全文获取类型
收费全文 | 326篇 |
免费 | 8篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 84篇 |
金属工艺 | 25篇 |
机械仪表 | 7篇 |
建筑科学 | 5篇 |
能源动力 | 4篇 |
轻工业 | 19篇 |
石油天然气 | 2篇 |
无线电 | 26篇 |
一般工业技术 | 107篇 |
冶金工业 | 39篇 |
原子能技术 | 4篇 |
自动化技术 | 8篇 |
出版年
2023年 | 2篇 |
2021年 | 7篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 5篇 |
2009年 | 10篇 |
2008年 | 12篇 |
2007年 | 20篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 9篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 22篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 9篇 |
1986年 | 15篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有338条查询结果,搜索用时 31 毫秒
21.
Naka R. Watanabe K. Kawarabayashi J. Uritani A. Iguchi T. Hayashi N. Kojima N. Yoshida T. Kaneko J. Takeuchi H. Kakuta T. 《IEEE transactions on nuclear science》2001,48(6):2348-2351
The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The monitor is sensitive to beta rays or charged particles, gamma rays, and fast neutrons. The spatial resolutions for beta-rays ( 90Sr-90Y), gamma-rays (137Cs), and D-T neutrons are 30, 37, and 13 cm, respectively. The detection efficiencies for the beta-rays, gamma-rays, and D-T neutrons are 0.11%, 1.6×10 -5% and 1.2×10-4%, respectively. The effective attenuation length of the detection efficiency is 18 m. In this paper, we describe the basic characteristics of this monitor 相似文献
22.
Michiaki Matsumoto Atsushi Kado Takayoshi Shiraki Kazuo Kondo Kazuharu Yoshizuka 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(11):1712-1716
BACKGROUND: Diols that can be produced biologically have attracted much attention because of the increased cost of producing them chemically. The cost of separating the diols from the broth forms a major part of the total cost of microbial production. Reactive extraction using organoboronate is one promising method for recovering diols from the dilute aqueous solution. RESULTS: A basic investigation of solvent extraction of diols was conducted at 303 K employing phenylboronic acid and trioctylmethylammonium chloride as coextractants in the mixed solvent. Both the tetrahedral boronate anion complex and trigonal boronate neutral complex were extracted. 1,3‐diols and vicinal diols were extracted, but 1,4‐diol was not extracted. Extraction equilibrium constants were correlated with the enthalpies of formation of the complexes, which were calculated by molecular modeling with semi‐empirical molecular orbital calculations considering the solvent effect. CONCLUSION: The complex extraction behaviour of diols with phenylboronic acid and quaternary ammonium salt can be predicted by using the quantitative structure–property relationship (QSPR). Copyright © 2009 Society of Chemical Industry 相似文献
23.
Synthesis and properties of carbons dispersed with α-iron particles from divinylbenzene-vinylferrocene 总被引:1,自引:0,他引:1
α-Iron-dispersed carbon was synthesized, through pressure pyrolysis of divinylbenzene-vinylferrocene above 750°C, and by reduction
of magnetite-dispersed carbon. Divinylbenzenevinylferrocene copolymer was pyrolysed at 125 MPa above 750°C to yield carbons
dispersed with α-iron accompanied by cementite. Magnetite in the carbon matrix was reduced to α-iron after heat treatments
at 500°C in a flow of hydrogen. Carbons synthesized by the pressure pyrolysis of divinylbenzene-vinylferrocene at 800°C and
125 MPa contained iron-compound particles up to 200 nm, whereas the median diameter of α-iron particles in the carbon matrix
after reduction treatments was 20 nm. α-Iron-dispersed carbon had a Curie temperature of 770°C. The saturation magnetization
of iron-dispersed carbon increased with increasing the pyrolysis temperature of divinylbenzene-vinylferrocene copolymer, and
reached a constant value of 183 e.m.u.g−1 at 800°C. The saturation magnetization of α-iron-dispersed carbon after the reduction treatment revealed practically the
theoretical value of α-iron. Carbons finely dispersed with only α-iron particles were synthesized successfully by reduction
of magnetitedispersed carbons. 相似文献
24.
Mizuno Makoto Imai Satoshi Tsukada Minoru Hida Eiki Naka Ken-Ichi 《IEEE transactions on bio-medical engineering》1985,(1):56-60
A microcomputer system was developed to measure visual spatiotemporal receptive fields. The system performs three functions: 1) generation of a binary spatiotemporal white-noise stimulus, 2) acquisition of spike discharges from retinal ganglion cells, and 3) extraction of the linear part of the spatiotemporal receptive flelds by cross correlating the input against the output. We have applied this system to the measurement of the spatiotemporal receptive fields of cat and catfish retinal ganglion cells. 相似文献
25.
26.
Yokoyama Kiyoko Ishii Naohiro Naka Ken-Ichi 《IEEE transactions on bio-medical engineering》1986,(3):308-314
A software system was produced to digitize neuronal images and to extract a set of simple parameters from the digitized images. The system was designed to classify a large number of neurons based on simple and automatically extracted features. The system was used to characterize catfish retinal ganglion cells. Several examples of parameter extraction and classification are presented. 相似文献
27.
Wettability of some metals against zirconia ceramics 总被引:2,自引:0,他引:2
28.
29.
Summary Poly(dithiafulvene)s having alkoxy group and mesogenic moiety in the side chain were prepared by cycloaddition polymerization.
The effects of the side chains on the structural and optical properties of poly(dithiafulvene)s in solution were investigated.
Furthermore, the film state properties of the polymers and their charge transfer complex with electron acceptor were studied
before and after annealing. 相似文献
30.
This paper is providing a design and evaluation methodology for biomass utilization networks (B-NETs) planning in local areas. The methodology is an effort to integrate various exertions of many researchers as well as stakeholders in the biomass field including process technologies, local area classification and renewable energy mechanisms to design and evaluate B-NETs. The proposed design methodology has three steps: classification, problem formulation and suggesting solution methods. The core part of planning the B-NETs utilization methodology is the superstructure that is a super class model for the processes of biomass utilization networks that has to be built for the local area. The biomass utilization superstructure (BUSS) relates the biomass resources to their products, available processes, and possible future processes of utilization in static manner. Although the local area BUSS is static in nature, it shows the decision makers what kinds of B-NETs are, or can be, available in their area. It is important to note that for each super class process there exists a number of elemental technologies, or what we call unit process (UP), that can perform the job under the same condition with different processing constraint. To support the design and operation process a technological information infrastructure (TII) needs to be built to work as an information pool and simulation tool. With the support of TII and the BUSS different scenarios can be synthesized, analyzed and compared. Scenarios development enables the designer to check processing alternatives as well as biomass promotion mechanisms that fit the concerns of various stakeholders. The results of the methodology application can be given in the form of suggestions of a specific network class(es) or scenarios that can be applied in a class of localities with the same characteristics. Following to methodology configuration, a proposal for optimization methods is discussed and a case study for comparing biomass network scenarios in mountainous city is introduced. 相似文献