全文获取类型
收费全文 | 7689篇 |
免费 | 474篇 |
国内免费 | 174篇 |
专业分类
电工技术 | 256篇 |
综合类 | 288篇 |
化学工业 | 5065篇 |
金属工艺 | 289篇 |
机械仪表 | 79篇 |
建筑科学 | 364篇 |
矿业工程 | 26篇 |
能源动力 | 21篇 |
轻工业 | 143篇 |
水利工程 | 71篇 |
石油天然气 | 146篇 |
武器工业 | 18篇 |
无线电 | 144篇 |
一般工业技术 | 1358篇 |
冶金工业 | 36篇 |
原子能技术 | 19篇 |
自动化技术 | 14篇 |
出版年
2024年 | 51篇 |
2023年 | 68篇 |
2022年 | 113篇 |
2021年 | 158篇 |
2020年 | 158篇 |
2019年 | 147篇 |
2018年 | 155篇 |
2017年 | 205篇 |
2016年 | 197篇 |
2015年 | 213篇 |
2014年 | 335篇 |
2013年 | 467篇 |
2012年 | 612篇 |
2011年 | 542篇 |
2010年 | 415篇 |
2009年 | 471篇 |
2008年 | 384篇 |
2007年 | 517篇 |
2006年 | 523篇 |
2005年 | 430篇 |
2004年 | 342篇 |
2003年 | 284篇 |
2002年 | 248篇 |
2001年 | 204篇 |
2000年 | 191篇 |
1999年 | 194篇 |
1998年 | 154篇 |
1997年 | 100篇 |
1996年 | 80篇 |
1995年 | 42篇 |
1994年 | 59篇 |
1993年 | 61篇 |
1992年 | 51篇 |
1991年 | 25篇 |
1990年 | 20篇 |
1989年 | 28篇 |
1988年 | 13篇 |
1987年 | 21篇 |
1986年 | 12篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 19篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有8337条查询结果,搜索用时 15 毫秒
101.
介绍了水性丙烯酸-环氧树脂纳米乳液的制备及其在油罐防腐工程中的应用,讨论了亲水侧链聚乙二醇相对分子质量大小对涂膜性能的影响,乳化剂各组分用量的改变对乳液粒径的影响。 相似文献
102.
环氧稀释剂十二烷基缩水甘油醚的合成 总被引:9,自引:0,他引:9
对稀释剂十二烷基缩水甘油醚的合成及影响产品质量的因素进行了研究,并以十二、十四混醇为原料进行了对比试验。 相似文献
103.
Compatibility between polysulfone (PSF) and epoxy oligomers in the melt state as well as the morphology and properties of alloys obtained were studied as a function of composition. The compatibility depends on the length and structure of epoxy molecules, and is best in the case of epoxysulfone oligomers (ESO).
The properties of hybrid matrices are determined by their composition and morphology. The most pronounced effects are observed in the regions of small concentrations of either component. A small quantity of PSF significantly improves thermal stability and heat resistance of the epoxy resin as well as its impact strength. On the other hand, on addition to PSF of small amounts of epoxysulfone oligomers, the processability of the matrix can be substantially improved. In particular, the melt viscosity decreases, and wetting and impregnation of fibrous reinforcement is facilitated. Besides, the matrix adhesion to fibers is increased.
Powdered PSF/ESO/curing agent mixtures are good for application in solvent-free technological processes of fibrous composites production, e.g. in electrostatic deposition of matrix particles onto a reinforcing fabric. Plastics based on hybrid matrices are distinguished by improved strength. 相似文献
The properties of hybrid matrices are determined by their composition and morphology. The most pronounced effects are observed in the regions of small concentrations of either component. A small quantity of PSF significantly improves thermal stability and heat resistance of the epoxy resin as well as its impact strength. On the other hand, on addition to PSF of small amounts of epoxysulfone oligomers, the processability of the matrix can be substantially improved. In particular, the melt viscosity decreases, and wetting and impregnation of fibrous reinforcement is facilitated. Besides, the matrix adhesion to fibers is increased.
Powdered PSF/ESO/curing agent mixtures are good for application in solvent-free technological processes of fibrous composites production, e.g. in electrostatic deposition of matrix particles onto a reinforcing fabric. Plastics based on hybrid matrices are distinguished by improved strength. 相似文献
104.
105.
Nanocomposites of epoxy resin with montmorillonite clay were synthesized by swelling of different proportions of the clay in a diglycidyl ether of bisphenol‐A followed by in situ polymerization with aromatic diamine as a curing agent. The montmorillonite was modified with octadecylamine and made organophilic. The organoclay was found to be intercalated easily by incorporation of the epoxy precursor and the clay galleries were simultaneously expanded. However, Na‐montmorillonite clay could not be intercalated during the mixing or through the curing process. Curing temperature was found to provide a balance between the reaction rate of the epoxy precursor and the diffusion rate of the curing agent into the clay galleries. The cure kinetics were studied by differential scanning calorimetry. The exfoliation behavior of the organoclay system was investigated by X‐ray diffraction. Thermogravimetric analysis was used to determine the thermal stability, which was correlated with the ionic exchange between the organic species and the silicate layers. The morphology of the nanocomposites was evaluated by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2201–2210, 2004 相似文献
106.
107.
108.
有机硅乳液稳定性的研究 总被引:1,自引:1,他引:1
以阳离子型乳液聚合为例,详细讨论了聚合反应因素及环境因素对环氧改性有机硅乳液稳定性的影响。结果表明:在聚合反应温度为65℃、催化剂的用量为总加料量的0.3%~0.5%、硅烷偶联剂的用量为D4质量的3%~5%、乳化剂用量为总加料量的10%、阳/非离子型乳化剂的质量比为1.5~1.8、D4与水的质量比为0.3~0.4条件下,制得的环氧改性有机硅乳液稳定性良好;采取急冷的方式中止聚合反应,并以醋酸中和至pH值为6~7,有利于环氧改性有机硅乳液稳定性的提高。 相似文献
109.
YAG掺铷——钇铝石榴石激光晶体胶粘剂以丁腈改性环氧树脂,酚醛变性胺为固化剂,用于掺铷——钇铝石榴石激光晶体与钢套粘接,安装在陕西省人民医院YAG激光医用治疗机,临床应用3年,效果很好。后中国电子科技集团第二十七研究所从1990年开始用YAG激光胶粘剂粘接各类激光产品至今,经高低温试验、振动试验、冲击试验等各项性能测试及15年来工程应用证明,在各类激光产品中从未出现开裂、脱胶现象,性能稳定可靠,其粘接强度、耐冲击、耐振动、耐高低温变化、耐水、耐化学介质、耐光、耐老化性能均好,能满足生产要求,用途广泛,符合激光及各种工程应用。文中详述了酚醛变性胺固化剂的选择及该胶粘剂的性能。 相似文献
110.