全文获取类型
收费全文 | 836篇 |
免费 | 30篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 62篇 |
化学工业 | 239篇 |
金属工艺 | 18篇 |
机械仪表 | 20篇 |
建筑科学 | 23篇 |
能源动力 | 68篇 |
轻工业 | 77篇 |
无线电 | 56篇 |
一般工业技术 | 136篇 |
冶金工业 | 21篇 |
原子能技术 | 48篇 |
自动化技术 | 99篇 |
出版年
2024年 | 3篇 |
2023年 | 12篇 |
2022年 | 22篇 |
2021年 | 29篇 |
2020年 | 19篇 |
2019年 | 15篇 |
2018年 | 21篇 |
2017年 | 19篇 |
2016年 | 22篇 |
2015年 | 21篇 |
2014年 | 29篇 |
2013年 | 62篇 |
2012年 | 48篇 |
2011年 | 87篇 |
2010年 | 58篇 |
2009年 | 46篇 |
2008年 | 39篇 |
2007年 | 47篇 |
2006年 | 36篇 |
2005年 | 33篇 |
2004年 | 22篇 |
2003年 | 19篇 |
2002年 | 25篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 5篇 |
1995年 | 11篇 |
1994年 | 4篇 |
1993年 | 9篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有867条查询结果,搜索用时 17 毫秒
111.
Long‐Lived Flexible Displays Employing Efficient and Stable Inverted Organic Light‐Emitting Diodes
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hirohiko Fukagawa Tsubasa Sasaki Toshimitsu Tsuzuki Yoshiki Nakajima Tatsuya Takei Genichi Motomura Munehiro Hasegawa Katsuyuki Morii Takahisa Shimizu 《Advanced materials (Deerfield Beach, Fla.)》2018,30(28)
Although organic light‐emitting diodes (OLEDs) are promising for use in applications such as in flexible displays, reports of long‐lived flexible OLED‐based devices are limited due to the poor environmental stability of OLEDs. Flexible substrates such as plastic allow ambient oxygen and moisture to permeate into devices, which degrades the alkali metals used for the electron‐injection layer in conventional OLEDs (cOLEDs). Here, the fabrication of a long‐lived flexible display is reported using efficient and stable inverted OLEDs (iOLEDs), in which electrons can be effectively injected without the use of alkali metals. The flexible display employing iOLEDs can emit light for over 1 year with simplified encapsulation, whereas a flexible display employing cOLEDs exhibits almost no luminescence after only 21 d with the same encapsulation. These results demonstrate the great potential of iOLEDs to replace cOLEDs employing alkali metals for use in a wide variety of flexible organic optoelectronic devices. 相似文献
112.
Satoshi Watanabe Shuji Ohsaki Akiko Fukuta Tatsuya Hanafusa Kento Takada Hideki Tanaka Taisuke Maki Kazuhiro Mae Minoru T. Miyahara 《Advanced Powder Technology》2017,28(11):3104-3110
Here we quantitatively evaluated the mixing performance of a tailor-made microreactor with central-collision type through the iodide/iodate chemical test reaction, and applied the microreactor to the synthesis of zeolitic imidazolate framework-8 (ZIF-8), which is a subclass of porous coordination polymers (PCPs) or metal organic frameworks (MOFs). The chemical test reaction demonstrated excellent mixing performance of the microreactor with a characteristic mixing time shorter than 1 ms, which is approximately 100 times faster than those of a batch reactor and a millimeter-sized Y-shaped mixer. Taking advantage of the rapid and uniform mixing, the microreactor successfully produced ZIF-8 particles with high reproducibility by simply mixing aqueous solutions of zinc nitrate and 2-methylimidazole. The synthesis at room temperature resulted in ZIF-8 particles with chamfered cube shape, while a lower temperature of 5 °C produced raspberry-type spherical particles. We confirmed that prepared ZIF-8 particles have BET surface area of ~1500 m2/g and exhibit the gate adsorption behavior caused by the structural transition of the ZIF-8 framework. 相似文献
113.
AI & SOCIETY - To investigate whether people with social anxiety have less actual and “anticipatory” anxiety when interacting with a robot compared to interacting with a person, we... 相似文献
114.
Young Joon Lee Takashi Miyahara Tatsuya Noike 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(6):694-698
The influence of initial pH of the culture medium on hydrogen production was studied using sucrose solution and a mixed microbial flora from a soybean‐meal silo. Hydrogen production was not observed at pH values of 3.0, 11.0 and 12.0 but low production was observed at pH values 5.0 and 5.5. The pH of the experimental mixture decreased rapidly and produced hydrogen gas within 30 h. Methane was not detected at initial pH values between 6.0 and 10.0. The sucrose degradation efficiency increased as the initial pH value increased from 3.0 to 9.0. The maximum sucrose degradation efficiency of 95% was observed at pH 9.0. The maximum specific production yields of hydrogen, VFAs and alcohols were 126.9 cm3 g?1 sucrose (pH of 9.0), 0.7 gCOD g?1 sucrose (pH of 8.0) and 128.7 mgCOD g?1 sucrose (pH of 9.0), respectively. The relationship between the hydrogen ion concentration and the specific hydrogen production rate has been mathematically described. The best kinetic parameters on the specific hydrogen production rate were KOH = 1.0 × 10?7 mol dm?3 and KH = 1.1 × 10?4 mol dm?3 (r2 = 0.86). The maximum specific hydrogen production rate was 37.0 cm3 g?1 VSS h?1. © 2002 Society of Chemical Industry 相似文献
115.
Tatsushi Saito Tatsuya Yokoi Atsutomo Nakamura Katsuyuki Matsunaga 《Journal of the American Ceramic Society》2020,103(9):5354-5364
First-principles calculations were performed to examine defect formation energies and site preference of substitutional divalent cations M2+ (M = Mg, Cu, Zn, Cd, Sr, Pb, and Ba) in hydroxyapatite (HAp, Ca10(PO4)6(OH)2) and carbonated apatite (CAp). All inequivalent substitutional sites of and M2+ were investigated to determine their most preferential sites. For all M2+ studied, their defect formation energies for the most stable substitutional sites were lower in CAp than in hydroxyapatite (HAp), demonstrating that M2+ are preferentially substituted into CAp over HAp. For Ca sites in CAp, correlations between the defect formation energies and Ca-O bond lengths showed that bigger and smaller M2+ than Ca2+ are preferentially substituted for Ca sites with longer and shorter bond lengths than those in HAp, respectively. In addition, Ca sites with lower coordination numbers than 6 are preferentially substituted by Zn2+ and Cu2+ that originally tend to form 4- or 5-fold coordination in their phosphate crystals. substitution is therefore likely to effectively stabilize substitutional foreign ions by modifying bond lengths and coordination numbers of Ca sites from those in pure HAp. These effects may play an important role in enhancing the M2+ solubility into CAp. 相似文献
116.
Satoshi Hasegawa Tetsunari Ebina Haruaki Tokuda Tatsuya Ito Nobumichi Nagano 《Journal of Nuclear Science and Technology》2016,53(9):1332-1341
The oxidation behavior of chromium and the corrosion behavior of austenitic stainless steel in boiling nitric acid solution containing highly concentrated nitrates were investigated using UV-visible spectroscopic measurements, Raman spectral measurements, immersion tests, and potentiodynamic polarization measurements. The oxidation rate measurement of chromium from Cr(III) to Cr(VI) was performed by 1 M boiling nitric acid solution containing each highly concentrated nitrates: Al(NO3)3, Nd(NO3)3, Ca(NO3)2, Mg(NO3)2, and NaNO3 as a simulant of uranium nitrate in uranium concentrator in reprocessing plants. As a result, the rate of chromium oxidation was different depending on the added nitrates even at the same nitric acid concentration. In addition, the oxidation rate of chromium was increased with increasing the calculated partial pressure of nitric acid in consideration of the hydration of cation of nitrates. Furthermore, the corrosion rate of type 310 stainless steel was accelerated by the solution having a high chromium oxidation rate containing nitrates. These results indicated that the acceleration of the corrosion rate in the solutions depending on the oxidation rate of chromium, and the rate is affected by the salt-effect of nitrates. 相似文献
117.
A chirped grating segmented into partitions each having a constant blaze angle to use in a demultiplexer for coarse wavelength division multiplexing with multimode optical fibers is developed. Its designed configuration utilizes a resonance region to achieve high diffraction efficiency and large dispersion. The width, blaze angle, and diffraction order of each partition were optimized by vector diffraction analysis. The diffraction loss of the manufactured grating was less than 1.5 dB, and polarization-dependent loss was less than 0.6 dB within a wavelength width of at least 70 nm. It is confirmed that a demultiplexer with the developed chirped grating had a wide passband and low cross talk. 相似文献
118.
Small peptides with less than 1000 in molecular weight are not considered amenable to sandwich immunoassays due to their difficulty of simultaneous recognition by two antibodies. As an alternative, we attempted noncompetitive detection of small peptides by open sandwich enzyme-linked immunosorbent assay (OS-ELISA) utilizing the antigen-induced enhancement of antibody VH/VL interaction. Taking fragments of human osteocalcin (BGP), a major non-collagen peptide produced in bone, as model peptides, OS immunoassay was performed using the cloned VH and VL cDNAs from two anti-BGP monoclonal antibodies either recognizing the N- or C-terminal fragment, respectively. When the clones were used for OS-ELISA with immobilized VL fragment and phage-displayed VH fragment, enhanced VH/VL interaction upon BGP addition was observed. Especially the clone for the C-terminal fragment showed a superior detection limit as well as a wider working range than those of competitive assay. The result was reproduced with purified VH-alkaline phosphatase and MBP-VL fusion proteins, where the latter was directly immobilized onto the microplate wells. The minimum detectable fragment was the hexamer including the C-terminus. This simple approach with a single monoclonal antibody with a short measurement time may prove a useful tool in immunodiagnostics as well as in proteomics research. 相似文献
119.
An original methodology to account for aerosol and cirrus cloud contributions to reflected sunlight is described. This method can be applied to the problem of retrieving greenhouse gases from satellite-observed data and is based on the equivalence theorem with further parameterization of the photon path-length probability density function (PPDF). Monte Carlo simulation was used to validate this parameterization for a vertically nonhomogeneous atmosphere including an aerosol layer and cirrus clouds. Initial approximation suggests that the PPDF depends on four parameters that can be interpreted as the effective cloud height, cloud relative reflectance, and two additional factors to account for photon path-length distribution under the cloud. We demonstrate that these parameters can be efficiently retrieved from the nadir radiance measured in the oxygen A-band and from the H(2)O-saturated area of the CO(2) 2.0 microm spectral band. 相似文献
120.
The effect of the probe arrangement on the reproducibility of topographic images of the concentration changes in oxygenated hemoglobin and deoxygenated hemoglobin is evaluated by a virtual head phantom. A virtual head phantom consists of five types of tissue the 3D structure of which is based on a magnetic resonance imaging scan of an adult head. Localized and broadened brain activation is assumed in a virtual head phantom. The topographic images are obtained from the reflectance detected by the standard probe arrangement and the double-density probe arrangement. The uneven thickness of the superficial layer, which cannot be evaluated by the previous slab model, affects the distribution of measured activation in the topographic image, and this reduces the position reproducibility of near-infrared (NIR) topography with the standard probe arrangement. The overlapping measurements by the double-density probe arrangement can improve the reproducibility of the image obtained by NIR topography. 相似文献