全文获取类型
收费全文 | 534篇 |
免费 | 2篇 |
国内免费 | 12篇 |
专业分类
综合类 | 5篇 |
化学工业 | 386篇 |
金属工艺 | 55篇 |
机械仪表 | 3篇 |
能源动力 | 13篇 |
无线电 | 6篇 |
一般工业技术 | 71篇 |
冶金工业 | 4篇 |
原子能技术 | 1篇 |
自动化技术 | 4篇 |
出版年
2023年 | 72篇 |
2022年 | 54篇 |
2021年 | 30篇 |
2020年 | 33篇 |
2019年 | 43篇 |
2018年 | 12篇 |
2017年 | 38篇 |
2016年 | 19篇 |
2015年 | 10篇 |
2014年 | 24篇 |
2013年 | 19篇 |
2012年 | 20篇 |
2011年 | 27篇 |
2010年 | 24篇 |
2009年 | 28篇 |
2008年 | 19篇 |
2007年 | 12篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1989年 | 3篇 |
排序方式: 共有548条查询结果,搜索用时 128 毫秒
1.
Sijia Huo Yujin Wang Mianyi Yao Zhikun Zhang Lei Chen Hui Gu Jiahu Ouyang Yu Zhou 《Journal of the European Ceramic Society》2021,41(11):5466-5473
Novel TiC-based composites were synthesized by reactive hot-pressing at 1800 °C for 1 h with ZrB2 addition as a sintering aid for the first time. The effects of ZrB2 contents on the phase composition, microstructure evolution, and mechanical properties were reported. Based on the reaction and solid solution coupling effects between ZrB2 and TiC, the product ZrC may be partially or completely dissolved into the TiC matrix, and then phase separation within the miscibility gap is observed to form lamellar nanostructured ZrC-rich (Zr, Ti)C. The TiC-10 mol.% ZrB2 (starting batch composition) exhibits good comprehensive mechanical properties of hardness 27.7 ± 1.3 GPa, flexural strength 659 ± 48 MPa, and fracture toughness of 6.5 ± 0.6 MPa m1/2, respectively, which reach or exceed most TiC-based composites using ceramics as sintering aids in the previous reports. 相似文献
2.
Strengthened interfacial bonding and its effects on fracture mode of TaC ceramics with addition of B
《Journal of the European Ceramic Society》2020,40(4):1067-1077
TaC ceramics with 0-0.237 wt% B addition were prepared by hot pressing. The effect of B addition on the phase constitution, interfacial chemistry/bonding and mechanical properties of the TaC ceramics were investigated. Upon B addition, the elimination of O impurity and segregation of B at grain boundaries were evidenced, accompanied by an increase in bonding strength of the TaC grains, to result in a fracture mode change from intergranular to transgranular and a reduced fracture toughness. Addition of excessive B resulted in the formation of TaB2 and C within TaC ceramics. Further, TaC-TaB2-SiC composites were prepared by Si addition. Coherent bonding between TaB2 and TaC was preserved in the TaC-TaB2-SiC composites, and residual stresses due to thermal expansion mismatch of the different phases increased flexural strength and fracture toughness of the composites. 相似文献
3.
4.
壳聚糖/羧甲基壳聚糖止血膜的制备与表征 总被引:1,自引:0,他引:1
针对壳聚糖止血膜柔韧性差的问题,以丙三醇和酚磺乙胺作为改性剂,采用溶液浇膜的方法制备了不同组成配比的壳聚糖(CS)/羧甲基壳聚糖(CMCS)止血膜,并评价了CS/CMCS止血膜拉伸性能和止血效果.丙三醇的引入可使CS/CMCS止血膜的断裂伸长率提高4~7倍,尽管其拉伸强度也降低了70%.丙三醇改性的CS/CMCS=8/2载药止血膜具有较好的拉伸强度(10.4±0.9 MPa)和断裂伸长率(50.4±4.5%);与未加入酚磺乙胺的CS/CMCS止血膜相比,酚磺乙胺的离子交联作用使CS/CMCS载药止血膜的拉伸强度提高55%,而断裂伸长率仅降低24%.止血评价结果表明经丙三醇改性的CS/CMCS=8/2止血膜均能使血液发生分离的时间明显缩短,并具有促使血液凝结形成黑色血块的能力. 相似文献
5.
《Journal of the European Ceramic Society》2021,41(15):7783-7791
Two 3Gd-TZP materials were manufactured from powders produced by intense mixing and milling of unstabilized zirconia starting powders and gadolinia as stabilizer oxide by hot pressing at 1250 °C – 1400 °C. The materials show a combination of high toughness and moderate strength. In detail depending on starting powder the two TZP showed distinct differences concerning transformation characteristics, sintering temperature dependence of mechanical properties and the tendency to develop R-curve related deformation features such as non-linear stress strain curves and formation of transformation bands prior to fracture. 相似文献
6.
《材料科学技术学报》2019,35(10):2144-2155
Ni-Cu nano-coatings were prepared by pulsed electroplating technique in the baths containing various amount of boric acid. Their microstructure, morphologies and corrosion resistance were characterized in detail. The addition of boric acid strongly influences on the microstructure of the Ni-Cu coatings. The coating with a grain size of 130 nm, obtained from the bath containing 35 g L−1 boric acid, shows the highest corrosion resistance. This is attributed to the low-valence Cu ion (Cu+) additions in nickel oxide, which could significantly decrease the oxygen ion vacancy density in the passive film to form a more compact passive film. The higher Cu+ additions and the lower diffusivity of point defects (D0) are responsible for the formation of more compact passive film on the coating obtained from the bath with 35 g L−1 boric acid. 相似文献
7.
8.
Y-α-sialon ceramics with different compositions were hot-press sintered. Varying the m or n value in theα-Sialon general formula, both the α-sialon grain morphology and phase assemblages present diversification, therefore, affecting the toughness and hardness. Meanwhile, varying the compositional parameters also influenced the composition and structure of the intergranular glass phase, as well as its oxidation behavior at 1100-1200 ℃. The oxidation of the intergranular phase Mt in the Y-α-sialon ceramics was significantly enhanced with further rising the oxidation temperature to 1300 ℃. 相似文献
9.
《Ceramics International》2017,43(8):5887-5895
Reaction bonded B4C-SiC composites were prepared by infiltrating silicon melt into porous B4C-SiC green preforms at 1500 °C in vacuum. The porous green preform was obtained from a mixture of polycarbosilane (PCS) and particle size graded B4C after pre-sintering at 1600 °C. For the first time, PCS was used to adjust the phase composition and microstructure of the reaction bonded boron carbide composites. It is indicated that the addition of PCS and its content has a significant influence on the microstructure as well as the mechanical properties of the subsequent reaction bonded B4C-SiC composites. For the B4C-SiC composite with 5 wt% PCS added, a flexural strength of 319±12 MPa, and an elastic modulus of 402±18 GPa can be achieved, which is 23% and 15% higher than those of the composite without PCS addition, respectively. While, with the higher content of PCS addition, the mechanical properties of the composites are decreased drastically due to the large amount of residual Si agglomeration in the composites. The reaction mechanisms as well as their microstructure evolution processes correlated with the mechanical properties of the reaction bonded B4C-SiC composites are further discussed in our work. 相似文献
10.
《Ceramics International》2019,45(12):15048-15056
A series of europium (Eu)-activated silicon oxynitride samples with various atomic ratios x of Eu/Si from 0.001 to 0.057 was prepared by employing the polymer-derived method with polycarbosilane and Eu acetylacetonate as starting materials. Chemical compositions, phase structures, morphologies, and luminescence properties of the samples were investigated. It was found that all samples contained a dominated β-Si3N4-like phase, and had emission spectra with two peaks. The emission colors of the samples under near-UV excitation were tunable from blue to white, and then to yellow as x in the samples increased from 0.009 to 0.030, and then to 0.057. The white emitting sample with x = 0.030 was in the β-Si3N4-like single phase with its particles being single-crystallized in two space groups P63 and P63/m. Eu2+ ions located at interstitial sites of lattices and were coordinated by nine N/O atoms with different average bond lengths for the two space groups. A discussion was given to attribute the difference in the lattice environments for Eu2+ ions in two space groups P63 and P63/m to the appearance of two emission peaks at the lower (597 nm) and higher (454 nm) energy levels for the sample with x = 0.030. 相似文献