全文获取类型
收费全文 | 6980篇 |
免费 | 446篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 98篇 |
综合类 | 28篇 |
化学工业 | 1950篇 |
金属工艺 | 183篇 |
机械仪表 | 153篇 |
建筑科学 | 418篇 |
矿业工程 | 39篇 |
能源动力 | 245篇 |
轻工业 | 469篇 |
水利工程 | 42篇 |
石油天然气 | 5篇 |
无线电 | 606篇 |
一般工业技术 | 1493篇 |
冶金工业 | 316篇 |
原子能技术 | 39篇 |
自动化技术 | 1348篇 |
出版年
2024年 | 14篇 |
2023年 | 101篇 |
2022年 | 152篇 |
2021年 | 269篇 |
2020年 | 187篇 |
2019年 | 191篇 |
2018年 | 192篇 |
2017年 | 186篇 |
2016年 | 283篇 |
2015年 | 301篇 |
2014年 | 350篇 |
2013年 | 519篇 |
2012年 | 475篇 |
2011年 | 630篇 |
2010年 | 415篇 |
2009年 | 419篇 |
2008年 | 405篇 |
2007年 | 359篇 |
2006年 | 278篇 |
2005年 | 253篇 |
2004年 | 193篇 |
2003年 | 152篇 |
2002年 | 150篇 |
2001年 | 73篇 |
2000年 | 102篇 |
1999年 | 93篇 |
1998年 | 92篇 |
1997年 | 89篇 |
1996年 | 94篇 |
1995年 | 60篇 |
1994年 | 49篇 |
1993年 | 50篇 |
1992年 | 49篇 |
1991年 | 35篇 |
1990年 | 21篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1972年 | 6篇 |
1954年 | 3篇 |
排序方式: 共有7432条查询结果,搜索用时 15 毫秒
981.
Multibody System Dynamics - The Floating Frame of Reference Formulation (FFRF) is one of the most widely used methods to analyze flexible multibody systems subjected to large rigid-body motion but... 相似文献
982.
Yazhi Liu Shuofeng Liang Chenrui Yuan Andreas Best Michael Kappl Kaloian Koynov Hans-Jürgen Butt Si Wu 《Advanced functional materials》2021,31(37):2103908
Anticounterfeiting materials are used to distinguish real banknotes, products, and documents from counterfeits, fakes, or unauthorized replicas. However, conventional anticounterfeiting materials generally exhibit a single anticounterfeiting function, resulting in a low level of security. Herein, a novel anticounterfeiting nanocomposite is demonstrated with numerous prominent security features. The nanocomposite is fabricated by doping upconverting nanoparticles (UCNPs) in a photoresponsive azobenzene-containing polymer (azopolymer). Because of the cis–trans photoisomerization of the azopolymer, the nanocomposite exhibits photoinduced reversible color changes suitable for anticounterfeiting applications. Additionally, the hard nanocomposite can be converted to a rubber-like soft solid by light irradiation. Imprinted microstructures are fabricated on the photosoftened nanocomposite, which result in photonic colors. Moreover, polarization-dependent structures are fabricated on the nanocomposite via photoinduced orientation for encryption. Importantly, UCNPs in the nanocomposite emit visible light upon excitation by near-infrared light, enabling the observation of various anticounterfeiting structures with high contrast. An advantage of the anticounterfeiting nanocomposite is that the security features can be observed by the naked eye for quick discrimination and can be analyzed using laboratory equipment for higher accuracy. The anticounterfeiting nanocomposite is easily processed on paper, glass, and plastic, which demonstrates its potential anticounterfeiting functions for banknotes, wines, and medicines. 相似文献
983.
Maximilian Dyga Andreas Keller Hans Hasse 《American Institute of Chemical Engineers》2022,68(4):e17573
Formaldehyde is an important chemical that is mostly handled in aqueous solutions, which generally also contain methanol; furthermore, also solutions of formaldehyde in other alcohols are used. The density of these solutions is an important thermophysical property. The available models of the density of formaldehyde-containing solutions, however, all have shortcomings, such as a poor accuracy or a limited range of applicability. Therefore, in the present work, a new model of the density in systems of the type (formaldehyde + water + alcohol) was developed. The alcohols that are presently included in the new model are methanol, 1-propanol, and isoprenol; an extension to other alcohols is straightforward. The model was developed using literature data and extensive new density data measured in this work covering binary, ternary, and quarternary solutions of formaldehyde in water, methanol, 1-propanol, and isoprenol at temperatures of K and formaldehyde concentrations of 0.06 − 0.30 g g−1. 相似文献
984.
A visible-light and infrared video database for performance evaluation of video/image fusion methods
Ellmauthaler Andreas Pagliari Carla L. da Silva Eduardo A. B. Gois Jonathan N. Neves Sergio R. 《Multidimensional Systems and Signal Processing》2019,30(1):119-143
Multidimensional Systems and Signal Processing - In general, the fusion of visible-light and infrared images produces a composite representation where both data are pictured in a single image. The... 相似文献
985.
Correlations of sensory parameters with physicochemical characteristics of Argentinean honeys by multivariate statistical techniques
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)
Mariela Patrignani Maria Cristina Ciappini Chrysoula Tananaki Guillermina Andrea Fagúndez Andreas Thrasyvoulou Cecilia Elena Lupano 《International Journal of Food Science & Technology》2018,53(5):1176-1184
Honey acceptability is mainly determined by its colour, crystallisation degree and aroma. In the present work, the sensory characteristics and physicochemical parameters of Argentinean honeys from different ecoregions were analysed. Moisture content, Pfund colour, diastase activity, hydroxymethylfurfural content, electrical conductivity, sugar profile and volatile compounds were analytically determined in honey samples, while sensory characteristics (crystal size, fluency score, sweetness, persistence, granularity, crystallisation, colour intensity and aroma) were evaluated by a trained panel. Significant correlations were found between honey crystallisation degree and hydroxymethylfurfural content and diastase activity (P ≤ 0.05). It could be confirmed that honey crystallisation interferes with the visual perception of colour. Floral, fresh fruit, ripe fruit, balsamic and wood aromas could be successfully linked to honey volatile profile (P ≤ 0.05). These results demonstrate that the parameters that could best guarantee the consumers’ preference can be successfully associated with the chemical composition of honey by multivariate statistical analysis. 相似文献
986.
Forster Yannick Hergeth Sebastian Naujoks Frederik Krems Josef F. Keinath Andreas 《Cognition, Technology & Work》2020,22(4):703-720
Cognition, Technology & Work - For a successful market introduction of Level 3 Automated Driving Systems (L3 ADS), a careful evaluation of human–machine interfaces (HMIs) is necessary.... 相似文献
987.
Chao Ma Anke Malessa Arnold J. Boersma Kai Liu Andreas Herrmann 《Advanced materials (Deerfield Beach, Fla.)》2020,32(20):1905309
Electrostatic interactions play a vital role in nature. Biomacromolecules such as proteins are orchestrated by electrostatics, among other intermolecular forces, to assemble and organize biochemistry. Natural proteins with a high net charge exist in a folded state or are unstructured and can be an inspiration for scientists to artificially supercharge other protein entities. Recent findings show that supercharging proteins allows for control of their properties such as temperature resistance and catalytic activity. One elegant method to transfer the favorable properties of supercharged proteins to other proteins is the fabrication of fusions. Genetically engineered, supercharged unstructured polypeptides (SUPs) are just one promising fusion tool. SUPs can also be complexed with artificial entities to yield thermotropic and lyotropic liquid crystals and liquids. These architectures represent novel bulk materials that are sensitive to external stimuli. Interestingly, SUPs undergo fluid–fluid phase separation to form coacervates. These coacervates can even be directly generated in living cells or can be combined with dissipative fiber assemblies that induce life-like features. Supercharged proteins and SUPs are developed into exciting classes of materials. Their synthesis, structures, and properties are summarized. Moreover, potential applications are highlighted and challenges are discussed. 相似文献
988.
Verena B. K. Kunig Dr. Marco Potowski Dr. Mateja Klika Škopić Dr. Andreas Brunschweiger 《ChemMedChem》2021,16(7):1048-1062
Understanding the ligandability of a target protein, defined as the capability of a protein to bind drug-like compounds on any site, can give important stimuli to drug-development projects. For instance, inhibition of protein–protein interactions usually depends on the identification of protein surface binders. DNA-encoded chemical libraries (DELs) allow scanning of protein surfaces with large chemical space. Encoded library selection screens uncovered several protein–protein interaction inhibitors and compounds binding to the surface of G protein-coupled receptors (GPCRs) and kinases. The protein surface-binding chemotypes from DELs are predominantly chemically modified and cyclized peptides, and functional small-molecule peptidomimetics. Peptoid libraries and structural peptidomimetics have been less studied in the DEL field, hinting at hitherto less populated chemical space and suggesting alternative library designs. Roughly a third of bioactive molecules evolved from smaller, target-focused libraries. They showcase the potential of encoded libraries to identify more potent molecules from weak, for example, fragment-like, starting points. 相似文献
989.
990.