全文获取类型
收费全文 | 1443篇 |
免费 | 64篇 |
专业分类
电工技术 | 15篇 |
化学工业 | 386篇 |
金属工艺 | 11篇 |
机械仪表 | 32篇 |
建筑科学 | 36篇 |
能源动力 | 38篇 |
轻工业 | 151篇 |
水利工程 | 4篇 |
石油天然气 | 24篇 |
无线电 | 97篇 |
一般工业技术 | 205篇 |
冶金工业 | 291篇 |
原子能技术 | 7篇 |
自动化技术 | 210篇 |
出版年
2024年 | 6篇 |
2023年 | 24篇 |
2022年 | 83篇 |
2021年 | 81篇 |
2020年 | 62篇 |
2019年 | 20篇 |
2018年 | 43篇 |
2017年 | 41篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 34篇 |
2013年 | 69篇 |
2012年 | 58篇 |
2011年 | 94篇 |
2010年 | 41篇 |
2009年 | 50篇 |
2008年 | 61篇 |
2007年 | 42篇 |
2006年 | 36篇 |
2005年 | 34篇 |
2004年 | 24篇 |
2003年 | 36篇 |
2002年 | 37篇 |
2001年 | 28篇 |
2000年 | 14篇 |
1999年 | 24篇 |
1998年 | 101篇 |
1997年 | 59篇 |
1996年 | 40篇 |
1995年 | 25篇 |
1994年 | 13篇 |
1993年 | 27篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 3篇 |
1971年 | 4篇 |
排序方式: 共有1507条查询结果,搜索用时 15 毫秒
31.
Joanna Dawczyk Ecaterina Ware Mahmoud Ardakani Joe Russo Hugh Spikes 《Tribology Letters》2018,66(4):155
Focussed ion beam milling (FIB) followed by TEM has been used to study ZDDP tribofilms on rubbed steel surfaces. It has been found that the impact of high energy platinum and gallium ions during FIB causes significant morphological and structural changes to the uppermost 30–50 nm of a ZDDP tribofilm. This can be prevented by the low energy deposition of a quite thick gold layer prior to installation of the sample in the FIB facility. This problem, and its solution, have been quite widely reported in the non-tribology literature but have not previously been highlighted in the application of FIB to study tribological surfaces. It has also been found, using this gold pre-deposition method, that the bulk of the ZDDP tribofilm studied has a polycrystalline structure. 相似文献
32.
33.
34.
Rhett Russo 《Architectural Design》2017,87(3):48-55
Specific Objects is a New York-based interdisciplinary design practice. Rhett Russo , one of its directors, is developing architectural assemblies that are informed by the specific properties of ceramics, how these traits become encrypted through technology, and at what cost. Drawing on the philosophical writings of Tristan Garcia, Bernard Stiegler and Graham Harman, the art of Jiří Kolář and a competition design by his own firm, he explores ways that the peculiar nature of objects initiate new workflows. 相似文献
35.
Thamires Rodrigues de Sousa Beatriz Oliveira Fagundes Andrezza Nascimento Lorena Abreu Fernandes Fbio da Ressureio Sgnotto Raquel Leo Orfali Valria Aoki Alberto Jos da Silva Duarte Sabri Saeed Sanabani Jefferson Russo Victor 《International journal of molecular sciences》2022,23(12)
Atopic dermatitis (AD) is a common relapsing inflammatory skin disorder characterized by immune-mediated inflammation and epidermal barrier dysfunction. The pathogenesis of AD is multifactorial and has not been fully elucidated to date. This study aimed to evaluate whether serum IgG from adult AD patients could modulate the thymic maturation of IL-22-producing T cells and CLA+ T cells of non-atopic infants. Given that miRNAs regulate immune response genes, we evaluated whether miRNA expression is also altered in cultured thymocytes. Thymocytes were cultured with purified IgG from AD patients or control conditions (mock, Intravenous-IgG (IVIg), non-atopic IgG, or atopic non-AD IgG). Using flow cytometry analysis, we assessed the expression of CLA and intracellular levels of IL-4, IFN-γ, and IL-22 on double-positive T cells (DP T), CD4 T cells, or CD8 T cells. We also investigated the frequency of IgG isotypes and their direct interaction with the thymic T cells membrane. The miRNA profiles were evaluated by the Illumina small RNA-seq approach. MiRNA target gene prediction and enrichment analyses were performed using bioinformatics. Increased frequencies of IL-22 and CLA+ producing CD4+ T cells cultured with IgG of AD patients was seen in non-atopic infant thymocytes compared to all control conditions. No alterations were observed in the frequency of IgG isotypes among evaluated IgG pools. Evidence for a direct interaction between IgG and thymic DP T, CD4 T, and CD8 T cells is presented. The small RNA-seq analysis identified ten mature miRNAs that were modulated by AD IgG compared to mock condition (miR-181b-5p, hsa-miR-130b-3p, hsa-miR-26a-5p, hsa-miR-4497, has-miR-146a, hsa-let-7i-5p, hsa-miR-342-3p, has-miR-148a-3p, has-miR-92a and has-miR-4492). The prediction of the targetome of the seven dysregulated miRNAs between AD and mock control revealed 122 putative targets, and functional and pathway enrichment analyses were performed. Our results enhance our understanding of the mechanism by which IgG can collaborate in thymic T cells in the setting of infant AD. 相似文献
36.
Lara Alessandrini Leonardo Franz Marta Sbaraglia Tommaso Saccardo Filippo Cappello Alessandro Drigo Anna Chiara Frigo Gino Marioni 《International journal of molecular sciences》2022,23(14)
Programmed cell death ligand 1 (PD-L1) seems to rely on close relations between neoplastic and immune cells in the tumor microenvironment. Tumor to stroma ratio (TSR) has been associated with prognosis in different malignancies. The aims of this exploratory investigation were to analyze for the first time the: (i) association between TSR, PD-L1 expression and other clinical–pathological features in laryngeal squamous cell carcinoma (LSCC) biopsies and paired surgical specimens; (ii) prognostic and predictive role of TSR and PD-L1. TSR, PD-L1 expression (in terms of combined positive score [CPS]), and other clinical–pathological features were analyzed in biopsies and surgical specimens of 43 consecutive LSCC cases. A CPS < 1 evaluated on surgical specimens was associated with a low TSR (stroma rich) on both biopsies and surgical specimens (p = 0.0143 and p = 0.0063). Low TSR showed a significant negative prognostic value when evaluated on both biopsies and surgical specimens (HR = 8.808, p = 0.0003 and HR = 11.207, p = 0.0002). CPS ≥ 1 appeared to be a favorable prognostic factor (HR = 0.100, p = 0.0265). The association between bioptic and surgical specimen TSR and PD-L1 expression should be further investigated for a potential impact on targeted treatments, also with regard to immunotherapeutic protocols. 相似文献
37.
38.
Two commercial SCR catalysts, with a nominal W content of about 9 wt.% and a V nominal content of 0.55 and 1.8 wt.%, respectively, were contacted with different amounts of Na and K and with HCl vapours in order to simulate poisoning by species more specifically contained in exhaust gases from MSW combustion. Catalysts were characterised using XRD analysis, SEM/EDX analysis, BET and pore size distribution measurements, NH3 TPD, TG analysis. Poisoning agents do not cause loss of surface area nor pore occlusion. A significant loss of surface acidity was observed upon alkali metals poisoning whereas a decreasing of vanadium content was observed for the more concentrated catalysts upon HCl poisoning. Catalysts deactivation is proportional to the number of acid sites neutralised by alkali metals adsorbing ammonia in the temperature range typical of SCR process. HCl promotes the formation of new acid sites showing a lower activity compared to the original one. 相似文献
39.
Walter Navarrini Tommaso Brivio Dmitrij Capobianco Maria Vittoria Diamanti Mariapia Pedeferri Luca Magagnin Giuseppe Resnati 《Journal of Coatings Technology and Research》2011,8(2):153-160
In this study amorphous fluorinated coatings applied to anodized titanium surface have been investigated. A copolymer between
tetrafluoroethylene and perfluoro-4-trifluoromethoxy-1,3-dioxole (AD60) and two perfluoropolyether containing ammonium phosphate
(F10) or triethoxysilane (S10) functionalities have been tested. To estimate the color alteration of the anodized titanium
surfaces due to the application of the coatings, spectrophotometric analyses have been made. Water and n-dodecane contact angles as well as apparent surface energy have been evaluated. Ellipsometry and atomic force microscopy
data have been used to measure the thickness of the fluorinated coatings. A tailored mechanical preliminary test has also
been explored to evaluate the adhesion of the coatings on the anodized titanium surface. The resistance to surface soiling
with castor oil was also preliminarily investigated. The fluorinated coating tested on anodized titanium showed a low apparent
surface energy and high chromatic aspect conservation, this is particularly evident for the titanium anodized coated with
triethoxysilane functionalities fluoropolymers S10. 相似文献
40.
The present investigation concerns the phenomena that occur during the non‐catalytic regeneration of Diesel Particulate Filters (DPFs). The temperature evolution in the filter has been correlated to the emissions of CO, HC, NO, and NO2 during the loading and regeneration process. The emissions were assessed over both the diesel oxidation catalyst (DOC) and the DPF, in order to characterise the chemical species evolution inside the after‐treatment line. Different regeneration temperatures, which have been found to have a strong impact on the evolution of the soot oxidation rate, have been assessed. Finally, the particulate emissions during regeneration have been measured on a number and size basis. 相似文献