全文获取类型
收费全文 | 663篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 84篇 |
化学工业 | 164篇 |
金属工艺 | 28篇 |
机械仪表 | 18篇 |
建筑科学 | 14篇 |
能源动力 | 22篇 |
轻工业 | 37篇 |
无线电 | 65篇 |
一般工业技术 | 115篇 |
冶金工业 | 94篇 |
原子能技术 | 9篇 |
自动化技术 | 20篇 |
出版年
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 10篇 |
2013年 | 20篇 |
2012年 | 16篇 |
2011年 | 26篇 |
2010年 | 11篇 |
2009年 | 14篇 |
2008年 | 16篇 |
2007年 | 18篇 |
2006年 | 27篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 17篇 |
2002年 | 19篇 |
2001年 | 19篇 |
2000年 | 20篇 |
1999年 | 23篇 |
1998年 | 48篇 |
1997年 | 33篇 |
1996年 | 20篇 |
1995年 | 16篇 |
1994年 | 24篇 |
1993年 | 15篇 |
1992年 | 19篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1973年 | 5篇 |
1970年 | 2篇 |
排序方式: 共有670条查询结果,搜索用时 0 毫秒
1.
K. Mizutani 《Journal of Materials Science》1993,28(8):2178-2182
Transparent epoxy resins modified with liquid chloroprene rubber (LCR), containing in a category of rubber-toughened resin were found. Transparency and toughness characterization of the modified epoxy resins were investigated as a function of LCR content. Epoxy resins modified with 0–10 vol % LCR showed complete phase-separation microstructure. However, these modified resins were transparent, because the refractive index of LCR was compatible with that of the epoxy resin matrix at room temperature. On the other hand, it was observed that above 10 vol % LCR, a certain amount of LCR dissolved into the epoxy matrix. In this case, the glass transition temperature decreased with increasing LCR content. It was also found that the critical stress intensity factor, K
c, of the modified epoxy resins exhibited a maximum between 10 and 15 vol % LCR. 相似文献
2.
The microporous polypropylene sheets were prepared by biaxially stretching polypropylene sheets containing CaCO3 filler (particle size, 0.08–3.0 μm), when the CaCO3 filler content was 59% by weight and the stretching ratio was 2.8 × 1.8. The microstructure of the sheets were investigated in relation to the CaCO3 particle size by a N2 gas permeation method. (1) Effective porosity increases with decreasing mean particle size of filler. (2) The tortuosity factor of the pore is in the range of 25–40 and becomes relatively smaller with decreasing mean particle size of filler. (3) The equivalent pore size becomes relatively smaller with decreasing mean particle size of filler. 相似文献
3.
The MOBILE is a logic gate exploiting the monostable-bistable transition of a circuit that consists of two resonant tunneling transistors connected in series. It has several advantages including multiple inputs and multiple functions. This paper describes the output characteristics of multiple-input MOBILE's and discusses their applications. For a two-input MOBILE, it is demonstrated that both NAND and NOR operations are possible with the appropriate control voltage. This implies the possibility of a variable function logic gate. Furthermore, the threshold logic operations for a weighted sum of input signals are demonstrated for a three-input MOBILE with a weight ratio of 4:2:1. The applications of MOBILE's in parallel processing architectures such as cellular automata and cellular neural networks are discussed based on the above results. Circuit simulations using a simple model of resonant tunneling transistors successfully reproduce the basic characteristics of MOBILE's, and demonstrate the usefulness of MOBILE's in such applications 相似文献
4.
Nobuo Ishizawa Atsushi Saiki Takeshi Yagi Nobuyasu Mizutani Masanori Kato 《Journal of the American Ceramic Society》1986,69(2):18-C-
Crystals of yttria partially stabilized zirconia were grown by the arc-image floating-zone technique and studied by transmission electron microscopy. Crystals annealed at 1700°C consist of tetragonal precipitates and a cubic matrix. The platelike domains in a precipitate are twin-related tetragonal variants stacked alternately parallel to the (011) twin plane. The axial relations between the tetragonal precipitate and the cubic matrix are [100]tetragonal |[100]cubic , [011]tetragonal |[011]cubic . 相似文献
5.
Preparation of spherical fine ZnO particles by the spray pyrolysis method using ultrasonic atomization techniques 总被引:1,自引:0,他引:1
Tian-Quan Liu Osamu Sakurai Nobuyasu Mizutani Masanori Kato 《Journal of Materials Science》1986,21(10):3698-3702
An ultrasonic atomizer was used in the spray pyrolysis method to prepare fine, spherical and uniform ZnO particles. Almost spherical particles were obtained successfully which had a mean particle size of 0.15 m and had a very narrow particle size distribution. By using alcohol as the solvent, it was found that the particles do not have hollow shell layers which could usually be observed in the spray pyrolysis process by using water as the solvent. The morphology of the ZnO particles was strongly affected by the concentration of the starting solution. 相似文献
6.
Takashi Ogihara Tadashi Ikemoto Nobuyasu Mizutani Masanori Kato Yukuaki Mitarai 《Journal of Materials Science》1986,21(8):2771-2774
The Ta2O5 powders synthesized by the hydrolysis of tantalum pentaethoxide, Ta(OC2H5)5 in alcoholic solution were monodispersed fine oxide particles, which were a uniform, spherical shape, non-agglomerate, and had a narrow size distribution. They grew to 1.2m after ageing for 1 h after hydrolysis. Powder X-ray diffraction and differential thermal analysisthermogravimetric analysis showed the particles were amorphous and hydrated. These particles lost the water at 290° C and gave well-crystalline Ta2O at 740° C. Throughout these thermal processes, the particle morphology was kept almost the same. 相似文献
7.
Takeshi Yagi Kazuo Shinozaki Nobuo Ishizawa Nobuyasu Mizutani Masanori Kato Akihiko Tsuge 《Journal of the American Ceramic Society》1988,71(7):334-C
The thermal diffusivity of AlN ceramics was significantly decreased by the addition of SiO2 . The AlN ceramics with 4 wt% SiO2 could not be densified by pressureless sintering in the temperature range 1400° to 1800°C. The thermal diffusivity of these samples was very low because of their porous structure. The AlN ceramics containing 2, 4, and 8 wt% SiO2 were densified by hot-pressing and also had low thermal diffusivity. In these samples, the grains of the 27R polytype that resulted from the reaction between AlN and SiO2 were dispersed, obstructing the conduction of heat. The relation between the amount of 27R polytype and the thermal diffusivity of the AlN ceramics was determined. 相似文献
8.
9.
Interaction of cation-exchange membrane with polycation I. Poly(N-methyl-4-vinylpyridinium chloride)
We elucidated the effect of the molecular weight of poly(N-methyl-4-vinylpyridinium chloride) (PMVP) on its adsorbed or ion-exchanged amount on the cation-exchange membrane and the preferntial permselectivity of the membrane for sodium ion to calcium ion. The amount of the adsorbed or ion-exchanged PMVP increases with time and then attains to a definite value at a definite concentration. Also, the ultimate value increases with increasing the concentration of PMVP. When the molecular weight of PMVP is 3090, the ratio of the pyridinium groups of PMVP ion-exchanged with the sulfonic acid groups on the membrane surface to the total pyridinium groups of the cohered PMVP is in the range of 70–80%. The relative transport number of calcium ions to sodium ions(PNaCa) decreases with increasing the amount of adsorbed or ion-exchanged PMVP and the numbe rof non-ion-exchanged pyridinium groups of PMVP and the number of non-ion-exchanged pyridinium groups of PMVP on the membrane surface. The smaller the molecular weight of PMVP, the more the adsorbed or ion-exchanged amount and the more preferable the permselectivity for sodium ion. 相似文献
10.
Photocatalytic activities for water decomposition were examined for photocatalysts using hexa- and octa-titanates and TiO2(B) with different tunnel space in the structure. Using RuO2 as promoter, M2Ti6O13 (M = Li, Na, K, Rb) showed the stoichiometric production of Hz and O2 except for Li, whereas H2Ti8O17 and TiO2(B) had very low activity producing only hydrogen as a product. The effects of promoters on Na2Ti6O13 showed that the activity increased in the order of RuO2 > RuO2 + IrO2 > IrO2 > RuO2 + Pt > MnO2. These effects along with other related ones are discussed: it emerges that the presence of the tunnels is important for the achievement of high photocatalytic activity. 相似文献