全文获取类型
收费全文 | 11050篇 |
免费 | 842篇 |
国内免费 | 331篇 |
专业分类
电工技术 | 53篇 |
技术理论 | 1篇 |
综合类 | 277篇 |
化学工业 | 5591篇 |
金属工艺 | 2852篇 |
机械仪表 | 375篇 |
建筑科学 | 161篇 |
矿业工程 | 55篇 |
能源动力 | 136篇 |
轻工业 | 215篇 |
水利工程 | 10篇 |
石油天然气 | 87篇 |
武器工业 | 42篇 |
无线电 | 399篇 |
一般工业技术 | 1495篇 |
冶金工业 | 378篇 |
原子能技术 | 27篇 |
自动化技术 | 69篇 |
出版年
2024年 | 17篇 |
2023年 | 204篇 |
2022年 | 210篇 |
2021年 | 364篇 |
2020年 | 390篇 |
2019年 | 327篇 |
2018年 | 353篇 |
2017年 | 315篇 |
2016年 | 288篇 |
2015年 | 304篇 |
2014年 | 570篇 |
2013年 | 672篇 |
2012年 | 675篇 |
2011年 | 884篇 |
2010年 | 767篇 |
2009年 | 654篇 |
2008年 | 667篇 |
2007年 | 697篇 |
2006年 | 754篇 |
2005年 | 616篇 |
2004年 | 563篇 |
2003年 | 368篇 |
2002年 | 244篇 |
2001年 | 213篇 |
2000年 | 177篇 |
1999年 | 196篇 |
1998年 | 179篇 |
1997年 | 118篇 |
1996年 | 87篇 |
1995年 | 61篇 |
1994年 | 57篇 |
1993年 | 48篇 |
1992年 | 40篇 |
1991年 | 35篇 |
1990年 | 30篇 |
1989年 | 34篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Currently, there is a growing interest in the application of silicon-based technologies for the development of advanced hybrid organic–inorganic coatings with strong weatherability. In this study, the sol–gel process is used to prepare such coatings on glass and their resistance to weathering effects is assessed afterwards. Various sols were prepared by mixing a silica-based inorganic matrix (tetraethyl orthosilicate) with different quantities of silica alkoxides functionalised with various organic groups. Subsequently, the sols were dip-coated onto glass samples at low temperatures without any heat treatment. The coatings prepared were analysed before and after three model ageing tests simulating various weathering parameters. After ageing, the best performing coatings showed good overall homogeneity and transparency (optical microscopy, SEM), improved water repellency and adhesion to the glass substrate (static contact angle measurements, cross-cut tape tests) and no colour or chemical composition changes (UV–VIS, FTIR). Compared with commercial hybrid silica products, the alkyl- and methacryloxy-functionalised silica coatings particularly displayed improved homogeneity, elasticity and barrier properties. Thus, these low temperature coatings, easily applicable to thin films, appear to fulfil the main requirements for the protection of the glass exposed to weathering phenomena. 相似文献
62.
随着我国环境保护法规《大气污染防治法》的修订和《涂料征收消费税通知》的公布,探讨了其对船舶涂料企业的冲击及其应对措施。 相似文献
63.
In this work, a one-step film formation method is demonstrated to obtain the patterned surface of an acrylate photocuring coating using nano-silica particles treated with a perfluoroalkoxysilane ((heptadecafluoro-1,1,2,2-tetra hydrodecyl) triethoxysilane) as a nanoadditive. Nanosilica particles were treated with perfluoroalkoxysilane and used in a UV-curable matrix. The typical patterns on the surface of the UV-cured films are revealed in AFM images. The surface properties of the cured films were investigated by measuring water contact angle and surface energy. The degree of conversion of the samples was obtained by FTIR analysis and pendulum hardness was measured using a Konig hardness meter. Scratch resistance of cured films was measured by standard scratch measuring pens. The characteristics obtained from AFM analysis showed that rough surface patterns in this system are controlled linearly by changes in the treated nano-particle concentration. The subtraction of surface energy of the cured film was clear and the water contact angle showed a 60% increase with the addition of a fluorinated nano-particle concentration. Surface hardness decreased and scratch resistance increased as the concentration of treated nanoparticles increased, while the final degree of conversion of the film remained unchanged. 相似文献
64.
The feasibility of using 2304 duplex stainless steel rebar in seawater concrete was determined by studying the passivation and corrosion behavior of steel in solutions simulated curing and service stage of concrete, respectively. The results demonstrate that 2304 duplex stainless steel rebar could be used with seawater concrete because of a stable passive film formed on the steel surface during the curing stage of concrete even in the presence of 2 M chloride ions. However, due to the synergistic effect of concrete carbonation, the rebar suffered a corrosive attack by chloride due to the lack of OH? inhibition. 相似文献
65.
66.
67.
Cerium malate (CeMal) was tested as a corrosion inhibitor for AA2024-T3 in this work. Corrosion inhibition on bare AA2024-T3 indicated that the inhibiting effect was a result of the synergistic effect of cerium cations and maleic anions. The corrosion of AA2024-T3 was stagnated by greatly reducing the corrosion current when CeMal was present in NaCl solutions. CeMal was adsorbed on the surface of AA2024-T3 forming a protective film in the initial stage. Then, cerium cations transformed to cerium oxide/hydroxides, precipitating on the cathode sites to inhibit the further corrosion. The electrochemical impedance spectra results of the sol-gel coatings proved that CeMal was an effective corrosion inhibitor in the sol-gel coatings to provide corrosion protection for AA2024-T3. 相似文献
68.
针对南方客户在使用我司客车一段时间后,车身涂层不同程度出现了起泡的质量问题,进行了现场查看,发现起泡位置在车身左右侧蒙皮,且发生在涂层最底层。初步分析原因是热镀锌板+阴极电泳漆 +原子灰三者之间配套存在问题,通过热镀锌板 +阴极电泳漆 +原子灰三者之间的耐高温 80 ℃配套试验,以及室外曝晒试验,得出镀锌板表面是否钝化、电泳漆膜致密程度和原子灰苯乙烯含量是造成涂层底层起泡的主要原因。为了控制涂层起泡问题,重新修订了我司原子灰、镀锌板、电泳漆的技术标准以及部分工艺文件。 相似文献
69.
70.
Monitoring the structural health and integrity of coated components is of vital importance to increase their lifetime and the overall sustainability of the targeted applications. Here, the temporal oxidation behavior of TiN thin films is tracked using in situ sheet resistance measurements. Based on correlative film morphology, structure, and local composition data, it is evident that observed resistance changes are caused by oxidation of TiN. Thickness measurements of the remaining TiN under the oxide layer are in very good agreement with thicknesses deduced from in situ sheet resistance measurements. Hence, the in situ measured sheet resistance is an autonomous self‐reporting property useful for tracking the temporal oxidation behavior of TiN coatings. 相似文献