全文获取类型
收费全文 | 625篇 |
免费 | 21篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 48篇 |
综合类 | 1篇 |
化学工业 | 172篇 |
金属工艺 | 14篇 |
机械仪表 | 9篇 |
建筑科学 | 15篇 |
能源动力 | 15篇 |
轻工业 | 36篇 |
水利工程 | 1篇 |
无线电 | 24篇 |
一般工业技术 | 100篇 |
冶金工业 | 137篇 |
原子能技术 | 10篇 |
自动化技术 | 67篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 24篇 |
2012年 | 16篇 |
2011年 | 32篇 |
2010年 | 18篇 |
2009年 | 16篇 |
2008年 | 28篇 |
2007年 | 23篇 |
2006年 | 16篇 |
2005年 | 21篇 |
2004年 | 13篇 |
2003年 | 16篇 |
2002年 | 19篇 |
2001年 | 14篇 |
2000年 | 18篇 |
1999年 | 17篇 |
1998年 | 58篇 |
1997年 | 37篇 |
1996年 | 24篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 20篇 |
1992年 | 10篇 |
1990年 | 3篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 11篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有649条查询结果,搜索用时 78 毫秒
1.
Takauchi H. Tamura H. Matsubara S. Kibune M. Doi Y. Chiba T. Anbutsu H. Yamaguchi H. Mori T. Takatsu M. Gotoh K. Sakai T. Yamamura T. 《Solid-State Circuits, IEEE Journal of》2003,38(12):2094-2100
We describe a CMOS multichannel transceiver that transmits and receives 10 Gb/s per channel over balanced copper media. The transceiver consists of two identical 10-Gb/s modules. Each module operates off a single 1.2-V supply and has a single 5-GHz phase-locked loop to supply a reference clock to two transmitter (Tx) channels and two receiver (Rx) channels. To track the input-signal phase, the Rx channel has a clock recovery unit (CRU), which uses a phase-interpolator-based timing generator and digital loop filter. The CRU can adjust the recovered clock phase with a resolution of 1.56 ps. Two sets of two-channel transceiver units were fabricated in 0.11-/spl mu/m CMOS on a single test chip. The transceiver unit size was 1.6 mm /spl times/ 2.6 mm. The Rx sensitivity was 120-mVp-p differential with a 70-ps phase margin for a common-mode voltage ranging from 0.6 to 1.0 V. The evaluated jitter tolerance curve met the OC-192 specification. 相似文献
2.
Koji Yamada Kiyotaka Tomari Umaru Semo Ishiaku Hiroyuki Hamada 《Polymer Engineering and Science》2005,45(8):1059-1066
Fracture toughness of adjacent flow weld lines, defined as weld lines that occur when two flow fronts meet and continue to flow together in the same direction (meld line or hot weld line), was evaluated by the single‐edge notched‐bend (SENB) method using three differently‐shaped obstructive pins. Although the fracture toughness varied depending upon the shapes of the pin, the values could be standardized as the distance from the meeting point of the two flow fronts flowing around the pin. The fracture toughness decreased drastically from the meeting point along the weld line and then slightly increased. These characteristic features could be explained by flow‐induced molecular orientation at the weld line interface. The molecules around the meeting point that were initially oriented parallel to the weld line due to fountain flow were able to relax, and then entanglement across the weld line interface developed because the flow stopped in the middle of the filling process, resulting in high fracture toughness. In contrast, the material at the downstream side of the weld line continued flowing during the filling process, being stretched along the flow direction. So, the molecular orientation at this area could not relax. In addition, the V‐notch shape, i.e., the depth and length at the surface of the weld line, which also varied depending on the shape of the obstacles, was considered to be identical when the meeting point was allowed to be a datum point. Thus, the meeting point was found to be a significant factor when the properties of weld lines are investigated. POLYM. ENG. SCI., 45:1059–1066, 2005. © 2005 Society of Plastics Engineers 相似文献
3.
Chemotaxis of guinea pig eosinophils induced by various stimuli in use of a modified Boyden chamber technique in vitro and the effect of a platelet-activating factor (PAF) antagonist, apafant (CAS 105219-56-5, WEB 2086 BS), on it were examined. The eosinophils were obtained by bronchoalveolar lavage from the animals treated by i.v. injection with Sephadex G-200 and purified by Percoll density gradient centrifugation. PAF significantly and potently induced the chemotaxis at a broad range of 10(-17) to 10(-7) mol/l, where no concentration-dependency was observed. Leukotriene B4 also induced the chemotaxis in a concentration-dependent manner at 10(-14) to 10(-12) mol/l and the enhanced migration was not declined until 10(-7) mol/l. Interleukin-5 (IL-5), IL-8 and regulated on activation normal T expressed and secreted (RANTES) only modestly enhanced the chemotaxis in some concentrations at 10(-13) to 10(-7) mol/l with or without significance and with no concentration-dependency while formyl-methionyl-leucyl-phenylalanine (FMLP), a known chemoattractant, increased the migration at 10(-7) to 10(-5) mol/l. Apafant at 10(-8) to 10(-6) mol/l strongly and concentration-dependently inhibited 10(-8) mol/l PAF-induced chemotaxis. However, the drug showed nominal or no influences on their chemotaxis stimulated by the other agonists, at the concentrations of which the enhanced migration was observed. From these results, it is concluded that IL-5, IL-8 and RANTES, different from PAF and LTB4, are not potent stimuli for the eosinophil chemotaxis and that apafant is a selective antagonist of PAF, which is expected to be therapeutically effective for PAF-associated diseases including bronchial asthma. 相似文献
4.
Kiyotaka Wasa 《Bulletin of Materials Science》1993,16(6):643-663
Sputter deposition is currently being widely used in the microelectronics industry for the production of silicon integrated
circuits. Recently interest has been focused on sputter deposition as a new materials processing technique. The highly energetic
sputtered atoms enhance crystal growth and/or sintering during film growth. This results in lowering of the growth temperature
of high temperature materials including cubic diamonds. Single crystals of complex ceramics materials could be prepared by
sputter deposition through epitaxial growth process. Atomically controlled deposition using multi-target sputter enables to
make man-made superlattice including high-T
C superconductors of layered perovskite. At present sputter deposition is one of key materials technologies for the coming
century. 相似文献
5.
The catalytic activity of KGa-priderite, K1.6Ga1.6Ti6.4O16, and its related compound KGa8Ga9Ti15O56 was investigated for the selective reduction of nitrogen monoxide (NO) with propylene (C3H6) in the presence of high oxygen concentrations. The KGa-priderite showed significant activity during this reaction, but the related compound showed only a little activity. These compounds are quite different from the conventional catalysts for NOx selective reduction and are characterized by the fact that their properties are free from the effects of solid acidity and support metals. This difference was attributable to the NO desorption rate at the surface of these compounds. It has become clear that the KGa-priderite catalyst remarkably adsorbed NO, and it is suggested that the amount of NO adsorbed and the amount of catalytic activity are able to be increased by the design of priderite structure. 相似文献
6.
S Maruyama T Kurosaki K Sada Y Yamanashi T Yamamoto H Yamamura 《Canadian Metallurgical Quarterly》1996,271(12):6631-6635
Human leukemic cell line K562 is induced to differentiate into the megakaryocytic lineage by stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA). We demonstrate here that TPA stimulation increases tyrosine phosphorylation of an 80-kDa protein at an early stage of megakaryocytic differentiation and that this 80-kDa protein is identical with cortactin. Since tyrosine kinase Syk was activated by TPA stimulation, we examined the possibility that cortactin is a potential substrate of Syk in K562 cells. TPA-induced tyrosine phosphorylation of cortactin was decreased profoundly by overexpression of dominant-negative Syk. Furthermore, cortactin was associated with Syk even before TPA stimulation. Since cortactin was previously referred as an 80/85-kilodalton pp60src substrate, we examined the association between Src and cortactin, whereas its association could not be detected. These data suggest that Syk phosphorylates cortactin in K562 cells upon TPA treatment. 相似文献
7.
A broadband power meter calibration system based on a newly constructed coaxial calorimeter has been developed in the frequency region 10 MHz-40 GHz. The RF power is measured as the difference of DC power supplied to the calorimeter built-in heater in the RF load, when RF is turned off and on, holding an isothermal control between the RF load and a temperature reference. To minimize the error due to the adiabatic coaxial waveguide, we devised a new method utilizing its output port as a test port. The evaluations showed a calibration uncertainty of (0.28-2.2)% expressed by one standard deviation at the 1 mW level in the full band 相似文献
8.
9.
10.
The electrochemical behavior of ferrocene (Fc) and ferricenium (Fc+) was investigated by cyclic voltammetry with convolutional and semi-differential electroanalyses in the temperature range 298-373 K in the hydrophobic room temperature ionic liquid systems consisting of bis(trifluoromethanesulfone)imide anion with quaternary ammonium cation. The experimental results indicated that the redox reaction of Fc/Fc+ was reversible in this ionic liquid and the charge-transfer rate constant (k0) has been obtained. Mass transport towards the electrode is a simple diffusion process and the diffusion coefficient (D) for Fc/Fc+ has been also calculated. These results indicated that the k0 and D increased with increasing temperature in ionic liquids. The validity of the Arrhenius law was verified by investigating the temperature dependences of k0 and D. 相似文献