全文获取类型
收费全文 | 312篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 41篇 |
金属工艺 | 2篇 |
机械仪表 | 2篇 |
建筑科学 | 7篇 |
能源动力 | 9篇 |
轻工业 | 11篇 |
水利工程 | 1篇 |
武器工业 | 1篇 |
无线电 | 11篇 |
一般工业技术 | 52篇 |
冶金工业 | 155篇 |
原子能技术 | 14篇 |
自动化技术 | 18篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 15篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 11篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 34篇 |
1997年 | 26篇 |
1996年 | 18篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 2篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 10篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有325条查询结果,搜索用时 31 毫秒
51.
Vaibhav Kumar Maurya Amita Shakya Khalid Bashir Satish Chand Kushwaha David Julian McClements 《Comprehensive Reviews in Food Science and Food Safety》2022,21(3):2772-2819
Vitamin A is an essential micronutrient whose deficiency is still a major health concern in many regions of the world. It plays an essential role in human growth and development, immunity, and vision, but may also help prevent several other chronic diseases. The total amount of vitamin A in the human diet often falls below the recommended dietary allowance of approximately 900–1000 g/day for a healthy adult. Moreover, a significant proportion of vitamin A may be degraded during food processing, storage, and distribution, thereby reducing its bioactivity. Finally, the vitamin A in some foods has a relatively low bioavailability, which further reduces its efficacy. The World Health Organization has recommended fortification of foods and beverages as a safe and cost-effective means of addressing vitamin A deficiency. However, there are several factors that must be overcome before effective fortified foods can be developed, including the low solubility, chemical stability, and bioavailability of this oil-soluble vitamin. Consequently, strategies are required to evenly disperse the vitamin throughout food matrices, to inhibit its chemical degradation, to avoid any adverse interactions with any other food components, to ensure the food is palatable, and to increase its bioavailability. In this review article, we discuss the chemical, physical, and nutritional attributes of vitamin A, its main dietary sources, the factors contributing to its current deficiency, and various strategies to address these deficiencies, including diet diversification, biofortification, and food fortification. 相似文献
52.
Pratibha Singh Chandra Shekhar Kushwaha G.C. Dubey 《Polymer-Plastics Technology and Engineering》2019,58(2):139-147
The exercising cooperative and interfacial properties of metal oxide and conducting polymer as a sensing material for humidity detection was the focal point of this study. In this piece of work nano sized NiO and its composite with polyaniline has been prepared. The cooperative effects of NiO on stuructural, morphology, humidity sensing behaviour of PANI has been investigated. Prepared materials were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM),UV–VIS spectroscopy and Four probe techniques. The result reveals that the NiO strongly influences on polymer chain, crystallinity, stability, electrical and optical properties of PANI, which improves its viability in technology development. Finally, PANI/NiO was used for electrochemical humidity sensing of a closed atmosphere. The result reveals that 100 times increase in sensitivity of PANI due to the presence of NiO nano particles. Finally, the results indicate that the impact of NiO on PANI makes it promising perspective materials for humidity monitoring of closed chamber with improved sensing parameters over several method and materials. 相似文献
53.
Palit Piyas Kushwaha Sanjay Kumar Mathur Jitendra Chaturvadi Abhay Kumar 《Journal of Failure Analysis and Prevention》2019,19(3):752-760
Journal of Failure Analysis and Prevention - Wire rope is an important part of any crane. Failure of wire rope may lead to major loss in terms of life and cost. Wire rope failures are attributed by... 相似文献
54.
JC Prechtl G von der Emde J Wolfart S Karamürsel GN Akoev YN Andrianov TH Bullock 《Canadian Metallurgical Quarterly》1998,18(18):7381-7393
To investigate the functional organization of higher brain levels in fish we test the hypothesis that the dorsal gray mantle of the telencephalon of a mormyrid fish has discrete receptive areas for several sensory modalities. Multiunit and compound field potentials evoked by auditory, visual, electrosensory, and water displacement stimuli in this weakly electric fish are recorded with multiple semimicroelectrodes placed in many tracks and depths in or near telencephalic area dorsalis pars medialis (Dm). Most responsive loci are unimodal; some respond to two or more modalities. Each modality dominates a circumscribed area, chiefly separate. Auditory and electrical responses cluster in the dorsal 500 micrometer of rostral and caudolateral Dm, respectively. Two auditory subdivisions underline specialization of this sense. Mechanoreception occupies a caudal area overlapping electroreception but centered 500 micrometer deeper. Visual responses scatter widely through ventral areas. Auditory, electrosensory, and mechanosensory responses are dominated by a negative wave within the first 50 msec, followed by 15-55 Hz oscillations and a slow positive wave with multiunit spikes lasting from 200 to 500 msec. Stimuli can induce shifts in coherence of certain frequency bands between neighboring loci. Every electric organ discharge command is followed within 3 msec by a large, mainly negative but generally biphasic, widespread corollary discharge. At certain loci large, slow ("deltaF") waves usually precede transient shifts in electric organ discharge rate. Sensory-evoked potentials in this fish pallium may be more segregated than in elasmobranchs and anurans and have some surprising similarities to those in mammals. 相似文献
55.
Data collection and its analysis in the field of nuclear safety is an important task in the sense that it powers the improvement of safety as well as reliability of the plant. Thus, occupational exposure data analysis is presented to measure the safety or reliability of radiation protection of a given facility. It also is required as a basic input in making decisions on radiation protection regulations and recommendations. A common practice in radiation protection is to record a zero for observation below minimum detection limit (MDL) doses, which leads to an underestimation of true doses and overestimation of the dose-response relationship. Exposure data (both external and internal) are collected by monitoring each individual and this kind of monitoring generally is graded as low-level monitoring. So, in such low-level monitoring, the occurrence of exposure below MDL invites statistical complications for estimating mean and variance because the data are generally censored, i.e observations below MDL are marked. In Type I censoring, the point of censoring (e.g. the detection limit) is 'fixed' a priori for all observations and the number of the censored observations varies. In Type II censoring, the number of censored observations is fixed a priori, and the point of censoring vary. The methodology generally followed in estimating mean and variance with these censored data was the replacement of missing dose by half the MDL. In this paper, authors have used the maximum likelihood estimation (MLE) approach for the estimation of mean and standard deviation. A computer code BDLCENSOR has been developed in which all these MLE-based advanced algorithms are implemented. In addition to the MLE-based method, an expectation maximisation algorithm has also been implemented. The code is written using Visual BASIC 6.0. The paper describes the details of the algorithms adopted for handling such censored data to estimate bias free mean and standard deviation. 相似文献
56.
Analysis of groundwater quality using fuzzy synthetic evaluation 总被引:7,自引:0,他引:7
This paper reports the application of fuzzy set theory for decision-making in the assessment of physico-chemical quality of groundwater for drinking purposes. Methodology based on fuzzy set theory used to express the quality of water in the imprecise environment of monitored data and prescribed limits given in a non-probabilistic sense. Fuzzy synthetic evaluation model gives the certainty levels for the acceptability of the water based on the prescribed limit of various regulatory bodies quality class and perception of the experts from the field of drinking water quality. Application of fuzzy rule based optimization model is illustrated with 42 groundwater samples collected from the 15 villages of Ateli block of southern Haryana, India. These samples were analysed for 16 different physico-chemical water quality parameters. Ten parameters were used for the quality assessment using this approach. The analysis showed that four samples were in "desirable" category with certainty level of 35-58%, 23 samples were in "acceptable" category whose certainty level ranged from 37 to 75% and remaining 15 samples were in "not acceptable" category for drinking purposes with certainty levels from 44 to 100%. This concludes that about 64% water sources were either in "desirable" or "acceptable" category for drinking purposes. 相似文献
57.
Tripathi RM Jha VN Sahoo SK Sethy NK Shukla AK Puranik VD Kushwaha HS 《Radiation protection dosimetry》2012,148(2):211-218
Ground water is the principal source of drinking water in the rural areas of India. With the aim of determining, the contribution of (226)Ra to natural background radiation through drinking water exposure pathway near an operating uranium mining industry at Jaduguda, Jharkhand state of eastern India, the (226)Ra activity concentrations were measured in potable ground water. The water analysed, both tube well and well water, was collected in areas near the uranium industry and away. The (226)Ra concentration was measured by emanometric technique. The (226)Ra level in ground water was ranging between minimum detection limit of 3.5 mBq l(-1) and a maximum of 208 mBq l(-1). The analysis of variance reveals that there is insignificant statistical variation in the median (226)Ra concentration up to a distance of >10 km from the mining complex. Variation in concentration of (226)Ra in sources is attributed to the local geochemistry and environmental factors. The (226)Ra concentration was significantly elevated in natural artesian wells in the vicinity of uranium mineralised hill and it varies from 53.4 to 754 mBq l(-1). The WHO [Guidelines for Drinking Water Quality. Third Edition, Vol. 1, Recommendation (2004)] guideline value of 1000 mBq l(-1) has not been exceeded in any of the sources investigated. 相似文献
58.
M. K. Samal B. K. Dutta H. S. Kushwaha 《Transactions of the Indian Institute of Metals》2010,63(2-3):641-645
Alloy steels of type 9Cr1Mo are being developed worldwide for the boiler and turbine components of supercritical and ultra supercritical thermal power plants and for the pressure vessel of fast breeder reactors. These steels exhibit very complex high temperature creep cavitation processes with coupled influences of creep strain, material softening and ageing etc. A new viscoplastic model considering both deformation and damage evolution has been developed in this work to predict high temperature creep deformation and damage of a 9Cr1Mo steel. Smooth tensile specimens have been analysed using this new model and the evolution of creep damage has been predicted. The results have been compared with those of experiment from literature. From the initial results, it is observed that this approach is very promising to carry out design and fitness-for-purpose of service of actual plant components. 相似文献
59.
A series of adsorbents were obtained from palm shell (Borassus flabellifer) powder (PSP) which is an agro-waste. PSP was carbonized using sulphuric acid (APSP). APSP was subjected to the following modification procedures: activation to different temperatures (3AAC, 6AAC, 7AAC and 9AAC); activation with steam and persulfate (SAPSP and PAPSP) at 140 °C. Further the effect of modification of PSP, APSP, SAPSP and PAPSP using formaldehyde (MPSP, MAPSP, MSAPSP and MPAPSP) was also investigated. The materials were characterized using SEM, FTIR, TGA and XRD. N2 adsorption isotherms, DR equation and BJH methods were used to characterize the pore structure of the prepared carbons. The iodine value for APSP, SAPSP and PAPSP were found to be 342.5, 199.8, 299.7 mg/g respectively. They were also found to have large pores as well as chelating functional groups indicating their potential adsorption capacity. The carbon 9AAC was found to have high BET surface area of 834 m2/g and a pore volume of 0.4474 cm3/g with predominant micro-pores. Selectivity coefficients for different mixtures containing mercury, copper, zinc and cadmium have been determined for PSP, MPSP, APSP, SAPSP, PAPSP and 9AAC. Though PSP, APSP, SAPSP, PAPSP and MPSP did not have appreciable surface area, they showed encouraging results for adsorption of heavy metals indicating the potential use of palm shell as an economic precursor in the activated carbon preparation process. 相似文献
60.
Pradeep K. Kushwaha 《Polymer-Plastics Technology and Engineering》2013,52(1):45-52
The effect of silane treatments on the water absorption properties of mercerized bamboo matting reinforced polyester composites were investigated. Treatments using γ-Aminopropyltriethoxy silane, 3-trimethoxysilylpropyl methacrylate, Vinyltris(2-methoxyethoxy)silane, Bis[3-(triethoxysilyl)propyl] tetrasulfide, 3-aminopropyltrimethoxy silane and n-Octyltrimethoxy silane were carried out to improve the water resistant property of the bamboo fibers. Water absorption in the composites was studied by long-term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Alkali treatment results in reduction of water absorption from 51% to 35%. Further reduction is observed with silane treatment. Water absorption varies between 19% and 44%, the minimum being for aminopropyl triethoxy silane-treated composites. 相似文献