全文获取类型
收费全文 | 1490篇 |
免费 | 113篇 |
专业分类
电工技术 | 31篇 |
综合类 | 3篇 |
化学工业 | 312篇 |
金属工艺 | 19篇 |
机械仪表 | 30篇 |
建筑科学 | 32篇 |
矿业工程 | 1篇 |
能源动力 | 50篇 |
轻工业 | 184篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
无线电 | 129篇 |
一般工业技术 | 275篇 |
冶金工业 | 172篇 |
原子能技术 | 6篇 |
自动化技术 | 350篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 41篇 |
2021年 | 41篇 |
2020年 | 31篇 |
2019年 | 51篇 |
2018年 | 53篇 |
2017年 | 59篇 |
2016年 | 53篇 |
2015年 | 40篇 |
2014年 | 67篇 |
2013年 | 110篇 |
2012年 | 88篇 |
2011年 | 123篇 |
2010年 | 64篇 |
2009年 | 68篇 |
2008年 | 97篇 |
2007年 | 68篇 |
2006年 | 52篇 |
2005年 | 41篇 |
2004年 | 42篇 |
2003年 | 38篇 |
2002年 | 29篇 |
2001年 | 24篇 |
2000年 | 27篇 |
1999年 | 23篇 |
1998年 | 57篇 |
1997年 | 41篇 |
1996年 | 23篇 |
1995年 | 20篇 |
1994年 | 20篇 |
1993年 | 21篇 |
1992年 | 3篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1969年 | 1篇 |
排序方式: 共有1603条查询结果,搜索用时 15 毫秒
41.
42.
M. S. Netto A. M. Annaswamy R. Ortega P. Moya 《International journal of control》2013,86(14):1312-1321
In this paper we deal with the problem of adaptive control of a class of non-linearly parametrized plants. The main contribution is to show that, through a well-chosen reparametrization, it is possible to transform the non-convex nonlinear parametrization into a convex one, a property that is used to design a globally stable adaptive controller. 相似文献
43.
Romário Mauricio Urbanetto Nogueira Carlos Enrique Niño Bohórquez Igor Giacomelli Zanella 《Welding International》2017,31(3):161-172
Despite their similarity, the MIG/MAG and Tubular Electrode processes display particular features with regard to arc stability and variability in the characteristics of the beads. Thus, selection of one of these processes for a specific application will have to consider how these particular features affect the quality of the welds. To support this choice, the present study aimed to investigate how changing the average current affects the stability and regularity of metal transfer in welds carried out with constant voltage and pulsed current and compare the variability in the geometry and dilution of these welds. To achieve these aims, automatic welding was carried out, with steel ABNT 1020 as base metal and wire AWS ER70S-6 and AWS E71T-1 as filler metals. Besides the welds with variation in the average current, the tests involved determination of the parameters for occurrence of stable short circuiting, drop and pulsed transfer. The results showed that the voltage that gives the highest stability in short circuiting transfer is independent of the welding speed and increases with the wire speed, and also showed that welds made with hollow wire displayed greater variability compared to solid wire. 相似文献
44.
45.
This research evaluated the in situ physicochemical changes and alterations occurring in an electrolytic chromium coated steel (ECCS), surface protected by polyethylene teraphthalate (PET) copolymer, after inducing a fracture on the coating in an acid acetic‐acetate medium. The delamination was characterized in the front of the failure by means of anodic and cathodic electrochemical mechanisms, and the resistance and degradation of the metal‐polymer composite's substrates were analyzed by means of Raman vibrational spectroscopy. The application of an electrochemical cell to generate in situ delamination, simulating the formation of pores or artificial defects, provided information on the activity inside the substrates of the PET‐coated ECCS composite as a result of the effect of the acetic acid. The anodic delamination mechanism is based on the diffusion of the electrolyte through the metal‐polymer interface and the pre‐existence of pores on the polymer layer. The cathodic delamination mechanism is based on the mechanical action of the gaseous hydrogen as a result of the reduction of H+. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
46.
Volnei Tita Mauricio Francisco Caliri Júnior Ricardo Afonso Angélico Rodrigo Bresciani Canto 《Polymer Engineering and Science》2012,52(12):2654-2663
Assessing a full set of mechanical properties is a rather complicate task in the case of foams, especially if material models must be calibrated with these results. Many issues, for example anisotropy and heterogeneity, influence the mechanical behavior. This article shows through experimental analyses how the microstructure affects different experimental setups and it also quantifies the degree of anisotropy of a poly(vinyl chloride) foam. Monotonic and cyclic experimental tests were carried out using standard compression specimens and non‐standard tensile specimens. Results are complemented and compared with the aid of a digital image correlation technique and scanning electron microscopy analyses. Mechanical properties (e.g., elastic and plastic Poisson's ratios) are evaluated for compression and tensile tests, for two different material directions (normal and in‐plane). The material is found to be transversely isotropic. Differences in the results of the mechanical properties can be as high as 100%, or even more depending on the technique used and the loading direction. Also, the experimental analyses show how the material's microstructure behavior, like the evolution of the herein identified “yield fronts” and a “spring back” phenomenon, can influence the phenomenological response and the failure mechanisms as well as the hardening curves. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
47.
Daniel Lobo Mauricio Solano George A. Bubenik Michael Levin 《Journal of the Royal Society Interface》2014,11(92)
A fundamental assumption of today''s molecular genetics paradigm is that complex morphology emerges from the combined activity of low-level processes involving proteins and nucleic acids. An inherent characteristic of such nonlinear encodings is the difficulty of creating the genetic and epigenetic information that will produce a given self-assembling complex morphology. This ‘inverse problem’ is vital not only for understanding the evolution, development and regeneration of bodyplans, but also for synthetic biology efforts that seek to engineer biological shapes. Importantly, the regenerative mechanisms in deer antlers, planarian worms and fiddler crabs can solve an inverse problem: their target morphology can be altered specifically and stably by injuries in particular locations. Here, we discuss the class of models that use pre-specified morphological goal states and propose the existence of a linear encoding of the target morphology, making the inverse problem easy for these organisms to solve. Indeed, many model organisms such as Drosophila, hydra and Xenopus also develop according to nonlinear encodings producing linear encodings of their final morphologies. We propose the development of testable models of regeneration regulation that combine emergence with a top-down specification of shape by linear encodings of target morphology, driving transformative applications in biomedicine and synthetic bioengineering. 相似文献
48.
Anne Stöbener Mario Fabuel Ortega Christoph J. Bolten Edwin Ananta Shantha Nalur Andreas Liese 《International Journal of Food Science & Technology》2020,55(3):1265-1271
Partial glycerides are widely used ingredients in confectionery products that can be produced from natural fats. In a biocatalytic partial hydrolysis of cocoa butter and palm oil fractions, a product mixture containing 1.5% monoglycerides and 5.5% diglycerides intended for the use in confectionery products was created. This study is a proof of principle that shows the feasibility of monitoring the biocatalytic partial hydrolysis of these two natural fats in situ with ATR-FTIR spectroscopy. An economic approach was utilised for calibration since partial glyceride calibration standards are costly and poorly available. The released compounds were quantified by means of chemometric modelling, and the model was validated with gas chromatography. Resulting root mean square errors were in the low per cent range. Additionally, the results indicate that distinction of the released free fatty acids is possible with ATR-FTIR spectroscopy. 相似文献
49.
Tamara Rodríguez-Prieto Borja Hernndez-Breijo Miguel A. Ortega Rafael Gmez Javier Snchez-Nieves Luis G. Guijarro 《International journal of molecular sciences》2020,21(23)
Antibodies are macromolecules that specifically recognize their target, making them good candidates to be employed in various therapies. The possibility of attaching a drug to an immunoglobulin makes it possible to release it specifically into the affected tissue as long as it overexpresses the target. However, chemical coupling could affect the functionality (specificity and affinity) of the antibody. It has been observed that the use of intermediaries, such as dendrimers, could resolve this issue. Because carbosilane dendrimers have aroused great interest in the field of biomedicine, this report describes the synthesis of an anionic carbosilane dendrimer with a fluorochrome on its surface that then forms a conjugate with an antibody. It has been used as immunoglobulin and infliximab, whose target is TNF-α, which is a cytokine that is overexpressed in the inflamed area or even in the blood of patients with autoimmune diseases, such as rheumatoid arthritis. In addition, the integrity and functionality of the antibody has been studied to see if they have been affected after the chemical coupling process. 相似文献
50.