全文获取类型
收费全文 | 1050篇 |
免费 | 113篇 |
国内免费 | 1篇 |
专业分类
综合类 | 2篇 |
化学工业 | 421篇 |
金属工艺 | 7篇 |
机械仪表 | 44篇 |
建筑科学 | 33篇 |
矿业工程 | 1篇 |
能源动力 | 33篇 |
轻工业 | 340篇 |
水利工程 | 16篇 |
石油天然气 | 9篇 |
无线电 | 23篇 |
一般工业技术 | 130篇 |
冶金工业 | 32篇 |
原子能技术 | 1篇 |
自动化技术 | 72篇 |
出版年
2024年 | 5篇 |
2023年 | 29篇 |
2022年 | 81篇 |
2021年 | 99篇 |
2020年 | 52篇 |
2019年 | 66篇 |
2018年 | 65篇 |
2017年 | 71篇 |
2016年 | 56篇 |
2015年 | 41篇 |
2014年 | 75篇 |
2013年 | 67篇 |
2012年 | 77篇 |
2011年 | 85篇 |
2010年 | 64篇 |
2009年 | 42篇 |
2008年 | 41篇 |
2007年 | 36篇 |
2006年 | 26篇 |
2005年 | 17篇 |
2004年 | 18篇 |
2003年 | 14篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1164条查询结果,搜索用时 15 毫秒
61.
Schmidt Jaison Dairon Ebertz De Marchi Ana Carolina Bertoletti 《Universal Access in the Information Society》2017,16(4):921-928
Universal Access in the Information Society - This paper aims to present the results of a systematic review focused on usability evaluation methods for serious games (SG) of mobile devices... 相似文献
62.
Carolina Merheb-Dini Graziele Aparecida Chiuchi Garcia Ana Lúcia Barretto Penna Eleni Gomes Roberto da Silva 《Food chemistry》2012
Prato cheeses were manufactured using coagulant from Thermomucor indicae-seudaticae N31 or a commercial coagulant. Cheeses were characterised using the following analysis: yield; fat; acidity; moisture; ash; salt; pH; total nitrogen; total protein; NS-pH 4.6/NT*100; NS-TCA 12%/NT*100; casein electrophoresis; and RP-HPLC. The results were statistically analysed and revealed that the proteolytic indices were not significantly different throughout the 60 days of ripening of cheeses made with either coagulant. Even though there were some quantitative differences in the peptide profile of cheeses, the enzyme from T. indicae-seudaticae N31 was used in the production of good quality Prato cheese without having to change the established technological parameters of the process. 相似文献
63.
Tamara Carolina; Timberlake William; Leffel Joseph 《Canadian Metallurgical Quarterly》2010,124(3):302
In two experiments we investigated the extent to which rats (Rattus norvegicus) use an egocentric trajectory and landmarks to locate a goal. In Experiment 1 we trained groups to locate the hidden platform in a water maze with either 1 of 3 or 3 of 3 predictive landmarks, and with either a random or fixed egocentric trajectory. A choice test revealed that regardless of the landmark configuration, rats relied on a directional, egocentric trajectory, when it was available, to locate the platform. In Experiment 2 we found that adding four predictive landmarks following training with a constant egocentric trajectory did not alter rats' initial attention to the trajectory. We conclude that the presence of nonpredictive landmarks in a predictive array did not affect the use of landmarks. With a blocking design, rats used initially an egocentric path, then landmarks. These results add to the notion that animals use available spatial cues sequentially. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Isabel Comino Ana Real Maria de Lourdes Moreno Raquel Montes Ángel Cebolla Carolina Sousa 《Journal of the science of food and agriculture》2013,93(4):933-943
BACKGROUND: Cereals used for beer manufacturing contain gluten, which is immunotoxic for celiac patients. The gluten remaining after processes of malting and brewing is mostly hydrolyzed, which makes practical evaluation of the immunotoxicity of the gluten pools challenging. RESULTS: We analyzed the presence of gluten peptides equivalent to the major immunotoxic protease‐resistant gliadin 33‐mer in 100 Belgium beers, using monoclonal antibodies (G12/A1). Immunochromatographic strips and enzyme‐linked immonosorbent assay G12/A1 methods estimated at least 20 ppm gluten equivalents in 90 beers and gluten‐free in 10 beers. The G12/A1 reactivity of beer high‐performance liquid chromatographic fractions correlated to the presence of T‐cell‐reactive epitopes identified by peptide sequencing. CONCLUSION: The determination of equivalent gliadin 33‐mer epitopes in beers has been shown to be practical, specific, and sensitive for the measurement of potential immunotoxicity for celiac patients. Copyright © 2012 Society of Chemical Industry 相似文献
65.
66.
Natalia A. Castillo Alejandra de Moreno de LeBlanc Carolina Maldonado Galdeano Gabriela Perdigón 《Food research international (Ottawa, Ont.)》2012,45(2):831-841
Salmonella produces infections of different nature and severity depending of many factors including the Salmonella serovar involved, strain virulence, infective dose, host animal species, age and immune status of the host. The treatments against Salmonella infections rely on supportive and antibiotic therapy to eliminate the pathogen, but the development of resistance by Salmonella to the antimicrobials most commonly used limits its efficacy. Other disadvantages of antibiotic treatments are that they can lead to acute diarrhea (antimicrobials normally induce an imbalance of intestinal bacterial flora) and may produce chronic toxicity. Considering this undesired consequences of antibiotics and because at the present there are no effective oral vaccines which protect against salmonellosis, scientists have been searching for alternative methods to control enteric infections. In the present review, probiotics are proposed as an attractive possibility to attend this concern. Probiotic are live microorganisms, which when administered in adequate amounts confer a health benefit on the host. In vitro and in vivo studies showed the effectiveness of probiotic administration in the prevention or in the treatment against Salmonella infection. There are several mechanisms by which probiotic strains might exert their effects. They include non immune mechanisms (stabilization of the gut mucosal barrier, competition for adhesion, secretion of antimicrobial substances, etc.) and the modulation of the mucosal and systemic immune responses. These mechanisms are species and/or strain specific. There are also evidences that in some cases, a mix of probiotic strains can be more useful than each strain alone against this infection. In addition, the presence of one or more probiotic strains in a fermented product can improve the beneficial properties of the probiotic strains involved. It was also reviewed the security of probiotics administration after Salmonella infection in healthy host and in immunosuppressed or babies hosts. Although, the major part of the researches were performed in animal models through in vivo assays or by in vitro studies using human cell lines, some studies carried out in humans to verify the probiotic effects were also addressed in the present review. Nevertheless, is of critical importance to perform more clinical trials in humans to validate the results obtained with each specific probiotic strain or probiotic product. 相似文献
67.
Carrasco C Rosu F Gabelica V Houssier C De Pauw E Garbay-Jaureguiberry C Roques B Wilson WD Chaires JB Waring MJ Bailly C 《Chembiochem : a European journal of chemical biology》2002,3(12):1235-1241
The structural selectivity of the DNA-binding antitumor drug ditercalinium was investigated by competition dialysis with a series of nineteen different DNA substrates. The 7H-pyridocarbazole dimer was found to bind to double-stranded DNA with a preference for GC-rich species but can in addition form stable complexes with triplex and quadruplex structures. The preferential interaction of the drug with four-stranded DNA structures was independently confirmed by electrospray mass spectrometry and a detailed analysis of the binding reaction was performed by surface plasmon resonance (SPR) spectroscopy. The BIAcore SPR study showed that the kinetic parameters for the interaction of ditercalinium with the human telomeric quadruplex sequence are comparable to those measured with a duplex sequence. Slow association and dissociation were observed with both the quadruplex and duplex structures. The newly discovered preferential binding of ditercalinium to the antiparallel quadruplex sequence d(AG(3)[T(2)AG(3)](3)) provides new perspectives for the design of drugs that can bind to human telomeres. 相似文献
68.
Escaja N Gómez-Pinto I Rico M Pedroso E González C 《Chembiochem : a European journal of chemical biology》2003,4(7):623-632
The structures and stabilities of cyclic DNA octamers of different sequences have been studied by NMR and CD spectroscopy and by restrained molecular dynamics. At low oligonucleotide concentrations, some of these molecules form stable monomeric structures consisting of a short stem of two base pairs connected by two mini-loops of two residues. To our knowledge, these dumbbell-like structures are the smallest observed to date. The relative stabilities of these cyclic dumbbells have been established by studying their melting transitions. Dumbbells made up purely of GC stems are more stable than those consisting purely of AT base pairs. The order of the base pairs closing the loops also has an important effect on the stabilities of these structures. The NMR data indicate that there are significant differences between the solution structures of dumbbells with G-C base pairs in the stem compared to those with A-T base pairs. In the case of dumbbells with G-C base pairs, the residues in the stem form a short segment of a BDNA helix stabilized by two Watson-Crick base pairs. In contrast, in the case of d, the stem is formed by two A-T base pairs with the glycosidic angles of the adenine bases in a syn conformation, most probably forming Hoogsteen base pairs. Although the conformations of the loop residues are not very well defined, the thymine residues at the first position of the loop are observed to fold back into the minor groove of the stem. 相似文献
69.
Leonardo Augusto dos Santos Vieira Sergio Fernando Mayerle Carolina Luisa dos Santos Vieira Mônica Maria Mendes Luna 《Optimization and Engineering》2016,17(4):761-780
Available productive capacity is determinant of a company’s success once it allows meeting the current and future demand. This article proposes a quantitative model for determining long-term productive capacity in competitive oligopolistic markets, based on the Nash Equilibrium formulated as a Variational Inequality problem. Numerical examples enable an analytical evaluation of the economic equilibrium’s sensitivity to marginal costs, investment costs, hurdle rate, and market saturation. Results show that, in order to achieve a greater market share, it is important to adopt strategies that reduce marginal costs. On the other hand, variations in the hurdle rate may or may not reinforce the position of a competitor in the market and his interest in investing in capacity expansion. Additionally, market saturation may be achieved, beyond which investment becomes unattractive. Each of these is a positive outcome for society, triggering diversified investments and competition in economic sectors where competition is low and profits are high. 相似文献
70.
Ana C. Lo Prete Clederson H. Dina Carolina H. Azevedo Camila G. Puk Neuza H. M. Lopes Whady A. Hueb Raul Cavalcante Maranhão 《Lipids》2009,44(10):917-924
The exchange of lipids with cells and other lipoproteins is a crucial process in HDL metabolism and for HDL antiatherogenic
function. Here, we tested a practical method to quantify the simultaneous transfer to HDL of phospholipids, free-cholesterol,
esterified cholesterol and triacylglycerols and to verify the lipid transfer in patients with coronary artery disease (CAD)
or undergoing statin treatment. Twenty-eight control subjects without CAD, 27 with CAD and 25 CAD patients under simvastatin
treatment were studied. Plasma samples were incubated with a donor nanoemulsion prepared by ultrasonication of the constituent
lipids and labeled with radioactive lipids; % lipids transferred to HDL were quantified in the HDL-containing supernatant
after chemical precipitation of non-HDL fractions and the nanoemulsion. The assay was precise and reproducible. Increase of
temperature (4–37 °C), of incubation period (5 min to 2 h), of HDL-cholesterol concentration (33–244 mg/dL) and of mass of
nanoemulsion lipids (0.075–0.3 mg/μL) resulted in increased lipid transfer from the nanoemulsion to HDL. In contrast, increasing
pH (6.5–8.5) and albumin concentration (3.5–7.0 g/dL) did not affect lipid transfer. There was no difference between CAD and
control non-CAD with regard to the lipid transfer, but statin treatment reduced the transfer to HDL of all four lipids. The
test herein described is a valid and practical tool for exploring an important aspect of HDL metabolism. 相似文献