全文获取类型
收费全文 | 399篇 |
免费 | 25篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 74篇 |
金属工艺 | 11篇 |
机械仪表 | 15篇 |
建筑科学 | 6篇 |
能源动力 | 20篇 |
轻工业 | 80篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 32篇 |
一般工业技术 | 58篇 |
冶金工业 | 52篇 |
原子能技术 | 1篇 |
自动化技术 | 71篇 |
出版年
2024年 | 3篇 |
2023年 | 4篇 |
2022年 | 17篇 |
2021年 | 35篇 |
2020年 | 23篇 |
2019年 | 24篇 |
2018年 | 28篇 |
2017年 | 11篇 |
2016年 | 18篇 |
2015年 | 16篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 19篇 |
2011年 | 36篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 15篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 11篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有425条查询结果,搜索用时 31 毫秒
1.
Bijan Nasri‐Nasrabadi Akif Kaynak Shayan Seyedin Zahra Komeily‐Nia Abbas Z Kouzani 《Polymer International》2019,68(5):922-928
Recent advances in three‐dimensional (3D) printing have enabled the fabrication of interesting structures which are not achievable using traditional fabrication approaches. The 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks, which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through a facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions with a chitosan polymer matrix are achieved. Consequently, the mechanical properties of the 3D printed composites improve when nanogrooved carbon microtubes are used, compared to untreated microtubes. We show that by carefully controlling the coagulation bath, extrusion pressure, printing distance and printed line distance, we can 3D print composite lattices which are composed of well‐defined and separated printed lines. The conductive composite 3D structures with highly customised design presented in this work provide a suitable platform for applications ranging from soft robotics to smart tissue engineering scaffolds. © 2019 Society of Chemical Industry 相似文献
2.
Shubneesh Batra Nanseng Jeng Akif Sultan Kyle Picone Surya Bhattacharya Keun-Hyung Park Sanjay Banerjee David Kao Monte Manning Chuck Dennison 《Journal of Electronic Materials》1993,22(5):551-554
When dopants are indiffused from a heavily implanted polycrystalline silicon film deposited on a silicon substrate, high thermal
budget annealing can cause the interfacial “native” oxide at the polycrystalline silicon-single crystal silicon interface
to break up into oxide clusters, causing epitaxial realignment of the polycrystalline silicon layer with respect to the silicon
substrate. Anomalous transient enhanced diffusion occurs during epitaxial realignment and this has adverse effects on the
leakage characteristics of the shallow junctions formed in the silicon substrate using this technique. The degradation in
the leakage current is mainly due to increased generation-recombination in the depletion region because of defect injection
from the interface. 相似文献
3.
Krishnan H Garth C Gühring J Gülsün MA Greiser A Joy KI 《IEEE transactions on visualization and computer graphics》2012,18(6):966-977
Many flow visualization techniques, especially integration-based methods, are problematic when the measured data exhibit noise and discretization issues. Particularly, this is the case for flow-sensitive phase-contrast magnetic resonance imaging (PC-MRI) data sets which not only record anatomic information, but also time-varying flow information. We propose a novel approach for the visualization of such data sets using integration-based methods. Our ideas are based upon finite-time Lyapunov exponents (FTLE) and enable identification of vessel boundaries in the data as high regions of separation. This allows us to correctly restrict integration-based visualization to blood vessels. We validate our technique by comparing our approach to existing anatomy-based methods as well as addressing the benefits and limitations of using FTLE to restrict flow. We also discuss the importance of parameters, i.e., advection length and data resolution, in establishing a well-defined vessel boundary. We extract appropriate flow lines and surfaces that enable the visualization of blood flow within the vessels. We further enhance the visualization by analyzing flow behavior in the seeded region and generating simplified depictions. 相似文献
4.
Mohd Akram Hira Lal Mohammad Osama Farah Ansari Sana Anwar Kabir-ud-Din Ajaz Ahmad Samreen Naved Azum Hadi M. Marwani Abdullah M. Asiri 《Journal of surfactants and detergents》2021,24(1):35-49
In this study, we prepared a novel series of diester-functionalized cationic gemini surfactants (Cm-E2O2-Cm) containing ethylene oxide as a spacer with varying alkyl chain lengths and characterized by 1H NMR, FT-IR, elemental analysis, and ESI-MS. The physicochemical properties of the geminis were explored by tensiometry, fluorescence, dye solubilization, and Krafft point. These geminis acquire superior surface activity than the conventional surfactants. Fluorescence spectroscopy analysis affirmed that the micropolarity and aggregation number of micelles diminished with increase in the alkyl chain length. These geminis represent a new group of amphiphiles of considerably high biodegradability, better cleavability, and low toxicity as assessed by BOD test, FT-IR analysis, and HC50 analysis, respectively. They also showed significant level of antimicrobial activity toward some specified bacterial strains of Gram-positive and Gram-negative by using agar well diffusion method. Furthermore, the thermogravimetric analysis provided information regarding thermal stabilities of the newly synthesized gemini surfactants. 相似文献
5.
Marilyn Arosemena Farah A. Meah Kieren J. Mather Sarah A. Tersey Raghavendra G. Mirmira 《International journal of molecular sciences》2021,22(4)
Type 2 diabetes (T2D) typically occurs in the setting of obesity and insulin resistance, where hyperglycemia is associated with decreased pancreatic β-cell mass and function. Loss of β-cell mass has variably been attributed to β-cell dedifferentiation and/or death. In recent years, it has been proposed that circulating epigenetically modified DNA fragments arising from β cells might be able to report on the potential occurrence of β-cell death in diabetes. Here, we review published literature of DNA-based β-cell death biomarkers that have been evaluated in human cohorts of islet transplantation, type 1 diabetes, and obesity and type 2 diabetes. In addition, we provide new data on the applicability of one of these biomarkers (cell free unmethylated INS DNA) in adult cohorts across a spectrum from obesity to T2D, in which no significant differences were observed, and compare these findings to those previously published in youth cohorts where differences were observed. Our analysis of the literature and our own data suggest that β-cell death may occur in subsets of individuals with obesity and T2D, however a more sensitive method or refined study designs are needed to provide better alignment of sampling with disease progression events. 相似文献
6.
Maria Jos O. C. Guimares Fernanda M. B. Coutinho Marisa C. G. Rocha Marcelo Farah Rosrio E. S. Bretas 《应用聚合物科学杂志》2002,86(9):2240-2246
The rheological and morphological properties of blends based on high‐density polyethylene (HDPE) and a commercial ethylene–octene copolymer (EOC) produced by metallocene technology were investigated. The rheological properties were evaluated in steady and dynamic shear experiments at 190°C in shear rates ranging from 90 s?1 to 1500 s?1 and frequency range between 10?1 rad/s and 102 rad/s, respectively. These blends presented a high level of homogeneity in the molten state and rheological behavior was generally intermediate to those of the pure components. Scanning electron microscopy (SEM) showed that the blends exhibit dispersed morphologies with EOC domains distributed homogeneously and with particle size inferior to 2 μm. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2240–2246, 2002 相似文献
7.
Ramzi Guesmi Mohamed Amine Ben Farah Abdennaceur Kachouri Mounir Samet 《Multimedia Tools and Applications》2016,75(8):4753-4769
This paper proposes a color image encryption scheme using one-time keys based on crossover operator, chaos and the Secure Hash Algorithm(SHA-2). The (SHA-2) is employed to generate a 256-bit hash value from both the plain-image and the secret hash keys to make the key stream change in each encryption process. The SHA-2 value is employed to generate three initial values of the chaotic system. The permutation-diffusion process is based on the crossover operator and XOR operator, respectively. Experimental results and security analysis show that the scheme can achieve good encryption result through only one round encryption process, the key space is large enough to resist against common attacks,so the scheme is reliable to be applied in image encryption and secure communication. 相似文献
8.
There is growing evidence that face recognition is "special" but less certainty concerning the way in which it is special. The authors review and compare previous proposals and their own more recent hypothesis, that faces are recognized "holistically" (i.e., using relatively less part decomposition than other types of objects). This hypothesis, which can account for a variety of data from experiments on face memory, was tested with 4 new experiments on face perception. A selective attention paradigm and a masking paradigm were used to compare the perception of faces with the perception of inverted faces, words, and houses. Evidence was found of relatively less part-based shape representation for faces. The literatures on machine vision and single unit recording in monkey temporal cortex are also reviewed for converging evidence on face representation. The neuropsychological literature is reviewed for-evidence on the question of whether face representation differs in degree or kind from the representation of other types of objects. 相似文献
9.
Brice T. Hughes Jordan M. Berg Darryl L. James Akif Ibraguimov Shaorong Liu Henryk Temkin 《Microfluidics and nanofluidics》2008,5(6):761-774
This paper presents a numerical steady-state model of ion transport in micro- and nanofluidic devices with widely varying
geometric scale, such as transitions between micro- and nanochannels. Finite element or finite volume simulation of such problems
is challenging, due to the number of elements needed to produce a satisfactory mesh. Here, only the lengthwise channel dimension
is meshed; standard analytical approximations are used to incorporate cross-channel properties. Singularly perturbed cases
are built up by continuation. The method is shown to reproduce our previously reported measurements of electric double-layer
effects on conductivity, ion concentration, and ion enhancement and depletion. Comparison with 2-D simulations reported in
the literature shows that effects on accuracy due to the 1-D approximation are small. The model incorporates analytical models
of surface charge density taken from the literature. This enables predictive simulation with reasonable accuracy using published
parameter values, or these values may be tuned based on experiment to give improved results. Use of the model for iterative
design and parameter estimation is demonstrated. 相似文献
10.
Zakaria Farah 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1979,168(5):394-396
Summary Non-casein protein fractions of raw skim med milk, obtained according to the Aschaffenburg and Drewry procedure, were studied by discontinuous polyacrylamide electrophoresis.Differences between the electropherograms obtained and the data of the above authors were observed in the fractions non-casein nitrogen minus proteose peptone nitrogen and total albumin nitrogen plus non-protein nitrogen.In the first fraction, instead of immunoglobulin, proteose-peptone was present and in the second fraction, besides the total albumin, immunglobulin and proteose-peptone were present. In our opinion the differences observed in the two fractions are due to incomplete salting out.
Überprüfung der Aschaffenburg und Drewry-Bestimmungsmethode der Nicht-Casein-Proteine durch Polyacrylamid-Elektrophorese
Zusammenfassung Es wurden Nicht-Casein-Protein-Fraktionen von roher Magermilch, die nach der Aschaffenburg- und Drewry-Methode getrennt wurden, discelektrophoretisch untersucht. Unterschiede zwischen den erhaltenen Elektropherogrammen und den Angaben der oben genannten Autoren wurden bei den Fraktionen Nicht-Casein-Stickstoff minus Proteose-Pepton-Stickstoff und Totalalbumin-Stickstoff plus Nicht-Protein-Stickstoff festgestellt.Bei der ersten Fraktion wurde das Proteose-Pepton anstatt Immunglobulin erhalten, und bei der zweiten Fraktion erhielt man neben dem Totalalbumin auch Immunglobulin und Proteose-Pepton. Nach unserer Auffassung sind die bei den beiden Fraktionen festgestellten Abweichungen auf unvollständiges Aussalzen zurückzuführen.相似文献