its fractions were studied in situ by small-angle (SAXS) and wide-angle (WAXS) X-ray scattering using synchrotron light. Polymorphic transitions were followed in real time tempering samples with a thermal cycle. For UCF, the main polymorphic form crystallized under selected conditions was the β’2. α and β’1-forms appeared in trace amounts. β2-form was obtained after storage at 25 °C for 3 months. Stearins obtained at 26 (S-26) and 24 °C (S-24) showed a similar polymorphic behavior. However, S-26 with improved physical properties might be more suitable for chocolate production or as a trans-fat alternative than UCF. Stearin fraction obtained at 29 °C (S-29) had a complex polymorphic behavior. The α-form was the first polymorphic form detected followed by β’2-form. There was a polymorphic transition from α to β’1-form but no transition between β’-forms. They were independent to each other showing fractionation in two different solid solutions. Increased contents of the triacylglycerols (TAG) SOA and SOB together with lower contents of SOO compared to UCF led to co-crystallization because there was no complete compatibility among all TAG present in S-29. β1-form crystallized after storage forming crystals with a double-layer arrangement and a characteristic morphology. This form could be useful for accelerating crystallization process in melted liquid systems. 相似文献
66.
Mnica Cicundez Laura Casarrubios María Jos Feito Iratxe Madarieta Nerea Garcia-Urkia Olatz Murua Beatriz Olalde Nerea Briz Rosalía Diez-Orejas María Teresa Portols 《International journal of molecular sciences》2021,22(8)
The decellularized extracellular matrix (ECM) obtained from human and porcine adipose tissue (AT) is currently used to prepare regenerative medicine bio-scaffolds. However, the influence of these natural biomaterials on host immune response is not yet deeply understood. Since macrophages play a key role in the inflammation/healing processes due to their high functional plasticity between M1 and M2 phenotypes, the evaluation of their response to decellularized ECM is mandatory. It is also necessary to analyze the immunocompetence of macrophages after contact with decellularized ECM materials to assess their functional role in a possible infection scenario. In this work, we studied the effect of four decellularized adipose matrices (DAMs) obtained from human and porcine AT by enzymatic or chemical methods on macrophage phenotypes and fungal phagocytosis. First, a thorough biochemical characterization of these biomaterials by quantification of remnant DNA, lipids, and proteins was performed, thus indicating the efficiency and reliability of both methods. The proteomic analysis evidenced that some proteins are differentially preserved depending on both the AT origin and the decellularization method employed. After exposure to the four DAMs, specific markers of M1 proinflammatory and M2 anti-inflammatory macrophages were analyzed. Porcine DAMs favor the M2 phenotype, independently of the decellularization method employed. Finally, a sensitive fungal phagocytosis assay allowed us to relate the macrophage phagocytosis capability with specific proteins differentially preserved in certain DAMs. The results obtained in this study highlight the close relationship between the ECM biochemical composition and the macrophage’s functional role. 相似文献
67.
68.
69.
The rheokinetics of the curing process of a resol resin was studied through isothermal analysis. The resin was subjected to a curing pretreatment until gelation was reached. Rectangular torsion was chosen as the appropriate strain form to carry out the study of the resin's curing kinetics, because the viscoelastic behavior of the material was closer to an ideal solid than to a Newtonian fluid. Seven operating temperatures were selected for analysis (80–110°C). The Arrhenius and Kiuna rheokinetic models were applied to the resin's complex viscosity (η*) evolution during the crosslinking of polymer. The resol resin had curing activation energies of 62.6 and 65.8 kJ/mol when the Arrhenius model was applied in four‐ and six‐parameter forms, respectively. The Kiuna model was proposed to fit the nonlinear viscosity region found at the highest temperatures. This model was suitable to predict changes in the resin's complex viscosity, obtaining a curing activation energy of 69.5 kJ/mol for the resin. In addition, the evolution of the degree of mechanical curing was obtained from the elastic modulus, rather than from the more common DSC technique. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
70.
Anthocyanin profile of red fruits and black carrot juices,purees and concentrates by HPLC‐DAD‐ESI/MS‐QTOF
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Patricia Garcia‐Herrera Maria‐Luisa Pérez‐Rodríguez Teresa Aguilera‐Delgado Maria‐Jose Labari‐Reyes Begoña Olmedilla‐Alonso Montana Camara Sonia de Pascual‐Teresa 《International Journal of Food Science & Technology》2016,51(10):2290-2300
A fast and reliable method for anthocyanin extraction and identification by HPLC‐DAD‐ESI/MS‐QTOF was used to analyse the anthocyanin composition of commercial red fruit juices (blackberry, redcurrant and pomegranate), purees (strawberry, cherry and raspberry) and concentrates (elderberry, blueberry and red grape). The anthocyanin profile of black carrot juice is also reported. The extraction and analysis method allowed us to detect and quantify a wide range of individual anthocyanins in a simple and rapid way. Pelargonidin‐3‐glucoside was detected in redcurrant for the first time and petunidin‐3‐galactoside quantified for the first time in blueberries. Considering the health benefits that have been associated with anthocyanin consumption, all these fruit and vegetables processed products could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food product or food supplements. 相似文献