全文获取类型
收费全文 | 2450篇 |
免费 | 85篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 24篇 |
化学工业 | 462篇 |
金属工艺 | 27篇 |
机械仪表 | 34篇 |
建筑科学 | 107篇 |
矿业工程 | 4篇 |
能源动力 | 41篇 |
轻工业 | 373篇 |
水利工程 | 14篇 |
石油天然气 | 10篇 |
无线电 | 139篇 |
一般工业技术 | 296篇 |
冶金工业 | 732篇 |
原子能技术 | 5篇 |
自动化技术 | 270篇 |
出版年
2023年 | 14篇 |
2022年 | 44篇 |
2021年 | 87篇 |
2020年 | 45篇 |
2019年 | 67篇 |
2018年 | 53篇 |
2017年 | 62篇 |
2016年 | 56篇 |
2015年 | 49篇 |
2014年 | 80篇 |
2013年 | 151篇 |
2012年 | 117篇 |
2011年 | 124篇 |
2010年 | 103篇 |
2009年 | 93篇 |
2008年 | 104篇 |
2007年 | 79篇 |
2006年 | 77篇 |
2005年 | 74篇 |
2004年 | 70篇 |
2003年 | 36篇 |
2002年 | 64篇 |
2001年 | 50篇 |
2000年 | 40篇 |
1999年 | 46篇 |
1998年 | 46篇 |
1997年 | 34篇 |
1996年 | 38篇 |
1995年 | 35篇 |
1994年 | 43篇 |
1993年 | 50篇 |
1992年 | 43篇 |
1991年 | 12篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 33篇 |
1987年 | 31篇 |
1986年 | 26篇 |
1985年 | 31篇 |
1984年 | 32篇 |
1983年 | 21篇 |
1982年 | 16篇 |
1981年 | 16篇 |
1980年 | 15篇 |
1979年 | 26篇 |
1978年 | 18篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1975年 | 20篇 |
1972年 | 12篇 |
排序方式: 共有2538条查询结果,搜索用时 15 毫秒
61.
The solubility of TiO2 in tetragonal ZrO2 is 13.8±0.3 mol% ui 1300°C, 14.9±0.2 mol% at 1400°C, and 16.1±0.2 mol% at 1500°C. These solid solutions transform to metastable monoclinic solid solutions without compositional change on cooling to room temperature. 相似文献
62.
63.
Dorian Zapp Judith Scheiber Oliver Gerner Edith Fuchs Jakub Dvorak Daniel Mayer Matthias Nemestothy Rupert Steiner 《世界建筑导报》2018,(3)
正科帕卡格拉纳位于新多瑙河12.5公里处,毗邻Reichsbrücke大桥。出于同旧有设计保持协调性考虑,力求能让大楼融入当地环境,迎合自身功能性需要,GERNER GERNER PLUS团队充分考虑现有周边环境,对大楼重新规划设计。新的设计突显建筑的特殊性和重要性,面向河流的立面是科帕卡格拉纳大楼最重要的部分,所以设计的重点也放在了这里。现有的城市中轴线是一个参照物,为了视觉上和氛围上形成一体化城市的感 相似文献
64.
Networks and Spatial Economics - In this paper, we propose a multi-objective spatial analysis framework to evaluate the economic, environmental and health impacts of transport investment strategies... 相似文献
65.
Guillermo Quints Florian Caiment Ivn Rienda Judith Prez-Rojas Eugenia Pareja Jos V. Castell Ramiro Jover 《International journal of molecular sciences》2022,23(16)
Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease worldwide, but a reliable non-invasive method to quantify liver steatosis in primary healthcare is not available. Circulating microRNAs have been proposed as biomarkers of severe/advanced NAFLD (steatohepatitis and fibrosis). However, the use of circulating miRNAs to quantitatively assess the % of liver fat in suspected NAFLD patients has not been investigated. We performed global miRNA sequencing in two sets of samples: human livers from organ donors (n = 20), and human sera from biopsy-proven NAFLD patients (n = 23), both with a wide range of steatosis quantified in their liver biopsies. Partial least squares (PLS) regression combined with recursive feature elimination (RFE) was used to select miRNAs associated with steatosis. Moreover, regression models with only 2 or 3 miRNAs, with high biological relevance, were built. Comprehensive microRNA sequencing of liver and serum samples resulted in two sets of abundantly expressed miRNAs (418 in liver and 351 in serum). Pearson correlation analyses indicated that 18% of miRNAs in liver and 14.5% in serum were significantly associated with the amount of liver fat. PLS-RFE models demonstrated that 50 was the number of miRNAs providing the lowest error in both liver and serum models predicting steatosis. Comparison of the two miRNA subsets showed 19 coincident miRNAs that were ranked according to biological significance (guide/passenger strand, relative abundance in liver and serum, number of predicted lipid metabolism target genes, correlation significance, etc.). Among them, miR-10a-5p, miR-98-5p, miR-19a-3p, miR-30e-5p, miR-32-5p and miR-145-5p showed the highest biological relevance. PLS regression models with serum levels of 2–3 of these miRNAs predicted the % of liver fat with errors <5%. 相似文献
66.
Zeolite Formation in Class F Fly Ash Blended Cement Pastes 总被引:5,自引:0,他引:5
Judith L. LaRosa Stephen Kwan Michael W. Grutzeck 《Journal of the American Ceramic Society》1992,75(6):1574-1580
Zeolite formation in Class F fly ash blended cement pastes is under investigation. A Na–P type zeolite and Zeolite Y were synthesized from Class F fly ash and NaOH solution after 2 days of aging at room temperature and 6 days of curing at 80°C. However, no zeolites formed when KOH was used. In additional experiments, a Na–P type zeolite, Zeolite Y, and chabazite developed in cement pastes blended with Class F fly ash and NaOH solution which had been aged 2 days at room temperature and then cured 6 days at temperatures ranging from room temperature to 90°C. Seeding the pastes with natural zeolites was also investigated. 相似文献
67.
68.
Laarnie Tumolva Ji-Yeon Park Jae-suk Kim Arthur L. Miller Judith C. Chow John G. Watson 《Aerosol science and technology》2013,47(3):202-215
The Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS) were used to determine morphology and elemental composition of a variety of freshly emitted soot particles (acetylene flame, candle flame, kerosene flame, diesel exhaust, electric arc, plastic burning, styrofoam burning, wood burning [white oak and pine bark], and rice straw burning), which can be possible candidate soot in the ambient atmosphere, and ultrafine particles sampled in urban, industrial, and coastal sites during ultrafine particle formation events (combustion and photochemical events). By using mobility-classified non-refractory ((NH 4 ) 2 SO 4 ) and refractory (Polystyrene latex (PSL) and salt (NaCl)) particles, limitation of the TEM was tested. Data showed that the TEM method can be used to examine shapes of both volatile particles such as (NH 4 ) 2 SO 4 (100 nm) at low, but not high magnification (refer to low and high beam intensity, respectively), and non-volatile particles like NaCl (100 nm) and PSL (84 nm) at either low or high magnification. Distinct differences in morphological properties such as primary particle diameter, fractal dimension, and microstructure were observed among the different types of fresh soot particles. The atmospheric ultrafine particles were classified as agglomerates, sulfate mixtures (spherical), metallic oxides (spherical and polygonal), C-rich refractory (not agglomerated), C-rich non-refractory (not agglomerated), Si-rich (spherical), Na-rich (porous), or P-containing (non-spherical) particles. At the urban Gwangju site, a higher fraction of fresh and aged agglomerates was observed than at other sites. The C-rich non-refractory and sulfate mixtures were often observed in the photochemical event. The C-rich refractory particles were abundant at the Gwangju and Yeosu sites. The coastal Taean site had few agglomerates due to limited anthropogenic combustion source. 相似文献
69.
Joana S. Cristóv?o Sónia S. Leal Isabel Cardoso Cláudio M. Gomes 《International journal of molecular sciences》2013,14(9):19128-19145
Superoxide dismutase 1 (SOD1) aggregation is one of the pathological markers of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. The underlying molecular grounds of SOD1 pathologic aggregation remains obscure as mutations alone are not exclusively the cause for the formation of protein inclusions. Thus, other components in the cell environment likely play a key role in triggering SOD1 toxic aggregation in ALS. Recently, it was found that ALS patients present a specific altered metabolomic profile in the cerebrospinal fluid (CSF) where SOD1 is also present and potentially interacts with metabolites. Here we have investigated how some of these small molecules affect apoSOD1 structure and aggregation propensity. Our results show that as co-solvents, the tested small molecules do not affect apoSOD1 thermal stability but do influence its tertiary interactions and dynamics, as evidenced by combined biophysical analysis and proteolytic susceptibility. Moreover, these compounds influence apoSOD1 aggregation, decreasing nucleation time and promoting the formation of larger and less soluble aggregates, and in some cases polymeric assemblies apparently composed by spherical species resembling the soluble native protein. We conclude that some components of the ALS metabolome that shape the chemical environment in the CSF may influence apoSOD1 conformers and aggregation. 相似文献
70.
Nina Pauline Holzapfel Boris Michael Holzapfel Simon Champ Jesper Feldthusen Judith Clements Dietmar Werner Hutmacher 《International journal of molecular sciences》2013,14(7):14620-14646
Lycopene is a phytochemical that belongs to a group of pigments known as carotenoids. It is red, lipophilic and naturally occurring in many fruits and vegetables, with tomatoes and tomato-based products containing the highest concentrations of bioavailable lycopene. Several epidemiological studies have linked increased lycopene consumption with decreased prostate cancer risk. These findings are supported by in vitro and in vivo experiments showing that lycopene not only enhances the antioxidant response of prostate cells, but that it is even able to inhibit proliferation, induce apoptosis and decrease the metastatic capacity of prostate cancer cells. However, there is still no clearly proven clinical evidence supporting the use of lycopene in the prevention or treatment of prostate cancer, due to the only limited number of published randomized clinical trials and the varying quality of existing studies. The scope of this article is to discuss the potential impact of lycopene on prostate cancer by giving an overview about its molecular mechanisms and clinical effects. 相似文献