全文获取类型
收费全文 | 495篇 |
免费 | 30篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 11篇 |
综合类 | 2篇 |
化学工业 | 165篇 |
金属工艺 | 22篇 |
机械仪表 | 10篇 |
建筑科学 | 13篇 |
矿业工程 | 1篇 |
能源动力 | 18篇 |
轻工业 | 46篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 64篇 |
一般工业技术 | 89篇 |
冶金工业 | 36篇 |
原子能技术 | 5篇 |
自动化技术 | 38篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 23篇 |
2020年 | 13篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 29篇 |
2014年 | 24篇 |
2013年 | 48篇 |
2012年 | 31篇 |
2011年 | 33篇 |
2010年 | 28篇 |
2009年 | 24篇 |
2008年 | 25篇 |
2007年 | 17篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 24篇 |
2003年 | 6篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有526条查询结果,搜索用时 15 毫秒
131.
Gerald Zach Milos Davidovic Horst Zimmermann 《Analog Integrated Circuits and Signal Processing》2011,68(1):59-68
This work describes time-of-flight distance measurements with a line sensor based on the correlation principle. It is capable
of suppressing maximum bright sunlight and even more electronically in each pixel autonomously without using any optical filters.
The optical fill factor of a pixel is 58% embodying a 100 × 100 μm2 photodiode. Working principle of the pixel circuit and
the mechanism for suppression of ambient illumination as well as physical limitation of accuracy are discussed. Characterizations
of the single-pixel performance with 650 nm laser and 850 nm LED sources with optical output powers of 1 mW and 900 mW, respectively,
are presented. Finally, measured characteristics of the line sensor for distances up to 3.2 m are shown. The standard deviation
is below 2 cm up to 1.2 m at a measurement time of 50 ms per distance point and the near-infrared LED illumination. 相似文献
132.
Hafiz Shahzad Maqsood Uzma Bashir Muhammad Zubair Jakub Wiener Jiri Militky 《纺织学会志》2017,108(8):1302-1307
In this work, composites were made by improved bonding of the cationized cellulosic fabric and some anionic matrix like Carboxymethyl Cellulose (CMC). Mercerized cotton fabric was cationized using cationization agent, TEXAMIN ECE with varying percentage from 1 to 10%. Those cationized cotton samples were incorporated in anionic matrices and the resultant composites were tested for mechanical properties on Universal Textile Tensile Testing machine. In the case of CMC as the matrix for the cationized reinforcement, the increasing trend in the tensile strength and elongation at break was observed. Scanning Electron Microscope images showed no extraordinary changes in the physical appearance of the cationized samples. Thermograms derived from Differential Scanning Calorimetry were informative for the evaluation of the thermal behavior of composites. 相似文献
133.
Tim Menzies Zach Milton Burak Turhan Bojan Cukic Yue Jiang Ayşe Bener 《Automated Software Engineering》2010,17(4):375-407
Building quality software is expensive and software quality assurance (QA) budgets are limited. Data miners can learn defect
predictors from static code features which can be used to control QA resources; e.g. to focus on the parts of the code predicted
to be more defective. 相似文献
134.
Ivana Kopova Lucie Bacakova Vasily Lavrentiev Jiri Vacik 《International journal of molecular sciences》2013,14(5):9182-9204
Fullerenes are nanoparticles composed of carbon atoms arranged in a spherical hollow cage-like structure. Numerous studies have evaluated the therapeutic potential of fullerene derivates against oxidative stress-associated conditions, including the prevention or treatment of arthritis. On the other hand, fullerenes are not only able to quench, but also to generate harmful reactive oxygen species. The reactivity of fullerenes may change in time due to the oxidation and polymerization of fullerenes in an air atmosphere. In this study, we therefore tested the dependence between the age of fullerene films (from one week to one year) and the proliferation, viability and metabolic activity of human osteosarcoma cells (lines MG-63 and U-2 OS). We also monitored potential membrane and DNA damage and morphological changes of the cells. After seven days of cultivation, we did not observe any cytotoxic morphological changes, such as enlarged cells or cytosolic vacuole formation. Furthermore, there was no increased level of DNA damage. The increasing age of the fullerene films did not cause enhancement of cytotoxicity. On the contrary, it resulted in an improvement in the properties of these materials, which are more suitable for cell cultivation. Therefore, fullerene films could be considered as a promising material with potential use as a bioactive coating of cell carriers for bone tissue engineering. 相似文献
135.
Michal Pechoucek Ales Riha Jiri Vokrinek Vladimir Marik Vojtech Prazma 《国际生产研究杂志》2013,51(15):3681-3692
This paper presents work carried out within the 'ExPlanTech' project (IST-1999-20171) funded in part by the European Commission's Information Technologies Programme. The mission of the ExPlanTech technology transfer project is to introduce, customize and exploit the multi-agent production planning technology (ProPlanT multi-agent system research prototype) in two specific industrial enterprises. An agent-driven service negotiations and decision process, based on usagecentred knowledge about task requirements, substitutes the traditional production planning activity. We introduce a methodology for integration of the projectdriven production planning based on agent-based engineering within the existing enterprise resource planning system. This novel production planning technology will facilitate optimization of resource utilization and supplier chain while meeting the customer demands. This paper describes a FIPA-compliant implementation of the ExPlanTech technology at the LIAZ Pattern Shop manufacturing company. We describe the structure of the agent community, types of agents, implementation of the planning strategy and its incorporation within the real production environment. 相似文献
136.
The paper presents results of water sorption tests of dried blood flour carried out tinder laboratory conditions and mathematical analyses of sorption isotherms obtained. Moisture equilibrium data were investigated at air temperatures in the range of 20-50°C and water activity ranging from 0 4 to 0 99. The experimental procedure used was a gravimetric dynamic method with continuous registration of sample weight changes. Sorption capacity decreases as temperature increases. Rehydration of the dried material results in hysteresis but this phenomenon was small. Four models of equilibrium moisture content/equilibrium relative air humidity (Chung—Pfost. Halsey. Henderson, and Oswin) were evaluated for their ability to fit data for the samples of dried blood. The modified Henderson equation was a good model for moisture adsorption and desorption of dried blood flour 相似文献
137.
Zach Evenson Tobias Schmitt Mathias Nicola Isabella Gallino Ralf Busch 《Acta Materialia》2012,60(12):4712-4719
The molten viscous behavior of Vitreloy 106, 106a, 105 and 101 bulk metallic glass-forming alloys was investigated at temperatures above Tliq. Couette concentric cylinder viscometry was used to determine the isothermal and continuous cooling melt viscosities. Isothermal three point beam bending measurements of the viscosity in the vicinity of Tg revealed a kinetically stronger liquid at low temperatures than at high temperatures, near Tliq. This behavior is revealed to be the result of a fragile to strong transition in the undercooled liquid, possibly due to polyamorphism. 相似文献
138.
Alexander Kromka Lubica Grausova Lucie Bacakova Jiri Vacik Bohuslav Rezek Milan Vanecek Oliver A. Williams Ken Haenen 《Diamond and Related Materials》2010,19(2-3):190-195
The impact of boron doping level of nanocrystalline diamond (NCD) films on the character of cell growth (i.e., adhesion, proliferation and differentiation) is presented. Intrinsic and boron-doped NCD films were grown on Si/SiO2 substrates by microwave plasma CVD process. The boron-doped samples were grown by adding trimethylboron (TMB) to the gas mixture of methane and hydrogen. Highly resistive (0 ppm), semiconducting (133 or 1000 ppm), and metallic-like (6700 ppm) NCD films were tested as the artificial substrates for the cultivation of osteoblast-like MG 63 cells. The conductivity and surface charge increased monotonically with the increasing boron content. All NCD substrates showed good biocompatibility and stimulated the adhesion and growth of MG 63 cells. Higher osteocalcin concentration (by more than 30%) for the cells growing on 1000 and 6700 ppm boron-doped NCD films was found which indicates an enhancement in the cell growth biochemistry. 相似文献
139.
Alumina and zirconia nanosuspensions with a mean particle size of 100 nm and 15 nm, respectively, were consolidated by centrifugal compaction in non-porous moulds. The nanosuspensions consolidated by high-speed centrifugation were deposited irregularly, resulting in a powder deposit with density profile. The homogeneity of the powder deposits was described and homogeneous and well packed deposit regions were identified. Plate-like bodies were prepared from the homogeneous regions of the deposit. The advantage of regular and dense nanoparticle packing by centrifugal compaction was demonstrated by fabricating transparent alumina and tetragonal zirconia ceramics. The transparent alumina had an in-line transmission of 55% in the visible light at a thickness of 0.8 mm. The transparent tetragonal zirconia reached a dense microstructure with an average grain size of 65 nm and an in-line transmission of 25% at a thickness of 0.5 mm. 相似文献
140.
The influence of reaction conditions (temperature, catalyst type, catalyst concentration – represented as molar ratio catalyst/acetone nc/na) on the composition of the product formed from the reaction of acetone and hydrogen peroxide (30%) under acid catalysis was studied. 3,3,6,6,9,9‐Hexamethyl‐1,2,4,5,7,8‐hexoxonane (TATP) was found to be the major product when the content of the catalyst in the reaction mixture is low (nc/na ≤ 0.5). A single side product (peak 10.2) in an amount ranging from 1.5 to 8% of the total peak area was present in all the prepared samples. Three other side products were found when catalyzing by hydrochloric and nitric acids. Temperature and catalyst type did not have a significant influence on the composition of the product at low catalyst concentration. Increasing the catalyst concentration led to the formation of 3,3,6,6‐tetramethyl‐1,2,4,5‐tetroxane (DADP) either as a co‐product of TATP or as an exclusive product depending on the concentration of the catalyst. 相似文献