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71.
The mechanical properties of metal fibre porous structures were studied in the light of their potential application as surface coatings of implants. Stainless steel AISI 316 L fibres with diameters of 50 and 100μm were compacted and sintered. The variation of the modulus of elasticity with density, as obtained in tension, corresponds closely with theoretical models. The ultimate failure of the tensile specimens proceeds through the fibres, and not through the sinter bonds, except at lower densities. Differences in yield strength between 50 and 100 μm fibre tensile specimens are explained on the basis of the onset of plastic deformation of the individual fibres. Upon compression the modulus of elasticity is nearly 10 times smaller than in tension. This result is due to the different deformation patterns of the fibres in compression and tension. 相似文献
72.
Investigations into the transcrystalline stress corrosion cracking of austenitic chrome-nickel steel in hot chloride solutions To obtain a further clarification of various details in respect of the transcrystalline stress corrosion cracking of austenitic Cr-Ni steels, tensile strength tests were carried out with X 5 CrNi 18 9 in hot, highly concentrated MgCl2, solutions. Tests without extraneous currents showed that, depending on the test conditions, the relationship between stress and service life can be formally described by an exponential function. Down to stresses of 2 kg/mm2, there was no discernible threshold below which stress corrosion cracking does not occur at all. By means of potentiostatic holding tests at different stresses, it was possible to plot a potential/tensile stress/service life diagram. The occurrence of stress corrosion cracking shows a distinct threshold on the side of negative potentials; on the side of positive potentials, however, the occurrence of stress corrosion cracking is increasingly accompanied by pit corrosion. Strain measurements carried out during the tests yielded, in a non-destructive way, a sufficiently exact criterion for the division of the total test period into incubation period and tearing period. The length of the incubation period depends on the tensile stress as well as on the specimen potential. As regards the tearing period it was found that the growth rate of the cracks is formally proportional to the stress at the bottom of the crack. The proportionality constant, in its turn, is a linear function of the test potential. By means of extrapolation, it is possible to deter-mine the minimum potential below which stress corrosion cracking can no longer occur. Electro-chemical measurements showed that, in the tested solutions, it is the hydrogen reduction which represents the vital catholic part-process. The tested material is in the state of passive stability; its rest potential in the non-stressed condition lies at the lower threshold of the pit corrosion range. Tensile stresses, or the deformations caused by them, have the effect of shifting the minimum potential for heterogeneous corrosion into the negative range. 相似文献
73.
Otto Brauns 《Holz als Roh- und Werkstoff》1956,14(7):271-277
Ohne Zusammenfassung
Mitteilung aus dem Zentrallaboratorium der schwedischen Faserplattenindustrie, Stockholm 相似文献
74.
B Jaulhac M Reyrolle YK Sodahlon S Jarraud M Kubina H Monteil Y Piémont J Etienne 《Canadian Metallurgical Quarterly》1998,36(7):2120-2122
A prospective study was conducted on 25 Legionella pneumophila culture-positive and 98 culture-negative bronchoalveolar lavage fluid samples to compare two DNA preparation methods: a rapid modified Chelex-based protocol and a proteinase K method. PCR was found to be more sensitive with the Chelex-based method (P = 0.03). N difference was found concerning the inhibition rate. 相似文献
75.
Eliel González‐García Yann Alexandrine Tatiana Silou‐Etienne Harry Archimède 《Journal of the science of food and agriculture》2009,89(11):1918-1926
BACKGROUND: The in situ technique (IS) is used for characterising, screening and evaluating feedstuffs in ruminants. However, it is often not adapted to the particular characteristics of feeds (i.e. kinetics of starchy feeds with a standard framework used in forage). This may lead to potential biases in the final conclusions. In two successive experiments, we evaluated the degradative characteristics of conventional (CON) and unconventional (UNC) starchy feedstuffs (ING) and factors affecting their washable fractions (WF). The suitability of IS was then assessed. RESULTS: Two well‐defined ruminal fermentation patterns (CON and UNC) were observed. The WF and insoluble washable (ISWF) fractions were affected by ING, state of presentation [WAY, fresh (F) or pre‐dried (D)], particle size (PSI) and their interactions. The UNC and F feeds had greater WF and ISWF than CON and D, respectively. Increasing PSI linearly reduced WF and its proportion of ISWF. CONCLUSION: The PSI and WAY are critical factors to consider when designing experiments for the evaluation of starchy feedstuffs for ruminants using IS. It is still very risky to propose ‘standard’ parameters as this will always depend on the particular ING evaluated. Conducting pre‐evaluation tests before implementing each research protocol could help to refine the procedure. Copyright © 2009 Society of Chemical Industry 相似文献
76.
Sam L. J. Page Md Elahi Baksh Etienne Duveiller Stephen R. Waddington 《Food Security》2009,1(1):99-109
This paper reports on a ‘bottom-up’ system of wheat seed technology transfer that was piloted in north–west Bangladesh with
45 mainly marginal (food insecure) farming families during the 2004–2005 wheat season, then scaled out to a further 545 mainly
marginal, farming families during the 2006–2007 season. The system was devised following a survey which indicated that such
farmers can obtain a 52% increase in wheat grain yield and extra income by switching from the old Kanchan variety to the newer, heat and disease-tolerant Shatabdi variety. The bottom-up wheat seed dissemination system involved the creation of an enabling environment which allowed poor
and ultra-poor farmers to store and sell selected seed of recently-released wheat varieties that they produced in 20 decimal
(0.08 ha) plots. During the pilot phase of the project in 2005, farmers produced 7, 976 kg of grain and more than 50% of this
was selected as high quality seed, stored during the monsoon season and marketed to other farmers just prior to the following
wheat season. This seed was sold at Tk25–30/kg and realised profits averaging Tk3,002 (€38.49; exchange rate was 78:1 in October
2005) per household. In 2007, the seed price had risen to Tk33–50/kg and a larger group of farmers produced, stored and marketed
168,800 kg of high quality wheat seed, which realised profits averaging Tk5,080, equivalent to €51 (exchange rate was 99.6:1
in October 2007), per household. This bottom up seed production and dissemination system met the wheat seed requirements of
more than 1,400 neighbouring farmers in areas with a deficit of wheat seed for planting, and enabled poor and ultra-poor farmers
to earn more than 50% of the income they needed to cross the local poverty line.
Sam L. J. Page Ph.D. I have been working in rural development for more than 30 years in both government and non-government sectors. My early research was concerned with pest management in food cropping systems and later I began investigating underlying causes of household food insecurity in southern Africa, as well as the use of indigenous food cropping systems to mitigate the impacts of HIV/AIDS. I am currently based at CABI Europe-UK, where I am implementing the Good Seed Initiative which aims to alleviate poverty by enabling food insecure farming families to profit from producing and marketing seed of indigenous and improved varieties. Dr. Baksh is an experienced agricultural economist and Principal Scientific Officer in the Wheat Research Centre of the Bangladesh Agricultural Research Institute (BARI). He specialises in economic aspects of the rice–wheat cropping system that characterises much of south Asia and has published 20 scientific papers. For the past 8 years he has been the Principal Investigator for several DFID, IFAD, IRRI and CIMMYT funded projects that aim to design and disseminate resource-conserving technologies to improve the livelihoods of the poorest farming families in the region. Dr. Etienne Duveiller is a plant pathologist specializing in cereal disease resistance and integrated crop management with more than 25 years experience in international agriculture and development projects. He received his M.Sc. (1980) and Ph.D. (1992) from University of Louvain (UCL) in Belgium and a special degree in social sciences from the Developing Countries Institute at the same university (1981). After working in capacity building in Bolivia for an NGO, and in Burundi on rice diseases, he joined CIMMYT Wheat Program in 1987. After10 years at CIMMYT headquarters in Mexico and frequent visits to South Asia, he spent 8 years on the Indian Subcontinent as CIMMYT regional pathologist based in Nepal and participated in several wheat disease surveys in central Asia and Iran. He returned to Mexico in 2006 as Head of Wheat Pathology at the CIMMYT Global Wheat program. Stephen Waddington is an agronomist. He has 26 years of experience working with the International Maize and Wheat Improvement Centre (CIMMYT) and its partners in Mexico, southern and eastern Africa and in Bangladesh. His main research interests involve smallholder farming systems and participatory research, maize and wheat crop production agronomy, soil fertility and water management, and cereal yield physiology. He has considerable experience in capacity building and networking in many of these areas. Waddington was South Asia regional agronomist and head of the CIMMYT Office in Bangladesh from 2005 to 2007 and is currently located in Mexico. 相似文献
Stephen R. WaddingtonEmail: |
Sam L. J. Page Ph.D. I have been working in rural development for more than 30 years in both government and non-government sectors. My early research was concerned with pest management in food cropping systems and later I began investigating underlying causes of household food insecurity in southern Africa, as well as the use of indigenous food cropping systems to mitigate the impacts of HIV/AIDS. I am currently based at CABI Europe-UK, where I am implementing the Good Seed Initiative which aims to alleviate poverty by enabling food insecure farming families to profit from producing and marketing seed of indigenous and improved varieties. Dr. Baksh is an experienced agricultural economist and Principal Scientific Officer in the Wheat Research Centre of the Bangladesh Agricultural Research Institute (BARI). He specialises in economic aspects of the rice–wheat cropping system that characterises much of south Asia and has published 20 scientific papers. For the past 8 years he has been the Principal Investigator for several DFID, IFAD, IRRI and CIMMYT funded projects that aim to design and disseminate resource-conserving technologies to improve the livelihoods of the poorest farming families in the region. Dr. Etienne Duveiller is a plant pathologist specializing in cereal disease resistance and integrated crop management with more than 25 years experience in international agriculture and development projects. He received his M.Sc. (1980) and Ph.D. (1992) from University of Louvain (UCL) in Belgium and a special degree in social sciences from the Developing Countries Institute at the same university (1981). After working in capacity building in Bolivia for an NGO, and in Burundi on rice diseases, he joined CIMMYT Wheat Program in 1987. After10 years at CIMMYT headquarters in Mexico and frequent visits to South Asia, he spent 8 years on the Indian Subcontinent as CIMMYT regional pathologist based in Nepal and participated in several wheat disease surveys in central Asia and Iran. He returned to Mexico in 2006 as Head of Wheat Pathology at the CIMMYT Global Wheat program. Stephen Waddington is an agronomist. He has 26 years of experience working with the International Maize and Wheat Improvement Centre (CIMMYT) and its partners in Mexico, southern and eastern Africa and in Bangladesh. His main research interests involve smallholder farming systems and participatory research, maize and wheat crop production agronomy, soil fertility and water management, and cereal yield physiology. He has considerable experience in capacity building and networking in many of these areas. Waddington was South Asia regional agronomist and head of the CIMMYT Office in Bangladesh from 2005 to 2007 and is currently located in Mexico. 相似文献
77.
Fluorescence spectroscopy coupled with independent components analysis to monitor molecular changes during heating and cooling of Cantal‐type cheeses with different NaCl and KCl contents 下载免费PDF全文
78.
Cristèle Delsart Céline Cholet Rémy Ghidossi Nabil Grimi Etienne Gontier Laurence Gény Eugène Vorobiev Martine Mietton-Peuchot 《Food and Bioprocess Technology》2014,7(2):424-436
The treatment of Cabernet Sauvignon red grapes by pulsed electric fields (PEFs) is performed prior to vinification in order to enhance the extraction of polyphenols. PEF treatments of the longest duration and of the highest energy (E?= 0.7 kV/cm, t PEF?=?200 ms, W?=?31 Wh/kg) changed the structure of grape skins and produced a wine that was richer in tannins (34 %), while treatment of the highest strength (E?=?4 kV/cm, t PEF?=?1 ms, W =?4 Wh/kg) altered the visual appearance of phenolic compounds in the skins and led to greater extraction of the anthocyanins (19 %). The PEF treatments caused the depolymerization of skin tannins, improving the diffusion of these decondensed tannins which are smaller. The PEF treatment of longest duration and of the highest energy had more impact on the parietal tannins and the cell walls of the skins while treatment of the highest strength modified more the vacuolar tannins. Changes in the operating parameters of the PEF treatment (E?=?0.7 to 4 kV/cm, t PEF?=?1 to 200 ms, W?=?4 to 31 Wh/kg) did not affect alcohol content, total acidity nor volatile acidity in finished wines compared to the values of the control wine, but seemed to cause a slight increase in pH (1–2 %). 相似文献
79.
The optimal design of an energy-intensive process involves a compromise between costs and greenhouse gas emissions, complicated by the interaction between optimal process emissions and supply chain emissions. We propose a method that combines generic abatement cost estimates and the results of existing (LCA) life cycle assessment studies, so that supply chain emissions are properly handled during optimization. This method is illustrated for a (NGCC) natural gas combined cycle power plant model with the following design and procurement options: procurement of natural gas from low-emissions producers, fuel substitution with (SNG) synthetic natural gas from wood, and variable-rate CO2 capture and sequestration from both the NGCC and SNG plants. Using multi-objective optimization, we show two Pareto-optimal sets with and without the proposed LCA method. The latter can then be shown to misestimate CO2 abatement costs by a few percent, penalizing alternate fuels and energy-efficient process configurations and leading to sub-optimal design decisions with potential net losses of the order of $1/MWh. Thus, the proposed LCA method can enhance the economic analysis of emissions abatement technologies and emissions legislation in general. 相似文献
80.
Cissé Mohamed N'guessan Elise Tia V. Etienne Gérard Loiseau Didier Montet 《Journal of Food Safety》2020,40(3):e12785
Lactoperoxidase system (LPOS) was incorporated into chitosan solutions (0.5, 1, and 1.5%) to protect mangoes against two strains of fungi. Coating solutions effectiveness in vitro (in Petri dish) and in vivo (on mango) were studied on fungal (Phomopsis sp. RP257 and Pestalotiopsis sp.) growth isolated from mango cv Amelie. In vitro, chitosan concentration at least 1% containing or not LPOS effectively inhibited Pestalotiopsis sp. growth at 100%. Presence of LPOS or Lactoperoxydase system with iodine (LPOSI) in chitosan at 0.5% increased the percentage of inhibition from 26 to 93%. Edible films with LPOS inhibited Phomopsis sp. RP257 particularly when LPOS was incorporated in chitosan concentrations of 1 and 1.5%. Iodine did not influenced antifungal activity of LPOS against Pestalotiopsis sp. but decreased activity antifungal toward Phomopsis sp. RP257. The properties (water vapor permeability and mechanical properties) of chitosan films were not significantly changed by the incorporation of the enzyme system. in vivo condition, chitosan coating at 1 and 1.5% with or without enzyme system was sufficient to inhibit totally (100%) Pestalotiopsis sp. and was 60% efficient against Phomopsis sp. with chitosan only at 1 and 1.5%. However, when coating solution mainly at 1 and 1.5% was enhanced by LPOS with or without iodine, it inhibited totally (100%) Phomopsis sp. RP257. The presence of iodine slightly reduced antifungal activity against Phomopsis sp. RP257. 相似文献