全文获取类型
收费全文 | 596篇 |
免费 | 55篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 87篇 |
金属工艺 | 7篇 |
机械仪表 | 7篇 |
建筑科学 | 21篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
轻工业 | 65篇 |
水利工程 | 10篇 |
无线电 | 56篇 |
一般工业技术 | 118篇 |
冶金工业 | 154篇 |
原子能技术 | 20篇 |
自动化技术 | 95篇 |
出版年
2024年 | 3篇 |
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 18篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 27篇 |
2017年 | 30篇 |
2016年 | 18篇 |
2015年 | 26篇 |
2014年 | 19篇 |
2013年 | 36篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 23篇 |
2009年 | 28篇 |
2008年 | 27篇 |
2007年 | 19篇 |
2006年 | 14篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 42篇 |
1997年 | 30篇 |
1996年 | 12篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1988年 | 6篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1979年 | 4篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1971年 | 3篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有652条查询结果,搜索用时 15 毫秒
51.
Dr. David J. Sumanth Associate Professor Director Juan Carlos Sol Graduate Student 《Computers & Industrial Engineering》1986,11(1-4):32-35
The Total Productivity Model (TPM), developed by Sumanth in 1979, has been applied to a number of situations involving manufacturing as well as service-oriented operations. The diversity of applications on the one hand, and the flexibility of usage of the microcomputers on the other hand, have helped to focus the need for a micro-computer based Decision Support System (DSS). This paper presents such a system using the Macintosh Computer. This DSS is a highly interactive, menu-driven program that can provide on-the screen capabilities of individual operational units as well as the firm that comprises of them. The system has several convenient features to assess the “PRODUCTIVITY- ORIENTED PROFITABILITY” of any type companies/organizations. The system logic and flow chart, data input and output formats, and sensitivity analysis will be shown and discussed in the paper. A balanced critique will be offered to view the system in a proper perspective with respect to structural elements of the Decision Support System. 相似文献
52.
53.
54.
Glenwick David S.; Brodsky Stanley L.; Franks Cyril M.; Hess Allen K.; Balch Katherine; Frank Jerome B.; Garfield Sol L.; Jason Leonard A. 《Canadian Metallurgical Quarterly》1987,42(4):405
Discusses the factors that should be considered when preparing to edit a high-quality, scholarly psychology book. The issues discussed include the book editor–publisher relationship, the book editor–chapter contributor relationship, and what makes a good final product. Three laws of editing are offered: (1) conceptualize clearly; (2) edit fiercely; and (3) edit for the reader, not the writer. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
55.
Nicolas Drogat Robert Granet Vincent Sol Pierre Krausz 《Nanoscale research letters》2010,5(3):566-569
Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV–vis absorption
spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance,
at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy
and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation. 相似文献
56.
Differentiation of Crude Lipopolysaccharides from Escherichia coli Strains Using Fourier Transform Infrared Spectroscopy and Chemometrics 总被引:1,自引:0,他引:1
Sol Kim Y. Burgula Tuula Ojanen-Reuhs Maribeth A. Cousin Bradley L. Reuhs Lisa J. Mauer 《Journal of food science》2006,71(2):M57-M61
Crude phenol‐phase extracts containing bacterial lipopolysaccharides (LPS) from 5 strains of Escherichia coli were investigated to differentiate the strains using Fourier transform infrared (FTIR) spectroscopy and multivariate statistical analysis. The strains used were E. coli K12, E. coli DH5α, E. coli O157:H7, E. coli O157:H12, and E. coli O157:H19. LPS‐containing extracts were isolated from each E. coli strain using a hot phenol‐water extraction procedure. The extracts were 1st analyzed by deoxycholic acid‐polyacrylamide gel electrophoresis and visualized by silver‐staining. Analysis of the extracts from E. coli K12 and E. coli DH5α showed rough‐type LPS on the lower half of the gel, whereas E. coli O157:H7, E. coli O157:H12, and E. coli O157:H19 yielded abundant smooth LPS (high‐molecular‐weight LPS that include the O‐polysaccharides). Spectra (4000 cm‐1 to 700 cm‐1) of crude E. coli LPS extracts and intact cells were collected using a FTIR spectrometer. Spectral data were compressed by principle component analysis and analyzed using canonical variate analysis (CVA) of 4000 cm‐1 to 700 cm‐1 or 1200 cm‐1 to 900 cm‐1 spectral regions. CVA showed better separation between strains using LPS extracts than intact cells in the 1200 cm‐1 to 900 cm‐1 spectral region. The same separation trend was found using Mahalanobis distances that quantified spectral differences between the E. coli strains, providing 80% and >95% correct classifications of intact cells and LPS extracts, respectively. This article is the first to report the successful differentiation of E. coli strains at a serotype level using FTIR spectra of bacterial phenol‐phase extracts (crude LPS preparations). 相似文献
57.
Elías Obreque‐Slier Remigio López‐Solís Álvaro Peña‐Neira 《International Journal of Food Science & Technology》2012,47(9):1918-1924
Grape seed and skin proanthocyanidins undergo significant changes during grape maturation. Those changes have been associated with a decreased astringency of grapes collected at later maturation stages. We have now compared the ability of proanthocyanidin‐rich extracts from Carménère grape seeds collected at two stages of berry development (veraison vs. harvest) both to interact with salivary proteins and to produce astringency. Interaction of proanthocyanidins with the salivary protein was assessed by analysing the concentration‐dependent effect of seed extracts both on inducing salivary protein precipitation and on restricting diffusion of the salivary protein on cellulose membranes. Seed extracts from grapes collected at veraison compared with those of grapes collected at harvest displayed a higher ability both to interact with the salivary protein fraction and to produce astringency. As a whole, our observations show that astringency is closely dependent on the magnitude of the interactions between proanthocyanidins and the salivary protein fraction. 相似文献
58.
Luis Abraham Sánchez Gaspariano Clara Iliana Martínez Gómez José Miguel Rocha Pérez Jesús Ezequiel Molinar Solís Jesús Manuel Muñoz Pacheco Carlos Muñíz Montero Alejandro Díaz Sánchez 《Circuits, Systems, and Signal Processing》2013,32(2):415-431
In this paper, the synthesis, design, and implementation of a programmable phase shifter circuit for sinusoidal signals is presented. The proposed circuit, built-up herein with operational amplifiers (OPAMPs), high precision resistors and low voltage switches, consists of a digitally controlled amplitude attenuator in combination with a single-tone orthogonalizer. Experimental results agree with theoretical background: the attained phase range was 252° in 256 steps with a median step of 0.9°. The inaccuracy of the circuit was determined to be of 0.03 %. Contrary to other OPAMP approaches for sinusoidal signals reported in the literature and based on a first-order all-pass filter structure, the approximation suggested in this work is based on a different concept. The achieved results demonstrate the functionality of the system for the case of a sinusoidal signal with frequency of 1 kHz. Notwithstanding, the proposed architecture can be extended to operate at higher frequencies by using different building blocks with larger bandwidth. Furthermore, it can be extended as well to work out with other periodic input waveforms, like triangular shapes or square waves, with the use of an appropriate orthogonalizer. 相似文献
59.
San Ling Patrick Solé 《Applicable Algebra in Engineering, Communication and Computing》2001,12(5):365-379
Duadic codes over F
2 + u
F
2 are introduced as abelian codes by their zeros. This is the function field analogue of duadic codes over Z
4 introduced recently by Langevin and Solé. They produce binary self-dual codes via a suitable Gray map. Their binary images
are themselves abelian, thus generalizing a result of van Lint for cyclic binary codes of even length. We classify them in
modest lengths and exhibit interesting non-cyclic examples.
Received: April 26, 2000; revised version: May 5, 2001 相似文献
60.
The collective excitations that minimize the Helmholtz free energy of a population-imbalanced mixture of a 6Li gas loaded in a quasi one-dimensional optical lattice are obtained. These excitations reveal a rotonic branch after solving the Bethe-Salpeter equation under a generalized random phase approximation based on a single-band Hubbard Hamiltonian. The phase diagram describing stability regions of Fulde-Ferrell-Larkin-Ovchinnikov and Sarma phases is also analyzed. 相似文献