全文获取类型
收费全文 | 1456篇 |
免费 | 71篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 502篇 |
金属工艺 | 17篇 |
机械仪表 | 15篇 |
建筑科学 | 52篇 |
矿业工程 | 1篇 |
能源动力 | 26篇 |
轻工业 | 297篇 |
水利工程 | 13篇 |
无线电 | 45篇 |
一般工业技术 | 214篇 |
冶金工业 | 158篇 |
原子能技术 | 6篇 |
自动化技术 | 177篇 |
出版年
2023年 | 18篇 |
2022年 | 105篇 |
2021年 | 94篇 |
2020年 | 45篇 |
2019年 | 35篇 |
2018年 | 48篇 |
2017年 | 41篇 |
2016年 | 62篇 |
2015年 | 30篇 |
2014年 | 75篇 |
2013年 | 100篇 |
2012年 | 85篇 |
2011年 | 119篇 |
2010年 | 100篇 |
2009年 | 73篇 |
2008年 | 77篇 |
2007年 | 60篇 |
2006年 | 40篇 |
2005年 | 45篇 |
2004年 | 27篇 |
2003年 | 31篇 |
2002年 | 22篇 |
2001年 | 13篇 |
2000年 | 18篇 |
1999年 | 24篇 |
1998年 | 9篇 |
1997年 | 20篇 |
1996年 | 7篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1528条查询结果,搜索用时 15 毫秒
1.
Differential scanning calorimetry and hot stage microscopy have been used to study the interactions between sulphamethoxazole and the sugars maltose, glucose, sucrose and mannitol. Only the sulphamethoxazole-mannitol system appeared to be stable and presented a eutectic containing 90.3% sulphamethoxazole. Heats of fusion for sulphamethoxazole, mannitol and their eutectic were 33.4, 73.6 and 39.9 cal g respectively. 相似文献
2.
Monica Bianco Ilenia Viola Miriam Cezza Francesca Pietracaprina Giuseppe Gigli Rosaria Rinaldi Valentina Arima 《Microfluidics and nanofluidics》2012,13(3):399-409
Solid surface/liquid interactions play an important role in microfluidics and particularly in manipulation of films, drops and bubbles, a basic requirement for a number of lab-on-chip applications. The behavior of solvents in coated microchannels is difficult to be predicted considering theories; therefore, experimental methods able to estimate the properties at the interface in real time and during the operational regime are amenable. Here, we propose to use an experimental setup to evaluate the effective dynamics of solvents inside PDMS microchannels. The influence of the solvent properties as well as of the channel wall’s wettability on the fluid movements was evaluated. Modification of the channel properties was achieved by introducing Teflon coatings that allow producing stable hydrophobic microchannel walls. The results were fitted according to Washburn-type power-law and compared with theoretical calculations of the parameter β that expresses the dependence of capillary dynamics on surface tension γ, liquid viscosity η, contact angles θ and the hydraulic radius R H. A comparison between the calculated and the experimental values reveled that parameters other than the contemplated ones influenced the measurements. The main parameter that affects the flow of solvents such as water, methanol ethanol, dimethylformamide, acetonitrile and acetone was found to be the γ/η ratio. Considering these results, the investigation tool described here is believed to be promising to predict the dynamics of common organic solvents inside integrated functional fluidic devices and to accurately control solvent flow, particularly in capillary-driven pumpless systems, a basic requirement for widening the application range of PDMS lab-on-chip devices. 相似文献
3.
Resistant starch formation during baking -effect of baking time and temperature and variations in the recipe 总被引:1,自引:0,他引:1
Monica Siljeström Nils-Georg Asp 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1985,181(1):4-8
Summary The dietary fibre content in white wheat bread, measured with an enzymatic, gravimetric method, was almost 20% higher than in the corresponding flour. The increment was largely explained by the formation of resistant starch, i.e. starch available to amyloglucosidase only after solubilization with 2m-KOH. The resistant starch was formed in the oven or upon cooling of the finished bread. The water content in the dough seemed to influence the extent of the resistant starch formation, whereas changes in the fat content had no effect. The results indicate that the resistant starch might be hard retrograded starch, possibly amylose.
Bildung von resistenter Stärke während des Backens in Abhängigkeit von Backzeit, Backtemperatur und Rezeptvariationen
Zusammenfassung Die Menge an Ballaststoffen, die nach einer enzymatisch-gravimetrischen Methode bestimmt wurde, war in weißem Weizenbrot fast 20% höher als in dem entsprechendem Mehl. Die Erhöhung konnte zum großen Teil auf die Bildung von resistenter Stärke zurückgeführt werden, d. h. auf eine Stärkefraktion, die nur nach Auflösung mit 2m-KOH für Amyloglucosidase zugänglich ist. Die resistente Stärke wird während des Backens oder während der Abkühlung des Brotes gebildet, und die Menge scheint vom Wassergehalt des Teiges, aber nicht vom Fettgehalt abhängig zu sein. Die Resultate dieser Untersuchung weisen darauf hin, daß die resistente Stärke retrogradierte Stärke, möglicherweise Amylose, ist.相似文献
4.
Joseph Akyeampong Silvanus Udoka Giandomenico Caruso Monica Bordegoni 《International Journal of Industrial Ergonomics》2014
This study evaluated newly proposed Human–Machine Interface (HMI) design concepts for improving the ergonomics of hydraulic excavators. The design concepts were based on an augmented interaction technique which involved the use of heads-up display (HUD) and coordinated control as HMI elements. Two alternative HMI designs were elaborated in order to separately evaluate the ergonomic impacts of the head-up display and the coordinated control by comparing them to the standard HMI design. The effectiveness of these three HMI designs in terms of the reduction of the operators' mental and physical workload were assessed by conducting experiments utilizing human subjects, ages 23–35 years. The National Aeronautics and Space Administration's Task Load Index (NASA TLX) method was used for collecting subjective workload scores based on a weighted average of ratings of six factors: Mental Demand, Physical Demand, Temporal Demand, Own Performance, Effort, and Frustration Level. The results showed that the type of HMI design affects different aspects of the operator's workload. Indeed, it showed how the proposed augmented interaction is an effective solution for reducing the ergonomic gaps in terms of mental workload, and to a lesser extent the physical workload, subjected by the standard HMI design. 相似文献
5.
Athula Ginige Luca Paolino Marco Romano Monica Sebillo Genoveffa Tortora Giuliana Vitiello 《Computer Supported Cooperative Work (CSCW)》2014,23(4-6):547-583
Recent natural disasters have led crisis management organizations to revise their protocols so as to rely on the contribution of a wider range of actors, including simple citizens as well as expert operators, to support decision making activities. Reliable and timely information sharing among members of distributed teams of disaster responders has become paramount for the success of the overall crisis management process. In this paper we propose a crisis management system based on spreadsheet-mediated collaboration among on-site responders and decision makers. To share data a common spreadsheet artifact has been developed by using a participatory design approach which is accessed through mobile user interfaces. The evaluation results showed that the use of the spreadsheet artifact has resulted in more effective decision making relating to set of earthquake management scenarios in high-risk areas located in Italy. 相似文献
6.
Fragmentation of support/catalyst particles during propylene polymerization in the gas phase is analyzed via a mathematical model including energy and mass transfer with chemical reaction processes. The rupture phenomenon is considered specifically by the model, and evaluated as it proceeds in time, Two different regions are recognized in the polymerizing particle at fragmentation time: an inner core resembling the original solid support/catalyst structure, and an external set of layers where most of the polymerization occurs. Model predictions concerning the effects of fragmentation on polymerization are discussed. The influence of different degrees of fragmentation on thermal runaways and monomer availability at active sites located inside the support/catalyst/polymer complex is shown. Monomer concentration profiles inside the growing particles are explained in terms of the combined fragmentation-polymerization interaction. Results show a strong influence of catalyst structure on critical phenomena during early polymerization stages, and suggest the possibility of controlling critical parameters via the definition of fragment structure at catalyst preparation time. 相似文献
7.
Cibrian Franceli L. Ley-Flores Judith Newbold Joseph W. Singh Aneesha Bianchi-Berthouze Nadia Tentori Monica 《Personal and Ubiquitous Computing》2021,25(2):391-410
Personal and Ubiquitous Computing - Interactive sonification is an effective tool used to guide individuals when practicing movements. Little research has shown the use of interactive sonification... 相似文献
8.
9.
Dan Selişteanu Monica Roman Dorin Şendrescu 《Simulation Modelling Practice and Theory》2010,18(9):1297-1313
This paper deals with the problem of modelling and on-line estimation of kinetics for a biomethanation process. This bioprocess is in fact a wastewater biodegradation process with production of methane gas, which takes place inside a Continuous Stirred Tank Bioreactor. The reaction scheme and the analysis of biochemical phenomena inside the bioreactor are used in order to obtain a nonlinear dynamic model of the bioprocess, by means of the pseudo Bond Graph method. Two nonlinear estimation strategies are developed for the identification of unknown kinetics of the bioprocess. First, an estimator is developed by using a state observer based technique. Second, an observer based on high-gain approach is designed and implemented. Several numerical simulations are performed in order to analyse and compare the behaviour and the performance of the proposed estimators. 相似文献
10.
Given a graph G where a label is associated with each edge, we address the problem of looking for a maximum matching of G using the minimum number of different labels, namely the labeled maximum matching problem. It is a relatively new problem whose application is related to the timetabling problem. We prove it is NP-complete and present four different mathematical formulations. Moreover, we propose an exact algorithm based on a branch-and-bound approach to solve it. We evaluate the performance of our algorithm on a wide set of instances and compare our computational times with the ones required by CPLEX to solve the proposed mathematical formulations. Test results show the effectiveness of our procedure, that hugely outperforms the solver. 相似文献