全文获取类型
收费全文 | 1552篇 |
免费 | 94篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 3篇 |
综合类 | 2篇 |
化学工业 | 454篇 |
金属工艺 | 16篇 |
机械仪表 | 33篇 |
建筑科学 | 62篇 |
矿业工程 | 4篇 |
能源动力 | 35篇 |
轻工业 | 281篇 |
水利工程 | 17篇 |
石油天然气 | 14篇 |
无线电 | 78篇 |
一般工业技术 | 172篇 |
冶金工业 | 269篇 |
原子能技术 | 11篇 |
自动化技术 | 200篇 |
出版年
2024年 | 3篇 |
2023年 | 26篇 |
2022年 | 53篇 |
2021年 | 79篇 |
2020年 | 68篇 |
2019年 | 71篇 |
2018年 | 62篇 |
2017年 | 64篇 |
2016年 | 62篇 |
2015年 | 49篇 |
2014年 | 55篇 |
2013年 | 114篇 |
2012年 | 82篇 |
2011年 | 80篇 |
2010年 | 76篇 |
2009年 | 75篇 |
2008年 | 69篇 |
2007年 | 58篇 |
2006年 | 55篇 |
2005年 | 32篇 |
2004年 | 47篇 |
2003年 | 33篇 |
2002年 | 28篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 23篇 |
1998年 | 31篇 |
1997年 | 34篇 |
1996年 | 27篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1976年 | 6篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有1651条查询结果,搜索用时 15 毫秒
991.
Leila Zummo Alessandra Maria Vitale Celeste Caruso Bavisotto Marco De Curtis Rita Garbelli Anna Teresa Giallonardo Carlo Di Bonaventura Martina Fanella Everly Conway de Macario Francesco Cappello Alberto J. L. Macario Antonella Marino Gammazza 《International journal of molecular sciences》2021,22(16)
Epilepsy is a pathologic condition with high prevalence and devastating consequences for the patient and its entourage. Means for accurate diagnosis of type, patient monitoring for predicting seizures and follow up, and efficacious treatment are desperately needed. To improve this adverse outcome, miRNAs and the chaperone system (CS) are promising targets to understand pathogenic mechanisms and for developing theranostics applications. miRNAs implicated in conditions known or suspected to favor seizures such as neuroinflammation, to promote epileptic tolerance and neuronal survival, to regulate seizures, and others showing variations in expression levels related to seizures are promising candidates as useful biomarkers for diagnosis and patient monitoring, and as targets for developing novel therapies. Components of the CS are also promising as biomarkers and as therapeutic targets, since they participate in epileptogenic pathways and in cytoprotective mechanisms in various epileptogenic brain areas, even if what they do and how is not yet clear. The data in this review should help in the identification of molecular targets among the discussed miRNAs and CS components for research aiming at understanding epileptogenic mechanisms and, subsequently, develop means for predicting/preventing seizures and treating the disease. 相似文献
992.
Effects of succinylation and deamidation on functional properties of oat protein isolate 总被引:5,自引:0,他引:5
The effects of two different modification methods (deamidation and succinylation) on the functional properties (solubility, water- and oil-binding capacity, foaming capacity and stability, emulsion activity and stability) of oat protein isolates were evaluated. Protein isolates extracted from defatted oat flour at alkaline pH were acylated by 0.20 g/g of succinic anhydride. The protein isolate was also modified using a mild acidic treatment (HCl, 0.5 N). Succinylation and deamidation improved solubility and emulsifying activity of the native protein isolate. Foaming capacity of oat protein isolate increased after deamidation, whereas succinylation decreased it. The deamidated and succinylated proteins had lower foam and emulsion stabilities than had their native counterpart. Water- and oil-binding capacity, in both modified oat proteins, was higher than those of the native oat protein isolate. 相似文献
993.
Leila El Bassi Mnasser Hassouna Naoya Shinzato Toru Matsui 《Journal of food science》2009,74(6):M335-M339
ABSTRACT: Two lactic acid bacteria (LAB) were selected from 100 LAB isolated from various sea products to examine their use in Dicentrarchus labrax preservation. The isolates, tentatively named strain nr 3 and 7, were identified as Lactobacillus plantarum and L. pentosus , respectively. They showed antagonistic activity against psychrotroph, pathogenic, and coliform bacteria. The antagonistic activity of strain 3 was suggested to be by bacteriocins since activity was abolished by protease treatment, while that of strain 7 was due to the effect of pH decrease caused by the produced organic acids. Their use prevented total volatile basic nitrogen contents (TVB-N) and trimethylamine (TMA) to some extent, suggesting that inoculation could extend the period of storage. 相似文献
994.
Ferreira TM Leonel AJ Melo MA Santos RR Cara DC Cardoso VN Correia MI Alvarez-Leite JI 《Lipids》2012,47(7):669-678
Mucositis affects about 40 % of patients undergoing chemotherapy. Short chain fatty acids (SCFA), mainly butyrate, are claimed to improve mucosal integrity, reduce intestinal permeability and act as anti-inflammatory agents for the colon mucosa. We evaluated the effects of oral administration of SCFA or butyrate in the 5FU-induced mucositis. Mice received water, SCFA or butyrate during all experiment (10 days) and a single dose of 5FU (200 mg/kg) 3 days before euthanasia. We evaluated inflammatory and histological score by morphometry, and by activity of enzymes specific to neutrophil, eosinophil and macrophage and TLR-4, TNF-alpha and IL6 expressions. Intestinal permeability and tight junction protein ZO-1 expression were evaluated. Mice from the 5FU (5-Fluorouracil) group presented weight loss, ulcerations and inflammatory infiltration of neutrophils and eosinophils, increased expression of IL6 and TNF-alpha and increased intestinal permeability. SCFA minimized intestinal damage, reduced ulcerations without affecting intestinal permeability. Butyrate alone was more efficient at improving those parameters than in SCFA solution and also reduced intestinal permeability. The expression of pro-inflammatory cytokines and ZO-1 tended to be higher in the SCFA supplemented but not in the butyrate supplemented group. We showed the beneficial effects of butyrate on intestinal mucositis and its promising function as an adjuvant in the treatment of diseases not only of the colon, but also of the small intestine. 相似文献
995.
Laélia Soares de Assunção José Maria Rodrigues da Luz Marliane de Cássia Soares da Silva Patrícia Aparecida Fontes Vieira Denise Mara Soares Bazzolli Maria Cristina Dantas Vanetti Maria Catarina Megumi Kasuya 《Food chemistry》2012
The capability of Pleurotus ostreatus mushroom to accumulate lithium (Li) and the accessibility of this Li compared with lithium carbonate (Li2CO3), often used as psychiatric medicine, were investigated. Mushrooms were produced on a substrate-based on coffee husk, with different added concentrations of lithium chloride (LiCl). Biological efficiency (BE), the crude protein content, the concentration of Li and other elements present in mushrooms were determined. The sequential extraction and in vitro test were used to verify the accessibility and the degree of solubility of this element. Li concentration in mushrooms was directly influenced by increasing LiCl concentration in the substrate (P < 0.05). The BE was not affected by different concentrations of LiCl. Li present in enriched mushrooms showed greater accessibility than in Li2CO3. Therefore, P. ostreatus mushrooms, enriched with lithium can be an alternative source of Li, as well as being a food with high nutritional value. 相似文献
996.
Leila Hatami Vahid Haddadi‐Asl Hossein Roghani‐Mamaqani Leila Ahmadian‐Alam Mehdi Salami‐Kalajahi 《Polymer Composites》2011,32(6):967-975
Polymer/clay nanocomposite latexes in the form of positively charged nanoparticles were synthesized by a newly developed initiating system, activators generated by electron transfer (AGET), which has been employed in atom transfer radical polymerization (ATRP). These clay‐dispersed latexes were synthesized using AGET ATRP of styrene and butyl acrylate in a miniemulsion system in which, ascorbic acid as a reducing agent was added drop wise to reduce termination reactions. Particle size and particle size distribution of resulted nanocomposite latexes were characterized by dynamic light scattering (DLS). These latexes were in the range of 138 to 171 nm in size. Gel permeation chromatography (GPC) was used to characterize the molecular weight and molecular weight distribution of the resultant copolymer nanocomposites. GPC traces showed that polymers of narrow molecular weight distribution and low Polydispersity Index (PDI) have been synthesized; this clearly shows ATRP reaction is conducted successfully. By increasing nanoclay content, molecular weight of the nanocomposites decreases. The presence of the nanofiller increases the thermal stability of the nanocomposites as investigated by thermogravimetric Analysis (TGA). Glass transition temperature of nanocomposites increases compared with the neat copolymer which was studied by differential scanning calorimetry (DSC). scanning electron microscope (SEM) showed sphere morphology of polymer particles synthesized by miniemulsion polymerization. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that mixed intercalated and exfoliated morphology is obtained. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
997.
Marcela Chiumarelli Leila M. Pereira Cristhiane C. Ferrari Claire I. G. L. Sarantópoulos Miriam D. Hubinger 《Journal of food science》2010,75(5):E297-E304
Abstract: Combination of citric acid dipping (5 g/L) and cassava starch coating (10 g/L), with and without glycerol (10 g/L), was studied to verify the effectiveness of these treatments to inhibit enzymatic browning, to reduce respiration rate, and to preserve quality parameters of “Tommy Atkins” fresh-cut mangoes during storage at 5 °C. Color characteristics (L* and C*), mechanical properties (stress at failure), weight loss, β-carotene content, sensory acceptance, and microbial growth of fruits were evaluated during 15 d. The respiration rate of fruit subjected to the treatments was also analyzed. Nontreated fresh-cut mango was used as a control sample. Cassava starch edible coatings and citric acid dipping promoted a decrease in respiration rate of mango slices, with values up to 41% lower than the control fruit. This treatment also promoted better preservation of texture and color characteristics of mangoes and delayed carotenoid formation and browning reactions during storage. Moreover, the treated fruit showed great sensory acceptance by consumers throughout the whole storage period. However, the use of glycerol in the coating formulation was not efficient in the maintenance of quality parameters of fresh-cut mangoes, promoting a higher weight loss of samples, impairing fruit texture characteristics, increasing carotenogenesis, and favoring microbial growth during storage. Practical Application: Consumer demand for tropical fresh-cut products is increasing rapidly in the world market. Fresh-cut mangoes are appreciated world-wide for its exotic flavor. However, its shelf life is limited by changes in color, texture, appearance, off-flavors and microbial growth. The edible coatings act as gas and water vapor barrier, extending the storage time of fresh-cut fruit and vegetables. Thus, cassava starch is an alternative to preserve minimally processed mangoes and the quality parameters of fresh fruit. The information of this work is useful for the fresh-cut produce industry to increase shelf life of fresh-cut mangoes, which can be considered an alternative to fast food and other ready-to-eat products, attending the demand for healthy and convenient foodstuffs. 相似文献
998.
Andreoli E Rooney DA Redington W Gunning R Breslin CB 《Journal of nanoscience and nanotechnology》2012,12(1):338-349
Nanothin sheets made of zinc sulfate hydroxide hydrate, ZnSO4[Zn(OH)2]3 x 5H2O, are easily and quickly prepared using an innovative electrochemical route onto polypyrrole-polystyrene sulfonate (PPy-PSS) films. The sheets are characterized using a range of experimental techniques. The deposits are formed on the film surface with instantaneous nucleation to grow into a network of entangled nanosheets. The effect of the experimental conditions on the deposition is reported. Interestingly, the formation of the nanosheets is observed on PPy-PSS films only, and not on films doped with other sulfate/sulfonate dopants. The zinc nanosheets can be easily electrochemically reduced to metallic zinc microdentrites. 相似文献
999.
Lorena Costa Garcia Leila Mendes Pereira Claire I. G. de Luca Sarantópoulos Miriam Dupas Hubinger 《Packaging Technology and Science》2012,25(7):413-425
Strawberry is a very sensitive fruit and presents a short post‐harvest shelf‐life. Among the factors responsible for strawberries' quality loss are high metabolic activities and mold decay. To increase product shelf‐life, cassava starch–based edible coatings (3%), added or not with potassium sorbate (0.05%), were applied on minimally processed strawberries. Uncoated minimally processed strawberries were used as control samples. Physical and chemical properties, respiration rate and sensorial acceptance of uncoated and coated strawberries stored up to 15 days at 5°C were monitored. The results showed that coatings had no significant effect on soluble solids, titrable acidity, pH and colour of strawberries. Besides reducing the respiration rate of samples, cassava starch edible coatings were efficient in delaying weight and firmness loss of strawberries during storage. In the studied conditions, potassium sorbate was not efficient in controlling microbial growth. Strawberries coated with cassava starch without the antimicrobial agent showed good conditions for consumption and good sensorial acceptance up to 12 days of storage, whereas the control samples and the samples treated with the coating containing potassium sorbate achieved a shelf‐life of 9 days because of microbial spoilage. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
1000.
Jorge Amim Jr. Denise F.S. Petri 《Materials science & engineering. C, Materials for biological applications》2012,32(2):348-355
Films of cellulose acetate butyrate (CAB) and carboxymethylcellulose acetate butyrate (CMCAB) were deposited from ethyl acetate solutions onto bare silicon wafers (Si/SiO2) or amino-terminated surfaces (APS) by means of equilibrium adsorption. All surfaces were characterized by means of ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The presence of amino groups on the support surface favored the adsorption of CAB and CMCAB, inducing the orientation of most polar groups to the surface and the exposition of alkyl group to the air. Such molecular orientation caused increase of the dispersive component of surface energy (γsd) and decrease of the polar component of surface energy (γsp) of cellulose esters in comparison to those values determined for films deposited onto bare Si/SiO2 wafers. Adsorption behavior of jacalin or concanavalin A onto CAB and CMCAB films was also investigated. The adsorbed amounts of lectins were more pronounced on cellulose esters with high (γsp) and total surface energy (γst) values. 相似文献