全文获取类型
收费全文 | 620篇 |
免费 | 48篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 199篇 |
金属工艺 | 3篇 |
机械仪表 | 21篇 |
建筑科学 | 17篇 |
矿业工程 | 1篇 |
能源动力 | 15篇 |
轻工业 | 159篇 |
水利工程 | 3篇 |
石油天然气 | 5篇 |
无线电 | 16篇 |
一般工业技术 | 75篇 |
冶金工业 | 61篇 |
原子能技术 | 5篇 |
自动化技术 | 81篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 19篇 |
2021年 | 38篇 |
2020年 | 23篇 |
2019年 | 27篇 |
2018年 | 21篇 |
2017年 | 24篇 |
2016年 | 25篇 |
2015年 | 11篇 |
2014年 | 38篇 |
2013年 | 48篇 |
2012年 | 34篇 |
2011年 | 45篇 |
2010年 | 24篇 |
2009年 | 26篇 |
2008年 | 38篇 |
2007年 | 27篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 15篇 |
2003年 | 6篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 21篇 |
1997年 | 13篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1937年 | 2篇 |
排序方式: 共有668条查询结果,搜索用时 31 毫秒
31.
Tsormpatzoglou A. Tassis D.H. Dimitriadis C.A. Frigeri P. Franchi S. Gombia E. Mosca R. 《Electron Device Letters, IEEE》2006,27(5):320-322
Local trap levels in Au/n-GaAs Schottky diodes with embedded InAs quantum dots, generated after a long time of the device operation, have been investigated with low-frequency noise measurements performed in the temperature range of 77-298 K and at the forward current of 30 nA. Whereas the initial devices show a pure 1/f noise behavior, after a long time of operation, recombination noise was observed at frequencies above 100 Hz, in addition to the 1/f noise at lower frequencies. Analysis of the recombination noise data obtained on structures where different GaAs cap layer thicknesses have been removed by etching allowed us to determine the activation energy of the local traps and have a rough estimation of their spatial distribution. 相似文献
32.
Obesity is a multifactorial pathology currently considered one of the main public health problems. Its prevalence is increasing dramatically in the last decades, reaching huge rates in Brazil and many other countries. Regardless of the factors associated with genetic predisposition, this pathology is often associated with abnormal food intake, and also with high consumption of caloric foods and sedentary habits. Thus, obesity is the result of an imbalance between food intake and energy expenditure. One of the greatest research interests in nutrition has currently been the dietetic determinants that may exert an influence on the process of food intake, as well as the role of foods on physiological, physical and chemical factors most related to the processes of satiation and satiety. Based on these aspects, this paper analyzes several research works to gain a better insight of the dietetic factors affecting food intake and body weight regulation. 相似文献
33.
Software architecture design is an interactive, complex, decision‐making process. Such a design process involves the exploration, evaluation, and composition of design alternatives. Increasingly, new computer‐aided tools are available to help designers in these complex activities. However, these tools do not know how design is actually done, in other words, by means of which design activities the final artefact was obtained. In fact, the architectural design knowledge exclusively rests in the mind of designers, and there is an urgent need to move it, as much as possible, to a computer‐supported environment that enables the capture of this type of knowledge. This contribution addresses this need by introducing a model for capturing how products under development are generated and transformed along the software architecture design process. The proposed model follows an operational perspective, where architectural design decisions are modelled by means of sequences of operations that are applied on the design products. Situation calculus is used to formally express the existence of an object in a given state of a design process. In addition, this formalism allows us expressing without ambiguities when an operation can be performed in a specific state of the design process. 相似文献
34.
Luciana A. Tacon 《Drying Technology》2013,31(5):841-852
The aim of this study was to evaluate the effects of paste properties on residence time during drying in a spouted bed dryer with inert bodies. The effect of paste solids content, surface tension, and viscosity on the residence time distribution and the mean residence times were studied using factorial experimental designs. The inert bodies used were glass and polyethylene beads. The mean residence times varied from 13.6 to 16.3 and 12.2 to 17.7 min for drying on glass and polyethylene beads, respectively. The analysis of variance showed that mean residence times significantly depended on solids content and surface tension for glass beads and also on viscosity for polyethylene beads. The residence time distributions for all conditions studied fitted well to the perfect mixing cell when applying the continuous stirred vessels in series model analysis. The powder density, flowability, and particle size depended on paste properties and inert type. 相似文献
35.
Luciana Katty Figueiredo Sanches Edmea Lodovici Leticia Cristina Cidreira Boaro Leonardo Eloy Rodrigues-Filho 《Journal of Adhesion Science and Technology》2013,27(12):1386-1394
The durability of adhesive interfaces is still a problem in adhesive restorations in dentistry. Laboratorial ageing methods have been proposed to predict the performance of materials, but they still require standardization. The objective of this study was to evaluate the resin-dentin microtensile bond strength of composite restorations subjected to pH cycling and different levels of mechanical loading. Resin blocks were built over a flat superficial dentin of bovine incisors (n = 40), using a three-step adhesive system. Half of the specimens were submitted to 10 cycles of pH cycling, followed by mechanical loading (0, 500,000; 1,000,000; 2,000,000 cycles – 98 N, 4 Hz). The other half was directly subjected to mechanical loading. After ageing, all groups were subjected to a microtensile bond test. Data were analyzed using two-way ANOVA and Tukey’s test (α = 0.05). The frequency of the early de-bonding was compared using the Chi-square test (α = 0.05). The statistical analysis revealed that the cross-product interaction ‘pH cycling’ vs. ‘number of mechanical loading cycles’ (p = 0.72) as well as the main factor ‘pH cycling’ (p = 0.49) was not statistically significant, and they were not able to reduce the resin–dentin bond strength values. Regarding the number of mechanical loading cycles, the groups subjected to 2,000,000 cycles showed lower bond strength values than the others (p = 0.003). The frequency of debonded specimens increased with mechanical loading. Therefore, it can be concluded that in this restorative model, at least 2,000,000 mechanical cycles are need to decrease the microtensile strength and simulate the ageing of the interface. 相似文献
36.
Stakeholders are the first emerging challenge in any software project. Their identification is a critical task for success.
Nevertheless, many authors consider them as a default product of a non-explained identification process. Several aspects must
be considered when the project is carried out in environments where multiple organizations interact. These complex contexts
demand extremely hard efforts. Stakeholders must be identified taking into account their attributes (types, roles), which
must be extended and defined for these environments. In general, there are no methodologies that allow performing this task
in a systematic way for the development of interorganizational information systems. The paper proposes a method for carrying
out stakeholder identification considering the diverse dimensions involved in interorganizational environments: organizational,
interorganizational and external. It allows the systematic specification of all the people, groups and organizations whose
interests and needs can affect or are affected by the interorganizational system. Also diverse stakeholders’ attributes such
as types, roles, influence and interest are defined, analyzed, and included in the method. They are all important in later
stages of any software project. 相似文献
37.
Giulia Di Donato Debora Mariarita dAngelo Luciana Breda Francesco Chiarelli 《International journal of molecular sciences》2021,22(12)
Systemic autoinflammatory diseases are a heterogeneous family of disorders characterized by a dysregulation of the innate immune system, in which sterile inflammation primarily develops through antigen-independent hyperactivation of immune pathways. In most cases, they have a strong genetic background, with mutations in single genes involved in inflammation. Therefore, they can derive from different pathogenic mechanisms at any level, such as dysregulated inflammasome-mediated production of cytokines, intracellular stress, defective regulatory pathways, altered protein folding, enhanced NF-kappaB signalling, ubiquitination disorders, interferon pathway upregulation and complement activation. Since the discover of pathogenic mutations of the pyrin-encoding gene MEFV in Familial Mediterranean Fever, more than 50 monogenic autoinflammatory diseases have been discovered thanks to the advances in genetic sequencing: the advent of new genetic analysis techniques and the discovery of genes involved in autoinflammatory diseases have allowed a better understanding of the underlying innate immunologic pathways and pathogenetic mechanisms, thus opening new perspectives in targeted therapies. Moreover, this field of research has become of great interest, since more than a hundred clinical trials for autoinflammatory diseases are currently active or recently concluded, allowing us to hope for considerable acquisitions for the next few years. General paediatricians need to be aware of the importance of this group of diseases and they should consider autoinflammatory diseases in patients with clinical hallmarks, in order to guide further examinations and refer the patient to a specialist rheumatologist. Here we resume the pathogenesis, clinical aspects and diagnosis of the most important autoinflammatory diseases in children. 相似文献
38.
39.
Rosalba Lanciotti Francesca Patrignani Luciana Iucci Maria Elisabetta Guerzoni Giovanna Suzzi Nicoletta Belletti Fausto Gardini 《Food chemistry》2007,104(2):693-701
The aim of this work was to evaluate the biogenic amine (BA) content during the ripening of both bovine and ovine cheeses obtained using milk subjected to a homogenization treatment at 100 MPa before cheese-making. The data obtained were compared with those from cheeses produced by the same milks without any treatment or thermized. The results showed that both microbial ecology and BA concentrations of cheeses during ripening were significantly influenced by the type of milk used for cheese-making and by the treatment applied to the raw materials. In particular, the microbial counts found in Caciotta indicated that the high pressure homogenization (HPH) of milk significantly reduced the presence of the yeasts, Micrococcaceae and lactobacilli at the end of ripening. On the other hand, the HPH treatment of milk favoured the proliferation of yeasts in ovine cheese. Moreover, the ovine cheeses were characterized by a remarkably higher accumulation of BA than bovine cheeses. However, the HPH treatment of milk was able to drastically reduce the biogenic amine concentrations in both cheese typologies at the end of ripening. 相似文献
40.
This paper proves the validity of a basic feasibility property which makes it possible to extend, to the case of set-point tracking in ANCBI systems under joint positional and incremental input saturations, the approach in [Mosca, E. (2005). Predictive switching supervisory control of persistently disturbed input-saturated plants. Automatica, 41, 55-67] restricted to positional input saturation and the pure regulation problem. An example on the use of the proposed technique is considered. 相似文献