全文获取类型
收费全文 | 4782篇 |
免费 | 91篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 216篇 |
综合类 | 3篇 |
化学工业 | 770篇 |
金属工艺 | 146篇 |
机械仪表 | 106篇 |
建筑科学 | 66篇 |
矿业工程 | 1篇 |
能源动力 | 113篇 |
轻工业 | 342篇 |
水利工程 | 24篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 582篇 |
一般工业技术 | 806篇 |
冶金工业 | 1292篇 |
原子能技术 | 103篇 |
自动化技术 | 313篇 |
出版年
2022年 | 38篇 |
2021年 | 52篇 |
2020年 | 24篇 |
2019年 | 25篇 |
2018年 | 47篇 |
2017年 | 54篇 |
2016年 | 88篇 |
2015年 | 57篇 |
2014年 | 78篇 |
2013年 | 179篇 |
2012年 | 156篇 |
2011年 | 175篇 |
2010年 | 127篇 |
2009年 | 169篇 |
2008年 | 161篇 |
2007年 | 123篇 |
2006年 | 116篇 |
2005年 | 126篇 |
2004年 | 92篇 |
2003年 | 108篇 |
2002年 | 118篇 |
2001年 | 114篇 |
2000年 | 103篇 |
1999年 | 148篇 |
1998年 | 515篇 |
1997年 | 291篇 |
1996年 | 254篇 |
1995年 | 150篇 |
1994年 | 142篇 |
1993年 | 130篇 |
1992年 | 63篇 |
1991年 | 69篇 |
1990年 | 56篇 |
1989年 | 45篇 |
1988年 | 57篇 |
1987年 | 48篇 |
1986年 | 44篇 |
1985年 | 46篇 |
1984年 | 52篇 |
1983年 | 52篇 |
1982年 | 43篇 |
1981年 | 43篇 |
1980年 | 51篇 |
1979年 | 32篇 |
1978年 | 29篇 |
1977年 | 26篇 |
1976年 | 47篇 |
1975年 | 14篇 |
1974年 | 25篇 |
1973年 | 14篇 |
排序方式: 共有4885条查询结果,搜索用时 46 毫秒
101.
A. Kobayashi 《Journal of Materials Engineering and Performance》1996,5(3):373-380
The surface nitridation of titanium was carried out at a low pressure in nitrogen atmosphere using a gas tunnel type plasma
jet. The titanium nitride (TiN) film, 10 μm thick and 2000 HV, could be formed in 10 s. The structure of the TiN film was
investigated by XRD. The Vickers hardness on the surface of the film was measured. The effects of deposition conditions on
the properties of TiN films (TiN thickness,Vickers hardness, etc.) were investigated, and the advantage of this deposition
method was identified from those results. 相似文献
102.
This article shows the quantitative evaluation of the residual grit on a blasted substrate, and the removability of the residual
grit is examined. Carbon steel plates were blasted by white alumina grit with mean diameters of 338 to 1106 μm. The velocity
and the number of grit particles were measured during blasting. The residual grit was removed from a substrate surface by
the dissolution of the blasted substrate surface. A mixed acid solution was used as the dissolution solution. The residual
grit weight was 7 to 17 g/m2. The amount of the residual grit and the penetration depth of the embedded grit increased with increasing grit size. The
penetration depth was 5 to 9% of the mean diameter of the grit. The residual grit weight and the penetration depth increased
with the increase of the momentum of the grit particle.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
103.
104.
研究激光退火对Inconel718时效合金的显微组织和硬度的影响.一台2.5kW的CO2激光机被用来照射试样的表面.在激光能作用下,试样表面层被加热后空冷.通过控制激光工艺参数,在表面不发生熔化的前提下,能够使一定厚度表面层内的硬度降低到标准退火合金的水平,而不影响试样内部母材的硬度.显微组织观察显示表面层的基体强化相(γ″和γ‘)在激光照射过程中被固溶,而其它二次相没有变化.γ″和γ‘的固溶被确定是表面层硬度下降的原因.在其它试验条件不变时,确立了退火层生成时由激光散焦距离和扫描速度描述的工艺参数范围. 相似文献
105.
通过灌草群丛划分、土壤采样以及室内测定、数理统计等方法,分析了黄河三角洲原生湿地灌草群落土壤的养分、盐分分布特征及相互关系,发现原生灌草群落土壤可溶性盐的垂直分布变异性较大,其中,碱蓬群丛与柽柳群丛土壤可溶性盐分布具有较强的表聚性,而土壤有机质含量表现为芦苇群丛>柽柳群丛>碱蓬群丛,且灌草群落中土壤C/N值都大于5,表明其有机质腐殖化程度较高。另一方面,土壤全氮与有机质存在明显的线性正相关;而土壤全盐与有机质、全氮之间存在明显的倒数关系,表明全盐对二者的制约作用,其中15~20g/kg的土壤盐分范围对应的是土壤全氮、有机质由迅速减少向缓慢减少的变化趋势。研究结果可以为盐碱土改良提供重要参考。 相似文献
106.
Go Kobayashi Hiroki Hatakeyama Kosuke Ota Yohei Nakada Takashi Kaburagi Takashi Matsumoto 《Multimedia Tools and Applications》2016,75(6):3081-3119
We attempted to predict activity/dominance for soccer games, where activity is defined as the degree of activity of the game as perceived by the viewer, whereas dominance is the degree at which the viewer perceives a particular team to dominate over the other team. Such activity/dominance information would help a layman viewer understand the game. It would also enable construction of an automatic digest creation system that extracts scenes having high activity/dominance. There are two facets of this study: 1. The main part of the underlying prediction model consists of a Stick-Breaking Hidden Markov Model, where the data automatically estimates the number of states of the Markov process behind the data. 2. The data used in this paper is vector time-series data consisting of player, referee, and ball positions, together with team information, acquired by a set of fixed cameras. The problem was approached with a Bayesian framework where learning and prediction were implemented by three different methods: Markov Chain Monte Carlo, Expectation Maximization, and Variational Bayes. The proposed method was tested using a dataset consisting of 10 professional soccer games and was compared against standard regression methods. 相似文献
107.
This paper describes a method of finding the proper points for dividing a corpus with time series information to extract local and frequent keywords. Previous works have proposed the corpus separating method for extracting keywords from a corpus. However, this method divides a corpus at equal intervals so that it cannot consider the topic changes. The present paper utilizes the idea of the topic model and the topic extracted through latent Dirichlet allocation to consider the topic change. This paper identifies the points at which large topic changes occur to divide the corpus using structural change detection method. An experiment involving newspaper articles with 5-year topics confirm that the points at which the topics of each document change are detected to find the division points based on the idea of structural change point detection and our method is better than previous methods based on recall measure. 相似文献
108.
Tetsuro Kobayashi Jeffrey Boase Tsutomu Suzuki Takahisa Suzuki 《Journal of Computer-Mediated Communication》2015,20(3):330-345
The tele‐cocooning hypothesis posits that mobile communication increases interaction with communication rich ties, while simultaneously weakening interaction with communication weak ties. In this study, we demonstrate how smartphones can be used to mitigate tele‐cocooning behavior by stimulating interaction with communication weak ties. Using a smartphone application to collect non‐identifying mobile communication log data, we conducted a field experiment with 193 Japanese participants. The treatment consisted of onscreen reminders designed to stimulate interaction with communication weak ties. The results indicate that the treatment promoted the activation of communication weak ties and the acquisition of information through those ties, suggesting that smartphones can be utilized to promote access to social capital. 相似文献
109.
110.
Isao Kobayashi Sayumi Hirose Takanori Katoh Yanping Zhang Kunihiko Uemura Mitsutoshi Nakajima 《Microsystem Technologies》2008,14(9-11):1349-1357
Microchannel (MC) emulsification is a promising technique for producing monodisperse emulsions consisting of highly uniform droplets. The authors developed a high-aspect-ratio microstructure (HARMST) made of poly(methyl methacrylate) (PMMA) as a new MC emulsification device. A PMMA straight-through MC array plate consisting of 31,250 through-holes with a 7.3 × 22.9-μm oblong section and a 200-μm depth was fabricated by a process of synchrotron radiation (SR) lithography and etching. Oblong MCs fabricated in a PMMA straight-through MC array were highly uniform with a coefficient of variation of less than 2%. The fabricated PMMA straight-through MC array plate was used to produce water-in-oil (W/O) emulsions. Monodisperse W/O emulsions with average droplet diameters of approximately 25 μm and a minimum coefficient of variation of 3.2% were produced via a hydrophobic PMMA straight-through MC array. The PMMA straight-through MC array plate also produced monodisperse W/O emulsions at droplet production rates of up to 1.7 × 104/s. The PMMA straight-through MC array plates developed in this work are expected to expand the application field of emulsification using straight-through MC array plates, which have previously been made of single-crystal silicon. 相似文献