全文获取类型
收费全文 | 370篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 102篇 |
金属工艺 | 7篇 |
机械仪表 | 7篇 |
建筑科学 | 18篇 |
能源动力 | 27篇 |
轻工业 | 58篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 28篇 |
一般工业技术 | 51篇 |
冶金工业 | 10篇 |
原子能技术 | 5篇 |
自动化技术 | 63篇 |
出版年
2022年 | 17篇 |
2021年 | 19篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 14篇 |
2016年 | 9篇 |
2015年 | 16篇 |
2014年 | 12篇 |
2013年 | 33篇 |
2012年 | 18篇 |
2011年 | 30篇 |
2010年 | 17篇 |
2009年 | 23篇 |
2008年 | 21篇 |
2007年 | 10篇 |
2006年 | 20篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有385条查询结果,搜索用时 0 毫秒
81.
Lombardo Gianfranco Fornacciari Paolo Mordonini Monica Sani Laura Tomaiuolo Michele 《Multimedia Tools and Applications》2019,78(3):3321-3339
Multimedia Tools and Applications - Hidradenitis Suppurativa (HS), also known as Acne Inversa, is a chronic, underdiagnosed, often debilitating and painful disease that affects the folds of the... 相似文献
82.
The IEEE 802.15.4 protocol offers great potential in several application fields, such as industrial Wireless Sensor Networks (WSNs). An industrial automation cell (field level) is characterized mostly by periodic traffic flows. Using the IEEE 802.15.4 protocol, it is necessary to manage Guaranteed Time Slots (GTSs) allocation and at the same time ensure adequate performance both to other periodic traffic flows and network management/control flows. For these reasons, this paper shows a flexible approach in order to improve GTSs assignment and medium access performance. Analytical results are shown in order to demonstrate benefits introduced by deadline-aware algorithm (for guaranteed access to reserved slots) and CSMA-CA-priority based (for latencies reduction during medium access attempts). Otherwise, obtained results show that the proposed technique improves the number of deadlines met and the probability to find the channel free for transmissions. 相似文献
83.
Gianfranco Bilardi Kattamuri Ekanadham Pratap Pattnaik 《International journal of parallel programming》2013,41(3):430-468
The Linear-Scan algorithm (1970), applicable to priority replacement policies, computes stack distances and the number of misses incurred on a given address trace, for all cache sizes, in time O(V) per access. Here, V is the number of distinct (virtual) items referenced within the trace. While the time bound was subsequently lowered to O(log V) for the Least Recently Used policy, no improvements have been reported for general priority policies. This work introduces the class of policies with nearly static priorities (NSP), which encompasses several known policies. The Min-Tree algorithm is proposed for NSP policies, whose performance is quite sensitive to the policy as well as to the address trace. Under suitable probabilistic assumptions, the expected time per access is O(log2 V). Experimental evidence collected on a mix of 30 benchmarks shows that the Min-Tree algorithm can be significantly faster than Linear-Scan, for interesting policies such as OPT (or Belady), Least Frequently Used (LFU), and Most Recently Used (MRU). Min-Tree can be parallelized to run in time O(log V) using O(V/log V) processors, in the worst case. A more sophisticated Lazy Min-Tree algorithm is also developed with ${O(\sqrt{V}\log V)}$ worst-case time per access. This bound applies, in particular, to the policies OPT, LFU, and Least Recently/Frequently Used (LRFU), for which the best previously known bound was O(V). Although random replacement is not an NSP policy, the framework developed in this work leads to a stack-distance algorithm with O(log V) expected time per access. 相似文献
84.
Exploitation of aggregates in the river po basin,near Turin,Italy, and its impact on the environment
E. Armando A. Di Molfetta M. Fornaro G. Gola S. Pelizza L. Stragiotti G. Verga 《Bulletin of Engineering Geology and the Environment》1984,29(1):211-216
The study carried out jointly by the Politecnico di Torino and the Ufficio Cave of Regione Piemonte examined the most troublesome interferences between quarry exploitation and other land uses alongside the river Po, south of Turin. Here a great number of large alluvial aggregate quarries, whose excavations extend below the water table, have long been active. Detailed geological and topographical investigations have been carried out, together with geophysical prospecting work (by electrical methods) and hydraulic tests on wells. The results of the investigations have permitted the setting up for the quarries involved of rational guidelines for the protection of the groundwater resources and of soil stability. The necessity of systematic preliminary studies, according to the law presently in force, is stressed for new quarries to be opened. Investigations should also involve an adequate number of exploration drillings and water pressure measurements, to determine the amount and the quality of the alluvial deposits as well as the hydraulic characteristics of the aquifers and the geotechnical properties of the ground where the excavation work has to be made. A rational program of land recovery, and an exploitation plan respecting other land uses, can be set only in the light of the aforesaid studies. 相似文献
85.
Shervin Shahvi Enrico Orsi Roberto Canziani Enrico Larcan Gianfranco Becciu 《Urban Water Journal》2017,14(10):1058-1064
Today, we know that not only the sewers carry urban wastewater, but also act as chemical and biological reactors, in which both organic and inorganic substances undergo significant transformations. This article describes a study on the western part of the sewer system of the city of Milan. The hydraulic model of the sewer system was coupled with the chemical and dynamic biological model to assess the extent of the degradation of organic matter in the network. The hydraulic and biological models were calibrated with real data obtained at the entrance of the wastewater treatment plant (WWTP) ‘Milan South’ and assuming standard values of daily per capita loads of COD and BOD5. 相似文献
86.
87.
In Situ Rheo-NMR Measurements of Solid Fat Content 总被引:2,自引:0,他引:2
Gianfranco Mazzanti Elizabeth M. Mudge Emmanuel Y. Anom 《Journal of the American Oil Chemists' Society》2008,85(5):405-412
The properties of crystallized fats depend on their solid fat content (SFC) and their fractal structures. The SFC and the
structures are dramatically affected during crystallization under shear flow. A mini-Couette cell was developed to crystallize
fat samples under shear. The cell was tested with blends of canola stearin (CS) in canola oil (CO) in a 20-MHz NMR spectrometer.
The blends were placed in the cell, melted at 80 °C, and then crystallized under different shear rates (58–460 s−1) at 40 °C inside the spectrometer for 4 h. Time averaged NMR free induction decay (FID) curves were captured at 20 s intervals.
SFC values were calculated using parameters determined by a calibration procedure. The SFC values determined by the direct
method with and without the shaft of the Couette device were reasonably close. Similar results were observed with and without
shear in the Couette device. The FID curves did not show a significant difference either. Therefore this system is accurate
for in-situ time-resolved determination of SFC under shear flow. Furthermore, a combination of the direct and the indirect
methods was successfully used to estimate the temperature increase due to viscous heating. The system developed will help
in understanding the effects of shear flow on SFC of nanostructured lipid multicomponent systems. This will permit the optimization
of the manufacturing processes. 相似文献
88.
The cultivation of crops for biomass production on good soils allows to reduce surplus production of food crops and increase the sustainability of energy production from the environmental point of view. The short rotation forestry (SRF), is only at a preliminary study level in Italy but, is already a reality in North Europe where was already developed an high planting density (6000–8000 cuttings ha-1) technique and a whole mechanization of plantation and biomass harvest.On the basis of this cultivation technique, it was realized as an energetic and economic evaluation of a poplar SRF in Northern Italy. In detail, they were considered data of poplar growth in a plantation for the production of two-year whips in Western Po Valley considering SRF duration of 8 years and a biomass (20 t ha−1 D.M.) harvest every 2 years. Indeed it was assumed to operate on a plantation in production (12.5% of the surface replanted every year) with a spacing 3.00 × 0.4 m (6700 cutting per hectare) that allows the use of conventional tractors.In this computing system it was pointed out a ratio between output and input energy of 13 and a cost of 80 € t−1 of D.M. Nevertheless a positive energetic balance, the economic sustainability of poplar SRF depends, due to the present monopolistic energy management in the same countries, on political choices of chip price or public subventions to the producers. 相似文献
89.
One of the most investigated heat transfer fluid or heat storage medium in the field of thermal solar conversion is the “solar salt”, a mixture of nitrates NaNO3/KNO3, 60/40% by weight, respectively. The content of potassium in this fluid allows exploiting the self activity of the isotope 40K to perform measurements useful for control or diagnostics of a solar plant. Here an experimental test on the non-invasive measurement of the salt level in a tank by means of gamma-ray spectrometry is shown. 相似文献
90.
Gianfranco Mazzanti Alejandro G. Marangoni Stefan H.J. Idziak 《Food research international (Ottawa, Ont.)》2009,42(5-6):682-694
A detailed synchrotron X-ray diffraction study on the kinetics of crystallization of anhydrous milk fat (AMF) and milk fat triacylglycerols (MFT) was done in a Couette cell at 17 °C, 17.5 °C and 20 °C under shear rates between 0 and 2880 s?1. We observed shear-induced acceleration of the transition from phase α to β′ and the presence of crystalline orientation, but no effect of shear on the onset time of phase α was observed. A two stage regime was observed for the growth of phase β′. The first stage follows a series–parallel system of differential equations describing the conversion between liquid and crystalline phases. The second stage follows a diffusion-controlled regime. These mechanisms are consistent with the crystalline orientation, the growth of the crystalline domains and the observed displacement of the diffraction peak positions. The absence of the polar lipids explains the faster kinetics of MFT. 相似文献