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61.
C. R. Kumaran Maneesh Chandran M. Krishna Surendra S. S. Bhattacharya M. S. Ramachandra Rao 《Journal of Materials Science》2015,50(1):144-156
It is important to understand the growth of CNT-diamond composite films in order to improve the inter-link between two carbon allotropes, and, in turn, their physical properties for field emission and other applications. Isolated diamond particles, continuous diamond thin films, and thin films of carbon nanotubes (CNTs) having non-uniformly distributed diamond particles (CNT-diamond composite films) were simultaneously grown on unseeded, seeded, and catalyst pre-treated substrates, respectively, using a large-area multi-wafer-scale hot filament chemical vapor deposition. Films were deposited for four different growth durations at a given deposition condition. The changes in surface morphology and growth behavior of diamond particles with growth duration were investigated ex situ using field emission scanning electron microscopy and 2D confocal Raman depth spectral imaging, respectively. A surface morphological transition from faceted microcrystalline nature to nanocrystalline nature was observed as a function of growth duration in the case of isolated diamond particles grown on both unseeded and catalyst pre-treated substrates. However, such a morphological transition was not observed on the simultaneously grown continuous diamond thin films on seeded substrates. 2D confocal Raman depth spectral imaging of diamond particles showed that the local growth of CNTs did not affect the growth behavior of neighboring diamond particles on catalyst pre-treated substrates. These observations emphasize the importance of surface chemical reactions at the growth site in deciding sp2 or sp3 carbon growth and the final grain size of the diamond films. 相似文献
62.
This paper presents several issues related to pricing in construction. First, problems with current pricing strategy in construction are explored. Second, pricing strategies based on a market-based approach are proposed. Third, survey findings of the top 400 US contractors are presented regarding their current pricing practices and the applicability of the proposed pricing strategies. In conclusion, the belief that current pricing strategy in construction is predominantly cost-based is confirmed by the survey findings; indeed, in setting the markup, most contractors rely on their intuition after subjectively assessing the competition. The three internal pricing variables that have the largest statistically significant contingency coefficients with pricing strategy are ‘marketing intelligence capabilities’, ‘annual contract value’, and ‘the type of client in most projects’. ‘Owner's characteristics’, ‘competitors'characteristics’, and ‘market demand’ are statistically significant external variables in making pricing strategy decisions. A change of bidding procedure is proposed so that all parties in construction can maximize the benefits of market-based pricing strategies. 相似文献
63.
This article reports the application of ozone for the selective oxidation of cyclohexane over 13X molecular sieve supported various metal oxides at ambient temperatures. From the SEM, XRD and HR-TEM results, the impregnated metal oxides are highly dispersed on the support. The activity results reveal that Co/MS, Mo/MS, Cu/MS, and Ag/MS catalysts produce cyclohexanone/cyclohexanol as selective oxidation products, whereas Ce/MS, Mn/MS, and V/MS catalysts yield, predominantly, CO and CO2. Among them, Co/MS catalyst exhibits better conversion of 12.2% with selectively of 58% to cyclohexanone/cyclohexanol, which is attributed to the simultaneous activation of ozone and cyclohexane (-C-H bond) at ambient conditions. 相似文献
64.
Moparthi Sandeep Lavudi Ramesh Suddapalli Subba Rao Saramekala Gopi Krishna 《SILICON》2022,14(3):1309-1314
Silicon - In this paper, for the first time, the performance evaluation of negative capacitance single-active layer double-gate (NC-SALDG) TFT is presented. In the proposed NC-SALDG TFT, amorphous... 相似文献
65.
Krishna Somaletha Chandran John Humphries Jason Q.D. Goodger Ian E. Woodrow 《International journal of molecular sciences》2022,23(6)
Flavonoids are ubiquitous polyphenolic compounds in plants, long recognised for their health-promoting properties in humans. Methylated flavonoids have received increasing attention due to the potential of methylation to enhance medicinal efficacy. Recently, Eucalyptus species with high levels of the O-methylated flavanone pinostrobin have been identified. Pinostrobin has potential commercial value due to its numerous pharmacological and functional food benefits. Little is known about the identity or mode of action of the enzymes involved in methylating flavanones. This study aimed to identify and characterise the methyltransferase(s) involved in the regiospecific methylation of pinostrobin in Eucalyptus and thereby add to our limited understanding of flavanone biosynthesis in plants. RNA-seq analysis of leaf tips enabled the isolation of a gene encoding a flavanone 7-O-methyltransferase (EnOMT1) in Eucalyptus. Biochemical characterisation of its in vitro activity revealed a range of substrates upon which EnOMT1 acts in a regiospecific manner. Comparison to a homologous sequence from a Eucalyptus species lacking O-methylated flavonoids identified critical catalytic amino acid residues within EnOMT1 responsible for its activity. This detailed molecular characterisation identified a methyltransferase responsible for chemical ornamentation of the core flavanone structure of pinocembrin and helps shed light on the mechanism of flavanone biosynthesis in Eucalyptus. 相似文献
66.
C. D. Hutchinson V. Krishna Mohan R. W. Millar 《Propellants, Explosives, Pyrotechnics》1984,9(5):161-171
This paper describes the synthesis and spectral investigations of two amino derivatives of N-methyl-N-(2,4,6-trinitrophenyl)nitramine (tetryl). Also discussed are the results from thermal decomposition studies on the three explosives, viz. tetryl, 3-aminotetryl (3 AT) and 3,5-diaminotetryl (3,5 DAT) and preliminary work on the explosive properties of the last two compounds. The aminotetryls have been prepared by the amination of the corresponding chlorotetryls. The yield was 87% for 3 AT, but was only 33% for 3,5 DAT, probably due to steric crowding around the benzene nucleus. The mass spectra show interesting differences in the electron impact fragmentation patterns of the three tetryls with the M+ ion relative intensities following the order 3,5 DAT > 3 AT > tetryl, which could be due to (a) resonance stabilization and (b) hydrogen bonding effects. Evidence for the latter is also found in the infrared spectra of these compounds. Arrhenius kinetic parameters derived from thermal decomposition studies of the three compounds are presented and show that 3,5 DAT is thermally less stable than 3 AT. Explosive sensitiveness tests indicate that the diamino compound is the most sensitive, the trend being 3,5 DAT > 3 AT > tetryl. This is contrary to the generally found desensitizing influence of NH2 groups on the thermal stability and explosive sensitiveness of trinitroaromatic energetic molecules. Mechanisms to account for the observed thermal decomposition behaviour and explosive sensitiveness patterns are discussed. 相似文献
67.
Zhiqiang Liu Jian Zhou Xiaomin Tang Fujian Liu Jiamin Yuan Guangchao Li Ling Huang Rajamani Krishna Kuan Huang Anmin Zheng 《American Institute of Chemical Engineers》2020,66(8):e16269
Zeolites have been widely used for the processes of adsorption, separation, and catalysis, which are strongly correlated with molecular diffusion. However, the correlation between pore dimension and diffusion properties has not been systematically investigated so far. In this work, the diffusion properties of alkanes in six zeolites with similar pore sizes but different pore dimension have been examined. It is found that the diffusion coefficients of alkanes in zeolites are 2–5 orders of magnitude smaller than that in gas phase. Moreover, the diffusion of alkanes inside zeolites is sensitive to the pore dimension, and can be differentiated by 1-D straight, 1-D tortuous, and 3-D intersecting channels, based on the derived quantitative correlation between the diffusion behavior and pore dimension. Our work may not only provide deep insights into the effects of pore dimension on diffusion, but also benefits for the future design and practical applications of zeolite catalysts. 相似文献
68.
Kiran Tiwari Rudramani Singh Vinai Kumar Singh Manoj Kumar Krishnamoorthi S. Kumar Krishna 《Iranian Polymer Journal》2020,29(7):615-623
Iranian Polymer Journal - In our recent work, we have reported on hydrogels devoid of cross-linkers. After observing the successful swelling and water retention properties, we have introduced... 相似文献
69.
Moisture diffusion through (hexadecyltrimethylammonium bromide ‐ Indian bentonite)/(vinylester) nanocomposites in artificial seawater and demineralized water 下载免费PDF全文
N. Raghavendra H. N. Narasimha Murthy Salim Firdosh R. Sridhar Gangadhar Angadi K. R. Vishnu Mahesh M Krishna 《乙烯基与添加剂工艺杂志》2016,22(4):441-451
This paper compares the moisture diffusion properties of organomodified (Indian Bentonite nanoclay)/vinylester containing different amounts of nanoclay on exposure to demineralized water and artificial seawater at room temperature. Moisture uptake behavior of (Indian Bentonite)/vinylester was investigated and compared with that of neat vinylester. Addition of 5 wt% nanoclay decreased the diffusivity and permeability of vinylester in artificial seawater medium, but these diffusion parameters increased in demineralized water medium. Degradation in glass transition temperature and microhardness of the nanocomposites were much greater in specimens aged in demineralized water than in those in artificial seawater medium. Moisture diffusion behavior of the specimens was analyzed by Fick's law and the Langmuir model. The aged specimens were chemically analyzed by using infrared spectroscopy after aging for 146 days. A significant amount of leached organic species was detected in the demineralized water–aged specimens but the same was absent in those aged in artificial seawater. J. VINYL ADDIT. TECHNOL., 22:441–451, 2016. © 2015 Society of Plastics Engineers 相似文献
70.
A. G. Gopala Krishna J. V. Prabhakar 《Journal of the American Oil Chemists' Society》1995,72(10):1219-1221
Addition of water at levels of 0.25 to 1.00% (wt/vol) to raw peanut oil inhibited the formation of peroxides in the oil. The
free fatty acid content of oils to which water had been added also did not increase appreciably compared to a control oil.
To improve the stability of the oil, a moisture content of 0.2%, which is about ten times higher than the Brunauer-Emmett-Teller
monomolecular moisture content of the oil, has been suggested. 相似文献