全文获取类型
收费全文 | 525篇 |
免费 | 30篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 158篇 |
金属工艺 | 15篇 |
机械仪表 | 17篇 |
建筑科学 | 13篇 |
能源动力 | 35篇 |
轻工业 | 107篇 |
水利工程 | 4篇 |
石油天然气 | 13篇 |
无线电 | 37篇 |
一般工业技术 | 67篇 |
冶金工业 | 10篇 |
原子能技术 | 4篇 |
自动化技术 | 71篇 |
出版年
2024年 | 3篇 |
2023年 | 20篇 |
2022年 | 38篇 |
2021年 | 43篇 |
2020年 | 29篇 |
2019年 | 27篇 |
2018年 | 38篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 17篇 |
2014年 | 15篇 |
2013年 | 57篇 |
2012年 | 24篇 |
2011年 | 32篇 |
2010年 | 26篇 |
2009年 | 25篇 |
2008年 | 18篇 |
2007年 | 18篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有555条查询结果,搜索用时 13 毫秒
71.
Multimedia Tools and Applications - Recently, many concepts in technology has been changed. According to the digital transformation trends, Internet of Things (IoT) represents an interested... 相似文献
72.
Vehicle routing problem (VRP) is an important and well-known combinatorial optimization problem encountered in many transport logistics and distribution systems. The VRP has several variants depending on tasks performed and on some restrictions, such as time windows, multiple vehicles, backhauls, simultaneous delivery and pick-up, etc. In this paper, we consider vehicle routing problem with simultaneous pickup and delivery (VRPSPD). The VRPSPD deals with optimally integrating goods distribution and collection when there are no precedence restrictions on the order in which the operations must be performed. Since the VRPSPD is an NP-hard problem, we present a heuristic solution approach based on particle swarm optimization (PSO) in which a local search is performed by variable neighborhood descent algorithm (VND). Moreover, it implements an annealing-like strategy to preserve the swarm diversity. The effectiveness of the proposed PSO is investigated by an experiment conducted on benchmark problem instances available in the literature. The computational results indicate that the proposed algorithm competes with the heuristic approaches in the literature and improves several best known solutions. 相似文献
73.
The optical dense comb filters are indispensable components for dense wavelength multiplexing systems. In this paper, a novel and basic method is proposed to realize optical dense comb filters. The reflection spectrum of sampled fiber Bragg grating is analyzed after applying a phase shifting technique that varies the phase of the grating. The spectral densification and shifting effects of periodic phase shifts are investigated and it is shown that desired amount of channel multiplying can be provided by using appropriate value of densification factor. Moreover, a quantization technique is proposed in order to reduce the phase shifting series which complicated by the increase of densification factor. 相似文献
74.
Smart structures and their applications on active vibration control: Studies in the Department of Aerospace Engineering, METU 总被引:1,自引:0,他引:1
Melin Sahin Fatih Mutlu Karadal Yavuz Yaman Omer Faruk Kircali Volkan Nalbantoglu Fatma Demet Ulker Tarkan Caliskan 《Journal of Electroceramics》2008,20(3-4):167-174
This work presents the theoretical and experimental studies conducted in Aerospace Engineering Department of Middle East Technical University on smart structures with particular attention given to the structural modelling characteristics and active suppression of in-vacuo vibrations. The smart structures considered in these analyses are finite and flat aluminium cantilever beam-like (called as smart beam) and plate-like (called as smart fin) structures with surface bonded lead–zirconate–titanate patches. Finite element models of smart beam and smart fin are obtained. Then the experimental studies regarding open loop behaviour of the structures are performed by using strain gauges and laser displacement sensor to determine the system models. Further studies are carried out to obtain H ∞ and μ-synthesis controllers which are intended to be used in the suppression of free and forced vibrations of the smart structures. It is observed that satisfactory attenuation levels are achieved and robust performance of the systems in the presence of uncertainties is ensured. In that respect a comparative study involving H ∞ and sliding mode controls is also conducted. Recently, the studies involving aerodynamic loading are also gathering pace. 相似文献
75.
Mohamed M. El Nady Fatma S. Ramadan Mahomoud M. Hammad Doaa A. Mousa Naira M. Lotfy 《Petroleum Science and Technology》2018,36(16):1250-1257
The objectives of this study are the correlation between the oil samples recovered from the Lower Cretaceous reservoirs and Lower and Upper Cretaceous source rocks. The investigated biomarkers of five oils indicated the oils were derived from mixed marine and terrigenous (lacustrine) organic matter and deposited under suboxic to anoxic conditions. These oils were also generated from source rocks of high thermal maturity at the peak oil window. So, based on the molecular indicators of organic source input,depositional environment and maturity parameters of oils and extracts, we can conclude that the oil recovered from Al Baraka oil field were derived from Lower Cretaceous source rocks especially KomOmbo (B) source rocks where it reached the oil window. Furthermore, we can indicate that the other lower Cretaceous formations as Abu Ballas Formation will have the opportunity to generate and expel oil at the deeper part of the basin as shown in the eastern part of the basin. 相似文献
76.
Walaa Mahmoud Shehata Abeer Mahmoud Shoaib Fatma Khalifa Gad 《Egyptian Journal of Petroleum》2018,27(4):553-565
Inter-plant hydrogen integration (IPHI) is getting more attention in recent years, as a result of the increasing demand for hydrogen in refinery processes, such as hydrotreating and hydrocracking. In this work, IPHI with regeneration scheme is analyzed. Indirect integration scheme is adopted, where hydrogen sources from different hydrogen networks are integrated via a centralized purifier, such as pressure swing adsorption (PSA) or membrane separation. The introduced model is able to select the optimum interception unit, which minimizes the total annualized cost. Besides, multi-period consideration is included in the analysis to address the effect of changes in operating conditions of the IPHI network on total hydrogen consumption. Two case studies are presented to demonstrate the applicability and usefulness of the proposed model. 相似文献
77.
lyas Çelik Fatma Ik & Ouz Gürsoy 《International Journal of Food Science & Technology》2004,39(3):263-269
Traditional Turkish couscous, a cereal‐based product, is made by covering bulgur with milk and flour. Traditionally Turkish couscous was produced from different flours (soyflour and oat flour) and eggs. The nutrient composition of traditional couscous was 90.6% dry matter, 11.27% protein, 2.58% fat, 71.80% carbohydrate, 42.25 mg sodium, 365.62 mg potassium, 2.73 mg iron and 48.30 mg calcium. The calorie content of traditional couscous is about 1487.41 kJ 100 g?1. The addition of soy and oat flours increased protein content and Ca, K and Fe levels. Sensory properties were also affected. Panellists preferred traditional couscous and couscous with eggs or soyflour over couscous with oat flour. 相似文献
78.
Said A. Khalil Lobna M. Mortada Fatma A. Ismail 《Drug development and industrial pharmacy》1984,10(6):929-948
An in vivo absorption study was performed in a crossover fashion on 6 healthy volunteers (4 males and 2 females) to compare the bioavailability of 8 brands of ampicillin capsules. Absorption was assessed by a urinary excretion method in which the drug was assayed chemically. Statistical analysis of the results was carried out to evaluate the significance of differences between brands and between subjects. Results of the analysis of variance indicated no significant differences between the tested brands of ampicillin capsules. However, significant differences between brand A and brand B were found on using the student t-test. A significant intersubject variation was also found between the volunteers participated in the present study. 相似文献
79.
2‐Hydroxyethyl methacrylate (HEMA)‐clay nanocomposites were prepared via in situ free radical polymerization using montmorillonite (MMT) as a crosslinker. The structure and surface morphology of the nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction, and scanning electron microscopy. It was found that exfoliated or highly expanded intercalated nanocomposite structure was obtained. The swelling degree was determined in distilled water and various pH buffered solutions. The highest swelling capacity in distilled water was observed for the nanocomposite sample prepared with the MMT amount of 10 % (w). It was seen that the diffusion mechanism was Fickian type in distilled water and also in various pH‐buffered solutions. It is interesting that the swelling degree of nanocomposites in alkaline pH values increased by the increasing of MMT in the polymer structure. This result supports the possibility of future applications of the novel nanocomposite in systems for the controlled released of drugs. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
80.
Nitya Sharma S. K. Goyal Tanweer Alam Sana Fatma Keshavan Niranjan 《Food and Bioprocess Technology》2018,11(1):209-222
Foxtail millet is one of the commonly cultivated, nutritionally competitive source of protein, fibre, phytochemicals and other micronutrients, as compared to major cereals like wheat and rice. Considering the potential of these grains, the high pressure processed flours of germinated (GFMF) and non-germinated foxtail millet (NGFMF) grains were studied for its functional, moisture sorption and thermodynamic properties. Germination and high-pressure processing of foxtail millet grains significantly improved the functional properties of the flour. Apart from this, the moisture sorption isotherms of both the flours were determined at 10, 25 and 40 °C and the sorption data was fitted to Guggenheim-Anderson-De Boer (GAB) sorption model. The monolayer moisture content for NGFMF and GFMF ranged between 3.235–2.364 and 2.987–2.063 g g?1, respectively. The isosteric heat of sorption ranged between ? 76.35 to ? 38.23 kJ mol?1 for NGFMF and 172.55 to ? 34.02 kJ mol?1 for GFMF at a moisture range of 0 to 36%, whereas, the integral entropy of sorption for NGFMF ranged between ? 0.404 and ? 0.120 kJ mol?1 K?1 and for GFMF between ? 0.667 and ? 0.383 kJ mol?1 K?1. Along with the validation of the compensation theory, the values of spreading pressures lied in the range of 0–0.078 J m?2 for NGFMF and 0– 0.124 J m?2 for GFMF, while, the glass transition temperatures ranged between 82.25 and 28.67 °C for NGFMF and from 51.11 to 11.83 °C for GFMF at all three temperatures. 相似文献