全文获取类型
收费全文 | 281篇 |
免费 | 19篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 118篇 |
金属工艺 | 4篇 |
机械仪表 | 2篇 |
建筑科学 | 23篇 |
能源动力 | 15篇 |
轻工业 | 44篇 |
石油天然气 | 2篇 |
无线电 | 10篇 |
一般工业技术 | 46篇 |
冶金工业 | 7篇 |
原子能技术 | 2篇 |
自动化技术 | 22篇 |
出版年
2022年 | 8篇 |
2021年 | 26篇 |
2020年 | 11篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 16篇 |
2013年 | 26篇 |
2012年 | 25篇 |
2011年 | 24篇 |
2010年 | 25篇 |
2009年 | 16篇 |
2008年 | 21篇 |
2007年 | 22篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
排序方式: 共有300条查询结果,搜索用时 31 毫秒
51.
Infrared microscopy investigation of oxidation and phase evolution in bitumen modified with polymers
Increase in traffic volume has led to a wider use of Polymer modified Bitumens (PmB’s) in road construction. Although the mechanical properties of such materials have been widely studied, their change with time in service, also called ageing, is yet to be fully understood.One of the most important issues is to identify the process involved: is PmB ageing a consequence of bitumen ageing, polymer ageing or both at the same time? Moreover, most PmB’s feature a two-phase structure made of polymer rich areas along with polymer poor regions, depending on the bitumen chemistry, the polymer nature and content. It is therefore important to take this peculiar structure into consideration when trying to sort out the respective effect on ageing of the polymer and the bitumen. Infrared microscopy allows characterizing separately different phases in heterogeneous products; therefore it is appropriate for PmB’s.In this paper, PmB’s were studied in their original state and after conventional tests claimed to simulate the ageing during the mixing process and several years of road service (RTFOT + PAV). The PmB’s included plastomers and elastomers, some of them being in situ crosslinked. Infrared microscopy was used to determine for each phase the polymer rate and functional indices characterizing the bitumen such as aromaticity, aliphaticity and condensation, and also to map the polymer distribution in the PmB.The characterization of PmB in their original state points out which species of the bitumen are involved in the polymer swelling and the effect of the polymer nature. The characterization of the same PmB’s after the RTFOT + PAV ageing shows how the bitumen species responsible for the swelling evolve during ageing. In addition, kinetic studies were performed using an heating cell fitted to the IR microscope. They confirmed the tendencies obtained with the conventional ageing tests.These studies come to the conclusion of an interdependence of the ageing of the different constitutive phases in a PmB and of chemical exchanges between them. They make clear the micro-morphological modification induced by ageing in a PmB. They finally help to better understand the effect of a crosslinking on the PmB microstructure and its ageing mechanism. 相似文献
52.
Dayon L Hainard A Licker V Turck N Kuhn K Hochstrasser DF Burkhard PR Sanchez JC 《Analytical chemistry》2008,80(8):2921-2931
A new 6-plex isobaric mass tagging technology is presented, and proof of principle studies are carried out using standard protein mixtures and human cerebrospinal fluid (CSF) samples. The Tandem Mass Tags (TMT) comprise a set of structurally identical tags which label peptides on free amino-terminus and epsilon-amino functions of lysine residues. During MS/MS fragmentation, quantification information is obtained through the losses of the reporter ions. After evaluation of the relative quantification with the 6-plex version of the TMT on a model protein mixture at various concentrations, the quantification of proteins in CSF samples was performed using shotgun methods. Human postmortem (PM) CSF was taken as a model of massive brain injury and comparison was carried out with antemortem (AM) CSF. After immunoaffinity depletion, triplicates of AM and PM CSF pooled samples were reduced, alkylated, digested by trypsin, and labeled, respectively, with the six isobaric variants of the TMT (with reporter ions from m/z = 126.1 to 131.1 Th). The samples were pooled and fractionated by SCX chromatography. After RP-LC separation, peptides were identified and quantified by MS/MS analysis with MALDI TOF/TOF and ESI-Q-TOF. The concentration of 78 identified proteins was shown to be clearly increased in PM CSF samples compared to AM. Some of these proteins, like GFAP, protein S100B, and PARK7, have been previously described as brain damage biomarkers, supporting the PM CSF as a valid model of brain insult. ELISA for these proteins confirmed their elevated concentration in PM CSF. This work demonstrates the validity and robustness of the tandem mass tag (TMT) approach for quantitative MS-based proteomics. 相似文献
53.
Virginie Treyvaud Amiguet Kari L. Kramp JinQin Mao Calum McRae Andrew Goulah Linda E. Kimpe Jules M. Blais John T. Arnason 《Food chemistry》2012
This study investigated the potential of Northern shrimp (Pandelus borealis Kreyer) by-products as a source of omega-3 polyunsaturated fatty acids (ω-3 PUFAs). The by-products (heads, shell and tail) of processing accounted for approximately 50–60% of the catch. Supercritical CO2 extraction (SFE) of the by-products at 35 MPa and 40 °C generated a deep red oil, rich in ω-3 PUFAs, specifically 7.8 ± 0.06% eicosapentaenoic acid (EPA) and 8.0 ± 0.07 % docosahexaenoic acid (DHA). 相似文献
54.
Virginie N. Kapchie Lili T. Towa Catherine C. Hauck Patricia A. Murphy 《Journal of the American Oil Chemists' Society》2012,89(5):947-956
The aim of this study was to investigate soy protein recovery feasibility after lab- and pilot-plant scale oleosome isolation.
The proteins were isolated by isoelectric precipitation and by ultrafiltration. The functional properties of the recovered
proteins were compared to soy protein isolate produced in our laboratory. The residual lipid content in the aqueous supernatant
affected the protein recovery yields and purities. Ethanol precipitation and ultrafiltration resulted in the best protein
yields, which were 25 and 26% greater than protein yield obtained by isoelectric precipitation with distilled water dilution.
The protein content of the isoelectric precipitated pilot-plant supernatant was higher (98%) than the protein content of ethanol-precipitated
proteins (80%). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed similar peptide profiles for laboratory and
pilot-plant supernatants. Protein solubility curves between pH 3 and 8 were typical for soy protein isolate with higher solubilities
for proteins obtained from pilot-plant supernatant. The soy protein isolate and ethanol-precipitated protein had the highest
emulsification capacity on a dry-weight basis. These desirable functional properties of proteins recovered as co-products
after oleosome isolation suggest they are highly suitable for industrial application as food ingredients and their recovery
would contribute to the economics of the overall oleosome fractionation process. 相似文献
55.
Christelle Vergnat Virginie Landais Jérôme Combet Alexei Vorobiev Oleg Konovalov Jean-François Legrand Martin Brinkmann 《Organic Electronics》2012,13(9):1594-1601
Polymeric substrates are of importance in plastic electronics. However, polymeric surfaces can exhibit different morphologies depending on whether they are amorphous or semi-crystalline. This work focuses on the impact of the surface structure of bisphenol A polycarbonate substrates on the nucleation and growth of a p-type semi-conductor, namely zinc phthalocyanine (ZnPc). ZnPc films were deposited under high vacuum at different substrate temperatures on oriented semi-crystalline as well as amorphous substrates of PC. The oriented substrates of PC were prepared by a method combining mechanical rubbing and solvent induced crystallization: the substrates show a periodic and regular alternation of oriented crystalline lamellae. Grazing incidence X-ray diffraction shows that the crystalline lamellae of PC have a preferential (a, c) contact plane. Moreover, the substrates show a bilayer structure made of a 60 nm-thick semi-crystalline overlayer atop an amorphous underlayer. UV–vis spectroscopy shows that the polymorphism of the ZnPc films is not modified by the surface structure of the PC substrate (amorphous versus semi-crystalline). However, the statistical analysis of domain size and density versus substrate temperature Ts evidences different apparent activation energies of the growth mechanism. High Resolution Transmission Electron Microscopy suggests that twinning along a (2 ?1 0) plane accounts for the bifurcations of the in-plane b-axis direction of the ZnPc nanocrystals. On oriented substrates of PC, such bifurcations are partly suppressed by the nanocorrugation of the surface, resulting in larger apparent domain sizes and unidirectional in-plane orientation. 相似文献
56.
57.
Estelle Talouarn Marc Teissier Philippe Bardou Hélène Larroque Virginie Clément Isabelle Palhière Gwenola Tosser-Klopp Rachel Rupp Christèle Robert-Granié 《Journal of dairy science》2021,104(1):588-601
The enhanced availability of sequence data in livestock provides an opportunity for more accurate predictions in routine genomic evaluations. Such evaluations would therefore no longer rely only on the linkage disequilibrium between a chip marker and the causal mutation. The objective of this study was to assess the usefulness of sequence data in Saanen goats (n = 33) to better capture a quantitative trait locus (QTL) on chromosome 19 (CHI19) and improve the accuracy of predictions for 3 milk production traits, 5 type traits, and somatic cell scores. All 1,207 50K genotypes were imputed to the sequence level. Four scenarios, each using a subset of CHI19 imputed variants, were then tested. Sequence-derived information included all CHI19 variants (529,576), all variants in the QTL region (22,269), 178 variants selected in the QTL region and added to an updated chip, or 178 randomly selected variants on CHI19. Two genomic evaluation models were applied: single-step genomic BLUP and weighted single-step genomic BLUP. All scenarios were compared with single-step genomic BLUP using 50K genotypes. Best overall results were obtained using single-step genomic BLUP on 50K genotypes completed with all variants in the QTL region of chromosome 19 (6.2% average increase in accuracy for 9 traits) with the highest accuracy gain for fat yield (17.9%), significant increases for milk (13.7%) and protein yields (12.5%), and type traits associated with CHI19. Despite its association with the QTL region of chromosome 19, the somatic cell score showed decreased accuracy in every alternative scenario. Using all CHI19 variants led to an overall decrease of 4.8% in prediction accuracy. The updated chip was efficient and improved genomic evaluations by 3.1 to 6.4% on average, depending on the scenario. Indeed, information from only a few carefully selected variants increased accuracies for traits of interest when used in a single-step genomic BLUP model. In conclusion, using QTL region variants imputed from sequence data in single-step genomic evaluations represents a promising perspective for such evaluations in dairy goats. Furthermore, using only a limited number of selected variants in QTL regions, as available on SNP chip updates, significantly increases the accuracy for QTL-associated traits without deteriorating the evaluation accuracy for other traits. The latter approach is interesting, as it avoids time-consuming imputation and data formatting processes and provides reliable genotypes. 相似文献
58.
Amel Ben Saad Virginie Vauthier Martine Lapalus Elodie Mareux Evangline Bennana Anne-Marie Durand-Schneider Alix Bruneau Jean-Louis Delaunay Emmanuel Gonzales Chantal Housset Tounsia Aït-Slimane Franois Guillonneau Emmanuel Jacquemin Thomas Falguires 《International journal of molecular sciences》2021,22(13)
ABCB4 (ATP-binding cassette subfamily B member 4) is an ABC transporter expressed at the canalicular membrane of hepatocytes where it ensures phosphatidylcholine secretion into bile. Genetic variations of ABCB4 are associated with several rare cholestatic diseases. The available treatments are not efficient for a significant proportion of patients with ABCB4-related diseases and liver transplantation is often required. The development of novel therapies requires a deep understanding of the molecular mechanisms regulating ABCB4 expression, intracellular traffic, and function. Using an immunoprecipitation approach combined with mass spectrometry analyses, we have identified the small GTPase RAB10 as a novel molecular partner of ABCB4. Our results indicate that the overexpression of wild type RAB10 or its dominant-active mutant significantly increases the amount of ABCB4 at the plasma membrane expression and its phosphatidylcholine floppase function. Contrariwise, RAB10 silencing induces the intracellular retention of ABCB4 and then indirectly diminishes its secretory function. Taken together, our findings suggest that RAB10 regulates the plasma membrane targeting of ABCB4 and consequently its capacity to mediate phosphatidylcholine secretion. 相似文献
59.
Multilayer films ageing under ultraviolet radiations: Complementary study by dielectric spectroscopy
Simon Lewandowski Virginie Rejsek‐Riba Alain Bernès Sophie Perraud Colette Lacabanne 《应用聚合物科学杂志》2013,129(6):3772-3781
The effect of ultraviolet (UV) irradiation on a multilayer film made of poly(ethylene terephthalate)/Polyamide 6/poly(ethylene terephthalate) was investigated by uniaxial tractions, UV‐visible‐NIR and Fourier transformed infra‐red‐attenuated total reflection spectroscopy, differential scanning calorimetry ( DSC), and dynamic dielectric spectroscopy (DDS). The multilayer was exposed to ultraviolet radiations (filtered at 270 nm) for 7 days, in air. The complexity of the multilayer thermograms recorded by DSC and DDS has required the study of each film constituting the multilayer to assess each the contribution of each one of them. A deterioration in mechanical properties and a decrease in UV transmission for low wavelengths are observed. These evolutions seem to result to the photo‐oxidation of the poly(ethylene terephthalate) film mainly localized at the exposed layer. This layer acts as a UV protection filter for the other layers. However, the DDS analyses show a plasticization effect of the primary mode in the Polyamide 6, which is evidence of photo‐oxidation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
60.
Cyrille Richard Nathalie Mignet Céline Largeau Virginie Escriou Michel Bessodes Daniel Scherman 《Nano Research》2009,2(8):638-647
The possibility of delivering DNA efficiently to cells represents a crucial issue for the treatment of both genetic and acquired
diseases. However, even although the efficiency of non-viral transfection systems has improved in the last decade, none have
yet proven to be sufficiently effective in vivo. We report herein our results on the functionalization of single-walled carbon nanotubes (SWNT) and multi-walled carbon nanotubes
(MWNT) by two cationic amphiphiles (lipid RPR120535 and pyrenyl polyamine), their use for the complexation of plasmid DNA,
and their efficiency in transfecting cells in vitro. The experiments have shown that the efficiency of transfection is higher when using SWNT instead of MWNT, and that transfection
efficiency is similar or slightly higher when using nanoplexes (SWNT/lipid RPR120535/DNA) instead of lipoplexes (lipid RPR120535/DNA)
and several orders of magnitude higher than that of naked DNA. This study therefore shows both that the transfection is better
when using SWNTs and that it is dependent on the nature of the amphiphilic molecules adsorbed on the nanotubes.
相似文献