全文获取类型
收费全文 | 553篇 |
免费 | 26篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 240篇 |
金属工艺 | 8篇 |
机械仪表 | 12篇 |
建筑科学 | 17篇 |
矿业工程 | 2篇 |
能源动力 | 18篇 |
轻工业 | 130篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 9篇 |
一般工业技术 | 64篇 |
冶金工业 | 24篇 |
原子能技术 | 3篇 |
自动化技术 | 46篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 44篇 |
2021年 | 56篇 |
2020年 | 17篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 16篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 32篇 |
2013年 | 33篇 |
2012年 | 38篇 |
2011年 | 45篇 |
2010年 | 26篇 |
2009年 | 26篇 |
2008年 | 29篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 22篇 |
2004年 | 16篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1966年 | 1篇 |
1963年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有579条查询结果,搜索用时 15 毫秒
1.
Chen S.F. Kingsbury B. Lidia Mangu Povey D. Saon G. Soltau H. Zweig G. 《IEEE transactions on audio, speech, and language processing》2006,14(5):1596-1608
This paper describes the technical and system building advances made in IBM's speech recognition technology over the course of the Defense Advanced Research Projects Agency (DARPA) Effective Affordable Reusable Speech-to-Text (EARS) program. At a technical level, these advances include the development of a new form of feature-based minimum phone error training (fMPE), the use of large-scale discriminatively trained full-covariance Gaussian models, the use of septaphone acoustic context in static decoding graphs, and improvements in basic decoding algorithms. At a system building level, the advances include a system architecture based on cross-adaptation and the incorporation of 2100 h of training data in every system component. We present results on English conversational telephony test data from the 2003 and 2004 NIST evaluations. The combination of technical advances and an order of magnitude more training data in 2004 reduced the error rate on the 2003 test set by approximately 21% relative-from 20.4% to 16.1%-over the most accurate system in the 2003 evaluation and produced the most accurate results on the 2004 test sets in every speed category. 相似文献
2.
Silvana?Martini Constantin?Bertoli Maria?Lidia?Herrera Ian?Neeson Alejandro?MarangoniEmail author 《Journal of the American Oil Chemists' Society》2005,82(5):305-312
An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead
of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in
concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples
were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was
followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships
were found between ultrasonic parameters [integrated response, time of flight (TF), and full width half maximum] and SFC.
TF, which is an indirect measurement of the ultrasonic velocity (v), was highly correlated to SFC (r
2>0.9) in a linear fashion (v=2.601 SFC+1433.0). 相似文献
3.
4.
5.
Marina Maslova Vladimir Ivanenko Polina Evstropova Natalia Mudruk Lidia Gerasimova 《International journal of molecular sciences》2022,23(21)
Lithium compounds are of high interest to many industries. The presence of undesirable impurities in Li precursors leads to uncontrolled change in the functional properties of final compounds. Therefore, the development of reliable methods for lithium salt purification is considered a key factor for their application in various industries. This work focuses on the application of a titanium phosphate ion exchanger (Li-TiOP) toward Cu2+, Co2+, Mn2+, Ni2+, and Cr3+ ions in the purification of a saturated LiNO3 solution. The sorption kinetics of the selected ions, considering external and internal mass transfer, as well as chemical interaction, were deeply studied. The kinetic study showed that the values of intraparticle diffusion rate and effective diffusion coefficients for the studied ions decreased in the following order: Cr(III) ˃ Cu(II) Mn(II) ˃ Co(II) ˃ Ni(II). For all the selected ions, chemical interaction was described with a pseudo-second-order reaction model. The sorption kinetics were controlled by the size of the solvated metal ion, its effective charge, the electronic structure of the adsorbed ion, and the interaction with the functional groups of the sorbent. Due to fast kinetics, the high degree of removal of trace quantities of the impurities this material gives it consideration as a promising sorbent for the deep purification of lithium salts. 相似文献
6.
Sara Perego Valentina Alari Gianluca Pietra Andrea Lamperti Alessandro Vimercati Nicole Camporeale Maria Garzo Francesca Cogliati Donatella Milani Aglaia Vignoli Angela Peron Lidia Larizza Tommaso Pizzorusso Silvia Russo 《International journal of molecular sciences》2022,23(22)
Rett syndrome caused by MECP2 variants is characterized by a heterogenous clinical spectrum accounted for in 60% of cases by hot-spot variants. Focusing on the most frequent variants, we generated in vitro iPSC-neurons from the blood of RTT girls with p.Arg133Cys and p.Arg255*, associated to mild and severe phenotype, respectively, and of an RTT male harboring the close to p.Arg255*, p.Gly252Argfs*7 variant. Truncated MeCP2 proteins were revealed by Western blot and immunofluorescence analysis. We compared the mutant versus control neurons at 42 days for morphological parameters and at 120 days for electrophysiology recordings, including girls’ isogenic clones. A precocious reduced morphological complexity was evident in neurons with truncating variants, while in p.Arg133Cys neurons any significant differences were observed in comparison with the isogenic wild-type clones. Reduced nuclear size and branch number show up as the most robust biomarkers. Patch clamp recordings on mature neurons allowed the assessment of cell biophysical properties, V-gated currents, and spiking pattern in the mutant and control cells. Immature spiking, altered cell capacitance, and membrane resistance of RTT neurons, were particularly pronounced in the Arg255* and Gly252Argfs*7 mutants. The overall results indicate that the specific markers of in vitro cellular phenotype mirror the clinical severity and may be amenable to drug testing for translational purposes. 相似文献
7.
Maria I. Morales-Lozano Paula Rodriguez-Otero Lidia Sancho Jorge M. Nuez-Cordoba Elena Prieto Maria Marcos-Jubilar Juan J. Rosales Ana Alfonso Edgar F. Guillen Jesus San-Miguel Maria J. Garcia-Velloso 《International journal of molecular sciences》2022,23(17)
Multiple myeloma (MM) is the second most common haematological malignancy and remains incurable despite therapeutic advances. 18F-FDG (FDG) PET/CT is a relevant tool MM for staging and it is the reference imaging technique for treatment evaluation. However, it has limitations, and investigation of other PET tracers is required. Preliminary results with L-methyl-[11C]- methionine (MET), suggest higher sensitivity than 18F-FDG. This study aimed to compare the diagnostic accuracy and prognostic value of 1FDG and MET in MM patients. We prospectively compared FDG and MET PET/CT for assessment of bone disease and extramedullary disease (EMD) in a series of 52 consecutive patients (8 smoldering MM, 18 newly diagnosed MM and 26 relapsed MM patients). Bone marrow (BM) uptake patterns and the detection of focal lesions (FLs) and EMD were compared. Furthermore, FDG PET parameters with known MM prognostic value were explored for both tracers, as well as total lesion MET uptake (TLMU). Median patient age was 61 years (range, 37–83 years), 54% were male, 13% of them were in stage ISS (International Staging System) III, and 31% had high-risk cytogenetics. FDG PET/CT did not detect active disease in 6 patients, while they were shown to be positive by MET PET/CT. Additionally, MET PET/CT identified a higher number of FLs than FDG in more than half of the patients (63%). For prognostication we focussed on the relapsed cohort, due to the low number of progressions in the two other cohorts. Upon using FDG PET/CT in relapsed patients, the presence of more than 3 FLs (HR 4.61, p = 0.056), more than 10 FLs (HR 5.65, p = 0.013), total metabolic tumor volume (TMTV) p50 (HR 4.91, p = 0.049) or TMTV p75 (HR 5.32, p = 0.016) were associated with adverse prognosis. In MET PET/CT analysis, TMTV p50 (HR 4.71, p = 0.056), TMTV p75 (HR 6.27, p = 0.007), TLMU p50 (HR 8.8, p = 0.04) and TLMU p75 (HR 6.3, p = 0.007) adversely affected PFS. This study confirmed the diagnostic and prognostic value of FDG in MM. In addition, it highlights that MET has higher sensitivity than FDG PET/CT for detection of myeloma lesions, including FLs. Moreover, we show, for the first time, the prognostic value of TMTV and TLMU MET PET/CT in the imaging evaluation of MM patients. 相似文献
8.
Effects of Rhizosphere Bacteria on Strawberry Plants (Fragaria × ananassa Duch.) under Water Deficit
Dominika Paliwoda Grzegorz Mikiciuk Magorzata Mikiciuk Anna Kisiel Lidia Sas-Paszt Tymoteusz Miller 《International journal of molecular sciences》2022,23(18)
Due to the observed climate warming, water deficiency in soil is currently one of the most important stressors limiting the size and quality of plant crops. Drought stress causes a number of morphological, physiological, and biochemical changes in plants, limiting their growth, development, and yield. Innovative methods of inducing resistance and protecting plants against stressors include the inoculation of crops with beneficial microorganisms isolated from the rhizosphere of the plant species to which they are to be applied. The aim of the present study was to evaluate 12 different strains of rhizosphere bacteria of the genera Pantoea, Bacillus, Azotobacter, and Pseudomonas by using them to inoculate strawberry plants and assessing their impact on mitigating the negative effects of drought stress. Bacterial populations were assessed by estimates of their size based on bacterial counts in the growth substrate and with bioassays for plant growth-promoting traits. The physiological condition of strawberry plants was determined based on the parameters of chlorophyll fluorescence. The usefulness of the test methods used to assess the influence of plant inoculation with rhizosphere bacteria on the response of plants growing under water deficit was also evaluated. A two-factor experiment was performed in a complete randomization design. The first experimental factor was the inoculation of plant roots with rhizosphere bacteria. The second experimental factor was the different moisture content of the growth substrate. The water potential was maintained at −10 to −15 kPa under control conditions, and at −40 to −45 kPa under the conditions of water deficit in the substrate. The tests on strawberry plants showed that the highest sensitivity to water deficiency, and thus the greatest usefulness for characterizing water stress, was demonstrated by the following indices of chlorophyll “a” fluorescence: FM, FV, FV/FM, PI, and Area. Based on the assessment of the condition of the photosynthetic apparatus and the analysis of chlorophyll “a” fluorescence indices, including hierarchical cluster analysis, the following strains of rhizosphere bacteria were found to have favorable effects on strawberry plants under water deficit: the Bacillus sp. strains DLGB2 and DKB26 and the Pantoea sp. strains DKB63, DKB70, DKB68, DKB64, and DKB65. In the tests, these strains of Bacillus sp. exhibited a common trait—the ability to produce siderophores, while those of Pantoea sp. were notable for phosphate mobilization and ACCD activity. 相似文献
9.
Determination of Iron Species in Samples of Iron-Fortified Food 总被引:1,自引:0,他引:1
Przemyslaw Niedzielski Magdalena Zielinska-Dawidziak Lidia Kozak Pawel Kowalewski Barbara Szlachetka Sylwia Zalicka Weronika Wachowiak 《Food Analytical Methods》2014,7(10):2023-2032
The paper presents the determination of iron forms in food products. The procedure of sample extraction was developed and optimized, preserving the content of particular forms of iron. The colorimetric method using 2,2′-bipirydyl (measurements at 520 nm) was applied in Fe(II) determinations, while in Fe(III) determinations, the colorimetric method with potassium thiocyanate (measurements at 470 nm) was applied. The total content of iron was determined by the technique of atomic absorption spectrometry, which allowed for the determination of iron content in organic and inorganic complex compounds. Detection limits of 1 mg kg?1 were obtained for all determined iron forms, with the precision ranging between 0.7 % and 1.5 % for 10 mg kg?1 concentration. The optimized analytical procedure was applied in the determinations of iron forms in iron-fortified food products. 相似文献
10.