全文获取类型
收费全文 | 1079篇 |
免费 | 64篇 |
专业分类
电工技术 | 3篇 |
综合类 | 3篇 |
化学工业 | 327篇 |
金属工艺 | 12篇 |
机械仪表 | 10篇 |
建筑科学 | 18篇 |
能源动力 | 20篇 |
轻工业 | 498篇 |
水利工程 | 4篇 |
石油天然气 | 5篇 |
无线电 | 28篇 |
一般工业技术 | 93篇 |
冶金工业 | 37篇 |
原子能技术 | 3篇 |
自动化技术 | 82篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 48篇 |
2021年 | 46篇 |
2020年 | 25篇 |
2019年 | 17篇 |
2018年 | 36篇 |
2017年 | 37篇 |
2016年 | 36篇 |
2015年 | 35篇 |
2014年 | 49篇 |
2013年 | 60篇 |
2012年 | 76篇 |
2011年 | 80篇 |
2010年 | 55篇 |
2009年 | 45篇 |
2008年 | 63篇 |
2007年 | 49篇 |
2006年 | 51篇 |
2005年 | 54篇 |
2004年 | 41篇 |
2003年 | 33篇 |
2002年 | 27篇 |
2001年 | 18篇 |
2000年 | 9篇 |
1999年 | 15篇 |
1998年 | 17篇 |
1997年 | 13篇 |
1996年 | 26篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 6篇 |
1984年 | 1篇 |
1976年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有1143条查询结果,搜索用时 15 毫秒
61.
62.
Fernando Corvillo Laura Gonzlez-Snchez Alberto Lpez-Lera Emilia Arjona Giovanni Ceccarini Ferruccio Santini David Araújo-Vilar Rebecca J Brown Joan Villarroya Francesc Villarroya Santiago Rodríguez de Crdoba Teresa Caballero Pilar Nozal Margarita Lpez-Trascasa 《International journal of molecular sciences》2021,22(12)
63.
Marta Gmez-Ferrer Estela Villanueva-Badenas Rafael Snchez-Snchez Christian M. Snchez-Lpez Maria Carmen Baquero Pilar Sepúlveda Akaitz Dorronsoro 《International journal of molecular sciences》2021,22(7)
Despite the strong evidence for the immunomodulatory activity of mesenchymal stromal cells (MSCs), clinical trials have so far failed to clearly show benefit, likely reflecting methodological shortcomings and lack of standardization. MSC-mediated tissue repair is commonly believed to occur in a paracrine manner, and it has been stated that extracellular vesicles (EVs) secreted by MSCs (EVMSC) are able to recapitulate the immunosuppressive properties of parental cells. As a next step, clinical trials to corroborate preclinical studies should be performed. However, effective dose in large mammals, including humans, is quite high and EVs industrial production is hindered by the proliferative senescence that affects MSCs during massive cell expansion. We generated a genetically modified MSC cell line overexpressing hypoxia-inducible factor 1-alpha and telomerase to increase the therapeutic potency of EVMSC and facilitate their large-scale production. We also developed a cytokine-based preconditioning culture medium to prime the immunomodulatory response of secreted EVs (EVMSC-T-HIFc). We tested the efficacy of this system in vitro and in a delayed-type hypersensitivity mouse model. MSC-T with an HIF-1α-GFP lentiviral vector (MSC-T-HIF) can be effectively expanded to obtain large amounts of EVs without major changes in cell phenotype and EVs composition. EVMSC-T-HIFc suppressed the proliferation of activated T-cells more effectively than did EVs from unmodified MSC in vitro, and significantly blunted the ear-swelling response in vivo by inhibiting cell infiltration and improving tissue integrity. We have developed a long-lived EV source that secretes high quantities of immunosuppressive EVs, facilitating a more standard and cost-effective therapeutic product. 相似文献
64.
Ramon Margalef‐Català Pilar Salagre Elena Fernández Carmen Claver 《Catalysis Letters》1999,60(3):121-123
Heterogenised homogeneous catalytic hydrogenation of aldimines by removable and reusable immobilised iridium complexes on montmorillonite clay. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
65.
Microbial inactivation by pulsed electric fields in a batch treatment chamber: effects of some electrical parameters and food constituents 总被引:1,自引:0,他引:1
Pilar Maas Laura Barsotti J. Claude Cheftel 《Innovative Food Science and Emerging Technologies》2001,2(4):239-249
The inactivation of Escherichia coli by high voltage pulsed electric fields in a batch treatment chamber was studied in liquid, solid and semisolid foods or model systems. Treatment heterogeneity was demonstrated and found to be due to the presence of an air bubble trapped inside the chamber. Agitation of the inoculated liquid samples (16 mM sodium phosphate buffer, pH 7, ρ=460 Ωcm) during pulse processing resulted in efficient microbial inactivation (five log cycles at 33 kV/cm and 25°C after 261 μs of cumulated pulses). A slower inactivation rate was observed in inoculated solid agar gels of the same pH and resistivity, under the same pulse processing conditions. The inactivation of E. coli in inoculated dairy cream (33% fat, pH 6.8, ρ=370 Ωcm), ovalbumin solution (10% protein w/v, pH 6.7, ρ=370 Ωcm) or fish egg suspension (pH 6.8, ρ=400 Ωcm) was almost identical to that in 16 mM phosphate buffer, pH 7. Thus emulsified lipids, soluble proteins or conductive food particulates do not appear to protect against microbial inactivation by electric pulses. 相似文献
66.
Denise Aparecida Delgado Anderson de Souza Sant’AnaDaniel Granato Pilar Rodriguez de Massaguer 《Food Control》2012,23(1):165-170
This study reports on the influence of heat and hydrogen peroxide combination on the inactivation kinetics of two heat resistant molds: Neosartorya fischeri and Paecilomyces variotii. Spores of different ages (1 and 4 months) of these molds were prepared and D-values (the time required at certain temperature/hydrogen peroxide combination to inactivate 90% of the mold ascospores) were determined using thermal death tubes. D-values found for P. variotii ranged from 1.2 to 25.1 s after exposure to different combinations of heat (40 or 60 °C) and hydrogen peroxide (35 or 40% w/w) while for N. fischeri they varied from 2.7 to 14.3 s after exposure to the same hydrogen peroxide concentrations and higher temperatures (60 or 70 °C). The influence of temperature and hydrogen peroxide concentration on the d-values varied with the genus of mold and their ages. A synergistic effect of heat and hydrogen peroxide in reducing D-values of Paecilomyces variotti and N. fischeri has been observed. In addition to strict control of temperature, time and hydrogen concentration, hygienic storage and handling of laminated paperboard material must be considered to reduce the probability of package’s contamination. All these measures together will ensure package’s sterility that is imperative for the effectiveness of aseptic processing and consequently to ensure the microbiological stability of processed foods during shelf-life. 相似文献
67.
J. S. Felton Pilar Pais Cynthia P. Salmon Mark G. Knize 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1998,207(6):434-440
Levels of known heterocyclic amines vary from undetectable in many meats sold in fast food restaurants, to over 10 ng/g for
meats prepared in restaurants that cook food to order, to hundreds of nanograms per gram for some meats cooked under certain
home or laboratory conditions. To simulate the dry reactions that seem to occur at the meat surface we developed a model system
to mimic these processes. Mixtures of free amino acids, creatinine and glucose, simulating the composition of beef or chicken,
heated at 200 °C, form eight heterocyclic amines. Besides the commonly found 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,6-dimethylimidazo[4,5-b]pyridine, 2-amino-1,5,6-trimethylimidazo[4,5-b]pyridine and 2-amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]pyridine were also found. The calculated risk of consumption of heterocyclic amines is determined by the dietary dose, the
extrapolation of carcinogenic potencies from rodents to humans, and the extrapolation of high rodent doses to low human exposures.
Results suggest that DNA binding is linear with dose, but that the human DNA forms more adducts per unit dose than that of
the rat. Altogether, the risk appears to be equivalent to that for many carcinogens that are regulated.
Received: 23 April 1998 相似文献
68.
J. S. Felton Pilar Pais Cynthia P. Salmon Mark G. Knize 《European Food Research and Technology》1998,207(6):434-440
Levels of known heterocyclic amines vary from undetectable in many meats sold in fast food restaurants, to over 10 ng/g for
meats prepared in restaurants that cook food to order, to hundreds of nanograms per gram for some meats cooked under certain
home or laboratory conditions. To simulate the dry reactions that seem to occur at the meat surface we developed a model system
to mimic these processes. Mixtures of free amino acids, creatinine and glucose, simulating the composition of beef or chicken,
heated at 200 °C, form eight heterocyclic amines. Besides the commonly found 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,6-dimethylimidazo[4,5-b]pyridine, 2-amino-1,5,6-trimethylimidazo[4,5-b]pyridine and 2-amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]pyridine were also found. The calculated risk of consumption of heterocyclic amines is determined by the dietary dose, the
extrapolation of carcinogenic potencies from rodents to humans, and the extrapolation of high rodent doses to low human exposures.
Results suggest that DNA binding is linear with dose, but that the human DNA forms more adducts per unit dose than that of
the rat. Altogether, the risk appears to be equivalent to that for many carcinogens that are regulated.
Received: 23 April 1998 相似文献
69.
María C Pilar Natividad Ortega Manuel Perez‐Mateos María D Busto 《Journal of the science of food and agriculture》2003,83(3):232-239
Alkaline phosphatase (EC 3.1.3.1) extracted from Escherichia coli ATCC27257 was immobilised by co‐flocculation with soil humates in the presence of Ca2+. The effects of time, temperature, pH and concentration of enzyme and support on immobilisation were studied. Between 58 and 92% of the added phosphatase was strongly bound to the humates, depending on the conditions of immobilisation used. Some characteristics of the humate–phosphatase complexes and of the free enzyme were compared. The enzymatic complexes showed values of Km (2.22 mM ) and activation energy (33.4 kJ mol?1) similar to those of the free enzyme (2.00 mM and 27.6 kJ mol?1). The pH/activity profiles revealed no change in terms of shape or optimum pH (10.5) upon immobilisation of alkaline phosphatase. However, the immobilised enzyme showed maximal activity in the range of 80–100 °C, while the free enzyme had its highest activity at 60 °C. The thermal stability of alkaline phosphatase was enhanced by complexation to the soil humates. © 2003 Society of Chemical Industry 相似文献
70.
Maria S Gião M L González‐Sanjosé Pilar Muñiz M D Rivero‐Pérez Monika Kosinska Manuela E Pintado F Xavier Malcata 《Journal of the science of food and agriculture》2008,88(4):633-640
BACKGROUND: Aqueous extracts of 48 herbal plants were obtained via alternative extraction protocols, and were assayed for their capacity to protect deoxyribose and DNA itself from degradation (or, conversely, for their capacity to promote DNA degradation), using electrophoresis as analytical tool. RESULTS: For a given (constant) volume of extract, deoxyribose protection ranged from 14.13 ± 1.35% (mean ± SD) inhibition by dwarf mallow powder infusion, up to 106.51 ± 15.93% inhibition by avocado powder infusion. DNA protection was tested at two extract concentrations, and was slightly greater at the higher concentration. Pro‐oxidant effects were essentially absent. CONCLUSION: The anti‐oxidative roles of plants upon deoxyribose and DNA displayed by our experimental results were rather promising with regards to practical applications of those plants, viz. as ingredients in the formulation of nutraceutical beverages and/or foods. Copyright © 2007 Society of Chemical Industry 相似文献