全文获取类型
收费全文 | 334篇 |
免费 | 11篇 |
专业分类
电工技术 | 17篇 |
化学工业 | 100篇 |
金属工艺 | 6篇 |
机械仪表 | 6篇 |
建筑科学 | 3篇 |
能源动力 | 6篇 |
轻工业 | 13篇 |
水利工程 | 3篇 |
无线电 | 16篇 |
一般工业技术 | 59篇 |
冶金工业 | 38篇 |
自动化技术 | 78篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 21篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 16篇 |
2013年 | 20篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 13篇 |
2008年 | 14篇 |
2007年 | 20篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 1篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 19篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有345条查询结果,搜索用时 406 毫秒
31.
Semantics and pragmatics of Real-Time Maude 总被引:2,自引:0,他引:2
At present, designers of real-time systems face a dilemma between expressiveness and automatic verification: if they can specify some aspects of their system in some automaton-based formalism, then automatic verification is possible; but more complex system components may be hard or impossible to express in such decidable formalisms. These more complex components may still be simulated; but there is then little support for their formal analysis. The main goal of Real-Time Maude is to provide a way out of this dilemma, while complementing both decision procedures and simulation tools. Real-Time Maude emphasizes ease and generality of specification, including support for distributed real-time object-based systems. Because of its generality, falling outside of decidable system classes, the formal analyses supported—including symbolic simulation, breadth-first search for failures of safety properties, and model checking of time-bounded temporal logic properties—are in general incomplete (although they are complete for discrete time). These analysis techniques have been shown useful in finding subtle bugs of complex systems, clearly outside the scope of current decision procedures. This paper describes both the semantics of Real-Time Maude specifications, and of the formal analyses supported by the tool. It also explains the tool's pragmatics, both in the use of its features, and in its application to concrete examples. 相似文献
32.
Elpiniki I. Papageorgiou Csaba Huszka Jos De Roo Nassim Douali Marie-Christine Jaulent Dirk Colaert 《Computer methods and programs in biomedicine》2013
This study aimed to focus on medical knowledge representation and reasoning using the probabilistic and fuzzy influence processes, implemented in the semantic web, for decision support tasks. Bayesian belief networks (BBNs) and fuzzy cognitive maps (FCMs), as dynamic influence graphs, were applied to handle the task of medical knowledge formalization for decision support. In order to perform reasoning on these knowledge models, a general purpose reasoning engine, EYE, with the necessary plug-ins was developed in the semantic web. The two formal approaches constitute the proposed decision support system (DSS) aiming to recognize the appropriate guidelines of a medical problem, and to propose easily understandable course of actions to guide the practitioners. The urinary tract infection (UTI) problem was selected as the proof-of-concept example to examine the proposed formalization techniques implemented in the semantic web. The medical guidelines for UTI treatment were formalized into BBN and FCM knowledge models. To assess the formal models’ performance, 55 patient cases were extracted from a database and analyzed. The results showed that the suggested approaches formalized medical knowledge efficiently in the semantic web, and gave a front-end decision on antibiotics’ suggestion for UTI. 相似文献
33.
BMP-7 has shown inductive potential for in vitro osteogenic differentiation of mesenchymal stem cells, which are an ideal resource for regenerative medicine. Externally applied, recombinant BMP-7 was able to induce the osteogenic differentiation of DPSCs but based on our previous results with BMP-2, we aimed to study the effect of the tetracyclin-inducible BMP-7 expression on these cells. DPSC, mock, and DPSC-BMP-7 cell lines were cultured in the presence or absence of doxycycline, then alkaline phosphatase (ALP) activity, mineralization, and mRNA levels of different osteogenic marker genes were measured. In the DPSC-BMP-7 cell line, the level of BMP-7 mRNA significantly increased in the media supplemented with doxycycline, however, the expression of Runx2 and noggin genes was upregulated only after 21 days of incubation in the osteogenic medium with doxycycline. Moreover, while the examination of ALP activity showed reduced activity in the control medium containing doxycycline, the accumulation of minerals remained unchanged in the cultures. We have found that the induced BMP-7 expression failed to induce osteogenic differentiation of DPSCs. We propose three different mechanisms that may worth investigating for the engineering of expression systems that can be used for the induction of differentiation of mesenchymal stem cells. 相似文献
34.
We develop a method to model the interaction of currents and domain walls in a standard micromagnetic simulator. The interaction
of spin-polarized currents and localized magnetic moments can be described by a current-induced effective field, which superposes
to other components of the effective magnetic field. Using our method, we examine domain wall propagation in ideal, rough-surfaced
and notched domain walls. 相似文献
35.
György Csaba Paolo Lugli Markus Becherer Doris Schmitt-Landsiedel Wolfgang Porod 《Journal of Computational Electronics》2008,7(3):454-457
This paper presents a computational study of ion-beam patterned cobalt-platinum multilayers, which could be used for field-coupled
computing. We use micromagnetic simulations to reproduce measured hysteresis curves. This parameterized micromagnetic simulator
then will be used for simulating interacting magnetic dots. We demonstrate how logic gates can be built from such coupled
dots. We also show how electrical wires—placed beneath or above the magnetic dots—can provide a magnetic field, which propagates
the magnetic signals. 相似文献
36.
Gréta Gergely Ferenc Wéber István Lukács Attila L. Tóth Zsolt E. Horváth Judit Mihály Csaba Balázsi 《Ceramics International》2010,36(2):803-806
Hydroxyapatite (HAp) was successfully produced by using recycled eggshell. The observed phases of the synthesised materials were dependent on the mechanochemical activation method (ball milling and attrition milling). The structures of the HAp were characterized by X-ray diffraction, scanning electron microscopy and infrared spectroscopy. Attrition milling proved to be more efficient than ball milling, as resulted nanosize, homogenous HAp even after milling. 相似文献
37.
This paper presents a numerical study on contact law between extremely fine particles taking into account of the effect of adhesion force and surface roughness. The adhesion force between two particles is calculated from the Erkoc inter-atomic potential. This force is incorporated into a material point model for the dynamic impact between the two particles. Unlike a molecular dynamics model, atoms in the model are embedded in the continuum solid such that they can only move relatively to each other as the continuum solid deforms. The model is numerically efficient while taking into account of the adhesion effect at the same time. Numerical study using this model shows that the Maugis theory (Maugis, 1992) is valid for spherical particles as small as 50 nm in size. The numerical study also shows that a slight change in surface roughness can alter the impact behaviour completely. Therefore an uncertainty in using the Maugis contact law for real particles is how to determine the effective specific surface energy for particles of different surface roughness. Because of the uncertainty, full numerical analysis may have to be used to obtain the adhesive contact law. 相似文献
38.
39.
Electrochemical synthesis of a novel carboxylic acid functionalized polythiophene – poly(3-thiophene-butyric-acid), PTBA – has been realized. Its morphology, electrochemical, spectral and conducting properties have been compared to those of poly(3-thiophene-acetic-acid), PTAA, which is widely used to immobilise both bioactive molecules and inorganic nanoparticles. According to scanning electron microscopic (SEM) images, the difference in the real and geometric surface area of the modified electrodes is much more expressed in the case of PTBA. Both the symmetry of the cyclic voltammograms and the concurrent, sustained optical changes proved that this polymer possesses an improved and more stable redox activity. According to simultaneously performed in situ ac. impedance and UV–Vis measurements, both films could be uniformly transformed between the insulating and conducting forms, but PTAA exhibited some degradation. The development of the conducting state during the redox switching of both thiophene derivative polymers proved to be primarily connected to the formation of di-cationic species. The electrochemical quartz crystal microbalance (EQCM) results evidenced also differences between the two polymers, which difference can be interpreted by assuming the more expressed effect of the deprotonation-connected (self-) doping process in PTAA. The results confirm that the new conducting polymer, PTBA is much more convenient for being considered as the polymer matrix of practically applicable composites. 相似文献
40.
The paper presents a general mathematical model for disperse systems in which direct interactions between particles are taken into consideration. The model is formulated in terms of transition measures, introduced on the basis of conditional Markov processes. The population balance equation, describing the behaviour of interactive populations, is developed in a general form of continuous and discontinuous terms. Moment equations are presented and analysed for the axial dispersion model with interparticle exchange processes of heat and mass. The applicability of the model is illustrated by applying it for describing a process of heating particles by gas with interparticle heat transfer, and a mass exchange process between fluid particles. 相似文献