全文获取类型
收费全文 | 463篇 |
免费 | 34篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 5篇 |
化学工业 | 164篇 |
金属工艺 | 4篇 |
机械仪表 | 7篇 |
建筑科学 | 38篇 |
能源动力 | 7篇 |
轻工业 | 81篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 22篇 |
一般工业技术 | 73篇 |
冶金工业 | 22篇 |
自动化技术 | 70篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 25篇 |
2021年 | 40篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 18篇 |
2017年 | 14篇 |
2016年 | 26篇 |
2015年 | 21篇 |
2014年 | 28篇 |
2013年 | 34篇 |
2012年 | 31篇 |
2011年 | 37篇 |
2010年 | 32篇 |
2009年 | 27篇 |
2008年 | 21篇 |
2007年 | 21篇 |
2006年 | 18篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 15篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有498条查询结果,搜索用时 15 毫秒
481.
Saxelin M Lassig A Karjalainen H Tynkkynen S Surakka A Vapaatalo H Järvenpää S Korpela R Mutanen M Hatakka K 《International journal of food microbiology》2010,144(2):293-300
Most clinical studies of probiotics use freeze-dried, powdered bacteria or bacteria packed in capsules. However, probiotics are commercially available in various food matrices, which may affect their persistence in the gastrointestinal tract. The objective of the study was to compare oral and faecal recovery during and after administration of a combination of Lactobacillus rhamnosus GG and LC705, Propionibacterium freudenreichii subsp. shermanii JS, and Bifidobacterium animalis subsp. lactis Bb12 as capsules, yoghurt, or cheese. This randomized, parallel-group, open-label trial (n = 36) included a 4-week run-in, 2-week intervention, and 3-week follow-up period. Participants consumed 1010 cfu/day of probiotic combination and provided saliva and faecal samples before, during, and after the intervention. Strain-specific real-time PCR was used to quantify the strains.L. rhamnosus GG was the only probiotic strain regularly recovered in saliva samples. During the intervention period it was recovered in the saliva of 88% of the volunteers at least once. No difference was found between the yoghurt and cheese groups. At the end of the intervention, L. rhamnosus GG and LC705 counts were high in faecal samples of all product groups (8.08 and 8.67 log10 genome copies/g, respectively). There was no matrix effect on strain quantity in faeces or the recovery time after ceasing the intervention. For P. freudenreichii subsp. shermanii JS and B. animalis subsp. lactis Bb12, a matrix effect was found at the end of the intervention (P < 0.01 and P < 0.001, respectively) and in the recovery time during follow-up (P < 0.05 for both). Yoghurt yielded the highest faecal quantity of JS and Bb12 strains (8.01 and 9.89 log10 genome copies/g, respectively). The results showed that the administration matrix did not influence the faecal quantity of lactobacilli, but affected faecal counts of propionibacteria and bifidobacteria that were lower when consumed in cheese. Thus, the consumption of probiotics in yoghurt matrix is highly suitable for studying potential health benefits and capsules provide a comparable means of administration when the viability of the strain in the capsule product is confirmed. 相似文献
482.
Für die Festbetoneigenschaften von Faserbetonen sind die Fasermenge, Faserorientierung und Faserverteilung ausschlaggebend. Dies macht eine Überwachung dieser Parameter notwendig, sei es zur Qualitätssicherung auf der Baustelle oder im Bereich der Forschung zur Weiterentwicklung solcher Betone. Gegenüber bisher angewendeten Methoden zur Untersuchung dieser Einflussgrößen eröffnet die Computer‐Tomographie die Möglichkeit, für Betone mit Fasern und Gelegen aller Art die Faserorientierung und Faserverteilung im gesamten Volumen eines Probekörpers zu betrachten und zu analysieren. Direction Analysis of Fibres in Concrete on Basis of Computed Tomography Decisive factors for the improvement of the hardened concrete characteristics of fibre reinforced concrete are the fibre‐volumeratio, fibre‐orientation and fibre‐distribution. The application of fibre reinforced concrete mixtures requires an appropriate control of these characteristics in the context of quality control at the building site as well as in research work done to improve this kind of concretes. Compared to the methods used up to now, the computed tomography offers the possibility to examine and analyze fibre‐orientation and fibre‐distribution in the entire volume of a specimen. 相似文献
483.
Influence of the C/N ratio on the performance of polyhydroxybutyrate (PHB) producing sequencing batch reactors at short SRTs 总被引:3,自引:0,他引:3
Many waste streams that are suitable substrates for mixed culture bioplastic (polyhydroxyalkanoate, PHA) production are nutrient limited and may need to be supplemented to allow sufficient growth of PHA accumulating bacteria. The scope of this study was to investigate the necessity of nutrient supplementation for the enrichment of an efficient PHA producing mixed culture. We studied the influence of different degrees of carbon and nitrogen limitation on the performance of an acetate-fed feast-famine sequencing batch reactor (SBR) employed to enrich PHA storing bacteria. The microbial reaction rates in the SBR showed a shift with a change in the limiting substrate: high acetate uptake rates were found in carbon-limited SBRs (medium C/N ratios 6-13.2 Cmol/Nmol), while nitrogen-limited SBRs (medium C/N ratios 15-24 Cmol/Nmol) were characterized by high ammonia uptake rates. Biomass in strongly nitrogen-limited SBRs had higher baseline PHA contents in the SBR, but carbon-limited SBRs resulted usually in biomass with higher maximal PHA storage capacities. The PHA storage capacity in a nitrogen-limited SBR operated at 0.5 d SRT decreased significantly over less than 5 months operation. For the microbial selection and biomass production stage of a PHA production process carbon limitation seems thus favourable and nutrient deficient wastewaters may consequently require supplementation with nutrients for the selection of a stable PHA storing biomass with a high storage capacity. 相似文献
484.
Influence of manufacturing conditions on thermo‐physical properties of ripened experimental Emmental‐type cheese and comparison with commercial Emmental cheese
下载免费PDF全文
![点击此处可从《International Journal of Dairy Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Katja Isabel Hartmann Ronny Reicherter Jörg Hinrichs 《International Journal of Dairy Technology》2016,69(4):497-506
Experimental Emmental cheese was produced at pilot plant scale with varied process conditions, and the ripened cheeses were analysed in terms of thermo‐physical properties. The amount of propionic acid and the temperature at tan δmax ( loss factor) were significantly influenced by varied process parameters. Experimental cheeses were compared to commercial Emmental cheese by the application of principal component analysis. Commercial Emmental cheese was clearly discriminated from experimental Emmental cheese mainly due to the melting behaviour. The results allow the establishment of a small‐scale process for Emmental cheese production to promote product development on a time and cost‐saving level. 相似文献
485.
Stefan?StübingerEmail author Katja?Nuss Alexander?Bürki Isabel?Mosch Miché?le?Sidler Steve?T.?Meikle Brigitte?von?Rechenberg Matteo?Santin 《Journal of materials science. Materials in medicine》2015,26(2):87
The aim of this study was to analyse the osseointegrative potential of phosphoserine-tethered dendrons when applied as surface functionalisation molecules on titanium implants in a sheep model after 2 and 8 weeks of implantation. Uncoated and dendron-coated implants were implanted in six sheep. Sandblasted and etched (SE) or porous additive manufactured (AM) implants with and without additional dendron functionalisation (SE-PSD; AM-PSD) were placed in the pelvic bone. Three implants per group were examined histologically and six implants were tested biomechanically. After 2 and 8 weeks the bone-to-implant contact (BIC) total values of SE implants (43.7 ± 12.2; 53.3 ± 9.0 %) and SE-PSD (46.7 ± 4.5; 61.7 ± 4.9 %) as well as AM implants (20.49 ± 5.1; 43.9 ± 9.7 %) and AM-PSD implants (19.7 ± 3.5; 48.3 ± 15.6 %) showed no statistically significant differences. For SE-PSD and AM-PSD a separate analysis of only the cancellous BIC demonstrated a statistically significant difference after 2 and 8 weeks. Biomechanical findings proved the overall increased stability of the porous implants after 8 weeks. Overall, the great effect of implant macro design on osseointegration was further supported by additional phosphoserine-tethered dendrons for SE and AM implants. 相似文献
486.
487.
Martin Ntzel Luise Ina Werder Tjalf Ziemssen Katja Akgün 《International journal of molecular sciences》2022,23(20)
The measurement of serum neurofilament light chain (sNfL) is of growing importance in the field of neurology. In the management of multiple sclerosis, it can serve as a useful marker to assess disease activity and treatment response. This paper compares two available methods, namely the Single Molecule Array (Simoa) and the Ella microfluid platform, to measure longitudinal sNfL levels of 42 highly active multiple sclerosis patients treated with alemtuzumab over a period of 36 months. In order to assess the methods agreement, Bland–Altman plots and Passing–Bablok regression were analyzed. Here, we show that despite the fact that Ella measures around 24% higher values than Simoa, both are equally suitable for longitudinal sNfL monitoring. 相似文献
488.
Alenka Vesel Nina Recek Rok Zaplotnik Albert Kurin
i
Katja Kuzmi
Lidija Fras Zemlji
《International journal of molecular sciences》2022,23(23)
A method for the immobilization of an antibacterial chitosan coating to polymeric urinary medical catheters is presented. The method comprises a two-step plasma-treatment procedure, followed by the deposition of chitosan from the water solution. In the first plasma step, the urinary catheter is treated with vacuum-ultraviolet radiation to break bonds in the polymer surface film and create dangling bonds, which are occupied by hydrogen atoms. In the second plasma step, polymeric catheters are treated with atomic oxygen to form oxygen-containing surface functional groups acting as binding sites for chitosan. The presence of oxygen functional groups also causes a transformation of the hydrophobic polymer surface to hydrophilic, thus enabling uniform wetting and improved adsorption of the chitosan coating. The wettability was measured by the sessile-drop method, while the surface composition and structure were measured by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. Non-treated samples did not exhibit successful chitosan immobilization. The effect of plasma treatment on immobilization was explained by noncovalent interactions such as electrostatic interactions and hydrogen bonds. 相似文献
489.
Manca Ogri
Polona
igon Snezna Sodin-Semrl Mirjana Zlatkovi-venda Marija Zdravkovi Milica Ovuka Tinka vec Katja Lakota Peter Radel
iga Rotar Saa u
nik 《International journal of molecular sciences》2023,24(1)
Antiphospholipid antibodies (aPL) comprise a group of autoantibodies that reflect prothrombotic risk in antiphospholipid syndrome (APS) but may also be present in a small proportion of healthy individuals. They are often transiently elevated in infections, including SARS-CoV-2, and may also be associated with vaccine-induced autoimmunity. Therefore, we aimed to investigate the dynamics of aPL in COVID-19 patients and in individuals (healthcare professionals—HCPs) after receiving BNT162b2 vaccine and to compare aPL levels and positivity with those found in APS patients. We measured solid-phase identifiable aPL, including anticardiolipin (aCL), anti-β2 glycoprotein I (anti-β2GPI), and anti-prothrombin/phosphatidylserine (aPS/PT) antibodies in 58 HCPs before and after vaccination (at 3 weeks, 3, 6, and 9 months after the second dose, and 3 weeks after the third booster dose), in 45 COVID-19 patients hospitalized in the ICU, in 89 COVID-19 patients hospitalized in the non-ICU (at admission, at hospital discharge, and at follow-up), and in 52 patients with APS. The most frequently induced aPL in COVID-19 patients (hospitalized in non-ICU) were aCL (50.6% of patients had positive levels at at least one time point), followed by anti-β2GPI (21.3% of patients had positive levels at at least one time point). In 9/89 COVID-19 patients, positive aPL levels persisted for three months. One HCP developed aCL IgG after vaccination but the persistence could not be confirmed, and two HCPs developed persistent anti-β2GPI IgG after vaccination with no increase during a 1-year follow-up period. Solid-phase aPL were detected in 84.6% of APS patients, in 49.4% of COVID-19 patients hospitalized in the non-ICU, in 33.3% of COVID-19 patients hospitalized in the ICU, and in only 17.2% of vaccinated HCPs. aPL levels and multiple positivity were significantly lower in both infected groups and in vaccinated individuals compared with APS patients. In conclusion, BNT162b2 mRNA vaccine may have induced aPL in a few individuals, whereas SARS-CoV-2 infection itself results in a higher percentage of aPL induction, but the levels, persistence, and multiple positivity of aPL do not follow the pattern observed in APS. 相似文献