全文获取类型
收费全文 | 417篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 41篇 |
综合类 | 3篇 |
化学工业 | 99篇 |
金属工艺 | 14篇 |
机械仪表 | 6篇 |
建筑科学 | 7篇 |
矿业工程 | 1篇 |
能源动力 | 15篇 |
轻工业 | 24篇 |
水利工程 | 3篇 |
无线电 | 32篇 |
一般工业技术 | 76篇 |
冶金工业 | 54篇 |
原子能技术 | 9篇 |
自动化技术 | 49篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 16篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 12篇 |
2017年 | 5篇 |
2016年 | 12篇 |
2015年 | 4篇 |
2014年 | 14篇 |
2013年 | 24篇 |
2012年 | 29篇 |
2011年 | 19篇 |
2010年 | 21篇 |
2009年 | 14篇 |
2008年 | 24篇 |
2007年 | 11篇 |
2006年 | 18篇 |
2005年 | 20篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 17篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 21篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有433条查询结果,搜索用时 31 毫秒
1.
A three‐dimensional flow simulation for epoxy casting has been developed. A control‐volume‐based finite‐element method is employed, containing a conservative upwind formulation for the advection terms and equal order interpolations for all variables. This simulation predicts the non‐isothermal and reactive flow behavior under the gravity. The viscosity and reaction‐rate parameters were estimated by using a dynamic rheometer and a differential scanning calorimeter. The predicted flow front advancement and temperature profiles in the calculation domain similar to the mold cavity were in close agreement with the corresponding experimental results. The variation of epoxy surface configuration with flow rate also showed the same tendency between the prediction and the experiment. This simulation seems to be applicable not only to the epoxy casting, but also to other molding processes of various thermoset resins. POLYM. ENG. SCI. 45:364–374, 2005. © 2005 Society of Plastics Engineers. 相似文献
2.
Takayuki Honma Yuichiro Kuroki Tomoichiro Okamoto Masasuke Takata Yukihiro Kanechika Masanobu Azuma Hitofumi Taniguchi 《Ceramics International》2008,34(4):943-946
Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca3Al2O6 (C3A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C3A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C3A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density. 相似文献
3.
Masahide Hojo Yasunori Mitani Toshifumi Ise Kiichiro Tsuji 《Electrical Engineering in Japan》2002,138(3):43-51
The advancement of power electronics technologies has significantly developed the power system stabilizing controllers. Quantitative as well as qualitative evaluation of their effectiveness in power systems is a matter of great importance for the feasibility investigation of these apparatus. In this paper, the possible control region of FACTS controllers with series and/or shunt configuration in a single machine to infinite bus system is formulated in the powerangle curve with a set of algebraic equations. The effectiveness of TCPST (Thyristor‐Controlled Phase Shifting Transformer), SSSC (Static Synchronous Series Compensator), and TCSC (Thyristor‐Controlled Series Compensator) for the improvement of the transient stability is evaluated quantitatively as a numerical example. The correctness of the proposed method has been confirmed by analysis based on the electromagnetic transients simulation with a detailed system model. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 43–51, 2002 相似文献
4.
The authors describe a planar process for the AlGaAs/GaAs HBTs in which collector vias are buried selectively, even to the base layers, with chemical vapor deposited tungsten (CVD-W) films. By using WF6 /SiH4 chemistry, W could be deposited on Pt films, which were overlapped 50 nm thick on the AuGe-based collector electrodes, without depositing W on the surrounding SiO2 layers. Current gains of planar HBTs with 3.5-μm×3.5-μm emitters were up to 150, for a collector current density of about 2.5×104 A/cm2 相似文献
5.
6.
Y Mitani 《Canadian Metallurgical Quarterly》1998,101(8):1000-1011
Most otitis media with effusion (OME) in children heals spontaneously, but it is sometimes persistent and intractable. The major factors determining these different courses of OME are unknown. Identifying such factors would be clinically helpful. Factors affecting on the outcome of OME were studied experimentally and clinically. In animal experiment OME was induced in rabbit by occluding the Eustachian tube. Clinical study was conducted by investigating a histology of the middle ear mucosa, sampled from 64 children with OME (87 ears) who underwent middle ear tube ventilation. Furthermore, these cases studied how the degree of mastoid pneumatization before and after treatment, changes in the volume of the middle ear air cavity and the course after removal of the middle ear ventilation tube affected lesions in the middle ear mucosa. In animals, histology of the middle ear mucosa showed that in the early stages, the subepithelial layer of the middle ear mucosa was characterized by edematous hypertrophy and enlarged blood vessels. In later stages, it became fibrous as a result of chronic inflammation. These results suggest that lesions of the subepithelial layer are unlikely to recover. In clinical cases, histological changes in mucosal samples were rated on a two-point scale: changes in the epithelium and changes in the subepithelial layer. Re-pneumatization, a sign of healing of middle ear mucosal inflammation, was seen 12 months to 18 months after surgery. Among patients in whom the tube was left inserted for more than 18 months, only 11% had unfavorable outcomes and the recurrence rate was low. All patients who had recurrence of disease despite more than 18 months of tube insertion had prolonged inflammation in the middle ear mucosa. There results indicate that the air cavity returns to approximately normal degree of pneumatization more than 18 months after surgery, and that the extent of lesions in the middle ear mucosa, especially the subepithelial layer, is closely related to the healing of OME. 相似文献
7.
M Mitani Y Yokoyama S Ichikawa H Sawada T Matsumoto K Fujimori M Kosugi 《Canadian Metallurgical Quarterly》1994,9(6):355-361
The chemiluminescence of the Cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin++ +-3-one (MCLA) was observed at 462 nm in the presence of horseradish peroxidase (HRP) and the total spectrum of light emitted was found to depend linearly on HRP concentration. Methods for the determination of HRP concentration using the chemiluminescence was investigated. HRP could be detected in the range from 100 pmol/L to 100 nmol/L under the optimum condition, H2O2 (10 mmol/L) and MCLA (10 mumol/L) at pH 5.8. 相似文献
8.
Yuichiro?Furukawa Kazuyuki?InubushiEmail author Mochamad?Ali A.?M.?Itang Haruo?Tsuruta 《Nutrient Cycling in Agroecosystems》2005,71(1):81-91
Monthly measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes in peat soils were carried out and compared with groundwater level over a year at four sites (drained forest, upland cassava,upland and lowland paddy fields) located in Jambi province, Indonesia. Fluxes from swamp forest soils were also measured once per year as the native state of this investigated area. Land-use change from drained forest to lowland paddy field significantly decreased the CO2 (from 266 to 30 mg C m–2 h–1) and N2O fluxes (from 25.4 to 3.8 g N m–2 h–1), but increased the CH4 flux (from 0.1 to 4.2 mg C m–2 h–1) in the soils. Change from drained forest to cassava field significantly increased N2O flux (from 25.4 to 62.2 g N m–2 h–1), but had no significant influence on CO2 (from 266 to 200 mg C m–2 h–1) and CH4 fluxes (from 0.1 to 0.3 mg C m–2 h–1) in the soils. Averaged CO2 fluxes in the swamp forests (94 mg C m–2 h–1) were estimated to be one-third of that in the drained forest. Groundwater levels of drained forest and upland crop fields had been lowered by drainage ditches while swamp forest and lowland paddy field were flooded, although groundwater levels were also affected by precipitation. Groundwater levels were negatively related to CO2 flux but positively related to CH4 flux at all investigation sites. The peak of the N2O flux was observed at –20 cm of groundwater level. Lowering the groundwater level by 10 cm from the soil surface resulted in a 50 increase in CO2 emission (from 109.1 to 162.4 mg C m–2 h–1) and a 25% decrease in CH4 emission (from 0.440 to 0.325 mg C m–2 h–1) in this study. These results suggest that lowering of groundwater level by the drainage ditches in the peat lands contributes to global warming and devastation of fields. Swamp forest was probably the best land-use management in peat lands to suppress the carbon loss and greenhouse gas emission. Lowland paddy field was a better agricultural system in the peat lands in terms of C sequestration and greenhouse gas emission. Carbon loss from lowland paddy field was one-eighth of that of the other upland crop systems, although the Global Warming Potential was almost the same level as that of the other upland crop systems because of CH4 emission through rice plants. 相似文献
9.
Computational Visual Media - Iris folding is an art-form consisting of layered strips of paper, forming a spiral pattern behind an aperture, which can be used to make cards and gift tags. This... 相似文献
10.
We have studied the cooperative manipulation of floating object by several space robots. For these cooperative motions, we
have reported that a tracking control method using the transpose of the generalized Jacobian matrix (GJM) can be utilized
for robots with joint torque controllers. For cooperative motions by some robots with joint velocity controllers, we proposed
a tracking control method using the transpose of the GJM. Simulation results show the effectiveness of the proposed control
method. 相似文献