全文获取类型
收费全文 | 1660篇 |
免费 | 32篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 96篇 |
化学工业 | 438篇 |
金属工艺 | 51篇 |
机械仪表 | 42篇 |
建筑科学 | 29篇 |
能源动力 | 61篇 |
轻工业 | 154篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 145篇 |
一般工业技术 | 253篇 |
冶金工业 | 203篇 |
原子能技术 | 88篇 |
自动化技术 | 134篇 |
出版年
2023年 | 9篇 |
2022年 | 12篇 |
2021年 | 22篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 21篇 |
2017年 | 18篇 |
2016年 | 30篇 |
2015年 | 18篇 |
2014年 | 29篇 |
2013年 | 83篇 |
2012年 | 49篇 |
2011年 | 89篇 |
2010年 | 65篇 |
2009年 | 57篇 |
2008年 | 69篇 |
2007年 | 68篇 |
2006年 | 50篇 |
2005年 | 72篇 |
2004年 | 47篇 |
2003年 | 53篇 |
2002年 | 63篇 |
2001年 | 36篇 |
2000年 | 29篇 |
1999年 | 40篇 |
1998年 | 99篇 |
1997年 | 88篇 |
1996年 | 50篇 |
1995年 | 45篇 |
1994年 | 43篇 |
1993年 | 39篇 |
1992年 | 24篇 |
1991年 | 24篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 20篇 |
1987年 | 14篇 |
1986年 | 15篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1983年 | 13篇 |
1982年 | 16篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 11篇 |
1978年 | 6篇 |
1977年 | 12篇 |
1976年 | 9篇 |
1972年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有1699条查询结果,搜索用时 0 毫秒
91.
Yuko Hamabe Ryoko Matsuura Akinori Jyo Masao Tamada Akio Katakai 《Reactive and Functional Polymers》2009,69(1):1-8
Bifunctional fibers containing phosphonate and sulfonate were derived from chloromethylstyrene grafted polyolefin fibers (PPPE-g-CMS) by phosphorylation and subsequent sulfonation reactions. It was clarified that phosphorylation of PPPE-g-CMS by Arbusov reaction is more suitable than one by the reaction with PCl3 in the presence of AlCl3, because the latter damaged fibers and gave phosphinate groups in addition to phosphonate ones. Then, bifunctional fibers containing phosphonate and sulfonate groups were prepared by sulfonation of monofunctional phosphonate fibers obtained via Arbusov reaction with chlorosulfonic acid. The metal ion selectivity of the bifunctional fibers was governed by both phosphonate and sulfonate groups. In addition, bifunctional fibers gave much more excellent kinetic performances in column-mode uptake of Cu(II) than the monofunctional phosphonate fibers and resin. 相似文献
92.
Masayuki Mizumoto Takeshi Ohgai Akio Kagawa 《Journal of Materials Processing Technology》2009,209(9):4264-4267
The SiCP/Al–4 mass%Cu alloy composites fabricated by a low-pressure infiltration process (LPI process) were remelted and separated by nozzle filtering method. In the separation process, the PRMMC specimen was placed in a container with a small nozzle at the bottom. The molten PRMMC was forced to flow out through the nozzle by applying a certain pressure of Ar gas. Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container consisted of SiC particles and a part of the matrix alloy. The particle volume fraction of the remainder was higher than that of the original PRMMC and the remainder would work as a filter to separate SiC particles from the matrix alloy melt. When nozzle tip angle was ranged from 60° to 120°, about 80% of matrix alloy in the PRMMC was separated and few SiC particles were observed in the separated matrix alloy. The surface of recovered SiC particles became slightly roughened due to the reaction with the molten matrix during the separation process. However, this is not expected to affect their reuse. 相似文献
93.
Hajime Haneda Isao Sakaguchi Akio Watanabe Takamasa Ishigaki Junzo Tanaka 《Journal of Electroceramics》1999,4(1):41-48
18O diffusion coefficients were measured in zinc oxide ceramics using a secondary ion mass spectrometer. The results are interpreted as indicating extrinsic behavior. The values of the lattice diffusion coefficients with higher valence dopants compared with zinc ions are greater than lower valence dopant such as lithium ions. Using the data at deeper depth, the grain boundary diffusivity of oxide ions was also evaluated. Although the lattice diffusion coefficients varied by two orders of magnitude, the products of grain boundary width and grain boundary diffusion coefficient were less sensitive to the type of dopants. 相似文献
94.
Effect of carbonization temperature on the basic properties of woodceramics impregnated with liquefied wood 总被引:10,自引:0,他引:10
In this paper, a new woodceramics impregnated with liquefied wood is developed and the effect of carbonization temperature on the dimension shrinkage, weight loss, density, compressive strength, and volume electrical resistivity is investigated. The results show that, the higher the carbonization temperature is, the higher the dimension shrinkage is, the higher the compressive strength is, and the lower the electrical resistivity is. 相似文献
95.
Morphology and damping characteristics of woodceramics 总被引:10,自引:0,他引:10
Zhang Di Xie Xian-Qing Fan Tong-Xiang T. Okabe T. Hirose 《Journal of Materials Science》2002,37(20):4457-4463
Woodceramics has attracted more and more attention as ecomaterial at low cost in recent years. The purpose of this paper is to investigate morphology, damping characteristics of woodceramics and relationship between them. The experimental results reveal that pores in woodceramics can be divided into macropores, micropores and nanopores according to their dimensional size. Macropores are the majority of interconnected pores while most micropores are closed pores. Based on formation process, nanopores are supposed to consist of isolated nanopores and dendritic nanopores. Woodceramics exhibits significant damping gains, especially at room temperature, higher strain amplitude and higher vibration frequency. The values of damping capacity increase with vibration frequency and strain amplitude, decrease with testing temperature. Macropores and some nanopores have little but micropores and some other nanopores have much contribution to damping properties of woodceramics. The possible damping mechanisms of woodceramics at normal temperature are defect damping and thermoelastic damping; at high temperatures, interface damping is likely to responsible for the majority of the damping of woodceramics. 相似文献
96.
Summary The binding of fibrinogen with heparin and dextran sulfates, and of antithrombin III with heparin and dextran sulfate were investigated by sedimentation velocity method. From the measurement of fibrinogen-acidic polysaccharide systems, it was confirmed that heparin and low molecular weight dextran sulfate(DSC) forms soluble complexes with fibrinogen, though the amount bound of the latter was rather small compared with high molecular weight dextran sulfate(DSD). Antithrombin III was also found to be bound by heparin and DSC. The numbers of heparin molecules bound to one molecule of fibrinogen and antithrombin III were estimated to be 4.2 and 0.3, respectively. 相似文献
97.
Two-fluid equilibria encompass more physics than the Grad–Shafranov (GS) equation for static equilibria, or even the flowing
MHD model. However the two-fluid system is more complicated, and, worse yet, is a singular perturbation problem. The latter
difficulty is overcome using the “nearby-fluids” ordering. A “1.5D” solution method has been used to interpret results from
the TCS experiment. These results, summarized here, exhibit trends indicative of the improved stability and transport observed
experimentally. An algorithm for solving 2D equilibria has been developed based on a relaxation method. The magnetic flux
function, governed by the extended GS equation, is updated by successive-overrelaxation, while the toroidal field and flow
components and the density are updated using a Newton–Raphson-like method. 相似文献
98.
Takeshi Kikuchi Makio Mogi Iichiro Okabe Kosuke Okada Hisashi Goto Yasuyuki Sasaki Takeki Fujimura Mitsuo Fukuda Akio Mitani 《International journal of molecular sciences》2015,16(10):24111-24126
Periodontal disease is caused by dental plaque biofilms, and the removal of these biofilms from the root surface of teeth plays a central part in its treatment. The conventional treatment for periodontal disease fails to remove periodontal infection in a subset of cases, such as those with complicated root morphology. Adjunctive antimicrobial photodynamic therapy (aPDT) has been proposed as an additional treatment for this infectious disease. Many periodontal pathogenic bacteria are susceptible to low-power lasers in the presence of dyes, such as methylene blue, toluidine blue O, malachite green, and indocyanine green. aPDT uses these light-activated photosensitizer that is incorporated selectively by bacteria and absorbs a low-power laser/light with an appropriate wavelength to induce singlet oxygen and free radicals, which are toxic to bacteria. While this technique has been evaluated by many clinical studies, some systematic reviews and meta-analyses have reported controversial results about the benefits of aPDT for periodontal treatment. In the light of these previous reports, the aim of this review is to provide comprehensive information about aPDT and help extend knowledge of advanced laser therapy. 相似文献
99.
Akira Yoshimura Khiem C. Nguyen Gregory T. Rohde Akio Saito Mekhman S. Yusubov Viktor V. Zhdankin 《Advanced Synthesis \u0026amp; Catalysis》2016,358(14):2340-2344
A mild catalytic procedure for the efficient oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo‐isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2‐iodobenzoic acid as precatalyst and m‐chloroperoxybenzoic acid (m‐CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI‐mass spectrometry and 1H NMR spectroscopy.
100.
采用无偏振片反射式LCD及超低功耗驱动技术制造移动显示器件 总被引:1,自引:1,他引:0
Kiyoshi Minoura Yasushi Asaoka Eiji Satoh Takashi Satoh Ichiro Ihara Sayuri Fujiwara Akio Miyata Yasuhisa Itoh Seijiro Gyoten Noboru Matsuda Yasushi Kubota 代永平 《现代显示》2010,(7):5-9,35
我们通过对材料和制备条件的精细化处理,生产出一种在低刷新频率下无闪烁和图像迟滞现象的反射式显示器。该显示器的功耗非常低,且可在宽温度范围内工作,是未来移动显示器件的潜力平台。 相似文献