全文获取类型
收费全文 | 304篇 |
免费 | 16篇 |
国内免费 | 26篇 |
专业分类
电工技术 | 24篇 |
综合类 | 4篇 |
化学工业 | 66篇 |
金属工艺 | 25篇 |
机械仪表 | 6篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 23篇 |
轻工业 | 54篇 |
水利工程 | 3篇 |
石油天然气 | 3篇 |
无线电 | 9篇 |
一般工业技术 | 75篇 |
冶金工业 | 8篇 |
原子能技术 | 18篇 |
自动化技术 | 17篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 13篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 10篇 |
2015年 | 3篇 |
2014年 | 10篇 |
2013年 | 25篇 |
2012年 | 12篇 |
2011年 | 27篇 |
2010年 | 15篇 |
2009年 | 22篇 |
2008年 | 27篇 |
2007年 | 14篇 |
2006年 | 7篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 14篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有346条查询结果,搜索用时 15 毫秒
91.
Chihiro Yoshimura Maichun Zhou Anthony S. Kiem Kazuhiko Fukami Hapuarachchi H.A. Prasantha Hiroshi Ishidaira Kuniyoshi Takeuchi 《The Science of the total environment》2009,407(20):5356-5366
A distributed hydrological model, YHyM, was integrated with the export coefficient concept and applied to simulate the nutrient load in the Mekong River Basin. In the validation period (1992–1999), Nash–Sutcliffe efficiency was 76.4% for discharge, 65.9% for total nitrogen, and 45.3% for total phosphorus at Khong Chiam. Using the model, scenario analysis was then performed for the 2020s taking into account major anthropogenic factors: climate change, population, land cover, fertilizer use, and industrial waste water. The results show that the load at Kompong Cham in 2020s is 6.3 × 104 tN a− 1 (+ 13.0% compared to 1990s) and 4.3 × 103 tP a− 1 (+ 24.7%). Overall, the noticeable nutrient sources are cropland in the middle region and urban load in the lower region. The installation of waste water treatment plants in urban areas possibly cut 60.6%N and 19.9%P of the estimated increase in the case without any treatment. 相似文献
92.
Daniel S. Likius Hiroki Nagai Sohei Aoyama Chihiro Mochizuki Hiroki Hara Norio Baba Mitsunobu Sato 《Journal of Materials Science》2012,47(8):3890-3899
To find the percolation threshold for the electrical resistivity of metallic Ag-nanoparticle/titania composite thin films,
Ag-NP/titania composite thin films, with different volumetric fractions of silver (0.26 ≤ φAg ≤ 0.68) to titania, were fabricated on a quartz glass substrate at 600 °C using the molecular precursor method. Respective
precursor solutions for Ag-nanoparticles and titania were prepared from Ag salt and a titanium complex. The resistivity of
the films was of the order of 10−2 to 10−5 Ω cm with film thicknesses in the range 100–260 nm. The percolation threshold was identified at a φAg value of 0.30. The lowest electrical resistivity of 10−5 Ω cm at 25 °C was recorded for the composite with the Ag fraction, φAg, of 0.55. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and transmission electron microscopic
(TEM) evaluation of the effect of the morphology and the nanostructures of the Ag nanoparticles in the composite thin films
on the electrical resistivity of the film revealed that the films consist of rutile, anatase, and metallic Ag nanoparticles
homogeneously distributed in the titania matrix. It could be deduced that the electrical resistivity of the thin films formed
at 600 °C was unaffected by the anatase/rutile content within the thin film, whereas the shape, size, and separation distance
of the Ag nanoparticles strongly influenced the electrical resistivity of the Ag-nanoparticle/titania composite thin films. 相似文献
93.
Hiroki Nagai Tatsuya Suzuki Hiroki Hara Chihiro Mochizuki Ichiro Takano Tohru Honda Mitsunobu Sato 《Materials Chemistry and Physics》2012
A transparent p-type Cu2O thin film of 50 nm thickness was successfully fabricated by means of a solution-based process involving the thermal reaction of molecular precursor films spin-coated on a Na-free glass substrate. The precursor solution was prepared by the reaction of an isolated Cu2+ complex of ethylenediamine-N, N, N′, N′-tetraacetic acid with dibutylamine in ethanol. The Cu2O thin films resulting from heat treatment of the precursor film at 450 °C for 10 min in Ar gas at a flow rate of 1.0 L min−1 were characterized by X-ray diffraction which indicated a precise cubic lattice cell parameter of a = 0.4265(2) nm, with a crystallite size of 8(2) nm. X-ray photoelectron spectroscopy peaks, attributable to the O 1s and Cu 2p3/2 level of the Cu2O film were found at 532.6 eV and 932.4 eV, respectively. An average grain size of the deposited Cu2O particles of ca. 200 nm was observed via field-emission scanning electron microscopy. The optical band edge evaluated from the absorption spectrum of the Cu2O transparent thin film was 2.3 eV, assuming a direct-transition semiconductor. Hall Effect measurements of the thin film indicated that the single-phase Cu2O thin film is a typical p-type semiconductor, with a hole concentration of 1.7 × 1016 cm−3 and hole mobility of 4.8 cm2 V−1 s−1 at ambient temperature. The activation energy from the valence band to the acceptor level determined from an Arrhenius plot was 0.34 eV. The adhesion strength of the thin film on the Na-free glass substrate was also determined as a critical load (Lc1) of 2.0 N by means of a scratch test. The method described is the first example of fabrication and characterization of a p-type Cu2O transparent thin film by a wet process. 相似文献
94.
Existing energy policy frameworks revolving around the acceleration of deployment1 of renewable energy technology can be broadly classified as the quantity vs. price approach. With this brief viewpoint, this paper suggests another perspective of viewing these instruments in terms of a more fundamental basis: whether the deployment in capacity is in terms of a cost minimization approach or a network externality approach. We suggest that the generic price or feed in tariff (FIT) approach in subsidizing renewable electricity generation and associated income would create a bandwagon or self-propagation effect among users rendering the renewable energy technology spreads like a software or information technology. Our objective is to raise awareness of this technology dynamics oriented perspective in renewable deployment supplementing the conventional installation subsidies perspective. We hope that it would inspire more empirical works and studies relating to the policy implications of this viewpoint. 相似文献
95.
The generation of white-light continuum by femtosecond laser pulses in transparent condensed media is investigated comprehensively with 262-, 393-, and 785-nm pump wavelengths. We find that the ratio of the medium's bandgap energy to the photon energy of the incident wavelength determines the amount of anti-Stokes broadening, independently of the pump wavelength and the medium's bandgap. It is also shown that, although the amount of anti-Stokes broadening is greater for the longer pump wavelength, the shorter pump wavelength is more advantageous for generating shorter-wavelength continua in the UV region. In addition, a self-induced change in polarization of the white-light continuum that is generated is observed in an isotropic material with a cubic crystal structure, such as CaF2 and LiF. After the investigation of polarization, the frequency chirp of the continuum is characterized by the Kerr-gate method with 70-fs temporal and 10-nm wavelength resolution. 相似文献
96.
In this study, a revised radial basis function (RBF) network is proposed and applied to the identification problems of a nonlinear
system and a media art system. In the revised RBF network, the structural parameters such as the means and variances of the
radial basis functions in the neurons are determined automatically, and so the revised RBF network can easily be applied to
practical complex problems such as the media art system. The media art system outputs art expressions such as sound and graphics
using the artificial sensibility surfaces that are identified using the revised RBF network. 相似文献
97.
新型抗辐照氧化物弥散强化(ODS)型铁素体不锈钢辐照损伤特性研究 总被引:1,自引:0,他引:1
研制了一种具有低肿用蒿强度的氧化物弥散强化型铁素体钢Fe-Cr-W-Ti-Y2O3,并对其抗辐照损伤行为进行了系统研究。电子辐照表明,Y2O3弥散氧化物质点在所研究的辐照下是稳定的,在辐过程中形成b=a〈100〉和b=a/2〈111〉两种类型的位错环。 相似文献
98.
Mako Naniwa Chihiro Nakatomi Suzuro Hitomi Kazunari Matsuda Takuya Tabuchi Daijiro Sugiyama Sayaka Kubo Yuichi Miyamura Kenichi Yoshino Sumio Akifusa Kentaro Ono 《International journal of molecular sciences》2021,22(22)
Despite the long history of use of steroid ointments for oral mucositis, the analgesic mechanism has not been fully elucidated. In this study, we examined the effects of triamcinolone acetonide (Tmc) on oral ulcerative mucositis-induced pain in conscious rats by our proprietary assay system. Based on evaluations of the physical properties and retention periods in the oral mucosa of human volunteers and rats, we selected TRAFUL® ointment as a long-lasting base. In oral ulcerative mucositis model rats, TRAFUL® with Tmc suppressed cyclooxygenase-dependent inflammatory responses with upregulations of glucocorticoid receptor-induced anti-inflammatory genes and inhibited spontaneous nociceptive behavior. When an ointment with a shorter residual period was used, the effects of Tmc were not elicited or were induced to a lesser extent. Importantly, TRAFUL® with Tmc also improved oral ulcerative mucositis-induced mechanical allodynia, which has been reported to be independent of cyclooxygenase. Ca2+ imaging in dissociated trigeminal ganglion neurons showed that long-term preincubation with Tmc inhibited the hypertonic stimulation-induced Ca2+ response. These results suggest that the representative steroid Tmc suppresses oral ulcerative mucositis-induced pain by general anti-inflammatory actions and inhibits mechanical sensitivity in peripheral nerves. For drug delivery, long-lasting ointments such as TRAFUL® are needed to sufficiently induce the therapeutic effects. 相似文献
99.
High-performance compact heat sinks have been developed for the effective cooling of high-density LSI packaging. Heat transfer and pressure loss characteristics of the heat sinks in both air-cross-flow and air-jet cooling have been experimentally studied. The present heat sinks were of plate-fin and pin-fin arrays with a fin pitch of 0.7 mm. The plate-fin heat sinks had higher cooling performance than the pin-fin heat sinks in the range of large airflow rates both in air-cross-flow and air-jet cooling. The thermal conductance in cross-flow cooling was 20 or 40% larger than that in jet cooling. The correlation of Colburn j-factor/Fanning friction factor versus the Reynolds number for the present heat sinks was found to be very close to that of a conventional large-size heat exchanger. © Scripta Technica, Heat Trans Asian Res, 28(8): 687-705, 1999 相似文献
100.
1%Hf(质量分数)被注入E911钢中.利用250keV的Ni离子在300℃辐照含Hf和不含Hf的E911钢,以研究Hf的添加对铁素体/马氏体钢中由辐照引起的偏析的影响.结果表明,Hf的添加抑制了晶界上P原子的富集和Cr原子的贫化.讨论和评估了Hf对自由迁移的缺陷数量的影响,结合一个辐照引起的非平衡偏析(RIS)模型以预测Hf对P3Cr等元素的晶界偏析行为的作用.对预测结果和实验数据作了比较. 相似文献